Brakes locking up on my 60 Electra

[JoelsBuicks]

On several occaisions when I had to really get on the brakes, my 60 Electra brakes locked up and stayed that way for a while. These are power brakes and I thought that a thorough brake job with master cylinder kit would do the trick but it didn't fix this. Whenever this problem occurs, I am unable to pull up on the brake pedal to unlock it, I usually take a line wrench and loosen the brake line from the master cylinder to bleed the pressure. Doing this will release everything to return back to normal. Otherwise, it takes about 5 minutes of waiting for the brakes to release on their own. Has anyone experienced this or know what I should be looking at next? Thanks!

[JoelsBuicks]

On several occaisions when I had to really get on the brakes, my 60 Electra brakes locked up and stayed that way for a while. These are power brakes and I thought that a thorough brake job with master cylinder kit would do the trick but it didn't fix this. Whenever this problem occurs, I am unable to pull up on the brake pedal to unlock it, I usually take a line wrench and loosen the brake line from the master cylinder to bleed the pressure. Doing this will release everything to return back to normal. Otherwise, it takes about 5 minutes of waiting for the brakes to release on their own. Has anyone experienced this or know what I should be looking at next? Thanks!

[JohnD1956]

I wonder if it is debris in the apportioning valve down on the frame? Or if you have not yet replaced the flex lines ( including the rear axle one) you may want to give that a try.

Please be sure to let us know what it was.

[JohnD1956]

I wonder if it is debris in the apportioning valve down on the frame? Or if you have not yet replaced the flex lines ( including the rear axle one) you may want to give that a try.

Please be sure to let us know what it was.

[Jim Cannon]

Sounds like the brake booster is getting stuck in the "applied" position when you press really hard. You tell of using a master cylinder kit. What have you done about rebuilding the booster?

Instead of waiting 5 minutes, what if you turn the engine off? That takes all engine vacuum away from the booster.

When you bleed off pressure with the wrench, do you see the brake pedal come up?

[Jim Cannon]

Sounds like the brake booster is getting stuck in the "applied" position when you press really hard. You tell of using a master cylinder kit. What have you done about rebuilding the booster?

Instead of waiting 5 minutes, what if you turn the engine off? That takes all engine vacuum away from the booster.

When you bleed off pressure with the wrench, do you see the brake pedal come up?

[Pete Phillips]

There are at least a dozen possible causes for this. I've experienced it most often when one of the rubber brake hoses has collapsed inside, even though it may look fine on the outside. The inner passage collapses after years of exposure to brake fluid, and this does not allow the pressure to be released from the wheel cylinder. It can also be caused by sticky or rusty wheel cylinders, if you have not rebuilt or replaced those in many years. Weak return springs could also cause it.

Pete Phillips, BCA #7338

Sherman, TX

[Pete Phillips]

There are at least a dozen possible causes for this. I've experienced it most often when one of the rubber brake hoses has collapsed inside, even though it may look fine on the outside. The inner passage collapses after years of exposure to brake fluid, and this does not allow the pressure to be released from the wheel cylinder. It can also be caused by sticky or rusty wheel cylinders, if you have not rebuilt or replaced those in many years. Weak return springs could also cause it.

Pete Phillips, BCA #7338

Sherman, TX

[JoelsBuicks]

Regarding the booster, I haven't done anything to it at all. I can tear into it but I'm not sure what I'd be looking for. I'll check my repair manual. I have tried removing the vacuum hose on the booster to see if it helps it relieve quicker and it doesn't. When I bleed the fluid pressure in order to get it to release, the pedal always returns to its up position (although I haven't witnessed it because I don't have direct sight whilst relieving the pressure). I have not changed the three rubber hoses and probably should but I wouldn't expect a bad hose to cause all four wheels to lock up. My recent brake job did include polishing all wheel cylinders, new shoes and turned drums. I'm somewhat puzzled by the fact that I cannot just reach down and pull up the pedal - almost like something is blocking a relief passage. Any other thoughts? Thank You!

