Hard Brake pedal??

[skweemish]

Just read about the long travel of the brakes in seebart's Sept 10 post.

I have the opposite issue. The pedal has very little play and is hard from start to finish. The brakes work fine with a little hesitation at the start of the move but only travels a rather short distance. I had work done with a new Master cylinder and upgraded to a 2 chamber unit for front and back. New lines were installed as well.

The restorer said it was normal for that year!

I recall them being sensitive and having a nice gradual increase of braking power the farther the pedal traveled.

These feel like they are not power assist brakes. I'm wondering if there is air in the lines?

Any help is appreciated. The restorer is 3 hours away now. I don't feel like driving it that far on the highway.

[dales65]

The brakes should have some degree of travel and the long travel that was discussed is not uncommon for these years. You're right it should be a gradually increasing braking not short & hard.

Air in the lines would give you spongy soft brakes so I'm doubtful on that, if they changed the master cylinder and didn't adjust the push rod it could be right up against the piston and perhaps even applying some brakes while your driving! Does it feel like the brakes are dragging a bit when you coast to a stop?

For the " no power brakes" pump the brakes a few times with the engine off to dissipate the vacuum in the booster, then with your foot on the pedal start the car and see if the pedal moves down, if so the booster is working.

Keep us posted

Cheers
Dale

[redstangbob]

skweemish welcome to the forum. You didn't mention what year your Tbird is. 64's were 4 wheel drum, where 65 & 66 were disc/drum. How much effort does it take to stop the car? Not many of us remember the feel of manual brakes, but even they didn't require a huge effort to come to a stop. Good luck, Bob C

[David Langhorne]

Sounds like a bad booster - sometimes even new ones are not to be trusted according to previous posts. However since you have updated to a split braking system each master cylinder will have less work to do and will not have so much fluid to push resulting in less travel - I'm trying to think logically here! My 65 will do a crash stop up there with modern cars so if yours does not there may be a problem with the booster

[skweemish]

Thanks for all your advise and knowledge.

I tried the engine off pump the pedal to release the pressure . I started her up with my foot on the brake and it did travel it's "normal" distance so I imagine the booster is functioning. I will get under there and see if the piston stem is fully extended and need to be re -postioned to a shorter throw????

Any other thoughts are appreciated.

[THUNDERMAN]

Hi all, after reading this post and many like it, i am working on a customer's 66 T-bird with the same HARD PEDAL problem. I tried 2 new boosters and i still have the same problem, hard pedal and the car will not stop properly. I have tried to lock up the brakes as well and nothing.
One thing I have that i have not seen before is, when the car is in park and I step on the brake pedal the rpm jumps about 200 rpms which would indicate a vacuum leak, but there is none that i can find. The other thing is the transmission vacuum line is connected to the manifold and not the booster but i tried hooking it up and it made no difference. All other brake components are in good shape or new.
The pedal does not have much travel whether engine is running or not. Its giving me all indications it's the booster but it's not. Any feedback would be great because after 45 years in restoring cars, this one is going to kill me. Thanks for listening.

[stubbie]

Push rod adjusted correctly? What size dual master did you use? I think original was 15/16th's.

[THUNDERMAN]

Thanks for seeing this post after 10 years !! Yes 15/16 bore and i have adjusted the rod several time, some play, no play, just touching.

[jtschug]

How much vacuum is the engine making at idle. My engine has a cam and was putting out 12-15 lbs, which I was told should be good enough for a vacuum booster, it isn't. I had to add an electric vacuum pump to bring it up to 20 lbs to get good brake pedal feel.

Engine idle change when you hit the brake pedal is a clear sign of a vacuum leak. That should not happen.

[David Langhorne]

Have you checked if the calliper pistons are stuck?

[Rt.146]

The adjustable pin from the booster to the MC, may need adjusting.

[stove]

Is this a Banded Midland booster?

[THUNDERMAN]

Sorry had to jump on another job. Vacuum us about 18-20 but when you push on the brake pedal it drops to 4 right away with car in park. it is a Midland booster and i have adjusted the pin about 5 time, tight, loose, just enough...ect
The calipers are new, the originals were still on it and that was my original diagnosis. I just got back the booster that was on the car when it came in, it was tested at Harmond Classic, and he said it was perfect so i will swap the new one out and let you know.

[THUNDERMAN]

Does anyone know if the Midland booster vs the crimped one makes a difference in performance vs just the period correct?

[stove]

Heads-up if you go to a Bendix booster, you would need the bracket too (which may or may not exist for '66 T-bird?).

You need to see what the pedal acts like with the MC out of the mix.
Unfasten the MC, and bend out of the way, then install the filter spacer, and tighten the MC nuts. This seals the bellows.

With engine running, and IN PARK:
Pedal should be beyond effortless, and you should have zero deviation in engine speed. you should be able to "hold" the pedal
at any position in it range of travel, and not feel it kick back, or fight against your foot.

If you have any of these negative symptoms, the booster needs to be properly repaired. They are good boosters, but complex, and
VERY easily goofed up. Hence the reason FoMoCO never offered a service kit for these, they were exchange replacement only units.
I am well versed on how these thing work now, and if everything is not just perfect, they will not work right, or at all. Don't let the fact
it holds vacuum at rest, fool you into thinking it's an OK booster.