weak brakes on IIA 88

[tmckeon88]

I have had a chronic problem with weak braking in my 69 IIA. The pedal does almost nothing on thre first press, then there is adequate braking on the second press. I have adjusted and adjusted the cams on each wheel and it's not leaking fluid anywhere. All the drums and shoes less than 2 years old and there's plenty of lining left on the shoes.

I have a dual circuit system with the vacuum booster. I also replaced the adjusters a number of years ago- is it possible the adjusters themselves are loose and don't stay in the position you set?

Any thoughts or suggestions would be welcome. We had a fender bender last week that makes this a more pressing issue. Thanks everyone-

Tom

[NickDawson]

Dont have a great answer to offer but mine is in the shop and having very similar symptons. I'm due to speak with him tomorrow - I'll find out what he has discovered.

Any chance there is some air? Have you tried bleeding them again - when I was working on it on my own I discovered that even the slightest big of air in the lines caused a soft pedal.

That said, what really caused the problem in the first place was a bad master cylinder. Is yours in good shape?

[Nium]

...is it possible the adjusters themselves are loose and don't stay in the position you set?

An easy way to test this theory would be to set the adjusters then use some sort of marking device(Sharpie, white out, paint) to make a mark on the adjuster and a corresponding mark on the brake backplate. If you use pencil instead it will probably last long enough to tell if they are moving and you could still easily wipe it off.

As Nick pointed out any air in the system needs to be bled out and can lead to a soft pedal/poor braking. It is odd with a brake booster that you still have to pump the brakes though. IMHO.

[4flattires]

Rule out the vac assist...

....by disconneting the vaccum hose.

If no change in effort or stopping power you have a bad booster.

Because you stated you CAN stop adequately with multiple pedal pumps, you know the linings are doing their thing.

Jeff