[JoelsBuicks]

Regarding the booster, I haven't done anything to it at all. I can tear into it but I'm not sure what I'd be looking for. I'll check my repair manual. I have tried removing the vacuum hose on the booster to see if it helps it relieve quicker and it doesn't. When I bleed the fluid pressure in order to get it to release, the pedal always returns to its up position (although I haven't witnessed it because I don't have direct sight whilst relieving the pressure). I have not changed the three rubber hoses and probably should but I wouldn't expect a bad hose to cause all four wheels to lock up. My recent brake job did include polishing all wheel cylinders, new shoes and turned drums. I'm somewhat puzzled by the fact that I cannot just reach down and pull up the pedal - almost like something is blocking a relief passage. Any other thoughts? Thank You!

[JohnD1956]

I had some problems with my 69 Electra like this. The car had a broken brake line and sat for close to 3 years. When I took it out after changing all the brake lines from the apportion valve to the wheels, including all the flex hoses, the brakes locked up on me and would not release. In my case I found NAPA had rebuilt cylinders so cheap it was easier to just replace mine, and that corrected the problem. Of course, the 1960 MC may not be so readilly available.

[JohnD1956]

I had some problems with my 69 Electra like this. The car had a broken brake line and sat for close to 3 years. When I took it out after changing all the brake lines from the apportion valve to the wheels, including all the flex hoses, the brakes locked up on me and would not release. In my case I found NAPA had rebuilt cylinders so cheap it was easier to just replace mine, and that corrected the problem. Of course, the 1960 MC may not be so readilly available.

[Guest ZondaC12]

What's an "apportion valve"? Naturally it sounds similar to "proportioning valve" and I know those exist in more modern cars to give more brake bias to the fronts, but I'm afraid I haven't heard of this one!

[Guest ZondaC12]

What's an "apportion valve"? Naturally it sounds similar to "proportioning valve" and I know those exist in more modern cars to give more brake bias to the fronts, but I'm afraid I haven't heard of this one!

[JohnD1956]

I may have gotten it wrong. We are talking about the same part I believe.

[JohnD1956]

I may have gotten it wrong. We are talking about the same part I believe.

[Mzdafrk]

I was searching on Google and found this topic. I am not trying to thread jack the topic, this is the closest problem I have found to what I am dealing with, so I am very interested. I have been searching for weeks, and this is the same problem I am having on a 1956 Desoto.

I was having a problem with the brake pedal falling to the floor, so I replaced the Master Cylinder, Bleed all 4 Drums, Flushed all the fluids, and found a leak in the booster, SO I sent it out and had it rebuilt. A few weeks later I got it back, and put it in. Then it sat for a couple weeks.

I decided to drive it on a nice day, I noticed that the Pressure switch on the master cylinder, to turn the brake lights on, was activated and the brake lights were on. I tried fiddling with the switch but nothing made the lights go off. So I started up the car, and tried to move and the brakes felt very stiff. SO I figured it was time to get the car home, I was only a few miles away. When I started it back up the brakes locked up completely. I was sitting in a parking lot so I tried to move forward and backward but was not able to move.

I then Borrowed a line wrench and bled the pressure off the master, everything returned to normal. So I drove the car home and parked it.

I went out the other day and the brake lights were on again...?!

I have been searching for similar problems, but couldn't find any until I found this thread. We are experiencing almost the same problem, and I am stumped. I have all new parts, and the brakes are locking up?

New Vacuum Canister, New Master Cylinder, New Brake Booster, flushed all the fluid, bled thoroughly. Any Ideas???

All I have come up with so far is that one of the parts is defective inside the master, and is not releasing pressure, so every time I step on the brake pedal it creates more pressure until it eventually locks up. But I question that theory simply because that doesn't seem right. I am open to trying different things to try and fix it, and will give any updates when I figure something out.

