Car: s1 RS turbo with cossie rear brake conversion

My passenger side handbrake is doing pretty much nothing and I'm baffled as to why. The piston in the caliper is not sized as I can turn it with a tool I made to wind it in. Also the rear brakes passed the mot, just failed on handbrake.

When I pull the handbrake on it moves the lever on the caliper but doesn't seem to move the piston.

Is there any special method to adjust it?

 

sounds like an internal fault with the caliper. They are common for sticking solid and needing either rebuilt or replaced . The handbrake side is controlled by and offset hole in the bar that drops into the caliper . This in turn has a pin that act's as the pushing force for the piston it's self .So either the pin is damaged or missing or the bar is seized solid and the plate has come adrift and is simply turning .

 

Thanks for the reply, it does seem odd, they aren't that old so anything you can suggest trying before shelling out for a new caliper? I guess I could pull it apart but I would need a seal kit to put it back together?

From the search I did it need some special tools too. Ahh 10 days to get it back to mot centre!!!

 

you sure it's not the cable?

 

Why do you say that out of interest?

Pretty sure I bought a mk5 rs2000 one, will check my history. I've not done many miles in the last year but then it may not have ever worked properly as handbrake has always been poor

When the handbrake is pulled on the cable moves the mechanism on the caliper just doesn't put enough clamping force to stop you turning the wheel round with a small amount of force. It does clamp just not very much

8% according to the not man

 

so it's not a case of not having adjusted the cable properly then?

it's very very easy, just wind up the 2 big plastic nuts and away you go

 

I was thinking this but would it explain why only one side is not working? Because putting the handbrake moves both mechanisms the same amount?

I did look at the adjuster this evening and it doesn't really want to turn any more. Doesn't help that the exhaust is in the way but it's almost like turning the large nut thing is trying to turn the cable, there's a fair bit of tension there. I guess I need a spanner or pipe grips?

 

U should be able to move the plate ont top with a pair of mole grips and should phisically see the piston move and grip the disk . There a fooker to put back together without another set of hands but do able . Technically yes you should change the seals and there not to expensive so it makes sence . But as Dojj said check your hand brake cable is adjusted up correctly and that when the handbrake is applied its not slack on the side the side thats inop

 

Thanks for the reply, I have ordered a set of seals from bigred.co.uk incase I take it apart.

I will try and get some pics tonight. From what I can see pulling up the handbrake does move the armatures on both calipers by a fair way so I don't think the cable would be at fault. I've had the caliper bolted on without a disk and pulled on the handbrake and the armature moves round but the piston moves like 1mm or so, barely anything

I guess the pin inside may have broken as mentioned above although I have no idea what this looks like!!

 

Although it may sound silly, but you are trying to adjust with the handbrake OFF aren't you?

There should not be massive tension at all, you want it so the mechanism just starts moving then you want to back it off slightly, you can use a marker to mark the position in relation to the caliper body, to make this job easier.

Martin

 

Just take the arm off, take out the piston with a shot of air, take out two circlips, give it a clean and refit, bet that sorts it out, same happened to me

 

Right I went ahead and pulled the caliper apart tonight. From what I can tell at maximum handbrake position something slips a bit, like its gone past its stop position, and let the piston return slightly. I guess this is why it's not clamping properly.???

So from what I can see it must be either the socket on the bottom of the central screw, the little bullet or the socket on the handbrake rod? Either 3 could be worn??

As you can see from the pics the caliper isn't that dirty and looks pretty new. I guess they could have been reconditioned recently? Can these bits been bought separately?

What do you guys think?

 

All looks quite good from the pics , they are quite a deep socket . Try fitting it back up dry and seal less ,make sure everything is is set to its stop points without the return spring on the top plate and see what kind of travel there is . Its possible that if it has been rebuilt it may not have bee fitted together right . Cant see how you could go wrong mind. cheers Al

 

will give it a go, whats the stop point that you mention? I didnt see any form of adjuster?

 

Just makes sure everything is set as far back as poss when you wind the piston in and see what happens

 

start from scratch again and wind in the calipers as far as possible

then, refit the calipers and use the foot brake to push the piston in as far as it normally goes to get it seats correctly

then use the handbrake to get the correct adjustment

you need the proper tool to wind the caliper back in again on it's thread, don't just push it back with a pair of grips

 

Yeah I will give it a go, thing is when I was looking at it last night I just put it together with just the central screw and pulled the handbrake mechanism round (holding it all in my hand and applying pressure to the central rod with my thumb to hold it in place) and you can see the central rod move outwards... all good I thought...

But then you can pull the handbrake mechanism just another few mill to its final extent and then the bullet appears to slip and the rod moves back down a bit.

It's almost like it goes past the point it should stop at??

Will have another play later!

 

Help!! I can't seem to get the piston to wind back in now I have put a new seal in!! Any ideas?? It just spins

 

It's not popped passed the seal by the sound of it . Plenty of lube on it and with a twist push it in . then it should wind onto it's thread .