1959 Cadillac Brakes Issue

[Coupe Deville]

Hello everyone, My 1959 Cadillac Series 62 is extremely hard to stop once its going. I think Ive traced it down to the power brake booster. The brake fluid is clean and there are no leaks in the system. The brake pedal does not sink and does not feel spongy. Does this sound like a power brake booster issue. I can feel no power assistance and the brake pedal is extremal hard to push down. The brake do work, it just takes more effort then it should. Is there a way to test the booster or the vacuum line going to it? Thank you

[curly]

Disconnect and plug the vacuum supply hose to the booster, then test drive the car. If the booster is working, you will notice a large increase in braking effort.  Sounds like the booster is defective on your car.
Dont forget to check the vacuum storage tank hose for leaking.

T Lewis

[Coupe Deville]

I disconnected the vaccum line to the brake booster and noticed no decrease in braking effort. I think the booster is at fault. Is there a check valve on this brake booster. And if so where? Thank You

[curly]

I'm going to say No, no brake booster check valve. I had to replace my booster when I first got the car, the vendor supplied a modern replacement that was bolt in. It has a check valve on it. That was around 1987/88.  IIRC, the original booster had a metal 'T' on it with one side of the T going to the engine and the other to the storage tank, but I do not remember any check valve.

T Lewis

[Coupe Deville]

Yes I know that T fitting where the vacuum lines go thru. What could be the cause of the bad booster? Just old age or did brake fluid leak in there. Can get the booster rebuilt or do I just get a new one? Thanks for responding

[Jeff Wilk]

There is a check valve. It is located in-line between the booster and the carb. 90degree connection right at the top of the firewall above the T-fitting on the booster. Do you have one at all?  Sure your booster is original?  Midwest Power Booster rebuilds these and does excellent work.  Post a picture.

Below is a picture of the OEM line between the booster and carb showing the check valve

[Coupe Deville]

I will post a picture today.
Thanks

[Coupe Deville]

Here is a few pictures of the brake booster and check valve I have on my car. Is there a way to check the check valve or do i just get a new one? Is the brake booster original? Any help is appreciated. Thanks!

[Big Fins]

Pic #3 is the check valve. And yes, fluid can leak internally into the booster if the seals on the back of the M/C go bad. Over time, it ruins the leather diaphram in the booster.

[Blade]

I have the opposite problem, my break pedal is all the way down to the floor.

I have not yet driven this car, I bought it in original unrestored condition. The engine runs and when it was delivered to me (on a trailer) the previous owner actually drove it into my garage so the breaks must have worked. I immediately started restoration on it so I never driven it.

I put the car up on the stand and the wheels turn freely so the breaks are not engaged. The fluid level is good, no leaks on the break line anywhere. Anyone could direct me where I should start looking for the problem?

[Coupe Deville]

It sounds like air in the brake system.

[Coupe Deville]

I replaced the check valve and a old vaccum hose and the braking effort was easier and it was more consistant. But I know there is a little more assistance that should be there. At-least that's what my dad says. It's kinda hard to diagnose to braking problem when your not old enough to drive the car to test it. But i have tested the car just in the driveway and there should be a little more power assistance. Any help? Thanks

[Jeff Wilk]

Id say the booster is starting to leak internaly

[Coupe Deville]

Is that something that i can replace like a diaphram or do i need to get it rebuilt or replaced?

[dplotkin]

There is no repairing the booster yourself. There is no off-the-shelf booster you can buy either unless you go to a modified system. You, my friend are in the same boat many of us have been and will be if you own old cars with power brakes long enough. It isn't your check valve, your booster is breached. Brake boosters are perishable items. They wear out.

There are many folks who fix them. Try these guys, who will do a 2 day turn-around.

http://www.midwestbooster.com/

Dan

[Jeff Wilk]

Gaven, the ONE thing to never skimp on is your brakes.  Call Midwest tomorrow at the link below and ask for Rick.  He will set you up fine and you will be dealing direct.  Now that you've examined the rest of the system for issues, it is the booster, and having the booster rebuilt wont cost an arm and a leg, but not getting it done might.......

[Coupe Deville]

Ok, I will call Midwest tommrow morning. I have heard that a master clyender leaking into the booster will cause the diphram in the booster to go bad. How can i tell that the master clyinder is not leaking. Will it be a hard leak to find or will it be obvious?

[66 Eldo]

To check to see if the booster is working pump the brake pedal enough times so the pedal is hard to push ( 5 to 10 times). If it is already hard pump it anyway. Then with your foot on the brake, start the engine. If the brake pedal drops some your booster is working. If it is working then shut your engine off and pump the brake pedal. You should get about 4 or 5 pumps of the pedal before it gets hard. If it does this then your check valve and booster are not leaking. 

Another reputable booster rebuilder is Booster Dewey in Portland. Like Midwest, you deal with him direct and he is good about explaining things over the phone. Link below.

http://boosterdeweyexchange.com/

[Blade]

http://www.midwestbooster.com/

What do they charge for like a complete rebuild? Do you know?

[dplotkin]

A couple hundred and change depending on type (Moraine vs Bendix). It is true a leaking master will assist a booster in its demise but that is not always the problem. the problem is the rubber or pleated bellows used inside, they plain wear out with time and use. When you remove the master from the booster look at the rear of the master, if it is wet with fluid then the rear seal is leaking. I would put a fresh master (or rebuilt master) on a newly rebuilt booster.

I have 8 cars and 5 of them have needed boosters over the past 6 years.

Dan