3 Buick LeSabre, 4 wheel drum power brakes, 401 cid. Here is whats happening. With the car off, the pedal is frozen all the way to the floor, and I can tell the brakes are engaged, because you can't push the car in neutral. With the car idling, the pedal is still frozen to the floor- You can pull it up by hand, but it's really hard and when you let go it's quickly sucked back to the floor. Now with it idling, when the vacuum line to the booster is disconnected, the pedal shoots back up into the normal position- until you press it down again with your foot- it goes down normal and actually feels like a good pedal, but then stays stuck to the floor again. I initially suspected the booster or mc, but was kind of hoping that after doing a whole brake job, the problem would go away. I replaced all four wheel cylinders, all three brake hoses, the rear brake line, and thoroughly bled the system of all old fluid. The fluid is now a clear steady stream. Still no brakes. There are no leaks anywhere. I've talked to a few people, and some think it's the booster, but others say its the mc. I also think it's the booster, but both are expensive, so I only want to replace what I need to. Also, how can I test the check valve? There is a 3 way valve on top of the booster, which accepts vacuum form the intake on one side, and the other side has a line that I can trace into some kind of a canister under the fenderwell- I have no idea what that is or what its for. So what do you think?
Sounds like the booster is bad. To check the check valve on the booster, just run the car for a few minutes, turn it off, and then try to pull the valve off the booster. If it is working correctly, it'll still hold vacuum until you pull it off. When you buy a new booster, it comes with a new check valve. Before going through all that, make sure the live that the vacuum hose is connected to is actually pulling a vacuum, not pressurizing the booster. Simply start the car, remove the hose from the check valve and see if it sucks to your finger. If you have decent suction, and the hose is not brittle or cracked, and is free of obstructions, then it's your power brake booster. Good luck, and I hope this helps. -Josh
Hello: I agree. Worn out booster. After 45 years of service it is not going to hurt anything by replacing it (except your wallet). I had mine done several years ago & it made a world of difference in the way the pedal felt. No more slow return. You can save a few bucks by not having the rebuilt booster anodized gold, but it looks great! I can't remember who it was I used for the rebuild. He had them already rebuilt & in stock, so turn around time was quick. I have the receipt somewhere. The check valve is NOT inside the booster. It is located at the end of the steel vacuum tube on top of the driver's side rocker cover. The hose that comes off of the booster goes to the vacuum reserve tank located under the driver's side fender. It is there to give you at least one easy push of the brake pedal if the engine stalls. Christopher
I took off the mc and found that the booster was full of fluid up to the hole. When the pedal is puched gently, the fluid rises up and out of the hole on the booster. I'm guessing the booster isn't supposed to be full of fluid?
Master cylinder leaked back into the booster. Either rebuild them yourself or purchase remans for about 121 bucks for the combo. http://www.partsamerica.com/ProductDetail.aspx?MfrCode=A1C&MfrPartNumber=501106&PartType=250&PTSet=A
Depending on how concerned you are about originality, you have a couple of options: 1) Purchase booster and MC from a parts place and you get what you get. They will be sprayed some dull grey color. 2A) Get your booster rebuilt by Booster Dewey in Oregon. He will gold anodize plate it for you if you want, like original. Be sure to tell Dewey that the booster was half full of brake fluid so that he knows to clean it out really well. http://boosterdeweyexchange.com/ 2B) Consider converting at this time to dual master cylinder for safety. You need a new MC anyway. Get a new (not rebuilt) one for a '67 full size Buick with drum-drum system (~$25 or so) from any decent auto parts store and use that instead of single system original '63. Connect front port of MC to front wheels and rear port to rear. A T-fitting can be used where you connect to rear steel line and you screw your brake light switch into that. Plug the opening in the little block down on the frame that feeds the rear line now and you're done. You have to make up the lines down from MC to block and to T-fitting. Whatever way you go make sure you put the o-ring on the neck of the new MC when you install on booster or you have major vacuum leak and no boost. If you buy booster/MC as a unit, it should have it. Any other way you go with pieces that you assemble, confirm you have rubber ring in groove. You will see what I mean when you see the new MC. Attachments are photo of my '63 Riviera booster/MC and the brake light switch down by block.
