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[JamesV6CDX]

My 3.2 is pulling sharply right on braking. Quite violently.

I’ve popped it on stands and had a look.

Front Nearside caliper seized solid. Won’t wind back in. The rubber boot has split and visible evidence of rust from moisture ingress.

Can’t find a new caliper anywhere - does anyone know how to overhaul them please?

[TheBoy]

Haynes Book of 'dangle berries', Chapter 9, section 4.

[countrywoman]

Or send it to Bigg Red at Worcester.

[cam.in.head]

someone of your talents won't have an issue with this surely ?.
i would
obtain seal kit
pop out the piston ( or as near as dammit then finish by hand) by pressing the pedal and pushing it out whilst still connected up
then remove from car and clamp hose


remove outer dust boot and ring
remove inner seal
clean up all areas , grooves etc and piston ( unless  you have a new one )with fine emery and brake cleaner
install inner seal ,piston and outer seal boot . i prefer using red rubber grease to lubricate and put some around the joining edges of the boot to help avoid any water ingress which is what caused it all in the first place
refit back to car , clean ,degrease pins
job jobbed
a doddle to you i'm sure
you may need to do the other side to match unless it's perfect anyway ?

[JamesV6CDX]

someone of your talents won't have an issue with this surely ?.
i would
obtain seal kit
pop out the piston ( or as near as dammit then finish by hand) by pressing the pedal and pushing it out whilst still connected up
then remove from car and clamp hose


remove outer dust boot and ring
remove inner seal
clean up all areas , grooves etc and piston ( unless  you have a new one )with fine emery and brake cleaner
install inner seal ,piston and outer seal boot . i prefer using red rubber grease to lubricate and put some around the joining edges of the boot to help avoid any water ingress which is what caused it all in the first place
refit back to car , clean ,degrease pins
job jobbed
a doddle to you i'm sure
you may need to do the other side to match unless it's perfect anyway ?

It's how to remove the piston that's troubling me. It's absolutely stuck solid. It won't even move outward when pressing the brake pedal!

[dave the builder]

hook the calliper up to a compressor ,pressurise it and tap the face of the piston with a hammer
obviously "elf and safety" kit advised /aim it elsewhere 
done this twice ,2 separate rusty Vauxhalls. 2 for 2 
clean up and buy seals from BIGG RED
they're on ebay too 

[Nick W]

A quick Ebay search returned THIS one if that's any use?

[Doctor Gollum]

Also don't ignore the Flexi hose as it could have failed internally if the brake is slow to release...

Heat cycles won't help the caliper release either.

[cam.in.head]

i'm surprised it won't push out with the pedal . never had one SO seized
however i know for a fact that there is a calliper at a breakers i went to this saturday cos i personally took it off to remove a strut . it's at 1st choice car spares , latham , accrington and is on the floor just in front of the blue omega . i'm sure they will post it if needed . cannot comment on its physical condition  thou ?

[YZ250]

Also don't ignore the Flexi hose as it could have failed internally if the brake is slow to release...

Also, as a basic check it's always worth loosening the bleed nipple on that caliper to make sure that the fluid is actually getting from the pump to the caliper. 

[Nick W]

I love all these just pop the piston out replies, after James described how bad the caliper is.


If it's that bad, even if he does get the piston out there's an excellent chance the bore will be damaged - either rusted or scored due to the crap in it - beyond any sensible repair. I wouldn't buy a seal kit and piston until I'd determined that. Pressing the new piston squarely into the bore so that it doesn't damage the new seal is the only bit of the job that is tricky, and being careful takes care of that - it should squeeze in easily by hand.


While an air compressor(I've used a foot pump on several occasions) will easily shift a brake piston in good condition on the bench, the brake master cylinder is capable of about 20 times as much pressure.


If I were in James' shoes at this point I would buy the caliper I showed, or try and collect a used one from as local a source as I could find. Just like he's trying to do

[Andy B]

I love all these just pop the piston out replies, after James described how bad the caliper is.


If it's that bad, even if he does get the piston out there's an excellent chance the bore will be damaged - either rusted or scored due to the crap in it - beyond any sensible repair.  .....

it doesn't matter about the bore of a brake caliper .... the piston moves on the static seal, not the other way round like a piston in the bore of an engine. New pistons are easily come by.

I've moved pistons before by swapping bleed nipple for a grease nipple & using a grease gun to move the piston.

[Doctor Gollum]

Also a caliper for the opposite side will work perfectly, but will need to be unbolted from the strut to be bled inverted. Just remember to place a block in the caliper to prevent the piston from escaping.

[JamesV6CDX]

Also a caliper for the opposite side will work perfectly, but will need to be unbolted from the strut to be bled inverted. Just remember to place a block in the caliper to prevent the piston from escaping.

I didn't think of that!

Thanks for replies, folks - all sorted now