Rear Brake Question

[chris-foci]

Bit of a strange one.
Just bought a 172 Cup and have started stripping down and re greasing all the brakes so they work ok. Piece of mind really.
On the rears I took everything apart, cleaned it all up but when I went to re fit the pads into the carrier the inner one went in fine but there was no room for the outer one. Probably need the gap to be around 3 mm wider to squeeze the outer pad in.
I didnt touch the piston so it shouldnt have moved out anymore.

I then took the caliper off the hub to wind the piston back in to create more room.

Now the piston turns and retracted slightly but it gets to a certain point and wont retarct anymore and just continues to spin.

What could the problem be with the caliper?

Surely if it was siezed it wouldnt turn at all?

Anyone shed any light on the problem?

 

[Budgie]

Lever bar. make it fit.

 

[chris-foci]

Tried that. There is no movement at all. I suspect there is a problem interally as the piston spins but wont retract further.

 

[Budgie]

The piston should retract almost all the way in..

Got a pic of where it is currently?

 

[chris-foci]

No I didnt take a pic. Ive put he wheel back on and wheeled it back into the garage.
It just wont go back all the way, gets to a certain point and just spins without retracting.
Im thinking of sending it to Big Redd for a refurb as something has to be amiss inside the caliper.

 

[MarkCup]

You removed/loosened the cap from the master cylinder resevoir before trying to do this?

 

[chris-foci]

Yep done that. Ive changed countless sets of brakes on all manner of cars and never had this problem.
Just thinking its got to have happened to someone else

 

[bloke]

you are pushing on the piston as well as winding i take it?

 

[Andy93]

Are you sure it's not retracting? I've just done mine and it feels like you're turning it for about 6 weeks before the face of the piston is level with the dust seal

 

[chris-foci]

Yeh, pushing it while turning. It's definitely not retracting.

Very odd, I've never had this problem before.

 

[bloke]

push harder then:wink:

 

[JamesBryan]

Handbrake off?

 

[chris-foci]

Yeh handbrake off.

Does anyone know if there is a mechanism inside the caliper which would cause the piston to spin and not retract?

What caliper rewind tool do people use on these? As the traditional type won't work on clio calipers.

 

[JamesBryan]

I use the length of a screwdriver slotted into the groove of the piston.

The caliper is on a slider too, which allows a bit of side to side movement. That should help you get the pads in if you have a tight space on one side.

 

[chris-foci]

I used both a screwdriver and a caliper rewind tool. Although it's a lot less fiddly with a screwdriver.

I had the caliper fully pushed back against the sliders as well, there just isn't the space. I'm talking 3 or 4 mm it just needs to give by.

The only answer is that something is amiss inside the caliper piston somewhere.

I can't be the only person that's had this problem surely?

 

[bloke]

take the disc off, big square repair washer in a set of mole grips and off you go:up:

 

[chris-foci]

take the disc off, big square repair washer in a set of mole grips and off you go:up:

Sorry but I don't follow?

 

[bloke]

use a big square washer to wind the piston back but you need to take the disc off to do it.

 

[chris-foci]

Ah yes, I could give that a try I guess. I'll dig out my massive breaker bar and crack off the hub nut!

I'm still convinced there is something wrong with the caliper.

 

[bloke]

nah, you just don't get anywhere near enough force against the piston unless you get straight on to it.

 

[chris-foci]

I'll give it a go and let you know how I get on.

You know the next problem will be the hub nut will be on stupid tight!! Haha.

 

[chris-foci]

So I tried @bloke suggestion and it worked like a dream, it retracted the rest of the way into the caliper.

The hub nut was only on finger tight so quite lucky I checked it. Now torqued back up to spec.

Cheers!

 

[bloke]

makes it so much easier.