[Guest brh]

More familiar with G.M. but I'll take a shot at this. Brake pedal going straight to the floor sounds like a master, been there done that. Are the lights going on but brakes not locked or are both happening at the same time? A trick we use to do on Fords after a brake job-- if after doing a brake job the brake light stayed on with the car running we use to have one person on the pedal with the other bleeding at the master, bleed till the light goes out. Don't know if that would help ya cause ya still have problem number 2 brakes locking. It sounds like a master to me, but I am just taking a SWAG at it. Scientific, Wild, -ss, Guess.

[JoelsBuicks]

My brake problem may be a little different. My pedal doesn't fall to the floor. If I am making a hard stop, I reach a point in braking where my wheels lock up and stay that way until I use the line wrench to bleed the pressure. At the point just before the brakes lock up, it seems as if another force (sounds rediculous) takes over and sucks the pedal down to make the wheels lock up. This is rather unsettling because I lose most of my control with the wheels lock up. Somehow, pressure in the line coming from the master cylinder is not being relieved after a hard stop. And, with all my strength I cannot pull up on the pedal to "reset" it. It sure points to the booster. Maybe I'll unhook the vac hose and see if I can duplicate the problem. I'd sure like to narrow it down before I start on this.

[Pete O]

It might be that one or both of the bypass ports (3 and 6 in the diagram below- which is not of a Buick part, but is representative of a dual master cylinder) are blocked in your master cylinder, which would prevent pressure from equalizing on either side of the pistons.

[Guest brh]

Pete- have ya got a cutaway of a single master? Since its a 60 he's probably got the "suicide" master. Good illustration maybe we can get a look at a single and see??

[64BuickCat]

If the ports in the piston aren't clear, they wouldn't let the fluid flow back into the master cylinder, causing the brakes to lock. I also thought about the rubber hoses as Pete did. Front hoses for my Wildcat were $11.00 at NAPA.

[Guest simplyconnected]

That diagram works for a single stage, too. (just look at the front half.) Good picture, Pete!

I have some silly questions about the condition of this fluid:

Did any petroleum product get (fall) in the reservoir?

Was DOT3 and DOT5 mixed, or changed over?

Did dirt get in? Or, a small lump of greasy dirt?

Something is going on with the spool-valve seals. They may have swollen, perventing the spool from returning properly. That would prevent the spool from un-covering port 3 (or 6). In any event, #9-spring cannot retract the spool.

Just a suggestion; make sure your brake pedal return spring causes the rod to return.

If all the wheels are locking up, I can't believe all three hoses went bad at the same time.

If it's raining outside, I never open my reservoir cover, not even to work on it. Cover the area with rags. Brake fluid will eat your paint. Water will wash it away, but don't let any water in your system. - Dave Dare

[Pete O]

It may be blasphemy on a Buick board, but the only image of a single circuit master cylinder I could find was from a Ford! Anyway, the basics are the same regardless.

[Guest brh]

Sounds nuts but I'll just throw it out there. Looking at the cut away, if the rubber on the piston covered the bypass or if the throw length were too long on the rod, covering the bypass, would this cause the problem???

[Pete O]

The push rod on my '51 is adjustable (bet it's the same on a '60), and the shop manual describes how to do it to set up the right amount of clearance. If there's not enough clearance, the piston can't return far enough to open up the port to allow the fluid back into the reservoir. No place for the pressure to go, and the brakes stay locked.

[JoelsBuicks]

On the single circuit drawing, what is the purpose of the "inlet valve?" I'm also confused on why I cannot pull the brake pedal up to its normal position when the locking condition occurs?

Thanks again for the help. I'm on the road and slow to respond so please be patient.

Joel

[Guest simplyconnected]

If the piston is stuck in the forward position, pulling up on the pedal will only retract the rod. It won't pull the piston (spool) back. The return spring pushes the piston back to its stop (if the piston will move freely).

