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1990 Chevy Brke Master Cylinder Question

Discussion in 'Chevy Trucks' started by wsmm, Aug 13, 2011.

  1. wsmm

    wsmm Member
    Messages: 80

    I don't know for sure if it's leaking, or if I just didn't put the cap back on tight. It seems like it may have leaked out where the plastic reservoir goes into the master cylinder casting. It only appears to be the rear brake portion that is doing this. My question is, if it is leaking can you just replace the gasket there or do you need to replace the whole master cylinder. I had broken brake lines to the rear and replaced them. Ever since I can't seem to get good pedal pressure and the brake light comes on when applying the brakes. If I tap the brake pedal when the light is on, it goes out. I have vacuum bled the brakes once and also beld them with an assistant pushing on the brake pedal. Any and all help and suggestions appreciated. Want to resolve this issue before the snow starts.
  2. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    I think you still have air in the line..

    Or you are sucking in air from the bad gasket..
  3. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    If you don't have a leak then I think you still have air in your lines. Give this a try. Instead of having someone pump the brakes and then opening the brake bleeder. Open the bleeder and have someone push the brake pedal all the way down. Do this 2-3 times on all four corners. I saw an old mechanic do this and it has worked for me many times when the pump the pedal method has failed.
  4. mcwlandscaping

    mcwlandscaping 2000 Club Member
    Messages: 2,557

    I agree....just make sure you close the bleeder before the person in the vehicle releases the pedal, otherwise you won't get anywhere!
  5. mossman381

    mossman381 2000 Club Member
    Messages: 2,410

    Yeah, you need good communication with the person pushing the pedal :nod: