Brake booster problems

[mpro69rr]

Hey Guys, I have a 69 RR 383 4 speed that originally had manual brakes. I switched to power brakes with a Bendix booster from pirate jacks. When I installed the booster the rod that goes to the brake pedal was too short to reach the brake switch. I had the rod lengthened and that worked. My brakes had little travel but worked. I thought if I went back to the correct length rod I would get more travel so that's what I did, I found an original rod and replaced the longer one. I do have a little more travel but it goes to the floor when I press it and stays there when the car is running. I have to pull it up with my toes (when its to the floor the brakes are on and the car will not move). When its not running and I press the brake pedal it returns. I may have done something to the booster when I changed the rods, I don't know? Do you think my booster is bad now?

 

[Kern Dog]

Read pages 8 and 9 of this:

Members with 4 wheel disc systems.....Can you get the tires to skid?

 

[mpro69rr]

Read pages 8 and 9 of this:

Members with 4 wheel disc systems.....Can you get the tires to skid?

Good info, I have all the bushings so no problem there. I had my other shaft lengthened but it wasn't adjustable, it was welded. I think I may go back to that one because now the brake light switch barely reaches and its always moving. One thing I didn't do is check for leaks. I'm thinking when I bleed the brakes maybe I left one end loose although that still doesn't explain why when the car is not running the brake pedal returns.

 

[davek]

dumb question but you do have the spring hooked up?

 

[mpro69rr]

dumb question but you do have the spring hooked up?

No, but thats just a anti rattle spring.

 

[mpro69rr]

Good info, I have all the bushings so no problem there. I had my other shaft lengthened but it wasn't adjustable, it was welded. I think I may go back to that one because now the brake light switch barely reaches and its always moving. One thing I didn't do is check for leaks. I'm thinking when I bleed the brakes maybe I left one end loose although that still doesn't explain why when the car is not running the brake pedal returns.

Well, I checked for leaks and found nothing. I was hoping that was it. It still only goes to the floor and stays there when running. When not running the brake returns. I have a feeling this might be the brake booster. Does anyone else have any thoughts?

 

[1STMP]

Well, I checked for leaks and found nothing. I was hoping that was it. It still only goes to the floor and stays there when running. When not running the brake returns. I have a feeling this might be the brake booster. Does anyone else have any thoughts?

The booster only assists brake pedal
force. If your pedal stays on the floor
I'd be checking the MC. Sounds like
a leak with the MC piston seals. It's
fluid pressure that brings your pedal
back up.

 

[mpro69rr]

The booster only assists brake pedal
force. If your pedal stays on the floor
I'd be checking the MC. Sounds like
a leak with the MC piston seals. It's
fluid pressure that brings your pedal
back up.

Thanks, I was thinking of replacing it. I think ill try that before the booster.

 

[Kern Dog]

The booster only assists brake pedal
force. If your pedal stays on the floor
I'd be checking the MC. Sounds like
a leak with the MC piston seals. It's
fluid pressure that brings your pedal
back up.

This isn't always true.
The multi piece linkage in the 1966-70 B body cars have bolts and nuts to retain the various parts.

If any of those three nut-bolt connections is too tight, the linkage will bind up and not allow the pedal to return to the top. This happened to me and before I figured it out, I changed to a different master cylinder.

 

[mpro69rr]

This isn't always true.
The multi piece linkage in the 1966-70 B body cars have bolts and nuts to retain the various parts.

View attachment 1519920

If any of those three nut-bolt connections is too tight, the linkage will bind up and not allow the pedal to return to the top. This happened to me and before I figured it out, I changed to a different master cylinder.

Hmm, I have to check this. When I replaced the rod I remember making sure everything was tight. Thanks, I guess I have more stuff to check.

 

[mpro69rr]

This isn't always true.
The multi piece linkage in the 1966-70 B body cars have bolts and nuts to retain the various parts.

View attachment 1519920

If any of those three nut-bolt connections is too tight, the linkage will bind up and not allow the pedal to return to the top. This happened to me and before I figured it out, I changed to a different master cylinder.

Ding Ding Ding, We have a winner! Thanks Kern Dog, you were correct, everything was too tight. I loosened everything and the brake pedal comes back up, I now have brakes! Its not the greatest feeling pedal but that's the way it was before I changed the rod. Its a little too easy going down but it stops. Thank God I don't have to remove the booster, that's a frustrating job.

 

[Kern Dog]

Alright! I'm glad the suggestion helped.
That is a great thing about these forums. The sharing of unusual problems and fixes sometimes helps someone else.
I went back after I'd loosened up the linkage and made sure that the nuts were tight enough to stay in place but not too tight where they'd bind. To be sure, I put Locktite on the threads.

 

[1STMP]

Alright! I'm glad the suggestion helped.
That is a great thing about these forums. The sharing of unusual problems and fixes sometimes helps someone else.
I went back after I'd loosened up the linkage and made sure that the nuts were tight enough to stay in place but not too tight where they'd bind. To be sure, I put Locktite on the threads.

Cool beans, KD.
I learned something.
mpro69rr...glad the problem is fixed.