Thanks Jim! I think I may got the upgrade route. Can you tell me the part # for the 67 mc? Or which model car it applies to? (you need to be real specific with the morons at the local auto parts store. If I say "full size", they'll panic and say "uuuuhhhhh...thats not in the computer!) Also, will I need a booster from the 67 as well, or will the 67 mc bolt to my existing 63 booster? Do I need to modify the pushrod at all? Do I need a proportioning valve? If so, do you have a part number for that? Thanks!
So my local Autozone has these two... http://www.autozone.com/R,APP17439/...partType,00007/shopping/partProductDetail.htm http://www.autozone.com/R,APP17601/...partType,00007/shopping/partProductDetail.htm Both are for drum/drum systems. The only difference is the first one says it's for bendix (black), and the second is for Moraine (gold). Which of these two, if either, will bolt to my 63 booster? I don't know if my booster is Bendix or Moraine. It's pretty dirty, but it looks as though it may have been gold at one time. I guess what I need to know first is whether the 67 mc will even bolt to the 63 booster, or if they have to match 67/67? Thanks!
Yup, you found 'em! The '63 booster works just fine. That's what's on my car in the picture. The MC was new. I sprayed it with a "cast iron gray" paint. It came with the gold anodized lid to match the booster. You have the MC off right now. Look at the end of the MC piston, where the booster rod pushes. The hole is either 1 inch deep or 1/4 inch deep. That's what you need to match up on the new '67 MC. I am pretty sure you have the Moraine. Get that one first. If the hole in the piston is not the same depth as your original MC, then you need to exchange it for the other MC. It's that simple. This new MC will not come with the o-ring I mentioned. You must get one somewhere. Booster Dewey has them for a few bux, if you can't find it anywhere else. You do not need to use a proportioning valve on drum/drum. Buick's distribution block in '67 for drum/drum was just a warning light to tell you if one system had higher pressure than the other, so you would know you were losing your brakes. You do not need to get that or use that. Any other questions, drop me a line. Jim
Thanks Jim. I just went and measured the depth of the hole in the back of the MC, and it's 1.75". On the old MC, it says "Wagner Lockheed" on the bottom.
Yea, that's the one. My 1 inch depth estimate was off. Trust me, when you see the other one, with almost no hole depth at all, you'd see what I mean. So with that measurement, get the Moraine unit and you will be good. Tell Dewey I said "Hi". Jim
Great, thanks Jim. I ordered the Moraine mc, and it should be here tomorrow. Tell me a little more about this o-ring. When I call Dewey, what exactly am I asking for? An o-ring for a 67 mc, or a 63 booster or what?
Hey Jim, I called Dewey yesterday and he didn't seem to know what I was talking about with the o-ring.
Well... it is a rubber ring that slides on the neck of and goes down in the groove of the MC before you slip it into the booster. He sold me mine. Maybe he just calls it a rubber seal. I don't remember. It is not exactly like an O-ring because if you cut an o-ring in half with a knife and look at the bit you just cut, it is a circle. With this rubber ring on the MC, if you cut through it with a knife it would be a square. I have attached a photo of my MC from the side so you can see what I mean. The black thing down in the groove is the seal. You have the MC you took out. Look in the groove on the neck for your old seal. Some guys reuse it but why do that, and risk a vacuum leak, when you can get a new one for $5. Jim
I got the new master cylinder today, and apparently I must have a Bendix booster, because the push rod was way too long. The hole in the back of the new master cylinder, which was for the Moraine booster, is only a slight dimple, probably no more than a half inch deep. The hole on the back of my old mc was 1.75" deep. I guess I'll try the other mc that is for the Bendix booster.
So I got the new mc, the one for the Bendix booster. One thing I noticed is that it didn't have the groove for the o-ring that my old one had. So I installed the new one with no o-ring. Seems fine, no leaks. But apparently my booster is bad also. So...new question. Since I now have a 67 MC, can I get a bendix booster for a 67 as well? Obviously the 67 mc will botl to it, but will the studs match the holes in my firewall, and will the pushrod mount to the brake pedal the same way? Thanks!
I have been told that the 67 booster should bolt in OK. I have not done it personally. The vacuum hose connection will be different size and will require adapter. Good news is you can eliminate the vacuum storage can because it is internal on the '67 booster. Jim
