Rear brake compensating valve leaking

Discussion in 'Mech Tech' started by Skyelectrix, Jul 11, 2019.

  1. Skyelectrix

    Skyelectrix Supporter

    Okey dokey all sorted and usual you clever lot on here have saved my butt again! Stripped the valve down and it was full of horrid black gunk. Unfortunately the gasket was in a few pieces so cut a new one from thin gasket paper. With a smear of sealant it was back together. I left it overnight before refilling the brake fluid and it seems to be leak free...so far!
    So once again I’m in debt for the great advice and one step nearer to actually getting away soon so hats off to you clever lot!!
    0C4642E6-800B-43D8-93A9-2C1FF82C5E96.jpeg

    6F0F63C0-851B-4338-989B-DBFB8AD10BC7.jpeg

    F89BA7FA-16F8-4E3D-AC85-4C8F331F1C45.jpeg
     
    garethpuk, nicktuft, mgbman and 7 others like this.
  2. DubCat

    DubCat Sponsor

    Ok this is embarassing. I've taken mine apart and can't remember how it goes back together! I've got an ali washer about the size of a penny and a rubber bit about the same size with a hole in the middle and I don't know where those two bits go. Anyone got an exploded diagram of how they go back together please?
     
    Razzyh likes this.
  3. :rolleyes:
     
    DubCat likes this.
  4. [​IMG]
    Think ur on about the rubber band seal goes in the ridge and the washer I think goes on end of spring

    @pkrboo has some great pics


    Sent from my iPhone using Tapatalk
     
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  5. Faust

    Faust Supporter

    Clean it up outside in the sun :)
     
    Skyelectrix likes this.
  6. DubCat

    DubCat Sponsor

    Thanks for the pic. Looks like the rubber bit is in on the left hand half over the shaft of the smaller slidey piston bit (no it's OK I knew where the o ring went). So does my washer go between the spring and the larger piston slidey bit that's under it, in your pic? Or does it go between the spring and the rubber in the opposite half? (Hope that makes sense)

    @pkrboo - Matt if you've got a diagram, please would you send it to me?
     
  7. pm me your mobile and I'll WhatsApp over the pictures I have
     
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  8. 77 Westy

    77 Westy Supporter

    Does the cross section help? It looks like the washer goes between the spring and the secondary piston (the larger slidey bit)
    Brake compensator valve.jpg
     
    Last edited: Jul 25, 2019
    mcswiggs and DubCat like this.
  9. DubCat

    DubCat Sponsor

    Mine is the later type and looks a bit different to that one, I assume the principal is the same though. Thank you. Neither Bentley or Haynes were any help.
     
    77 Westy likes this.
  10. Skyelectrix

    Skyelectrix Supporter

    If you look at mine stripped down the washer goes between the spring and the smaller piston, or between 2 & 3 in @77 Westy diagram
     
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  11. 77 Westy

    77 Westy Supporter

    I’ve never had one apart and I don’t really know what the spring does but doesn’t the washer give the spring something to push against? The shoulder is smaller on the secondary piston side compared to the primary piston.

    What does the washer do if it’s on the primary piston side?
     
  12. DubCat

    DubCat Sponsor

    I called "2" the bigger piston as I went by diameter, so we agree I think.
     
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  13. 77 Westy

    77 Westy Supporter

    Now I’ve had a look at @Skyelectrix pic I think he’s calling the secondary piston the smaller piston, even though it’s larger diameter. The cross section drawing is correct and we’re in agreement – probably.
     
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  14. Skyelectrix

    Skyelectrix Supporter

    Yep 2 is the shorter piston I guess but fatter!
     
  15. DubCat

    DubCat Sponsor

    I finally realised where this pesky rubber bit goes
    [​IMG]
    It looks like it'll fit in here
    [​IMG]
    It fits! It was nothing to do with the plungers after all - doh! It goes under the ball bearing :)
    [​IMG]
     
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  16. 77 Westy

    77 Westy Supporter

    That’s the valve seal (#8 on the drawing); I thought you were talking about the washer between the pistons earlier.:)
     
    DubCat likes this.

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