Fitting new piston seals to brake calipers ....

Fitting new piston seals to brake calipers ....

Author
Discussion

fatpasty

Original Poster:

1,561 posts

173 months

Friday 20th April 2012
quotequote all

I have an old set which I have just removed from my 92 SPI. Wondering how hard this is to do. Some say very hard, some say it is easy.

Does any one have a guide of anykind I can use. Step by step etc to show me how it needs to be done.

Cheers


Cooperman

4,428 posts

257 months

Sunday 22nd April 2012
quotequote all
First of all get the stainless steel caliper re-build kit which comes complete with all seals and new stainless pistons.
Also make sure you also get the small 'O-ring' which geos between the two caliper halves. A new bleed screw is also a good idea.
Once you get the old pistons out, and you may have to use compressed air to get the outer one out, it's just a matter of cleaning everything very, very thoroughly, then using clean brake fluid or rubber grease, fit the new pressure seals into the calipers, then fit the new pistons. Then comes the only difficult bit, fit the new dust seals. A small smear of rubber grease or a light oil helps put these in, but it's still easy to 'kink' a seal carrier. Just do it very carefully and it'll be fine.
Finally re-assemble the two halves using the new O-ring, put a bit of Loctite on the bolts which join the two halves and torque the bolts to 45 lb.ft.Fit the new bleed screw.
When attaching to the car, screw the caliper onto the flexible hose before bolting to the car, unless fitting new hoses, to ensure the hose will not have a kink in it.
Bolt the caliper to the hub using a bit of Loctite on the bolts. These are special bolts, so don't just replace with bolts of unknown quality. Torque to 40 lb.ft. (or just nice and tight).
You need a 5 litre can of 'Brake & Clutch Cleaner'. Use lots and ensure TOYTAL cleanliness when doing this job.
I hope this helps.


fatpasty

Original Poster:

1,561 posts

173 months

Tuesday 24th April 2012
quotequote all
Cheers mate. Think I'll give it a go, I have a spare set I've just taken off my 93 Cooper.

Cooperman

4,428 posts

257 months

Tuesday 24th April 2012
quotequote all
As I mentioned, the biggest problem is fitting the dust seals and dust seal carriers. Several times I've had to use the original carriers because the new ones have 'kinked'.
Best idea is when the calliper halves are on the bech, clean up around the register where the dust seal carriers sit with fine wet & dry before fitting the main pressure seals and pistons.
Once again, TOTAL CLEANLINESS is the key to this job.

fatpasty

Original Poster:

1,561 posts

173 months

Wednesday 25th April 2012
quotequote all
Cheers Cooperman. Will give this a go fairly soon. Will let you know how it goes.

Just spent the last couple of nights cleaning and painting my drums and other calipers. Well the primer is down at the moment, will add another coat later on.