Identify If Needing New Later Carrera 3.2 Caliper - IOM next week!

[NeilH]

Hi all, in a bit of a panic - front caliper piston just seized SOLID while trying to sort slight binding! Had been "exercising" the piston in and out while the caliper was still in place, after cleaning pads etc. Suddenly seized solid and can't retract!
Supposed to be off to Isle of Mann in 1.5 weeks.

In desperation looking to order new caliper. But remember previous owner saying he upgraded the front "brakes" to Carerra 3.2. I'm assuming this applies to the calipers?

Anyone able to help identify please? Car is 1981 SC

Was original SC also vented? I assume possibly just larger discs? Anyone know the size for me to use as reference?

Looking to order from design911 but don't have time for the wrong part to arrive!

Any help advice welcome.

Thanks
Nei

 

[NeilH]

Another image

 

[Stirls]

An old school garage should be able to rig a hydraulic line to it….even seized they tend to “pop out” when extra force applied. Don’t hammer it. If you have a press, it can be pushed back in and give it another go. All has to be very clean so as not to introduce debris in-between surfaces. The fun we have!

 

[Lancerlot]

I take it it's the RH piston as it lies on the bench.

Lock the calliper in a vice, remove the bleed screw, take 2 flat blade screwdrivers and try to lever out evenly using the dust cover slot in the piston. Often the piston "rocks" in the barrel making it difficult to extract, so try to centralise the piston before extracting.

Alternatively, flat blade screwdriver and gently tap the piston around it's circumference until it starts to move. Use a hot-air gun on the outside of the calliper to ease it, if necessary.

Once out, it would be best to clean the barrel using a fine abrasive, thoroughly clean the components with brake cleaner or methylated spirit. Check all surfaces for pitting and corrosion, then refit using a new piston and seals - parts should be available at any good local motor factors, if you take the originals in as a pattern.

Good luck.

Clive

 

[richardstephens777]

Hi,
Yes the original SC brake disc's are vented. The 3.2 discs are the same diameter 282mm but are 4mm thicker so do not fit SC calipers. I think the 3.2 has a wider spacer between the caliper halves.
design911 sell refurb units to keep cost down. Staying original will mean you have no complications. Do not forget to apply your 10% discount if you go for them.

Rich

 

[NeilH]

Thanks all for your replies and details of disk sizes.

I think Clive (Lancerlot) was absolutely right - the piston possibly tilted and became wedged! I'd replaced the brake pad with a bit of steel bar that was a bit thinner than the pad thickness when exercising the piston back and forth (using the foot brake then easing the piston back in via the steel bar) I did this to clean and free up the bore with a longer stroke than the pad offered - so to speak. I'd not realise though the pistons skirt (against the rear of the pad) is actually semi circular as almost half of its circumference is cut back slightly - possibly causing the "tilt" to happen as I applied the brake pedal!


In the end, managed to recover it on the bench. None of my windback tools would do it! But placing the caliper on its side with the bad piston downwards, i threaded a long piece of wood through the caliper and pressed down on it like a pair of bicycle handlebars - managing to "level" the piston and it suddenly popped back!

All good now after bleeding and testing.

Huge relief!

Many thanks, Neil