1963 Power Brakes locking up

[Gerald C.]

I'm now putting my 63 on the road and doing "shake down" cruises. I've had it out about 6 times and the last two times, after about an hour's ride, I pull into my driveway/garage and the brakes lock up slightly. I can still move the car, but you can tell the brakes are on. It did it this morning. When it did it the time before, I let the car sit and afterwards, the brakes are fine. Again, it happened this morning after about an hour's ride in 75-degree weather.

Is it the check valve on the booster??? OR is it that small hole in the M/C that could be blocked as mentioned in another post on the TDR?

Andy Cannizzo rebuilt this unit and I've always had great luck with Andy's boosters (both of them that I bought from him)

Thoughts??

[Leif A.]

Re: 1963 Power Brakes locking up

Gerald,
Are you still running the stock drum brakes? If so, are they properly adjusted? If they're adjusted a bit too tight when cold, when they heat up they expand and could be causing the problem. Just a thought.

[Peter H.]

Re: 1963 Power Brakes locking up

Hello Gerald. It Sounds Like A Collapsed Brake Hose. After Sitting For A While The Back Pressure Is Released. Someone More Experienced Can Chime In. Just My Two Cents And I Hope It Helps. Peter Hannigan (3522) 🇨🇦

[Gerald C.]

Re: 1963 Power Brakes locking up

Leif,

Yes I'm still running stock drum brakes. I believe they are adjusted properly since this just happened and hasn't happened previously.

Thanks

[Gerald C.]

Re: 1963 Power Brakes locking up

Peter,

I replaced all the brake hoses recently during my restoration. It could be that these are defective and I might replace all of them! Before I do that, I think it best that I see a few more replies. You're idea has real merit!! Thanks

[David M.]

Re: 1963 Power Brakes locking up

Agreed with the collapsed hose theory.
How old are the 4 flex hoses? They are consumable and should be replaced every so often time & mileage dependant.
Verify the E-Brake is 100% released.
Verify shoe drag is even on all 4 wheels.

I've witnessed bad new hoses where the person crimping it didn't do it properly and crimped a chunk of the hose on the inside diameter. It acted like a one-way check valve.

If it is a collapsed/blocked hose, to locate which hose is the culprit get the car up on jack stands or on a 2-post lift.
Stand on the brake pedal a few times and immediately try to rotate each tire. The one hanging up will have the bad hose.

To verify it have a bleeder wrench at your fingertips. Repeat this procedure and crack the locked-up wheels bleeder. It should shoot brake fluid and release the wheel to allow free rotation.

[Gerald C.]

Re: 1963 Power Brakes locking up

Thanks David. One other thing I just remembered about the brakes.....when the car gets warm after several miles of driving, the brakes get VERY sensitive and grab very quickly. Could this also be a result of a bad hose?

It looks like I should replace all 4 hoses, just to be on the safe side!

Thanks

[David M.]

Re: 1963 Power Brakes locking up

Is the brake system all new or not? I see the master booster assembly is new. New means nothing today.

Best to troubleshoot vs throwing parts at it. Find known USA-made parts.
Pull the drums and inspect for loose hardware, leaking cylinders, glazed drum surfaces and if the primary & secondary shoes are in the right locations.

Sticking sensitive grabby brakes can be a few different things.
1. Adjustment is wrong, shoes are too far out.
2. Contaminated shoes
3. Primary & secondary shoes reversed
4. Inferior shoe composition
5. Wrong shoes all together
6. Hardware is worn out
7. Booster is leaking vacuum. Turn engine off. Wait a few mins and remove the check valve. Should hold vacuum for a while.
8. Contaminated fluid
9. Glased drum surface.
10. OR You have superhuman leg muscles.

Also, do a complete power bleed of the system to flush out any chunks.
DOT 3 & 4 Brake fluid is hydrophilic and should be changed every 3-5 years. Hoses every 10 or so.

Report back when you find the problem.

[Gerald C.]

Re: 1963 Power Brakes locking up

Dave,
Brake shoes are new
I've had the hoses for a while and then put them on. I do not know how old they were, but they were new "at the time"
I don't see any leakage around the wheels at all.
The brakes worked fine for a while until these incidents occurred
The shoes are installed properly
I will pull the shoes and see what's going on
I'll try #7 later today
Fluid is brand new Dot #3
I'll check the drum surfaces
I'm old, I no longer have superhuman leg muscles!
I'll keep you posted.

Thanks!

[Owen L.]

Re: 1963 Power Brakes locking up

How full is the master? I believe it needs some headroom for the brake fluid to expand back into as the fluid heats up at each wheel.

[Richard M.]

Re: 1963 Power Brakes locking up

If the booster push rod to the master cylinder is too long it could cause a lockup condition. This happens because the inner MC seal blocks the return port. The condition is exacerbated with heat.

It's tricky to measure the rod clearance, but a simple method to verify if it's too long is to space out the master cylinder to the booster by adding flat washer(s) between them. A thick gasket is another method.

Another possibility is that the emergency brake cables are hanging up and not releasing completely.

Rich

[Harry S.]

Re: 1963 Power Brakes locking up

Because the booster rod is adjustable on a 63. I used this tool for setting the proper depth on the rod.

Amazon.com: (Upgraded) Brake Adjustment Tool, Brake Booster Rod Adjustment Tool, Brake booster with master cylinder,Pushrod Power For Adjustable Braking Distance of Brake Pedal(N48 Magnetic CNC Aluminum) : Automotive

[Gerald C.]

Re: 1963 Power Brakes locking up

Master cylinder is filled to specs.

Thanks

[Gerald C.]

Re: 1963 Power Brakes locking up

Rich,

The brakes worked fine the first few times I took the car out and then this situation occurred. The Parking Brake is adjusted to spec's and doesn't come into play.

Thanks

[Gerald C.]

Re: 1963 Power Brakes locking up

Since this just started to happen, I'm going to check the brake adjustments on the wheels first. The booster rod you refer to is the rod that comes out of the booster and onto the brake pedal? And not the one that goes into the master cylinder, correct?