Im running the disc brake Versaillie rear end.... and im using the Maverick Disc brake master cylinder, but since The rear of the maverick was drum Brakes i dont think My master cylinder is Putting out enough pressure... to the rear Discs ..... Is anybody else running a Versaille rear end?
What proportioning valve are you running? That seems to me where I would look. One that adds more bias to the rears.
When I installed my Versailles disc rear and the Granada disc front spindles, I looked through the auto parts books and came up with a master cylinder for a T-Bird which ran 4 wheel discs stock. The car got parked and never was driven with that combination but I don't see why it wouldn't work. The only thing that I would look for would be the 4 disc T-Bird proportioning valve to match.
That seems to make sense to me - unless there is some physical reason the rears are not working correctly, if the pressure from the T-Bird master cylinder is correct for a disc rear - the only thing that would interfere with that pressure is the proportioning valve.
I figured that if everything matched, how would those parts know that they still weren't bolted to the T-Bird. The only thing that I wondered about was that the T-Bird M/C was originally used with a power brake booster and I wasn't going with power brakes. Would it take more manual pedal pressure to get the car to stop?
Well im using the disc front/ drum rear Master cylinder.... maybe i need to do a test to see just how much brake pressure im getting to the rear Discs. Anybody ever done this im not sure how.
Absolutely more pressure will be needed - But it will still be fairly easy to lock the wheels. If you are standing on it and still not getting the wheels to lock up - there is a mechanical issue somewhere. When the bias is set properly, the fronts will lock up a little sooner then the rears do.
There isn't a tester you can just slap on to check it. What you want in correct bias is the front wheels to be able to lock up a little sooner than the rear wheels do. You can do this by locking the brakes on a gravel road and having a friend watch from the side what wheels lock up first. You can even attach a piece of duct tape to the sidewalls if you don't have raised white letter tires - will make it easier for your spotter to see the lock up happen. That disc/drum valve may not be letting enough pressure get to the back, as calipers use way more fluid volume than a drum wheel cylinder does. The original drum/drum valve might be a better choice. Will have to see what other Versailles users are using for thir set up, once more of them post.
I need to re-phrase my question. If you took a T-Bird m/c, originally designed to be used with a power brake booster and took the booster away, would it be any harder or different to apply than a m/c designed for manual brakes?
The problem you may encounter with a power brake M/C on a non power app is more peadal travel to achieve a stop.Reason being most power brake apps have more travel in em to allow for booster pickup/release.Peadal effort should be no worse than any other manual brake application.Just remember you dont want a rear caliper piston diameter that is greater than 80% of the front caliper pistons dia.When hybridizing a brake system your best bet is to get an aftermarket proportioning valve to adjust rear brake bias.Dont forget the residual line pressure to the rears either.On rear drum apps it is 10lbs. On rear disc apps it is 2 lbs of residual pressure to maintain a good peadal feel.Most M/C's have this residual pressure valve built into the M/C.Sometimes it is best to get a M/C that does not have this and add the residual press valves in line to the rear brakes.The biggest problem people end up having when makeing brake system upgrades is to end up with a M/C that does not supply enough line pressure either due to M/C piston size or calipers with pistons that are too big/too small for their app causing either too much peadal effort to stop or not enough and a mushy peadal.When going to 4 wheel disc brakes and useing parts from different cars to achieve your goal...you should know the piston dia of the M/C from the donor car you are useing the brake calipers from as well as the caliper piston diameters front and back.These measurements are important in order to have a system that workes properly in your application.Next thing is peadal travel and piston travel in the M/C.Too much travel will result in too little peadal effort and a broken master cyl.Not enough travel will result in a car that wont stop well due to lack of piston travel and low line pressure.best bet is get a Master cyl for a manual disc brake maverick and add an aftermarket prop valve to adjust brake bias and use a small diameter piston in your rear caliper set up such as the ones from crown vics or exploders.Good luck.hope some of this helps you out.
I agree. Very well written. Now I have more to think about. My Mustang II spindles use the adapters for the small light weight GM metric calipers. My original Versailles rear calipers were the type with the parking brake built into them. They seized/froze long long time ago and I got rid of them. I found that Granada front calipers will fit the rear caliper frames but you have to use 1 pad from the Granada fronts and 1 pad from the Versailles rear for it to work. I already have a Wilwood brake bias valve and 2 of the blue Wilwood 2 lb residual valves left over from my stock car days that I could use, if needed. I guess the first thing I need to do is measure all of my caliper pistons. By using all front calipers, I'm thinking that I'm screwed on the "the rears no larger than 80% of the fronts". We'll see.
I did a Versailles swap with front discs on a 67 Stang using a manual brake master cylinder for a 71 Ford Custom (full size car) I also kept the 4 wheel drum proportioning valve. Everything worked fine.
