Master cylinder issue

[Rob M.]

Looking for some suggestions regarding a master cylinder issue on my non PB 66. I've got brakes that don't want to release completely, at least not right away. For example, if I stop at a light with a slight slope, I may not have to apply brakes to stay still. I've been told that it's the master cylinder. Question is, do I rebuild the original or buy a new reproduction from Paragon? I know mine has been rebuilt in the past, so is ok to do it again (safety)? How does Paragon's compare to an original? Or, is the diagnosis all wrong?

Thanks in advance,
Rob
39795

[Rob A.]

Re: Master cylinder issue

Rob,

Do you know if your master cylinder was just "honed" or "sleeved"? You can certainly have it sleeved if it hasn't been yet. Sounds like the return spring for the piston may have failed or wore out. I would recommend reusing your original if possible. If by chance, you're in southern CA, I can recommend a place that can do it in one day...almost while you wait.

[Joe R.]

Re: Master cylinder issue

Hi Rob:

Another problem that can cause the symptom you describe is a bad brake hose on one or more of the wheels. As the hoses age they can develop internal restrictions that resist allowing the brake fluid to reverse direction in the lines when you let off the brake pedal. I have had this experience myself, although in my case it also caused the car to pull to one side as I drove.

In theory, a stuck piston in a caliper might cause similar behavior, but in my experience this does not hold the wheel quite as firmly as a bad hose can (the bad hose will affect all four pistons in the caliper).

I suggest that you jack up the car so that the wheels can spin freely, then apply and release the brakes and see if one or more wheels tend to stick even after you let off the brakes.

If the problem affects only one wheel, it is probably the hose on that wheel rather than the master cylinder.

[Rob M.]

Re: Master cylinder issue

Rob,

If I recall, it had a brass sleeve when I pulled it and had it honed. That's how I knew it had been done before. I'm in San Diego, north county coastal if you've got a good shop, I'm all ears. Feel free to send me an email.

Thanks,
Rob

[Rob M.]

Re: Master cylinder issue

Joe,

It could be as you describe. However, it doesn't pull one way or the other. I will have to check that out and see. Thanks for the suggestion.

Rob

[Rob A.]

Re: Master cylinder issue

Rob,

You could try pushing the brake pedal forward by hand and seeing how much free play there is, then push it all the way in, release it and see if it returns to the same position with the same amount of free play. If you do this several times and the amount of free play is constant, it would suggest the problem is elsewhere.( I emailed you the info on the shop in Orange, CA.)

[Rob M.]

THANKS ROB & JOE *NM*