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Binding Brakes

944Fripp

944Fripp

PCGB Member
Member
Hi all.

I've just replaced a shim on the a rear passenger caliper and at the same time put in vibration dampers all round as none of the pads had any.
The rear passenger side brake felt very tight when I assembled it all and I did have to use quite a bit of force to get the pads into the caliper and seated on the dampers.
I've just gone to test drive it and the bloody thing won't move! It's like the hand brake is on as I pull up the clutch. Its almost completey seized on that one caliper.

I used a wind back tool to push the pistons back and all the others rotated fine after the work. It all looked pretty good in the caliper. I used the same pads and disks as before as there wasn't much wear, genuine parts for the shims and dampers and between each corner pushed down on the brake hard to reseat each corner.

So, I'm going to have to take it all apart again. It's clear the pads are binding onto the disk but why? So far I've got the following:

Perhaps I didn't wind back the pistons enough in that corner?

Is the handbrake linked in any way to the disk brake, maybe this needs adjusting?

Maybe the brake system needs bleeding to correct the problem?

Could the additional space now being taken up by the damping plates have emphasised an existing problem with the caliper? A stuck piston parhaps?

Does anybody have any other ideas of things I should be looking for?

Thanks all.
 
Hi, another possibility, particularly if you clamped the flexible lines during the work, is a collapsed inner rubber line creating a valve effect. If it's this, opening the bleed screws should unlock it. The handbrake is a separate drum brake inside the rear disc and isn't linked mechanically to the disk brake but could be out of adjustment. Good luck!
 
Sounds like a classic case of plate lift, you really don’t need the damping plates as most pads come with a anti squeak backing

the hand brake is inside the rear disk and should have no effect on the hydraulic brakes,
 
Thanks Waylander and Steve.

The back story to this exercise was that the pads actually jumped about in the caliper so much that they rattled. It was constant! So, I looked at every solution I could to resolve it. Hence the new shims and damping plates.

The calipers were refurbed some time ago and there's very little corrosion on them. The old shims were reused and have just worn I guess. I'm not sure it's plate lift but you're right, the pads do have a backing and I suspect it's this additional thickness which is causing the problem I have now so I'll remove the dampers on that side to see what happens. Odd though that it's not a problem on the drivers side with the same pad type....but old, worn shims still I suppose.

Steve, the rear brakes use a solid line and I didn't clamp the fronts at all. Great suggestion though, never even though that could be an issue!

Thanks both. Maybe get it out for a run before the week is out after all!
 
The thing with pads are if they were tight when done by someone else who just wants to get it done, the quick fix it to just grind off the side of the pads so they fit easy, try to fit full size ones and the bind and jam, shame your so far away I would gladly help you,

I have rebuild lots of these brembo brakes
 
944Fripp said:
Hi all.

I've just replaced a shim on the a rear passenger caliper and at the same time put in vibration dampers all round as none of the pads had any.
The rear passenger side brake felt very tight when I assembled it all and I did have to use quite a bit of force to get the pads into the caliper and seated on the dampers.
I've just gone to test drive it and the bloody thing won't move! It's like the hand brake is on as I pull up the clutch. Its almost completey seized on that one caliper.

I used a wind back tool to push the pistons back and all the others rotated fine after the work. It all looked pretty good in the caliper. I used the same pads and disks as before as there wasn't much wear, genuine parts for the shims and dampers and between each corner pushed down on the brake hard to reseat each corner.

So, I'm going to have to take it all apart again. It's clear the pads are binding onto the disk but why? So far I've got the following:

Perhaps I didn't wind back the pistons enough in that corner? (they should push back anyway otherwise every time you press the pedal you would get stuck!)

Is the handbrake linked in any way to the disk brake, maybe this needs adjusting? (separate system, though if you change the discs it does factor)

Maybe the brake system needs bleeding to correct the problem? (Air in the system reduces efficiency so would result in less braking)

Could the additional space now being taken up by the damping plates have emphasised an existing problem with the caliper? A stuck piston parhaps? (possibly a stuck piston but unlikely)

Does anybody have any other ideas of things I should be looking for? (I agree with other comments - plate lift - thew calipers corrode under the plates the pads slide on which makes inserting the pads harder - they bind on the ends - classic bodge (quick fix) is to file the ends of the pads down - this allows pads to move but if over done it allows the pads to rattle - whilst the pads rattle it allows additional corrosion / movement in the plates which then makes the next pads even tighter. You dont usually need new slider plates 'just' remove the old ones and clean behind. The 'just' is because the fixings can be reluctant to extract. Soak in penetrating fluid, tap hard with a hammer, apply heat, turn gently both ways if all that fails, weld on a nut. Or grind a bit of the edge of the pads and save it till next time [:mad:] )

Thanks all.
Click to expand...
Tony
 
944Turbo said:
944Fripp said:
Hi all.

