New brake guide pins are called for when servicing rear brakes on 100k mile +, first generation MINIs. The bad news is these stainless steel guide pins list for more than $20 each. Indeed my guide pins had surface pitting and rubber transferred from the guide bushings, but they were still straight, and I don't see these requiring a precision fit. I polished them with 2000 grit sandpaper to give them close to a new finish. New guide bushings went on the calipers plus a little high temp synthetic/PTFE grease for the guide pins. Replacement clips were installed too, although I don't think there was anything wrong with the old ones. The piston boots and seals were still doing their job, and I've discovered over time some things are better left untouched.
Kieth the last time I checked the rear R53 calipers are a non serviceable part requiring to replace the whole caliper no re-build kit or piston available? You can get a seal using the oem number and crossing it over in Federal Mogul National seal/BCA. Has this changed? I had to build my own tools to dis-assemble/assemble mine when I powder coated them so I can understand why they are NS. Nice information about how to clean up the guide pins. Real OEM RealOEM.com BMW R53 Cooper S REAR WHEEL BRAKE
Did you consider changing the rubber boot and/or piston seal? Edit: didn't read the last line. gotcha.
I replaced the rubber OEM guide pins with the solid ones and love them. I just service them a couple of times a year with my wheel/tire change over.
I have had rear calipers not work right on my 2002 and 2003 Coopers. The inside of one and the outside of another was not making enough contact with the rotor. Would solid guide pins help with that? What are the downsides of using them?
If you're not getting even contact... make sure that the pins don't have stuff on them (like Keith mentioned) and that the pads are free to move in thier slots. If everything is really clean and free to move, then you won't get that pronounced uneven wear. I can't think of any downside to the solid caliper bushings other than having to maintain them. When I was running stock calipers in the front, they were a great addition. I'm still running them in the back. When I do a pad change, I take the pins out, clean them up, and lube them again with some moly lube. Mine have got almost 80k miles or so on them. Anyway, I love them and wish they were on the car from the factory. Matt
the rear calipers can be serviced...all it is back there is just a rubber boot and a seal...you can buy the kits on amazon for a few bucks...you can service them like any other brake caliper
TyrolSport makes a bushing kit to replace the rubber boots with hard bushings. Comes with new pins as well: TyrolSport Brake Caliper stiffening kit for Mini Cooper S/ Non S Front/Rear Have had these back there for over 100K, and just did my pads about 3 weeks ago. I had these on the fronts too, but upgraded to the R56 calipers. Still work great.