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Removing pistons from caliper (2014)

Discussion in 'Norton Commando Motorcycles (Classic)' started by cbacejr, Dec 20, 2014.

  1. cbacejr

    cbacejr

    Joined:
    Apr 8, 2014
    Hi All,

    I'm rebuilding the caliper on my 1972 and the pistons seem to be stuck. Not real bad, don't seem to be pitted.

    How is the best way to get them out?

    Thanks,
     
  2. Guido

    Guido

    Joined:
    May 23, 2011
    Put a block of wood in the caliper and use compressed air it force them out.
     
  3. dynodave

    dynodave

    Joined:
    May 28, 2003
  4. Beach

    Beach VIP MEMBER

    Joined:
    Aug 27, 2013
    Pump grease in the caliper...plug hole for line and put grease fitting in place of bleeder valve..
     
  5. Jed

    Jed

    Joined:
    Mar 23, 2012
    air worked for me and they were pretty stuck
    new ones were needed so I replaced them with stainless
     
  6. olChris

    olChris

    Joined:
    Oct 6, 2013
    If you havn't got a compressor, then you need to acquire one.... Spray the pistons with good quality penetrant, like CRC (not ya busta arse WD40 excuse of a penetrant) and "move and manipulate" the pistons whilst giving the occasional blast of compressed air, in the fluid or bleeder hole. (either one will b OK) also with a few raps on the block of wood on the bench it/they will eventually give up and pop out .....
     
  7. concours

    concours VIP MEMBER

    Joined:
    Dec 29, 2011
    Remember to use a shop rag doubled up to cushion the exit, and keep your fingers clear, they will nip. Have you got the spanner tool to remove the plug? Be sure to heat the caliper before trying to remove the plug.
     
  8. B+Bogus

    B+Bogus

    Joined:
    Jun 28, 2009
    The last one I did was in a sorry state and defied all attempts, and I was reduced to drilling and tapping the blind-side piston and slide-hammering it out - and even then it only shifted after applying substantial heat.

    Sounds like yours is nowhere near this bad.

    If facilities are limited, what about removing the pads, inserting the wood spacer (I use a tyre-lever) to prevent one piston popping out first (as already stated) and using the bike hydraulics to drive them out?

    The Workshop manual is a great help - 'non-repairable'!
     
  9. cbacejr

    cbacejr

    Joined:
    Apr 8, 2014
    Hi All,

    After all the help from many people on the site, what work for me:

    With the caliper removed from the bike I took the cap off and filled the inside of the piston cup with fender washers. I had the spanner I bought the take the cap off it is about 14 in long, ΒΌ in thick, and 2 in wide. It fit great just above the washers. With the cap side down on the bench I pressed down on both ends of the tool. The piston moved a little, I added another washer and repeated the process till the piston popped out.

    Leaving piston just above o-ring, I put the cap back on and with the bleeder valve closed applied 90lb of air to the fluid inlet. The other piston popped free. Next I took the cap off, took the piston out, and then the o-ring. I need to square up the second piston and when done, it came right out.

    Thanks for all the help!
     
  10. Jdub

    Jdub

    Joined:
    Dec 1, 2018
    Reviving this 2014 thread as I've just purchased a caliper with difficult pucks and cap. The thread directly above is intriguing. My process will be to totally soak, brass brush, and clean all residual particulate, then begin the heating (boiling water, and later maybe MAPP gas) to get the items to dislodge.

    These things are beasts!
     
    Last edited: May 9, 2019
  11. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Another way to remove a stiff outer piston. I've used this method so I know it works and is quicker/easier than fiddling about with levers and washers.

    Remove the pads.
    Unscrew and remove the caliper cap and seal and insert a suitable size square drive socket and hold it against the outside of piston as you put the caliper and socket between the suitably protected jaws of a vice/vise and use the vice and socket to press the outer piston INWARDS until the piston seal is uncovered.

    Remove from the vice and extract the piston seal from its groove. With the seal now out of the way the outer piston will often push (almost fall) out quite easily.
     
