Converted stock manual brakes to power, BOOSTER QUESTION 66 Fury

[Rusty Muffler]

Well I managed to do a swap from my stock manual brakes to power on my 66 Fury III. It took getting a power brake pedal and backing plate off a donor 66 and a rebuilt booster and master cylinder from Oreilly's.

Everything fit like a glove as I wanted a bolt up stock setup. My problem is during a road test the brakes were slow to release (about 3 sec) as was the pedal to lift back up to it's home position. The stopping power was fine.

After a lot of haggling I just took off the master cylinder and tried the pedal again on the car with vacuum and it was the same. If I grab the pedal with my hand to pull it home it has a lot of resistance.

I disconnected the pedal from the booster and the pedal is totally free.

Any ideas?

 

[john66ny]

Well I managed to do a swap from my stock manual brakes to power on my 66 Fury III. It took getting a power brake pedal and backing plate off a donor 66 and a rebuilt booster and master cylinder from Oreilly's.

Everything fit like a glove as I wanted a bolt up stock setup. My problem is during a road test the brakes were slow to release (about 3 sec) as was the pedal to lift back up to it's home position. The stopping power was fine.

After a lot of haggling I just took off the master cylinder and tried the pedal again on the car with vacuum and it was the same. If I grab the pedal with my hand to pull it home it has a lot of resistance.

I disconnected the pedal from the booster and the pedal is totally free.

Any ideas?

Similar circumstance for me it was the push-rod length not adjusted correctly. Been there, done that.

 

[66SportFury]

Sounds like the diaphram spring inside the booster being weak or just shot. Did you pull vacuum to see if it's leaking also?

 

[Rusty Muffler]

Sounds like the diaphram spring inside the booster being weak or just shot. Did you pull vacuum to see if it's leaking also?

There are no leaks, the booster is releasing slowly like it's binding up. By coincidence, my Father is converting his 70 Dart to power brakes and was able to tell me that with his new booster in hand and not in the car, when he puts engine vacuum on it it's very easy to push in, and it realeases back pretty quickly when you let go.

I tried that with mine and it still releases slowly. It's got to be binding or a check valve or something not working to be keeping the brakes applied for a few seconds before releasing when the master cylinder is attached!

I'll get the new booster tomorrow and will let you know. Thanks in advance for all your guys help!

 

[commando1]

It took getting a power brake pedal and backing plate off a donor 66 and a rebuilt booster and master cylinder from Oreilly's.

Obviously a Cardone unit. Their success rate in properly rebuilding these units is a roll of the dice.

 

[Rusty Muffler]

Obviously a Cardone unit. Their success rate in properly rebuilding these units is a roll of the dice.

Yep, Cardone. I don't think I've seen different anywhere for rebuilds?

 

[commando1]

Over on Moparts I've seen some other places mentioned that were highly recommended. I forget who.

 

[Rusty Muffler]

Well, got another booster from Oreillys and it works as it should. The booster was not assembled properly or something.

Also, the newest booster had a gasket between the master cylinder and booster where the other one was missing! (that wasn't my original problem but would have made the rod too long).

I have seen this more and MORE is recent years across the board, new or rebuilt products it would seem (for me anyway, and not just automotive products) 50% of the time something is wrong with the replacement item. Pathetic!

 

[Clover]

Please pronounce Cardone correctly: Car Done.

 

[john66ny]

Glad you solved your problem!

For future reference, for booster rebuilds a lot of people use "Booster Dewey", just Google him.

 

[tdenkler]

There is a check valve on master cylinder that holds small amount of residual pressure(in case of brake failure) Need to change/release pressure?
Heard others talk about this.
Tom Denkler

 

[Rusty Muffler]

There is a check valve on master cylinder that holds small amount of residual pressure(in case of brake failure) Need to change/release pressure?
Heard others talk about this.
Tom Denkler

The check valve you refer to is on the BOOSTER which sits behind the Master Cylinder. It is Vacuum actuated and has a 5/8" hose going to it. Where that hose connects is a fitting that is a check valve that keeps vacuum in the booster even if the engine is off so you will have one or two pumps of braking left.

I suppose if you remove the vacuum hose and pump the brakes it will release booster pressure but be aware you won't have power brakes anymore and be prepared to push a lot harder on the brake pedal.

 

[Rusty Muffler]

There is a check valve on master cylinder that holds small amount of residual pressure(in case of brake failure) Need to change/release pressure?
Heard others talk about this.
Tom Denkler

I'm sorry, I misunderstood your post thinking you were asking me for info on the booster. My issue has been resolved but thanks for your input!