Rear Brake Calipers

[venetian-red]

I haven't posted for a while as the car (2001 Passat Estate Tdi 130) has been very much behaving itself, majestically passing the 150k miles mark recently. Went to change the rear discs and pads today but quickly realised that both rear calipers are seized and are not serviceable. I guess I need to change the both rear calipers. I have disconnected the handbrake cables and loosened the bolts in readiness, but wondered whether when it comes time to swap over, does the spring loaded bit 'explode' everywhere, or is it pretty straightforward to swap the workings over? Any advice / tricks of the trade from someone who has done this before would be welcome please. On the off-chance (as I need these asap otherwise no car for work on Monday!) anyone in the South/West Wales area got a good pair of these please? Thanks.

[venetian-red]

Another thing to query please, is the rear caliper failure common? The handbrake works, but, looking at the discs the footbrake I would say is hardly working at all? Is that normal? Thanks.

[zollaf]

how have you come to the conclusion that the rear calipers are siezed ? what method and tool are you using to push the pistons back ?

[venetian-red]

I have loosened the bleed nipple (with a one man bleeding kit on the nipple) and tried retracting the caliper with the usual brute force, no joy, with a G clamp, no joy, absolutely no movement at all. The discs when they came off were both very rusty, as if the pads had been hardly rubbing them at all? When I changed the front pads, I used the same technique of loosening the bleed nipple, then pushing in as above, which worked fine. Both these rears have about 1/4" protruding and just refuse to budge at all?

[zollaf]

ok, your calipers are, or rather were, working fine. the rear brakes do about 10 % of the braking, so never really get used, especially if you are light on the brakes. to retract the caliper pistons you need to twist and turn. a special tool is available for this purpose. using brute force can damage the screw inside that operates the handbrake mechanism. make sure the rear pads are free in the carrier, the caliper slid pins are free and well greased, put the whole lot back together and see if it all works or not, then replace the pads and discs and possibly the calipers if you have now lost the handbrake.
incidentally, there are lots of guides online on how to do this sort of job, it might be best to look at some of these first, especially if you are contemplating any other jobs on your car.

[venetian-red]

Thanks; I was only intending replacing the discs and pads, which I had watched a 'you tube' video on and was pretty confident. The problems started when I couldn't get the pistons back in to fit the new pads. When you say twist and turn to retract the caliper,if I haven't got a special tool to do that (and being a Sunday!) how else can that be achieved, or indeed is there a way that can be achieved without such a tool please?

[zollaf]

there are slots or holes on the face of the piston. you need something that can locate into these to enable you to push and turn the caliper. some sort of plate with lugs on ??

[venetian-red]

Got you, thanks. I will try that before purchasing a new unit. The drivers side however semms to have had some previous butchery as the thread in the bleed nipple hole has been stripped, so, this unit would have to be replaced because there is not enough thread to hold the bleed nipple in securely, in particular under pressure. The other unit may well be OK if I can get hold of the correct tool. Thanks again, may well have saved me a few quid on one caliper at least.

[JustinM3]

I have a joint splitter that fits the piston well, but must get a proper tool. You can push and turn 100's of times, then it will just start to wind in when you are doing nothing different. Whole things a bit crap really.

[mjhamilton]

Laser tool is £30 from Halfords which is open on Sundays - you can get the same tool for less on eBay

[venetian-red]

Thanks all; I did buy a special retraction tool but they were both stuck solid so I bought 2 new (recon) VW calipers on an exchange basis and, to be fair, they work a treat with the new discs and pads I also had. All new back brakes now!! Job went surprisingly well, no real hitches. Handbrake cable a bit of a fiddle but not too bad. Thanks again guys much appreciated.

[venetian-red]

A follow up question please; the handbrake now needs 'adjustment' as it is a lot higher on the lever than it was before. Any tips of the trade with tightening this up as I would imagine this is a bit of a fiddle? Thanks as always.

[JustinM3]

Beat **** out of the pedal whilst ripping **** out of the handbrake, and take turns holding one on/down whilst pulling/pumping the other.

[venetian-red]

Tried that, no joy! Still a high handbrake lever. Did I read about taking apart the rear ashtray and accessing the cables through there? Should that need to be done?

[JustinM3]

As far as I know it's self adjusting - at least on cables. If it was ok before, shouldn't need adjustment now as they haven't been wound off.

[venetian-red]

Yes, I know what you are saying and it makes perfect sense. I think the problem may be that when I had the old calipers on, the pistons were 'out' (and were siezed), so the cables I guess were for that piston position. When I fitted the new calipers, the pistons were dead flat 'in', but the cable was attached in the position it came off. Hope that makes sense? I did think some self adjuster would kick in though, but not in this case? Do you think the cable now actually needs tightening to take up the 'slack'. If so any ideas on that? Thanks.

[zollaf]

right, there is a lever on the caliper that the hb cable goes on, and when this lever moves it pushes the pad out. how much does this need to move ? it shouldn't be that much. does it come back right onto its stop. if the cable is over adjusted and the lever doesn't return properly it will never work. so, remove the cable and operate the foot brake a few times. now fit the cable and adjust it until there is little slack, the levers should return properly and all should work well.

[JustinM3]

. Mine took a lot of pumping and working for it to adjust up after new pads - can't find a write up on here of correct procedure so just bashed it all 'til it came up.

[venetian-red]

Thanks both; I will take the advice on board, remove the cables, operate the foot brake then reassemble and see the result. Fingers X.

[JustinM3]

That's interesting Zollaf, will have to remember that. Is a ballache set up on these.

[zollaf]

no, easy to set up really. as with any caliper that is a footbrake and handbrake you need to wind the piston out until the pads just slide over the disc. many people wind the pistons all the way back and leave too much clearance which then risks damage to the caliper and/or takes a lot of pedal pumping to take up the gap, or they over adjust the cables as i said, which means they will never work. done properly there will be dim problem.

ooh, i see you are in poole. i am down that way tomorrow to collect a landrover. a nice big drive.

[JustinM3]

I'm used to old disc/drum cavaliers, prefer them.... So I had to jump up and down on pedal/lever because I wound piston right back in huh! Thought footbrake would have had that pushed out correctly after one pump. Any advice on applying handbrake on a slope whilst you're here? This set up seems to let off once you release pedal, so have to wrap lever round your neck to compensate this. Enjoy your drive, especially the A31 :Blush:

[mjhamilton]

Did you slacken the handbrake cable before winding in and fitting the pads?

[venetian-red]

Well all now fine guys, thanks for the help. The nut at the rear of the caliper which holds the spring loaded return mechanism had worked itself loose which was contributing greatly to this issue I think!! Had her up on axle stands today, sorted it all out, nice 'normal' handbrake again thank goodness. You live and learn!!