Tonight I spotted a leak on my new aluminum Corvette style master cylinder. This is my second new AND bad master and the car isn't even on the road yet! They both leak at the rear, past the piston. They are both 1 1/8" bore. The first one was a 45 USD cast iron from Summit. The second one is identical, but of aluminum. Bought from Pirate Jack's for 125 USD plus freight cost. Since I live in Norway, sending it back probably will cost too much. Summit gave me a 25 USD gift card to make up for the first one and I accepted. I have contacted the seller of the second one, of course. But besides that. What do you suggest? Should I buy an overhaul kit and try to fix one of them, or is the leak probably caused by an unaccurate bore that still will be a problem after an overhaul? The leak is very small. It's over 2 months since I filled it with fluid. I suspect it to leak only when I press the pedal, since I haven't seen it earlier. If I decide to buy a 3rd one, where do you suggest to buy? Where do they sell good quality Corvette 1 1/8" bore masters? I must have that type due to my remote reservoir setup. Aluminum of cast iron I don't care. I just want a master cylinder that works! Maybe it is better to buy an american overhauled one? This issue is driving me nuts. I have a 90 degree transverse set up and working on the master is a real PITA.
Where is it leaking? Out the bore? If so, a simple dis-assembly, inspect and reassemble may cure your issues. Something could be a little cock-eyed in their from the factory.
Sorry to hear you have had bad luck with master cylinders. Years ago, I had a Corvette with brake fluid leakage and contacted this company...http://www.muskegonbrake.com/ They rebuilt my stuff (stainless liners) and no problems after that. You might want to check with them. Good Luck. Stu
Thanks for your responses. It leaks past the piston, yes. I will probably look into it, They are useless now anyway. But I have never disassembled one of these before.
the fluid they put in them to keep them from rusting can cause this. I pull apart all brake parts and clean them with brake fluid.
Im having the same problem, ordered the 2nd one from honest Charlies speed shop, 9 days ago, it was special order, should have it Friday, I will let you know.
Is it possible that the seals could be dry from sitting and they will swell and seal better over time?
How is the geometry on the 90 degree set up, any binding, could the pushrod be putting pressure off to one side on the piston?
Just a FYI The new MC that I just put into my Olds had a sticker on it telling the users to not push the rod full stroke when bench bleeding, if it was pushed a full stroke it would force fluid out the back past the piston.
make sure the push rod on the petal is pushing strait i had a master cylinder leak because the push rod did not push evenly on the piston and cocked it so that it leaked after a little re engineering it worked great
Agreed with posts #10 & 13... when bench bleeding a 1" stroke should do, that's either with the return hoses or the ports plugged
The brake fluid is the recommended type. Since I have power brakes, the push rod is coming from the booster and shold therefore push in a correct, straigth line. However, enclosed with the first master it was a bench bleeding instruction that pointed out that I had to push the piston in FULL lenght to get rid of all air...! On the second master there wheren't any instructions at all, so I did the same thing on that one. All other sourches I have searched (internet, Haynes) also say the same....? What do you think? Is the piston seal destroyed because of the full stroke bleeding?
Agreed on LESS than FULL STROKE, watch the bubbles inside the chambers. The key is to only stroke far enough so that the tiny little bublles- the trapped air- will escape up into the fluid chambers, I like to bench bleed all my M/C's by using the plug method, plugging the brake line ports. That's what the little plastic plugs are for, people just think they are there to keep out dirt, not so. Never a problem this way, good luck. TR
Thanks for your replys. Guess we have found out what caused the leak then... Haven't heard a word from the store, either. Guess they don't care since I live outside The US...
Dont feel bad friend, customer service is becoming a thing of the past. There are a few good names out there, big and small company's. It doesn't matter if you live down the street or around the world, some company's just dont care anymore. TR
What would you have done? Is it worth spending another 25-30$ for a repair kit, or should I just buy a cast iron MC for 45$?
I think I would try what Stu listed in post #3. Click on it and look at Brakes-then master cylinders. Half way down is a NEW Corvette M/C, 1 year warranty, for $65- no core required. Bottom line its hit or miss anymore with all the Chinese imported parts. Even some of the BIG U.S.A. names, the parts are Chinese, its all a gamble. Maybe someone will chime in on a genuine U.S.A. cylinder. Check E-bay for a N.O.S. one, but again, it might need a seal kit from sitting. Which leads me right back to your first question of putting a kit in one, ask your self are you capable to trust your life with the job? If so, you have 2 good ones to build, pick the best looking one, especially the best looking bore, that's most important. be sure to get the correct bore size to match your braking system. Another choice is Wilwood, stop monkeying around with the stock stuff and upgrade to the real deal. These guys will help you and guarantee thier product. You might need the adapter to go from the verticle mount to the horizontal mount. They should also have the kind that will not need the adapter. I use thier products on our high end race cars, very high quality you can trust! TR
Good news! Got a mail from Pirate Jacks. The will send me a new one. Freight costs to Norway covered, and I didn't have to return the leaky one. I call that good costomer service. Thumbs up for Pirate Jacks Hot rod and Restoration parts!
The Jalopy Journal
