'66 power brakes seem weak

[Tauno M.]

I have had the brakes completely gone over and there was a small hole in the diaphram of the booster which was replaced. The mechanic says everything is as per spec. To me however they seem really weak.
Even when I stand on them they don't seem to stop as fast as they should. Maybe they are as good as "new" and I am getting what I
should expect. I want to ask you folks for your experience, thoughts
and suggestions. Thanks in advance and happy new year. T

[John H.]

Re: '66 power brakes seem weak

Tauno -

That's not normal at all. Make sure the plastic check valve where the vacuum hose from the intake manifold fitting connects to the booster is working - it holds vacuum in the booster. If it isn't working, you'll have the equivalent of manual brakes.

[Tauno M.]

Re: '66 power brakes seem weak

The mechanic did check the pressure and said it was alright but i will check it again.

[Richard M.]

Re: '66 power brakes seem weak

If he just replaced the booster, maybe your hydraulic system had a problem also and it needs attention. Did he bleed the system?

If not, IMO it sounds like air in the lines. I just went through that on a '67 I just converted to PB. After a long bleeding exercise, after a few short rides it appears they need bleeding again. It's amazing that just a little air in the system can make a huge difference.

Rich

[Claus S.]

Re: '66 power brakes seem weak

Came loose on my car once but i stopped after about a 100 meters and put it back on.

Tauno -

That's not normal at all. Make sure the plastic check valve where the vacuum hose from the intake manifold fitting connects to the booster is working - it holds vacuum in the booster. If it isn't working, you'll have the equivalent of manual brakes.

[Bob H.]

Re: '66 power brakes seem weak

If your brakes were working properly, I doubt you would ever question their effectiveness. Something is wrong somewhere and it likely is air trapped in the system.

Is the pedal firm or low?

Are there bleeders on the master cylinder? When those lines were removed, there was likely air induced in the system that is still there somewhere. If there are no bleeders, it would really take some bleeding to get it out especially if air was sucked into the m/c.

Bob

[Tauno M.]

Re: '66 power brakes seem weak

thanks for all the help. i will bleed and rebleed and see what happens.

[Domenic T.]

Re: '66 power brakes seem weak

Tauno,
Did you say the brakes were completely done?
If so maybe there is a difference in the type pad he used or fluid on the pads if all else checks out.

DOM