So, what happens when dirt, water, or oil enter the system? Dirt scores, water rusts, and oil swells the seals. ANY of these conditions will cause the piston to stick, eventually. - Dave Dare

[Pete O]

As Simplyconnected said, there is no actual connection between the push rod that leads back to the pedal and the piston in the master cylinder. The push rod just presses against the piston. This is why the push rod clearance is a critical adjustment after a master cylinder rebuild. If you pull up on the brake pedal and find it's already completely at the top of its travel, I'd suspect the push rod clearance. But if you find that the pedal is not at the top of its travel, I'd look elsewhere first.

You wrote that you had a thorough brake job including master cyclinder kit. Did it also include rebuilt wheel cylinders, new brake shoe springs, new hoses and a flush, refill and bleed of the whole system? Again, as Simplyconnected said, the pedal return is dependant upon the brake shoes completely retracting, and any binding due to weak springs, crud in the lines, etc. could be contribute to the problem.

[Guest simplyconnected]

Thanks Pete.

I'm still harping on the fact that he can't 'pump-up' his brakes. Even if he has worn shoes, or weak springs, when he gets off the pedal, the piston should return allowing for repeated pumps.

Which leads me to believe his master cylinder spool is sticking. A newly installed job raises red flags. I immediately suspect dirt, water, or mixing incompatable fluids (which swells seals). In any case, the return spring inside the master, can't overcome the spool (piston) resistance. - Dave

[Guest simplyconnected]

Lifting the brake pedal, he should hear the rod and spool 'jiggle.'

[JoelsBuicks]

First, thank you all very much for the input and discussion. This sticking problem was the reason I decided to do the brake job in the first place. I honed and polished all wheel cylinders and the master cylinder and all recieved new kits. The drums were all turned and the brake lines flushed with the new fluid. I did my best to keep things oil and water free. However, I did not replace any brake shoe springs.

To me, the mystery is why I cannot pull up the pedal when this locking occurs. Indeed there is no connection between the cylinder piston and the push rod and I don't see why I can't pull it up. Does this mean the rod is binding somewhere? And if so, why would relieving the pressure remedy this? Keep in mind that normal driving and braking is fine, it's just when I have to get on the brakes that this lockup occurs. Thanks again and I'm back in the saddle for a while now.

[Guest brh]

As I understand the problem, it occured before all the brake work correct? So my first question is what happened with the car prior to the sticking? Was something replaced, rebuilt or worked on? Does not need to be brake related. I understand you want to know why you can't pull the pedal up, but the problem still exists. Give us some info please.

[JoelsBuicks]

Good question. I bought the car last year with 57K miles on it. It had been stored in dry dark storage for 31 years. The previous owner inhereted the car but didn't drive it. I called him and asked him about the brakes sticking and he wasn't aware of the problem. He did a little work on the car to prepare it for sale. The work included a new water pump, battery, fresh gas, and new exhaust. He did tell me that he would not drive the car very far because he felt that it needed brake work and that a person could lose all brakes if something failed.

I noticed the problem on the second day that I had the car. It took a while to figure out to relieve the pressure to get it unstuck. The car seemed to be only braking on one or two wheels and so I quickly put the car on blocks and did the brake work.

The master cylinder had nearly a half-inch of sludge in the bottom and I removed and cleaned it all up with solvent followed by compressed air drying. I will go out on a limb here and say that the brake system looked original to me. That is, the wear on the shoes and the overall crudiness of the system was consistent with 57K miles. All but two wheel cylinder pistons were stuck with a whitish material resembling cement. I made a wooden dowel to hammer these loose. Of course, all of that was thoroughly cleaned before assembly.

After the brake job, I tested it by stepping hard on the brakes and the problem was still there as if I had done nothing. Except for this, the car brakes evenly just as I'd expect.

I did not dismantle any of the power booster portion of the brakes.

I hope this helps, thanks again!

