Hot brake caliper
Discussion
The nearside front AP brake caliper on my Monaro is running a bit hotter than the offside. I jacked the car up and noticedi that it takes a bit more effort to spin the nearside wheel than the offside but its not a massive difference however I'm worried about overheating the disc.
I bled both front calipers, and removed the pads to make sure they weren't binding, everything looked fine.
The only thing that is causing me some concern is that the outer pistons on the nearside don't seem to retract enough back into the caliper when the brake pedal is released but I'm only talking a millimetre or so.
I removed the brake pad and pressed the three Pistons back into their bores and they seemed free and are not binding.
Any ideas would be appreciated.
I bled both front calipers, and removed the pads to make sure they weren't binding, everything looked fine.
The only thing that is causing me some concern is that the outer pistons on the nearside don't seem to retract enough back into the caliper when the brake pedal is released but I'm only talking a millimetre or so.
I removed the brake pad and pressed the three Pistons back into their bores and they seemed free and are not binding.
Any ideas would be appreciated.
Thanks for the replies.
I have pushed the Pistons back into the caliper and they don't feel like they are binding.
The pads are difficult to remove, so I have to carefully lever them out.
Once the Pistons have been pushed back into their bores and I replace the brake pads they are free to move back and forwards (before I fit the pins) Mind you like a mug I didn't check for free movement side to side. I'll do that tomorrow.
I was thinking I have a faulty braided brake line, maybe it's not allowing the brake fluid to return properly when you lift off the brake pedal.
These are Russell brake lines and were fitted 9 years ago. They have only 42000 miles of use and I hoped they would last the life of the car.
John
I have pushed the Pistons back into the caliper and they don't feel like they are binding.
The pads are difficult to remove, so I have to carefully lever them out.
Once the Pistons have been pushed back into their bores and I replace the brake pads they are free to move back and forwards (before I fit the pins) Mind you like a mug I didn't check for free movement side to side. I'll do that tomorrow.
I was thinking I have a faulty braided brake line, maybe it's not allowing the brake fluid to return properly when you lift off the brake pedal.
These are Russell brake lines and were fitted 9 years ago. They have only 42000 miles of use and I hoped they would last the life of the car.
John
No luck would be an understatement !!!!!!
Sadly no warranty left, but I doubt it's the AP caliper itself as I've checked it over several times.
I'm hoping it's an internal problem with the brake hose.
I'm going to carry out a few more checks and If I need to I'll order two front hoses from HEL brakes. If that doesn't work then I'm back on the real ale......then the whisky.....and the Brandy.....
John
Sadly no warranty left, but I doubt it's the AP caliper itself as I've checked it over several times.
I'm hoping it's an internal problem with the brake hose.
I'm going to carry out a few more checks and If I need to I'll order two front hoses from HEL brakes. If that doesn't work then I'm back on the real ale......then the whisky.....and the Brandy.....
John
mfp4073 said:
The pads are difficult to remove, so I have to carefully lever them out.
Pads should always be free to move. If they are not loose in the calliper this is your problem, as they wont fall away from the disk when you release the brake. Its not uncommon that they need a little shave from the edges of the backing plates. fred bloggs said:
Pads should always be free to move. If they are not loose in the calliper this is your problem, as they wont fall away from the disk when you release the brake. Its not uncommon that they need a little shave from the edges of the backing plates.
+1I had to have my brake pads "massaged" a bit to stop them sticking a few years back
fred bloggs said:
Pads should always be free to move. If they are not loose in the calliper this is your problem, as they wont fall away from the disk when you release the brake. Its not uncommon that they need a little shave from the edges of the backing plates.
I had another look at the pads this morning and they do not move in the caliper, so it appears that I should remove some of the backing plate on each end (where you normally add a little lubricant?)It's worth a try thanks.
As others have said, the pads must be free to move.
Some calipers can corrode in the top/bottom plate area where the pad backing slides causing a tight fit. Some pads are just a tight fit etc etc.
Sometimes the easiest fix is simply file or grind a little off the top or bottom edge of the pad until it is a loose fit.
Not too loose however unless there are good anti-rattle shims, otherwise they can get a little noisy at times. Not a problem, but can potentially be annoying.
But pads sticking to the caliper is a problem, not an annoyance.
Some calipers can corrode in the top/bottom plate area where the pad backing slides causing a tight fit. Some pads are just a tight fit etc etc.
Sometimes the easiest fix is simply file or grind a little off the top or bottom edge of the pad until it is a loose fit.
Not too loose however unless there are good anti-rattle shims, otherwise they can get a little noisy at times. Not a problem, but can potentially be annoying.
But pads sticking to the caliper is a problem, not an annoyance.
I removed a small amount from the edge of the backing plate as advised, but it made no difference.
I then removed the anti rattle shims from both pads and that appeared to have worked and allows some side to side movement in the caliper.
I have also noticed with the wheel back on and the car still up on the jack I can spin the wheel without any excess dragging.
So at least I have a temporary fix, but you really should not have to remove the shims. I still suspect some underlying issue but at the moment my enthusiasm has waned.
Thanks for all the info guys.
I then removed the anti rattle shims from both pads and that appeared to have worked and allows some side to side movement in the caliper.
I have also noticed with the wheel back on and the car still up on the jack I can spin the wheel without any excess dragging.
So at least I have a temporary fix, but you really should not have to remove the shims. I still suspect some underlying issue but at the moment my enthusiasm has waned.
Thanks for all the info guys.
mfp4073 said:
I had another look at the pads this morning and they do not move in the caliper, so it appears that I should remove some of the backing plate on each end (where you normally add a little lubricant?)
It's worth a try thanks.
Use a little smear of copper grease on pad sides that helps keep them freeIt's worth a try thanks.
stevieturbo said:
pads will not retract...unless you push them back.
Pressure may get released from the pads, but there isnt anything that will actually push the pistons back in.
So are the pads free in the caliper, and are all the pistons free to move back in if you push them ?
Of course they retract. The compliance of the seal causes them to retract slightly when releasing the pressure, thats what stops them rubbing the disks.Pressure may get released from the pads, but there isnt anything that will actually push the pistons back in.
So are the pads free in the caliper, and are all the pistons free to move back in if you push them ?
My 911 has a problem with a caliper at the moment (again), and one caliper is running hotter than the other as the piston isnt retracting properly and causes the disk to 'sing'. Needs a stripdown and the pistion polishing.
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