[dunhookin]

Guys,

Hoping for some ideas/knowhow/intel on rear brake caliper pistons in my 2001 156. I'm half way through doing a brake overhaul - new discs and pads all round.

Fronts are done and were straightforward - but I'm getting nowhere trying to retract the rear caliper pistons. I've got a wind back tool - but can't get either piston to move at all....?

They seem to be seized - feels unlikely that both would seize - unless I'm missing something....? The brakes have been neglected before I got the car - the pads worn well down to the metal - and the discs totally destroyed.

Can anyone please shed any light - make suggestions? Thank you.

Regards

Andy H

 

[rarebear]

reading the condition of the brakes, I assume that the rear pistons are rusted solid in their cylinders...
try to get the winding tool to work, apply WD40 or some such or heat the calipers...

 

[David C]

How much effort are you putting on the wind-back tool?

Mine needed the use of a 60cm breaker-bar to get them to start to move.

 

[Malheus]

Guys,

Hoping for some ideas/knowhow/intel on rear brake caliper pistons in my 2001 156. I'm half way through doing a brake overhaul - new discs and pads all round.

Fronts are done and were straightforward - but I'm getting nowhere trying to retract the rear caliper pistons. I've got a wind back tool - but can't get either piston to move at all....?

They seem to be seized - feels unlikely that both would seize - unless I'm missing something....? The brakes have been neglected before I got the car - the pads worn well down to the metal - and the discs totally destroyed.

Can anyone please shed any light - make suggestions? Thank you.

Regards

Andy H

The piston could become skewed since they went too far out. Try moving the handbrake arm if its at the end point, then center the piston. Else push out the piston and refit it with new seals.

Unless you want change calipers.

 

[rarebear]

Pushing the rear pistons is a no go, they have to be pushed and turned in the same instant

 

[Spacecadet]

Guys,

Hoping for some ideas/knowhow/intel on rear brake caliper pistons in my 2001 156. I'm half way through doing a brake overhaul - new discs and pads all round.

Fronts are done and were straightforward - but I'm getting nowhere trying to retract the rear caliper pistons. I've got a wind back tool - but can't get either piston to move at all....?

They seem to be seized - feels unlikely that both would seize - unless I'm missing something....? The brakes have been neglected before I got the car - the pads worn well down to the metal - and the discs totally destroyed.

Can anyone please shed any light - make suggestions? Thank you.

Regards

Andy H

Do the pistons turn?

Or are they stuck solid?


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[dcbain]

Bear in mind also that it's a fine thread so you seem to be twirling the piston for ages and not getting anywhere.

 

[pubsinger]

Might be worth applying gentle pressure to the brake pedal, with the pads removed the piston has plenty of room to travel further out, might be enough to get it moving. Don't allow it to move too far out or you'll never get the rewind tool in.

You should be able to lift the rubber dust boot/cover and squirt some Plusgas (other freeing agents are available) into the caliper. Once you get it moving wind it fully in, brake pedal out, wind in, keep repeating till it's operating smoothly.

All the best

Pub

 

[gibot123]

You will have to bleed the brakes but undo the bleed nipple to relive some of the pressure in the system this may help try pushing it in then try winding as mentioned it is possible due to the state of the brakes they have over heated and seized .
I would recommend that you try and get the pistons out clean and fit new seals or you may end up with the same problem again. Bigg red do loads of kits look them up on the net a lot cheaper than replacement calliper s. :thumbs:

 

[Spacecadet]

The other thing I've found that stops the pistons rewinding is forgetting to take the fluid tank cap off!


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[gibot123]

You can try a large set of plumbers grips just to see if you can get it to move long handles gives you a bit of leverage pushing it back not turning it:thumbs:

 

[dunhookin]

Nope Andymac - neither caliper piston will budge a fraction. I'm about to go and have another go using some of the suggestions made on here.

Will post back again later with an update. Thanks guys for the helpful suggestions - fingers crossed I can get the 'flippin' things moving - really holding me up, need the thing sorted.

Regards

Andy H

 

[Spacecadet]

I know this will sound stupid, but you are turning the pistons clockwise?


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[dunhookin]

Yes - definitely clockwise. No joy again tonight - even applying an extension bar to the T handle of the wind back tool - the b***** thing will not budge - on either side. Very frustrated and fed up - I've always really disliked wind back caliper pistons - right now it's hate the damned things.

Need the car sorted and back on the road - and will probably have to - reluctantly - bite the bullet and lob out for reconditioned calipers

 

[Spacecadet]

Last possible option I can think of, try disconnecting the handbrake cables from the back of the calipers. Then give it another go. After that, I reckon a pair of recon calipers will be the only way to go!


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[gibot123]

Silly never even thought to ask if he had the hand brake on even :tut:
Well spotted andymac :thumbs:
Are the calliper s still on the car and did you get the calliper s off the bracket as appossed to taking the pads out? Only wondered if there was any movement in the piston at all?
As it looks like you need to change them when you can stand no more try using the system to push the pistons out rather than trying to wind them in ?
Without the pads
As pubsinger mentioned

 

[Amgg]

I know thos is old thread..but I knw exactly what you going through. .I had exactly the same problem I took the entire caliper off tightened it on a vice got a leverage bar solid metal one, 3ppl pulling and jumping still wouldn't budge at all we even got a sledge hammer and smacked the living lights out of the bar still wouldn't budge it was drenched in WD40 nightmare ..I ended up buying recondition one which cost me £90 and hand my old part in

 

[gerardsalfa]

I was interested in this thread having had my fair share of grief with brake calipers.
I've acquired a box of currently unserviceable calipers with problems ranging from frayed rubber sleeves to the immovable piston situation.
I wondered if its worth trying to replace the seals/overhaul them as spares.
Is the rubber sleeve just there to stop dirt or is it a fluid seal too?
How do you actually get the old sleeve off and securely fit a new one?
What about the internal seals?
I'm particularly interested in sorting some of the rear calipers I have, they've got the handbrake levers on, but not sure how to dismantle it all assuming one needs to.
Thanks

 

[gerardsalfa]

Can anyone help with this please?

 

[pubsinger]

Is the rubber sleeve just there to stop dirt or is it a fluid seal too?

Just there to stop dirt getting it, you can ease the rubber away from the top of the piston and squirt (for example) plusgas into the caliper.

How do you actually get the old sleeve off and securely fit a new one?

Can't help you with that one, never taken one apart. If you got a one where the rubber is damaged you're not going to lose anything by being heavy-handed with it, rip it off, may find it just sits on/under a lip or held in with some sort of clip.

Good luck

Pub