Locked Brakes

[Michael Greenspan]

Last week I pulled the car out of the garage and after leaving the driveway had to brake. I got started again and the car felt like it was dragging and as soon as I took my foot off the accelerator the car quickly stopped. I thought it might be a momentary hiccup of the brakes so I started off again and got the same instant stop without hitting the brakes. I managed to get the car back into the garage by essentially overpowering the brakes. Fortunately I only had to go a couple of hundred feet. I thought that if something was jammed, it might ease up so I left the car and went back to the city. Today I jacked the front left side up and tried to rotate the wheel. I could turn it but it was difficult and certainly wasn't free. I am scheduled to bring the car in for other work next week and if possible, I want to release the brakes so that I can roll (rather than drag) it on a flatbed. Any suggestions?

Thanks

Michael
330 America 4969

[tyang]

Hi Michael,
I would check two things. Either your booster is acting up, or the weird brake equalizing valve is doing something strange. I believe there is pressure relief valve on the top of the booster. Slowly open this bleeder (you may want to put a hose on it with a bottle to catch any stray fluid), and see if the brakes release. Occasionally, the booster hangs up, and causes the brakes to reamain on. A rebuild may be in your future if this is the problem. The second possibility is the strange valve mounted by the bottom of the radiator. It is not really a proportioning valve, as it only goes to the front brakes. Francois explained that it was an early form of anti-lock brakes. If it fails, only a few people have successfully rebuilt one of these, let alone open one, and the brakes work fine without it. If it is this unit, I would by pass it.

Good luck, and let us know what you find.

Tom

[Michael Greenspan]

Like all those fifties TVs that were all snow until the moment the TV repairman walked in the door, the solution was to just ask for an answer to the problem. I actually tried to rotate the front wheel at about 9AM today. After Tom's reply, I went back to the garage to at least try the vacuum booster bleeder screw. Of course I have no hoses but I did find some shrink tubing that would go over the nipple to guard against brake fluid leakage. Then I jacked up the car and, of course, the wheel rotated pretty freely. I was going to try the screw anyway but it was VERY tight so I decided that since the wheels are turning I had achieved my goal - ability to roll and not drag the car on the flatbed - I was done. I still want to know what happened (since I wouldn't like this to happen on the turnpike). I am betting that Murphy's law (or is it the Ferrari owner's karma) will prevail and the Booster will need to be rebuilt.

The car goes in after Labor Day.

Michael

[330GT]

Hi Michael,

Check for a partially collapsed front brake hose on that side. I had a similar problem only the brake was just dragging, not locked. The hose will pass fluid under the brake pedal pressure, but won't release the pressure back like it should, leaving the brake on. Over time, it will release, which is what happened in your case if I understand it correctly.

When mine was dragging, the knockoff got so hot that you would burn your hand touching it.

I would replace the hoses on both sides if this turns out to be the problem. And this is a lot cheaper than getting anything rebuilt.

[Michael Greenspan]

Kerry - thanks for the suggestion. Actually this car has already suffered from just that issue. The former owner was experiencing exactly that problem on the way home and thought that he could make it back. He was very unpleasantly surprised when the heating caused a fire in the front wheel well. I have had all of the brake lines replaced in the car but the fire story is certainly a cautionary tale for me and I hope anyone having dragging brakes.

Michael

[whturner]

I have had the same thing 3 times. In all three cases the brake hoses had swelled shut - you could force fluid past them but it would not release, unless the car sat for many hours, or the pressure was manually released. I was using good fluid, but the hoses apparently reacted in some way with the fluid.This swelling happened over a period of years, not instantly.
I have no idea why the hoses did this.

Cheers
Warren

[David Booth]

Michael: are you sure it's just the one wheel? I've had a situation where my master cylinder was sticking just enough to keep the pads in light-to-moderate contact with the discs after a hard application of the brakes, which would then cause them to heat up, in turn expanding the brake fluid, increasing the brake pressure and bringing my cab to a stop like it was in one of those tractor pull competitions. After things would cool off, it would be okay again until the next hard application of the brakes, and the process would repeat itself. I just bring this up to illustrate that the culprit in your situation could be hiding in a number of places in your braking system.

[Jimmyr]

If you intend to drive the car only a short distance follow Tom's advice and be able to open the bleeder on the booster to release the preaaure. You can use a rag to cover it if you do not have any hose. A six point socket is your best bet, do not use an open end or 12 point socket on a stuck bleeder. Jim

[tyang]

Use PB Blaster on the bleeder before you try to turn it!

Tom

[Michael Greenspan]

Thanks to all for the suggestions. The problem now is since the brakes seem to have freed up without my actually doing anything I don't know what caused the problem. I am thinking of trying to just repeat getting the car out of the garage and hitting the brakes as I did last time and see if they lock up again - or maybe I will try to do that at the shop when the car is delivered.

Again - thanks for all the help and knowledge.

Michael

[tyang]

Hi Michael,

I would bet it is the booster, but the only way to be sure is to make it happen again. It may not do it the again in the same manner, or do it again for a while!

Tom