[Guest brh]

Sounds like your car came with the problem. Don't get me wrong not knocking your method of rebuilding. I took my system down after a blown line, rebuilt the master and wheel cylinders....I did not follow proceedure on honing the master or the wheel cylinders as there were no previous problems and no ridges, pits or anything that would indicate a problem. You may not have been as lucky as me. Did you hone the wheel cylinders and master before installation of the new parts? Whiteish stuff indicates moisure, maybe other parts are binding, you should not have to bang out the pistons, did ya check for binding before everything was reassembled? Not trying to insult ya just get to the bottom of this.

[JoelsBuicks]

I did hone the wheel cylinders and the master cylinder. They all appeared to be in excellent condition with only minor staining. I used a standard brake hone with brake fluid as the honing fluid. I followed this honing with a polishing step using 800 grit sand paper wrapped about 1-1/2 times around the brake hone. They all looked great. The pistons looked to be some sort of alloy and I think you are right about the whiteish stuff being a salt derived from the corrosion of the pistons - perhaps something like magnesium oxide. I did check the fit of the wheel pistons after cleaning them but I don't recall checking the fit of the master cylinder piston - which did not have any of the white stuff.

One thing to add, on a couple occaisions, I could release the brake pedal by striking it soundly with my foot. This technique no longer is effective in getting it to release. Another thing I noticed was that the brake light switch must have been change because the wire connectors looked to be some aftermarket job.

I'm not smart enough to be easily insulted, learning stuff the hard way seems to be my mode of operation. So please, keep the questions coming and thank you for your help.

[JoelsBuicks]

Here's something else I thought of. When the brakes are locked and the pedal is down, I try very hard to pull the pedal up. It feels like I am pulling against a very stiff spring. That is, I'm able to pull it up about a 1/2" or less against an opposing force pulling it back down.

[Guest brh]

Hmmm.... O.K. I think the place to start is the master, here is the reason why, if you were able to get the pedal to release by jarring it, it seems to me that the rest of the system is O.K. I would pull the master down one more time, check for binding, sounds like ya did a great job on rebuild, you are just trying to overcome an existing problem. Also if your throw rod is adjustable check to make sure its set right. Do you have a detailed parts manual just in case someone put in a wrong part before you so you can double check. When reinstalling bench bleed the master it will cut down on your bleeding time. Hope this helps.

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JoelsBuicks</div><div class="ubbcode-body">The master cylinder had nearly a half-inch of sludge in the bottom and I removed and cleaned it all up with solvent...I don't recall checking the fit of the master cylinder piston...I could release the brake pedal by striking it soundly with my foot. </div></div> What kind of solvent? (I hope not petroleum based.)

Aahh. New information:<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JoelsBuicks</div><div class="ubbcode-body">To me, the mystery is why I cannot pull up the pedal when this locking occurs. Indeed there is no connection between the cylinder piston and the push rod and I don't see why I can't pull it up. Does this mean the rod is binding somewhere? And if so, why would relieving the pressure remedy this? </div></div> Alright, now we're getting somewhere. You should ALWAYS be able to pull the pedal up. As you said, it is simply a detached rod. Or is it? If the power booster is hanging on to the rod, and the rod is in mid-stroke, bleeding pressure makes perfect sense, because the spool is held in (possibly under power assist).

Pull your power booster out and test it thoroughly. You may need to detach the rod from your brake pedal ass'y. The booster should unbolt easily. If you don't have the means to test it, tell a pro what it is doing and let him test it. (Personally, I would make a vacuum hose extension, and test it myself.)

I have never seen this type of power boost problem, but why not? Usually vac-boosters leak, sucking brake fluid into the engine. If you are using Silicone (DOT-5) when this happens, it turns to sand under high heat (scoring the cylinders). DOT-3 is not detrimental.

[Jim Cannon]

I agree with simplyconnected that the problem is the booster. It is applying and not releasing.