  12. marshg246

    marshg246 VIP MEMBER

    Joined:
    Jul 12, 2015
  13. cliffa

    cliffa

    Joined:
    May 26, 2013
    I did pretty much the same, however once the outer is removed, if you drill a hole into the exposed side of the inner piston (visible through the pad retainer recess) you can get a long rod, auger or bradawl into the hole and move it each way a few degrees while it's warm. I also used brake fluid around the end of the piston which will seep down onto the seal and aid removal (brake fluid is also a rubber lubricant). Once you start it moving it comes out pretty quick.

    When you have it apart check all the fluid ways, as they get full of crystallized brake fluid. Mine were almost completely blocked so I ran a drill bit ( around 3mm I seem to remember) through each. The machined seal grooves need to be meticulously cleaned as well, otherwise the pistons may stick once you have new seals in place. I used a strip of 1.5mm aluminium, cut at 45 degrees, then bent over to form a scratch free scraper, and a small mirror.


    Cheers,

    cliffa.
     
  14. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    Whatever of these removal methods you choose , fit new seals and stainless pistons so you don't have to do it again ....hopefully.
     
  15. DevonNorton

    DevonNorton VIP MEMBER

    Joined:
    May 7, 2015
    Hello Jdub
    Hope the job is progressing well.
    One option for new caliper pistons is a modified inner piston with a threaded boss (5/16" UNF) for easier removal.
    I have this type fitted to my '72 Roadster.
    Available from Norton Owners Club (image below) and RGM Norton (their part no. 061896M). Both in the UK.

    upload_2019-5-11_9-32-40.png

    Andy
     
    elefantrider likes this.
  16. chaztuna

    chaztuna VIP MEMBER

    Joined:
    May 5, 2017
    Check out the thread linked below. I included photos of how I got mine out. To see photos on this site, you need to use either Chrome or Firefox as your browser. You also need to add a Photobucket image block defeat add on. See the Tech sticky thread at the top of this forum for a "how to". I just checked that thread. The Photobucket info is no longer there. I'm using Firefox. The add on I use is called Photobucket Embedded Image Fix. Contact me via a conversation if you need more help with that.

    https://www.accessnorton.com/Norton...down-yes-with-pictures.5131/page-4#post-53981

    Charlie
     
    Last edited: May 12, 2019
  17. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    What I do is remove the bleed nipple, push the point of a pencil into the cross drilling in the outer piston chamber (the outer piston having already been removed) and hold it there whilst blowing compressed into the bleed nipple hole (with a short length of tube on the blow gun nozzle to form a seal) and out pops the piston.
     
  18. Jdub

    Jdub

    Joined:
    Dec 1, 2018
    Hi all, thank you very much for your replies. I was having issues getting both the cap and the outermost (cap-side) puck out and decided to improvise. I am not sure how many here re-purpose their tools, but I have always had a lot of luck doing this with the multitude of bicycle-related tools I own (I used to build custom steel bicycle frames for a local frame shop).

    Here I have setup up an old Campagnolo pedal wrench (it broke!) as a cap remover. Two 5x.8 socket head screws spaced using bicycle inner tube (presta version) valve lock rings.

    [​IMG]

    [​IMG]

    Here I am using a typical lock ring wrench and the flat of a tool (not shown - goes above the ring wrench) to apply, via a fulcrum position and leverage, centralized force to the outer caliper - either our trusty Norton tool, or any of a number of lock ring tools from my bicycle toolbox:

    [​IMG]

    Popped right out. Now the kicker: The innermost caliper puck just bounced right out with a couple of hard whacks!

    I believe that pre-threaded puck setup is brilliant.
     
    Last edited: May 13, 2019
  19. cliffa

    cliffa

    Joined:
    May 26, 2013
    I like it, I like it a lot !

    ;)
     
  20. Jdub

    Jdub

    Joined:
    Dec 1, 2018
    Thank you Cliff! I have always found that people who ride motorcycles usually preceded that activity with bicycles. I know I was swept up in the '70's bicycle craze and everything I learned to not be afraid of mechanically I broke on a bicycle first. God hates a coward!

    All: Link to pictures that may not appear in my post above: https://photos.app.goo.gl/Yq52T9TKpx6SGJfU9
     

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