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Brake Master Cylinder

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Andrew_Grannis

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Hi,
I havnt been on the forum for a long time. If you all remember my Healey was starting up but dying soon after. We finally found that it was a fuel starvation issue. Two things had gone wrong. The SU fuel pump we had rebuilt wasnt pumping like it should have, and the tank we sealed, got sealed too well. We put pressurized air in through the fuel send coming out of the tank and air went into the tank, but the sealent must have covered the hole just enough for it not to work. So, we bought a universal pump and a new tank and it runs like a charm. As a matter of fact, yesterday, after about two months of sitting through the Cleveland winter, we went out and it started right up. The next project is the brakes. The brake pedal does not budge. After looking things over and getting a few opinions about it, weve decided that the rubber gasket (I'm going to call it that) on the push rod of the cylinder must be fused to the cylinder not allowing it to move. So I guess I have two questions. One guy that has helped us along the way has told us that he has had to do this many times and he has just heated it so the rubber melts allowing him to pull the master cylinder off even though he is heating aluminum. We are planning on using this method but I am just curious of other methods that may work. We have also heard a method of using a grease gun with other fittings to get the thing free. My second question is, just so I am sure, which master cylinder is the one for the brakes, as I dont want to mess with the clutch master cylinder. Thanks, Andrew
 
The inboard one is for the breaks. As you sit in the car the left foot does the clutch, the right is the brake. I have heard of using an air compressure to get out the parts. The old rubber parts may stick to the cylinder wall and MUST be removed completly or the new parts will hang-up. Don't scrape with metal or you will score the walls.
 
Thanks, thats a good way of remembering which cylinder is which, never thought of it, thanks for the response. As for the air compressor, what do you do, just take off the lines and blow the air in through there? Thanks
 
Andrew, IMHO just buy a new master. It is not worth messing with the old one if it has been seized up a long time. As difficult as it is to remove and then install and bleed, If yours won't seal you'll be kicking yourself for a long time. Just as an aside, about 5 years ago I had all my cylinders brass sleeved. One of the master cylinders just would not hold up after that. I spent a whole summer messing with it, trying to bleed it, then removing it, then sending it back, then trying it again, etc, etc, etc. Finally I got a refund on that particular part, went and ordered a new one from another supplier, put it on and bled it up in about an hour, and its been good ever since.
Also, they can be a bear to bleed. Pressure bleeding from the resouvour is the best way.
 
vette said:
Andrew, IMHO just buy a new master. It is not worth messing with the old one if it has been seized up a long time. As difficult as it is to remove and then install and bleed, If yours won't seal you'll be kicking yourself for a long time. Just as an aside, about 5 years ago I had all my cylinders brass sleeved. One of the master cylinders just would not hold up after that. I spent a whole summer messing with it, trying to bleed it, then removing it, then sending it back, then trying it again, etc, etc, etc. Finally I got a refund on that particular part, went and ordered a new one from another supplier, put it on and bled it up in about an hour, and its been good ever since.
Also, they can be a bear to bleed. Pressure bleeding from the resouvour is the best way.
Click to expand...

:thumbsup: I second what Vette has said, a new master cylinder can be had for about $100, once you get the carbs off, it's easy to get to. Change out that nasty old brake fluid while you're at it. You might consider giving the brake cylinders the once over as well, you wouldn't want to get that beast up to speed without good brakes!
 
I agree with replacing the master cylinder. And if it's seized up, chances are pretty good that the brake cylinders and calipers are in rough shape too. At the very least disassemble the calipers and cylinders, replace the seals and flush the system with new fluid. This is the system that keeps you from very serious consequences, and just can't be taken any less than very seriously. Time is not kind to automobile brake systems.
 
Cutlass said:
I agree with replacing the master cylinder. And if it's seized up, chances are pretty good that the brake cylinders and calipers are in rough shape too. At the very least disassemble the calipers and cylinders, replace the seals and flush the system with new fluid. This is the system that keeps you from very serious consequences, and just can't be taken any less than very seriously. Time is not kind to automobile brake systems.
Click to expand...

Agreed! Especially with fluid that retains moisture! The brakes are fairly simple to rebuild and maintain, given the right tools (EZ Bleeder) and it's very gratifying to have them operate well.
 
Thanks to all, just for a Healey update in general, not about brakes. Last friday, my dad and i rolled it out of the garage, put some gas in it, and... it started right up! Thanks to all of you that have helped us before, it seems that at the moment it is great running order, thanks again
 
Well, the emergency brake works amazingly and the very slow speeds we drive it around the block. Cant wait to get these brakes figured out and actually drive it somewhere. The big reach goal is to get it stopping in time for the local annual Healey show in May... We'll see how that goes.
 
Do the foot brakes seem to work at all? While I'd still go through the whole system, a thorough flush with new fluid might not hurt at this point.
 
when i try to depress the brake pedal it moves probably a half centimeter and then hits a brick wall
 
I don't think there's any safe substitute for taking that master cylinder out, and probably replacing it. What may not be clear to you is that traditional brake fluid absorbs water from the atmosphere. That water then corrodes metal, especially cast iron and steel. Aluminum doesn't fare well either. That's one reason you just must go through the entire system before putting your life on the line. It's a pain, and a moderate expense, but please don't skip this process. A reason to flush the system and replace fluid with new is that under the pressure of braking, water in the fluid will boil, causing spongy, ineffective braking. While you're at it, flush the clutch master and slave cylinders also.
 
Cutlass said:
I don't think there's any safe substitute for taking that master cylinder out, and probably replacing it. What may not be clear to you is that traditional brake fluid absorbs water from the atmosphere. That water then corrodes metal, especially cast iron and steel. Aluminum doesn't fare well either. That's one reason you just must go through the entire system before putting your life on the line. It's a pain, and a moderate expense, but please don't skip this process. A reason to flush the system and replace fluid with new is that under the pressure of braking, water in the fluid will boil, causing spongy, ineffective braking. While you're at it, flush the clutch master and slave cylinders also.
Click to expand...

:yesnod:------------- what he said!!!
 
Andrew_Grannis said:
Well, the emergency brake works amazingly and the very slow speeds we drive it around the block. Cant wait to get these brakes figured out and actually drive it somewhere. The big reach goal is to get it stopping in time for the local annual Healey show in May... We'll see how that goes.
Click to expand...
Which local annual show, in Cleveland?

There is a pretty big annual show in Perrysburg (Toledo suburb) the first weekend in June every year too. My car was there a couple years ago (on a trailer) but this year I should be able to drive it now that it's registered in Ohio.
 
Thanks for all of your help, the show is put on by the North East Ohio Austin Healey Club and it is in Solon. If you want more information about it just let me know.
 
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