Handbrake issues, seized piston?

[RichCup]

My handbrake has been progressively getting worse and I knew the pads were low so changed them and it's still no better. I took it down to a garage I know as I thought it could be the cable but they said that was fine. When the rear pads were fitted they reckon the piston must have been turned too far back in so that when the handbrake is pulled, the piston is pushing the pad but not enough to come into contact with the disc.

I've took the caliper etc off today and it does look as though the cable is fine as it pulls the 'L bit' as far as it'll go. However when this happens the piston doesn't move at all and it doesn't move when the foot brake is applied either (although it probably doesn't move if at all when working anyway).

I'm thinking it's gotta be a siezed piston? If so is it just a case of stripping the brakes down and cleaning everything up? How long will this take as I fancied getting it done today while I've got it in bits.

Apologies for the long post, hope someone can help!

 

[Henry]

will it not pump out with the pads removed? think you're in trouble if it won't

if it will, try carefully lifting back the rubber boot and WD'ing the piston; pump it out; spray it; wind it in; repeat until it's free and smooth

ed. or just wind it in and out manually if it won't pump out

 

[RichCup]

Nope won't do anything. Pushed against it with my finger when the brakes were applied so there was definately no movement.

The side that seems to work does brake a little when the handbrake is applied, the ns cable does seem slacker than the os though.

Winded it in and out last week for the new pads so can't see that doing anything, may be worth spraying some wd40 in anyway.

 

[Da]

Which side is it?

I have a spare rear caliper that works fine, just has a leaky seal which you could swap from yours. Takes an hour to swap if you know what you're doing

 

[Henry]

possibly a compensator issue? try lubing it to see if that helps and also bleed it - do you get much fluid out of it in comparison with the other side?

 

[RichCup]

Just sprayed them with a bit of wd40 to see if it helps. Da its the passenger side which seems to be the issue although the drivers side isn't great either! I'll leave it till I know for definate what the issue is, but thanks for the offer anyway

Do the brakes work with 'pressure' i.e. will one side still work even if the other has no pads on?

Brakes were bled about 2 weeks ago with new fluid. When i removed the nipple on the rears, next to no fluid ran out but when I pushed the pedal it came out fine (a similar amount on both sides).

Worst comes to worst I'll leave it til I go to birchdown in 2 weeks to get the cambelt done and will get them to have a look.

 

[Henry]

it's a diagonally split system, so the other rear should be pumping at normal effort if you've removed the pads from one

when WD'ing, you really need to be winding the piston in/out to lube it up properly. if it's at all sticky, it should be obvious as you begin, and you'll be able to feel the piston free-up as you work it in and out

 

[RichCup]

Ah right, I'll turn them in and out, just trying to work inbetween the weather atm! :dapprove:

 

[Da]

My spare is near side Rich so just PM me and it's yours.

 

[RichCup]

Cheers. Just as an updated, I've worked and lubed both pistons. O/S does seem to be a little more free than the N/S, but both move nicely.

Will put it all back together when it stops raining and see what happens..

Thanks for the help so far guys!

 

[richy22]

kind of related question. My rear drivers caliper was sticking and i free'd it up with the wd40 method. But i noticed the black seal around the piston had split, causing it to lock in the first place. Can u buy or get the piston seal?

 

[Da]

Richy - have a look at www.biggred.co.uk they will sort you out with a repair kit.

 

[richy22]

Richy - have a look at www.biggred.co.uk they will sort you out with a repair kit.

Top Man! :star:

 

[Da]

No problem, hope you get it sorted

 

[RichCup]

Well I've tried adjusting the handbrake (which has been tightened up quite a bit) which has had no effect. It seems as though it's pulling the lever on the caliper fine, as I can't pull the handbrake all the way to the top.

When using the footbrake the rear brakes worth, both apply an even amount of braking power too. This suggests the pistons are moving freely

Due to the cable that's been adjusted a lot I'm still inclined to think it's this that needs replacing, but is it possible that it's the mechanism in the caliper itself? i.e. where the lever on the caliper moves causing the piston to be pushed onto the pad? Seems strange that it's happened to both sides too.

Starting to annoy me now lol!