Rear brakes dragging
#11
Guest
Posts: n/a
Re: Rear brakes dragging
Well Thanks to you both - I have noticed that many people have had
issues with these calipers, whether as a result of their own
inexperience or due to the calipers. The service manual was limited
help ( A standard Audi manual, not after market )
In response to 'cleaning', I did clean and lube.
Although it says nothing about it in the Audi service manual, there
seems to be (based on web pages and responses elsewhere) an implied
requirement to retract the pistons COMPLETELY back into the caliper.
It is not clear how this is determined nor is there any real comment on
having to do this. In past experience, with non-Audi brakes, simply
retracting the piston far enough to allow the new pads to clear the
disk was sufficient. I really think that not fully retracting the
piston was the error that I made, so if anyone else can think of
anything else that I may have done wrong, I will assume that was my
fault and move on.
Thanks for the responses - didn't think I would get any for a while
there!
Steve
issues with these calipers, whether as a result of their own
inexperience or due to the calipers. The service manual was limited
help ( A standard Audi manual, not after market )
In response to 'cleaning', I did clean and lube.
Although it says nothing about it in the Audi service manual, there
seems to be (based on web pages and responses elsewhere) an implied
requirement to retract the pistons COMPLETELY back into the caliper.
It is not clear how this is determined nor is there any real comment on
having to do this. In past experience, with non-Audi brakes, simply
retracting the piston far enough to allow the new pads to clear the
disk was sufficient. I really think that not fully retracting the
piston was the error that I made, so if anyone else can think of
anything else that I may have done wrong, I will assume that was my
fault and move on.
Thanks for the responses - didn't think I would get any for a while
there!
Steve
#12
Guest
Posts: n/a
Re: Rear brakes dragging
Well Thanks to you both - I have noticed that many people have had
issues with these calipers, whether as a result of their own
inexperience or due to the calipers. The service manual was limited
help ( A standard Audi manual, not after market )
In response to 'cleaning', I did clean and lube.
Although it says nothing about it in the Audi service manual, there
seems to be (based on web pages and responses elsewhere) an implied
requirement to retract the pistons COMPLETELY back into the caliper.
It is not clear how this is determined nor is there any real comment on
having to do this. In past experience, with non-Audi brakes, simply
retracting the piston far enough to allow the new pads to clear the
disk was sufficient. I really think that not fully retracting the
piston was the error that I made, so if anyone else can think of
anything else that I may have done wrong, I will assume that was my
fault and move on.
Thanks for the responses - didn't think I would get any for a while
there!
Steve
issues with these calipers, whether as a result of their own
inexperience or due to the calipers. The service manual was limited
help ( A standard Audi manual, not after market )
In response to 'cleaning', I did clean and lube.
Although it says nothing about it in the Audi service manual, there
seems to be (based on web pages and responses elsewhere) an implied
requirement to retract the pistons COMPLETELY back into the caliper.
It is not clear how this is determined nor is there any real comment on
having to do this. In past experience, with non-Audi brakes, simply
retracting the piston far enough to allow the new pads to clear the
disk was sufficient. I really think that not fully retracting the
piston was the error that I made, so if anyone else can think of
anything else that I may have done wrong, I will assume that was my
fault and move on.
Thanks for the responses - didn't think I would get any for a while
there!
Steve
#13
Guest
Posts: n/a
Re: Rear brakes dragging
Well Thanks to you both - I have noticed that many people have had
issues with these calipers, whether as a result of their own
inexperience or due to the calipers. The service manual was limited
help ( A standard Audi manual, not after market )
In response to 'cleaning', I did clean and lube.
Although it says nothing about it in the Audi service manual, there
seems to be (based on web pages and responses elsewhere) an implied
requirement to retract the pistons COMPLETELY back into the caliper.
It is not clear how this is determined nor is there any real comment on
having to do this. In past experience, with non-Audi brakes, simply
retracting the piston far enough to allow the new pads to clear the
disk was sufficient. I really think that not fully retracting the
piston was the error that I made, so if anyone else can think of
anything else that I may have done wrong, I will assume that was my
fault and move on.
Thanks for the responses - didn't think I would get any for a while
there!
Steve
issues with these calipers, whether as a result of their own
inexperience or due to the calipers. The service manual was limited
help ( A standard Audi manual, not after market )
In response to 'cleaning', I did clean and lube.
Although it says nothing about it in the Audi service manual, there
seems to be (based on web pages and responses elsewhere) an implied
requirement to retract the pistons COMPLETELY back into the caliper.
