Guys: After owning many cars, five of them hot rods, four of which had 40-48 ford brakes, I can't seem to get a good left front wheel cylinder. On my previous build, a '32 ford p.u.. I installed all four wheel cylinders new. The all came from Macks. It took three (3) left fronts to get one that didn't leak. Well now!!!...on my cabriolet, I have installed new wheel cylinders, from a different supplier and guess what? You guessed correctly. the left front is now leaking, a lot. I was carefull not to push the pistons in to far, only the return spring put any pressure on it. The vendor is more than willing to replace it, but whats goin on? Any of you have a similar problem? I bled the system before I went on vacation and it appeared to be OK. When I got back.....a puddle. Tim
Position should not matter so that is a good question ! Do you have a 10lb residual check in the front system? Leak issues like that were a reason some cars had cup expanders and springs installed.
John: The cylinders had a printed notice in the box with them warning about pushing the pistons in to far. I took one apart and the inlet holes are all the way in the rear of the bore...so much so that I don't see how fluid could past the cups. Plus, the brake shoes DID stop the wheels, proving that there was fluid behind the cups where it belongs. Also, the master cylinder is firewall mounted so I think a check valve is not needed. If I hadn't polished my Buick drums and found a mint set of '40 backing plates I'd take the crap off and put F-100 brakes on it and be done. I'm going to fight it to the end!!! Tim
Read this from the ford barn. Chinese junk. I had the same problem. They bored the holes in the wrong place. Good luck with it.. http://www.fordbarn.com/forum/showthread.php?t=99059
ZZ: Thanks for the link and wow what a deal. I have found out through my own time and efforts what I believe to be the real problem. The "new" wheel cylinders we are getting now D O NOT have the metal disk/cup that backs up the rubber cup behind the piston. I have heard since this that the new cylinders sometimes don't even have springs in them!!! A friend of mine that went to the LARS asked the guy at the Old Ford store in San Demas about this and he just smiled and said "I know what your up against" WELL!!! I found and old EIS brake parts box at a Bumper to Bumper about 3 miles from my house and it had the 1 3/8ths metal cups in it. The guy gave them to me..free. The one inch ones are not so hard to find. I went home and put them in and don't you know it...no more leaks!!! After some final adjusting I have brakes. Also, the pistons don't have a groove for the outer cup to "seat" in the way the older cylinders had. So, I am seeing three cheap#$%^& corner cutting techniques done to save money that is extremely dangerous to have in a brake system. How long will it be before this comes to the surface in the form of an accident? Hope this helps guys. Tim
Have you contacted the manufacturer about the 3 cheap ass cost issues? If not, please do. If we don't let people know we hate getting screwed, they'll just keep screwing.
One issue that needs to be addressed is upon initial installation of the brake return spring the brake shoe adjusting cams are too far in the closed position and this allows the wheel cylinder puck to be forced too far inward in the wheel cylinder and exposes a portion of the wheel cylinder inlet port. When this is exposed upon initial pumping of fluid a leak is produced. Care should be taken when installing the brake return spring when the wheel cylinder is empty of fluid. The cam adjusters on the backing plate at 10 and 2 position should be adjusted to the outward position to prevent the shoe from returning inward too far when installing the shoe return spring between shoes and then slowly reduced in diameter to allow the brake drum to be installed.
I am on my third set of new NAPA wheel cylinders in less than 6 months. The crappy chinese rubber just does not hold up. Some times they leak immediately, some times it takes a while. I need to score some NOS rebuild kits.
If the cylinder is leaking drive extra careful because the first time you step on the petal hard you might find that the wheel cylinder just let go completely. I had it happen to me years ago. Jimbo
Went through the same hassle when building my '33. The new wheel cylinders wouldn't stop leaking. I found that by grinding an 1/8-inch flat into the brake shoe landing, the piston cups extend out a little further, and now they don't leak. Anyway, give it a whirl, it may end the frustration.
I got some wheel cylinder for my 40 Ford front brakes from Macs a few years ago and the bleeder valves leaked. They were made in Argentina. I sent them back, then called my local auto parts store and they got me a pair the next day. No leaks.