Well that's shit

Discussion in 'Maintenance' started by Bikeboy, Apr 25, 2020.

  1. Bikeboy

    Bikeboy Active Member

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    Doctor told me I need to move more and do stuff. I've been sat for 3 months since a knee injury.torn cartilage. I've gained a stone in weight and used up all my brownie points with the wife.
    So thought I'd start with a brake service. Get me mobile .. nice and straight forward.
    Removed the calipers and stripped out the very tight pistons. First alarm bell..
    So new seals needed.
    Inspection of the pistons finds one of them is corroded and pitted. So new piston needed. Might as well do the pads while I'm at it.
     
  2. Bikeboy

    Bikeboy Active Member

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    20200425_152128.jpg
     
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  3. Bikeboy

    Bikeboy Active Member

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    20200425_152109.jpg 20200425_152109.jpg
     
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  4. Bikeboy

    Bikeboy Active Member

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    I thought the pistons might have been cracked as there are some very odd markings on the end . But I've worked out it's where the piston contacts the anti squeal shim on the back of the pad. 20200425_150401.jpg
     
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  5. raphael

    raphael Elite Member

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    Pretty common for the pistons mate, I went down the stainless route when replacing mine, slick did the same,
     
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  6. Slick

    Slick Elite Member

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    Those piston aren't too bad to be honest!

    I've recently found over use of solvent cleaners cause the seals to swell so this may have caused the tightness but crud behind the seals is also common

    Though SS pistons are good you still need to polish them to get the best performance, but the going cost is 120 buck, goes a long way for a set of aftermarket such as Hel, brembo etc
     
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  7. Bikeboy

    Bikeboy Active Member

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    It's only one piston I need so I'll just replace that. The seal kits are quite cheap compared to what I've paid in the past.and I'm not using the bike so it's no rush.
     
  8. RR7

    RR7 New Member

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    I've never done it but would those pits, if polished out, be a problem?
    I mean, if the seals were'nt passing before why would they now, and new as well?
     
  9. Slick

    Slick Elite Member

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    My OEM pistons are pretty fecked, what grease, if any, do you use on the backs of the pads?. Wondering my use of copper slip accelerated the corrosion
     
  10. Bikeboy

    Bikeboy Active Member

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    First time I've had these apart. But I do use copper slip.
     
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  11. Slick

    Slick Elite Member

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    These are one of the worst examples, the pitting is close to the edge so caused slight dragging for brand new pads

    Not sure what would cause such bad corrosion, road salt, using the wrong cleaning/ lube products etc


    E73AA949-D8F7-4B87-9921-2B14B6D1792A.jpeg
     
    #11 Slick, Apr 27, 2020
    Last edited: Apr 29, 2020
  12. Bikeboy

    Bikeboy Active Member

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    That is a mess. Last time I saw them that bad was a 94 zx9r.
    Unless you know the history it might just be down to neglect.
     
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  13. Phil_M

    Phil_M Active Member

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    Personally i would never use any sort of grease anywhere near the brakes - its a friction based system after all!
     
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  14. DazK

    DazK Active Member

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    Erm....your supposed to lube all contact surfaces between caliper, mount and pads.
    Back side of brake pads...copper slip and doubles as anti-squeal. Slides should be lubed as well but not overly lubed. Marine grease is great as it seals and lubes.
     
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  15. Slick

    Slick Elite Member

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    I'm testing out a few greases namely Mintex Ceratec and Proslip (Clip, Pad and Pin)

    Whats this Marine grease you mention? I'm looking for alternative to red grease or silicon for the seals.
    Doing a long term test on ACF corrosion block for the seals but early indications are not good, I think it marginally expands the seals and requires over 30psi to activate the pistons.
     
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  16. Selmer50mark

    Selmer50mark God Like

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    That's a Debatable one o_O,,,, personally I don't ,
    I found that copper slip attracts dust n crap ,
     
  17. DazK

    DazK Active Member

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    https://www.lanoguard.co.uk/products/lanoguard-marine-grease
     
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  18. DazK

    DazK Active Member

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    I only ever put a very thin smear on the pads but always done it and with all my cars. Old Skool :D
     
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  19. Mr_Chin_LK

    Mr_Chin_LK Well-Known Member

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    I do the same, a little dab of copper slip on the backs of the pad.

    That's how I was taught to change pads, but I'm a Monkey-See-Monkey-Do type of guy!

    And Yes, I would jump off of a cliff if you did...

    Chin
     
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  20. Slick

    Slick Elite Member

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    9F64C6AE-7FF6-4B26-847C-851948593924.jpeg
    7517BBCF-B7DC-43D7-8CCA-0AB2DEB2B2B5.jpeg

    Just finished polishing my stainless steel pistons to an inch of their life, 3 stage polish to a mirror finish.

    like i said above was testing with acf corrosion block on the seals, like butter going in but after an hour over 30psi to activate! So do not recommend!
     
    #20 Slick, Apr 28, 2020
    Last edited: Apr 28, 2020
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