It is not clear how this is determined nor is there any real comment on
having to do this. In past experience, with non-Audi brakes, simply
retracting the piston far enough to allow the new pads to clear the
disk was sufficient. I really think that not fully retracting the
piston was the error that I made, so if anyone else can think of
anything else that I may have done wrong, I will assume that was my
fault and move on.
Thanks for the responses - didn't think I would get any for a while
there!
Steve
#14
Guest
Posts: n/a
Re: Rear brakes dragging
"stvnjns" <smjns51-local@yahoo.com> wrote in message
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
#15
Guest
Posts: n/a
Re: Rear brakes dragging
"stvnjns" <smjns51-local@yahoo.com> wrote in message
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
#16
Guest
Posts: n/a
Re: Rear brakes dragging
"stvnjns" <smjns51-local@yahoo.com> wrote in message
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
#17
Guest
Posts: n/a
Re: Rear brakes dragging
"stvnjns" <smjns51-local@yahoo.com> wrote in message
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI
news:1165700218.115376.202660@j72g2000cwa.googlegr oups.com...
> Well Thanks to you both - I have noticed that many people have
> had
> issues with these calipers, whether as a result of their own
> inexperience or due to the calipers. The service manual was
> limited
> help ( A standard Audi manual, not after market )
>
> In response to 'cleaning', I did clean and lube.
>
> Although it says nothing about it in the Audi service manual,
> there
> seems to be (based on web pages and responses elsewhere) an
> implied
> requirement to retract the pistons COMPLETELY back into the
> caliper.
> It is not clear how this is determined nor is there any real
> comment on
> having to do this. In past experience, with non-Audi brakes,
> simply
> retracting the piston far enough to allow the new pads to clear
> the
> disk was sufficient. I really think that not fully retracting
> the
> piston was the error that I made, so if anyone else can think
> of
> anything else that I may have done wrong, I will assume that
> was my
> fault and move on.
>
> Thanks for the responses - didn't think I would get any for a
> while
> there!
> Steve
OK, I'll add my two (British) pence worth - about 3.9 US cents
today, that's a v.good exchange rate!
Anyhow, whilst I haven't actually done the rears on my B6 S4
yet - I am familiar with similar rear callipers.
There are a number of important "tips", which the manuals often
don't cover. Firstly, disconnect the handbrake cable from the
calliper arm. Secondly, wind the caliper pistons back in fully
(observing usual cautions re: master cylinder level & piston
boots). After fitting new pads and re-assembling caliper - do
NOT re-attach handbrake cable yet. Pump the brake pedal, slowly,
but hard, reaching maximum travel on each pump. Continue pumping
until pedal reaches normal pedal travel. Start engine & allow to
idle, then press brake pedal v.hard again a couple more times -
this allows the benefit of servo assistance to apply max pressure
to brake pedal.
Now, this next part is not critical, and it can be omitted if you
are not comfortable with driving without a handbrake. It does
help to get the correct rear caliper piston adjustment, but, and
it's a big but - there is a WARNING. Read it properly and
understand that by following this particular point, you will NOT
have a working parking/emergency/hand brake, and any relevant
safety and legal requirements are your own responsibility. OK -
warning fully understood and responsibility for you own actions
accepted - with the handbrake cables still disconnected, drive
the car to bed-in the new rear brake pads - this can take upto
about 150miles (but the first 20 or so miles removes the biggest
of "high spots").
After this initial bedding-in, you can re-connect the handbrake
cables to the rear calipers. Before you do re-connect them, two
more good tips. With the rear wheels raised (and the car
properly supported on stands), spin both rear wheels to make sure
they spin freely, to check for no obvious binding from a stuck
piston. Next, re-connect the handbrake cables - making sure
there is enough free play in the handbrake cable, and with the
handbrake in the OFF position, the actuating arms in the calipers
are resting against the caliper stops. (Some service manuals on
different cars state a specification of upto 2-3mm between the
arm and the stop, but I personally try to aim for zero
clearance - however, this depends on the strength of the return
springs, and also the travel on the handbrake lever.)
With the cables re-attached, work the handbrake fully on and off
a few times, then fully release (in the off position) the
handbrake. Re-check that the rear wheels spin freely - hopefully
exactly the same as before refitting the h.brake cables. If
there is obvious binding of the rear wheels - two things can be
wrong. Look at the caliper levers to see if they are resting
against the stops (or within the appropriate tolerance). If they
are not, use a lever on one side, then the other, to pry the
caliper lever back to its stop. If both the caliper levers can
be helped to the stops, then you may either have weak return
springs, or a stiff handbrake cable. If, however, you can get
one caliper lever to rest against the stop, but the opposite side
then moves away from the stop, and vice-versa for the opposite
side, then you need to add more free play in your handbrake cable
itself.
Rgds
Sean
B6 S4, A5 GTI