I've just replaced a shim on the a rear passenger caliper and at the same time put in vibration dampers all round as none of the pads had any.
The rear passenger side brake felt very tight when I assembled it all and I did have to use quite a bit of force to get the pads into the caliper and seated on the dampers.
I've just gone to test drive it and the bloody thing won't move! It's like the hand brake is on as I pull up the clutch. Its almost completey seized on that one caliper.

I used a wind back tool to push the pistons back and all the others rotated fine after the work. It all looked pretty good in the caliper. I used the same pads and disks as before as there wasn't much wear, genuine parts for the shims and dampers and between each corner pushed down on the brake hard to reseat each corner.

So, I'm going to have to take it all apart again. It's clear the pads are binding onto the disk but why? So far I've got the following:

Perhaps I didn't wind back the pistons enough in that corner? (they should push back anyway otherwise every time you press the pedal you would get stuck!)

Is the handbrake linked in any way to the disk brake, maybe this needs adjusting? (separate system, though if you change the discs it does factor)

Maybe the brake system needs bleeding to correct the problem? (Air in the system reduces efficiency so would result in less braking)

Could the additional space now being taken up by the damping plates have emphasised an existing problem with the caliper? A stuck piston parhaps? (possibly a stuck piston but unlikely)

Does anybody have any other ideas of things I should be looking for? (I agree with other comments - plate lift - thew calipers corrode under the plates the pads slide on which makes inserting the pads harder - they bind on the ends - classic bodge (quick fix) is to file the ends of the pads down - this allows pads to move but if over done it allows the pads to rattle - whilst the pads rattle it allows additional corrosion / movement in the plates which then makes the next pads even tighter. You dont usually need new slider plates 'just' remove the old ones and clean behind. The 'just' is because the fixings can be reluctant to extract. Soak in penetrating fluid, tap hard with a hammer, apply heat, turn gently both ways if all that fails, weld on a nut. Or grind a bit of the edge of the pads and save it till next time [:mad:] )

Thanks all.
Click to expand...
Tony
Click to expand...



Wow, thanks for the response Tony! There's a lot of advice there! [:)]
 
So I've fixed the rattling pad (original problem) and now sorted the binding brake. Turns out I missed off a couple of washers between the caliper and the trailing arm body meaning that the caliper was off center on the disk so the back of the disk was actually contacting the ineer face of the caliper/shim). Not good and will mean it needs new rear disks as it's scored quite badly but at least I now know!

New problem now is terrible squealing from brakes when not braking (I took it for a spin this evening for 50 miles or so). It's particularly noticeable when cornering left so something is moving around when I corner.

I'm thinking it's either lack of lubricant/grease or perhaps that the system needs bleeding properly. Having said that there's plenty of brake feel and the pedal is plenty firm enough.

Can lubricant/grease be used on the shim surfaces that contact the top and bottom edges of the pads? I assume the squealing is coming from the pad passing vibration through to the shims and making them vibrate somehow. Any recommendations for a good brand of grease at all?

Thanks as ever.
 
I use Comma Copper Ease on any likely "touch" areas-same on wheel studs-people may come along & say-No No use the correct aluminium paste but it's not readily available & I haven't had any problems over many years.
 
For what it's worth I run my rears shim free and they are silent. Pagid discs with Brembo pads. I had years of front squeal and ultimately realised it was Pagid pads causing the problem. I now have Pagid front discs and Textar front pads running the proper OEM shims (rectangular plate with 2 cylinders that fit into the pistons. No noise whatsoever from that set-up and decent braking. I also use copper slip for the non touch surfaces.

It's much discussed that Pagid stuff from ECP is pretty crap these days and not of the old standard. This is probably reflected in the current pricing. I have found though the discs to be perfectly good when mated with non Pagid pads. The Pagid pads themselves are a horror show and must be avoided!!

On the calipers themselves, my rear calipers were brand new about 15 years ago and have zero plate lift. The fronts have been rebuilt for a 2nd time in that timeframe due to plate lift.

Incidentally I have no idea what makes you are using, but thought I would share this with you!!

Good luck

Stuart
 
Turns out I had put a wear sensor in on a bit of a wonk and it was rubbing on the disk.

God I'm such an amateur. [:(] :ROFLMAO:
 
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