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Disc brake puck removal

Discussion in '"Stock" Alpine' started by absunbeam, Feb 12, 2020.

  1. absunbeam

    absunbeam Platinum Level Sponsor

    Is there a easy way of getting the puck removed from the caliper? They have been sitting awhile and don't budge.
  2. 65beam

    65beam Bronze Level Sponsor

    Pump grease into the bleeder screw opening. I found a grease fitting that fits.
  3. Warren

    Warren Silver Level Sponsor

    Pumping grease is the easy way if you can find a fitting. A lead on the exact one would be helpful. Grabbing them with a wrapped pair of Channel locks most always makes the next call to Sunbeam Specialties for those expensive stainless steel pistons.

    PS yes I get it the size of your grease gun may vary :)

    PROCRAFT Gold Level Sponsor

    Air pressure works also.
    belmateo likes this.
  5. 65beam

    65beam Bronze Level Sponsor

    I've used air before but I don't separate the halves of the caliper . You need to restrict the piston from hitting something else. I have a cone shaped rubber chuck for the air hose for things like this. The chuck is cheap at Harbor Freight.
  6. absunbeam

    absunbeam Platinum Level Sponsor

    Thanks for the suggestions, tried air pressure first no luck. Will look for fittings to hookup a grease gun. Since they have been sitting for 30 years the rubber is probably stuck to the inside of the cylinder, just hope they are not pitted.
  7. Barry

    Barry Platinum Level Sponsor

    A typical home / shop air compressor provides about 125 PSI. A typical hand operated grease gun can generate several thousand PSI. Advantage, grease gun.
  8. mikephillips

    mikephillips Donation Time

    I have to admit I always separate the halves and I've never had an issue with doing that. To get the pistons out I use a piece of wood against the mating surfaces and then clamp them in a vise against the outer surface and the wood. The first try grabbing the piston with vise grips and pull, while hitting the grips to cause the piston to turn while pulling. You may also want to use a torch to apply heat to the piston to help break the rust that can develop between the outside and the sealing ring. I find that both helps break the seal. If that doesn't work, and pumping air or grease doesn't if used, then you'll have to get more aggressive. I took apart a pair that were on a car left in a field for what they told me was close to 20 years that a brake shop couldn't remove. What I did was split them, then take the halve and heat them until the remaining fluid was steaming out of the connections, then took the halves and tossed them into a bucket of cold water. One half needed this twice, the other 3 just once and the thermal shock broke the pistons loose so I could twist them out. But, if you go this route you're committed since the water will get sucked into the piston chamber as it so quickly cools and you don't want to leave it in there.

    Being apart also allows you to more easily clean the rust out of the pressure seal groove in the bore and the one for the dust seal, as well as clean the surface between the pressure seal and the outside. I've use a rotary tool and stone for the pressure seal groove and a small cutoff wheel to clean the dust seal groove. It's easy that way to get all the dirt and rust out without really risking damaging the castings since it is easy to feel the difference between the junk and the cast iron.
  9. sunalp

    sunalp Platinum Level Sponsor

    Where did you find the fitting?

    PROCRAFT Gold Level Sponsor

    How about a piece of wood ? Just like we used on the Brembo stuff and there is a tool around that that expands to the inside of the piston to yank it out so to speak.
  11. jumpinjan

    jumpinjan Gold Level Sponsor

    I got every piston out in all the calipers I have rebuilt using compressed air. And I probably used heat like Mike Phillips suggested
    puff4 likes this.
  12. puff4

    puff4 Gold Level Sponsor

    Ditto. Air seems to have worked for me. I've not ever gone the grease route for calipers or crank pilot bearings, simply because I didn't want to deal with the mess. For pilot bearings I use a tappet puller... works great.
  13. jumpinjan

    jumpinjan Gold Level Sponsor

    On the contrary, I have removed pilot bushings using grease & an old input shaft way back years and years ago. But yes, now I also have & use an I.D. bushing puller.
    On one occasion the bushing was so worn, I wrapped the input shaft with masking tape to get a tight fit in the bushing. And hit the shaft with a hammer and it came right out.

    PROCRAFT Gold Level Sponsor

    I just use grease and hydraulic it. Not that big of a deal.

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