brake caliper questions

Discussion in 'Workshop Forum' started by myredracer, Nov 6, 2019 at 9:25 PM.

  1. myredracer

    myredracer True Classic

    Something like 10 years ago I bought 4 sets of rebuilt calipers from various sources - 128 & 850 fronts and 124 & scorpion rears. Before I put them into service, I want to disassemble them, make sure all is good and then put them back together. I also have a few pairs of used ones lying around that might be re-usable for someone or good to keep as spares.

    The bore for the e-brake rod in one of the used rear ones has what looks like a very tiny spot of corrosion. I think it needs to be honed. I took it to a machine shop who said they couldn't do it. Then I took it to a brake shop who said it "should be fine". I'd like to see it get honed. Is that ever done to these? If I wanted to do it myself, what type of hone to use?

    When I re-assemble the previously rebuilt calipers, what grease to use. I know not to use petroleum based grease or anti-seize compound but what type & brand of grease is recommended? I found that Krytox is highly regarded but it's not cheap. Permatex has a few versions of brake parts lube. Which one to use? I think there's one or two other brands that are popular.

    Should I be greasing the pistons/bores? I'm not sure if all brake greases can be used for that?

    Lastly, what to use to clean out the crusty dried out crud in the caliper piston groove for the seal? Is there anything that maybe can used to soak the calipers in to soften it up? Tried some brake cleaner and lacquer thinner but didn't do anything. The brake cleaner dries up way too fast to be useful anyway.

    Thanks!
     
  2. Dan Sarandrea (Phila)

    Dan Sarandrea (Phila) Waitin' On Parts...

    Location:
    Philadelphia, PA
    The ebrake plunger bore hole is pretty small, maybe 3/8 - 5/16? How about a short strip of 400 or 600 sandpaper rolled up and worked in and out of the hole?
     
  3. I've been using Volvo white silicone based brake grease that comes in a plastic squeeze tube for many years with good results. A tube seems to last me a decade or so, and I'm near the end of the one I have now.

    A few weeks before I blew up my engine in 1995, I replaced the rear calipers. When I recently got the car running again, I found the e-brake plungers on both calipers frozen in their bores and no amount of lubricant, force, and/or heat would move them. This also happened to one of the original rear calipers so I guess it is a vulnerability of the design. Something to prevent corrosion there would be a good idea. I gave up on fixing them when I found that Auto Ricambi had brand new calipers (they sell them for 124s) for less than many of the rebuilt ones (which at the time were mostly out of stock). After putting those on, I found that the emergency brakes worked much better than they ever did when the car was new. I can actually park on a steep grade now. I'm not sure if the design was modified or if this set just works better than the factory set and first replacement set. The castings look slightly different than the old set but it could be cosmetic.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice