Lamborghini Urraco P250 ATE BMW 2002 front brake calliper rebuild

Urraco P250 front brake callipers (ATE similar to those fitted BMW 2002) are dry but each piston has rust residue on, usually caused by the section of calliper forward of the hydraulic seal which rusts. It shouldn't as each piston has a rubber dust/moisture seal, but most people don't add rubber grease behind the seal to help prevent moisture sitting between the calliper and housing.

With the hydraulics still attached, push each piston nearly all the way out by clamping the other three at various stages.

Calliper removed use compressed air to push them out the last bit. Be careful!

You can see the ring of rust on the calliper body which is beyond the hydraulic seal (removed). It's expansion is usually the cause of seizure x 4 pistons per calliper = stiff brakes that don't freely return.

A careful trim with a Dremel to clean the rust off has the diameter back to normal. Compressed air and brake cleaner to clean off the resulting dust.

The pistons on this calliper were perfect after cleaning off rust residue. Main ring seals back into the cleaned up calliper.

A drop of brake fluid spread around the calliper and pushed back in by hand. Add red rubber grease around the exposed part of the piston and push it back all the way. Refit the old or new dust seals and it's ready for refitting to the car following a degrease and repaint in Hammerite smooth silver.

Lamborghini Urraco P250 suspension rebuild

I appear to have taken my Lamborghini apart.. I'm detailing up the suspension and fixing some knocks at the front end. The factory "don't remember" where they sourced some of the suspension components from and they didn't write stuff down in the 70's, so it's an extra fun challenge trying to renew parts  Turns out Volvo 240 (brick) suspension tops are similar and the front brakes are ATE BMW 2002 4-pot (40mm pistons) as fitted to the Turbo models but with a space to accommodate vented discs on the Urraco

Urraco P250 rear suspension and hub re-assemble

So with the hub and strut dismantled I set about cleaning things up. The lower part of the hub carrier mounts to the rear suspension arm with a simple long king-pin design. It was all in good condition with no wear on the kingpin or bushes, but either end is sealed by these discs which are like mini-pistons and have three sprung piston-rings to provide the seal. One was ok, the other the rings were seized.

After a good soaking and cleaning the sealing rings freed up. I cleaned everything up and painted the solid disc for protection.

Here you can see the rear suspension arm and where the hub carrier lower pivot king-pin mounts.

And the cleaned up parts, kingpin, thrust washers, sealing rings and big suspension bolt!

With the hub carrier cleaned up and painted, king-pin reassembled and greased from the bottom (on it's side for access in this photo). The bolt inserted just to keep the sealing plates in place whilst greasing.

Cleaned and painted strut re-assembled and back in the place. I used the original strut top mount which actually seems to be in good condition. Spring was media blasted and painted in a close match to the original green.

View of the cleaned and painted hub carried bolted up. You can see the handbrake cable mounting lug - all very simple.