66 Power brake MC issues

[Randy S.]

Hello,

I am posting this question for a friend so I hope I get all the details correct.
Factory 66 Power brake car in final stages of restoration and working out the bugs. Master cylinder was rebuilt by White Post a "while back" and installed and now recently for initial road test he could not get the system to hold pressure but no leaks at the calipers. White Post rebuilt again and still there is an internal leak in the master cylinder according to mechanic that is installing and bleeding the brakes.

Any feedback would be appreciated

Randy

[Larry S.]

Re: 66 Power brake MC issues

What did white post say the first time they got the master back? Did they say it was bad.

I have used white post several times over the years and have never had a problem.

Might be a little tough to do but, you friend may have to question how they are bleeding the brakes and what type of fluid they are using. If some one is using the silicone style and still trying to bleed by the old pump method that could be the problem.

I have never heard of White Post putting out a bad product.

I have heard several times of an improperly bled brake system blamed on a
misdiagnosed master cylinder or bad calipers .

I now use a motive power bleeder, Very affordable and simple to use
Good Luck

[Randy S.]

Re: 66 Power brake MC issues

Larry,

My friend used silicone the first time and White Post said they would honor warranty but normally don't with silicone. I had White Post do my 66 manual brake MC and I recall a note in the box advising against silicone so I went the Dot 4 route. In my fiend's case, his mechanic flushed the system of silicone and switched to Dot 4 the second time and still continues to have no pedal pressure and suspects the MC.

I think his mechanic will figure it out. He was hoping for some tips from this post.

Randy

[Rob A.]

Re: 66 Power brake MC issues

Randy,

As an alternative idea...you can install one-way bleeder valves in the calipers, re-bleed them and see if that helps. I assume the mechanic bled the master cylinder prior to installation?

[Brian K.]

Re: 66 Power brake MC issues

I had White Post restore a 69 Camaro MC for a customer and had the same problem, no brakes. I purchased a cheap 20.00 MC one out of an auto parts store and instant brakes. I then called White post and sent it back for them to fix, it came back and still didn't work!!!! I was totally pissed by now and had the customer buy another numbers match MC and installed it, problem solved, Except the customer was out the White Post money, they would not stand behind it. I will not deal with White Post again.

[Randy S.]

Re: 66 PB MC issues ......final chapter

Brian Larry and Rob,

Thanks for the responses, just thought I'd provide update. My friend borrowed a 67 master cylinder and adapted to his 66 Power Brake setup and "presto" instant brakes. SO I guess that narrows down the culprit to the twice rebuilt 66 master cylinder by XXXXX XXXX.

Randy