since I let National tyres do the rear brakes one of the calipers isn't engaging whilst handbrake is on. cables all look good. Im assuming they haven't wound the calipers back & or properly adjusted them afterwoods. any advice before I start on them in the morning appreciated.
rear handbrake caliper out of adjustment
- Thread starter mymorph
- Start date
They are auto adjusting so can't see how they have done anything wrong.
My guess would be the lever has siezed, it's a fairly common problem on these, have a search for rear caliper spring mod on google.
If you look under the car with the handbrake on, both levers should be pulled down and look the same.
My guess would be the lever has siezed, it's a fairly common problem on these, have a search for rear caliper spring mod on google.
If you look under the car with the handbrake on, both levers should be pulled down and look the same.
the lever hasn't seized and moves when the handbrake is applied - but doesn't engage the brake. i know about the spring mod but as the brakes have never stuck on i havn't felt the need. I'll have a play in the morning but i will have little tolerance to ordering a new caliper. the brake oil needs changing anyway.
Ok well ye sounds like a new caliper job, I've got one in bits if you want any pics of how it works? One theory is that when they pushed the piston back, instead of turning pushing (the piston is on a screw thread thing) they just forced it back and buggered the thread?
THE irony here is that I normally do all this kind of basic servicing etc myself but on this occasion I was feeling lazy/ had a distinct lack of time and didn't have a windback caliper tool. so thought id take it to national tyres to have it done properly. lol. 
the only job I havn't done on the car and guess what - its f****ed.
I don't quite see/understand how the handbrake lever connects to the piston?? does the lever turn the piston on the thread??
the only job I havn't done on the car and guess what - its f****ed. I don't quite see/understand how the handbrake lever connects to the piston?? does the lever turn the piston on the thread??
Almost, the lever is attached to a threaded bar, this runs into the inside of the piston, when you turn the lever, the threaded bar turns and forces the piston out irrespective of brake pressure, it auto adjusts when you press the brakes, the piston just moves down the thread some more to mate the braking surfaces, then when you let off brakes, the piston rests at a certain point on the threads ready for the handbrake to turn the threads, pushing the piston out again, simples eh?!
If they have forced the piston in hard enough, it could have stripped the threads meaning when the lever is turned, the piston won't move.
Other more optimistic problem is a simple airlock behind the piston meaning you won't be getting any brake pressure at all, meaning it won't auto adjust, therefore the handbrake won't engage...
Try a good bleed on it first, or spin the wheel, hit the brakes and see if your getting any pressure
Sorry for the essay! Been at work all night so in technical mode!
If they have forced the piston in hard enough, it could have stripped the threads meaning when the lever is turned, the piston won't move.
Other more optimistic problem is a simple airlock behind the piston meaning you won't be getting any brake pressure at all, meaning it won't auto adjust, therefore the handbrake won't engage...
Try a good bleed on it first, or spin the wheel, hit the brakes and see if your getting any pressure
Sorry for the essay! Been at work all night so in technical mode!
many thanks for that -
nice work. I reckon the threads must be stripped them, the hydraulic components are all working correct with normal breaking. & from the photos & your decription I can see no other logical option. the photos make the thread look fairly substantial but I guess were only talking like m8 kinda size. I guess the piston is the most likely thread to have stripped and therefore replaceable
nice work. I reckon the threads must be stripped them, the hydraulic components are all working correct with normal breaking. & from the photos & your decription I can see no other logical option. the photos make the thread look fairly substantial but I guess were only talking like m8 kinda size. I guess the piston is the most likely thread to have stripped and therefore replaceable
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Ye it's more likely the piston side, although would still take a daft gorilla to strip them! Personally I'd be taking it bac to them, make tem strip it then they can see that they caused the damage and hopefully cover some costs! Although a new piston won't be too much, it's then the seals and the time taken. Also if it's the caliper side then it's more money so if defo be having a word with them!
fixed.
took caliper off to investigate. appeared handbrake lever would move piston. but could I screw in the piston - bugger no. unscrewed anticlockwise and finally it started to withdraw(as if removing the piston) and only then I was able to screw it back in.
had to slacken off the seriously overly adjusted handbrake.
I think they may have wound in the calipers with the the handbrake on then when they realised the handbrake was defunct they just wound the adjuster to get some form of handbrake function?? not sure but it was some kinda mega bodge job.
in 20yrs driving this was the first & last time i'll be getting my brake done by any1 but myself.
took caliper off to investigate. appeared handbrake lever would move piston. but could I screw in the piston - bugger no. unscrewed anticlockwise and finally it started to withdraw(as if removing the piston) and only then I was able to screw it back in.
had to slacken off the seriously overly adjusted handbrake.
I think they may have wound in the calipers with the the handbrake on then when they realised the handbrake was defunct they just wound the adjuster to get some form of handbrake function?? not sure but it was some kinda mega bodge job.
in 20yrs driving this was the first & last time i'll be getting my brake done by any1 but myself.
They've just wound it in too much, did the same myself a couple of weeks ago. Unwind it 1 turn and it's back to normal
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