Dual diapham power brake booster

[danno 128]

I have been questioning my factory power disc/drum brakes for years, trying to get better stopping ability. I must have read a dozen threads, and no real answer. I cannot lock up my front wheels with the system I have, and I should not need to spend huge money to get the factory system to work like it was originally. I have tried all the tricks, new pads, new flex lines, new master, rebuilt wheel cylinders, etc.

 

I was chatting last week with a older local person who knew a lot about brakes, and he mentioned that the 69/70 Mustangs have a dual diaphram vacuum booster. In other full size Fords, there was enough room to put a larger diameter diaphram on the booster, so that worked fine. 1971 thru 73 Mustangs also had a much larger diameter single diaphram booster. Because of size limits, in 69 they used a dual diapham, which is why it is smaller diameter and longer from front to back.

 

The problem comes from what happens if only one of the diaphrams in the booster is good, and the other has a leak. You will get some stopping ability improvement, but not total. The usual check everyone does when they step on the brake with the engine off, and keep the foot on it while starting the engine. You can feel the pedal go down further if the booster is working. But if one of the diaphams is working and one is not, this test is not effective.

 

Does anyone have any suggestions or experience with this? I am tempted to buy a new booster, just to see if my assumptions are correct.

Edited June 6, 2011 by danno

[danno 128]

I have been questioning my factory power disc/drum brakes for years, trying to get better stopping ability. I must have read a dozen threads, and no real answer. I cannot lock up my front wheels with the system I have, and I should not need to spend huge money to get the factory system to work like it was originally. I have tried all the tricks, new pads, new flex lines, new master, rebuilt wheel cylinders, etc.

 

I was chatting last week with a older local person who knew a lot about brakes, and he mentioned that the 69/70 Mustangs have a dual diaphram vacuum booster. In other full size Fords, there was enough room to put a larger diameter diaphram on the booster, so that worked fine. 1971 thru 73 Mustangs also had a much larger diameter single diaphram booster. Because of size limits, in 69 they used a dual diapham, which is why it is smaller diameter and longer from front to back.

 

The problem comes from what happens if only one of the diaphrams in the booster is good, and the other has a leak. You will get some stopping ability improvement, but not total. The usual check everyone does when they step on the brake with the engine off, and keep the foot on it while starting the engine. You can feel the pedal go down further if the booster is working. But if one of the diaphams is working and one is not, this test is not effective.

 

Does anyone have any suggestions or experience with this? I am tempted to buy a new booster, just to see if my assumptions are correct.

Edited June 6, 2011 by danno

[m3rol 10]

I dont know if you care about originality, but I'm planning to put a booster from a sn95, and 13" discs in front of my 69, i think this is the best in braking I can go.

 

Some 2 piston calipers ( 4 piston if you have the $$$ ) and high performance brake pads.

 

well, this is my plan, im getting rebuild my current brakes now until i found the 13" discs and all necessary stuff required for the mod

[m3rol 10]

I dont know if you care about originality, but I'm planning to put a booster from a sn95, and 13" discs in front of my 69, i think this is the best in braking I can go.

 

Some 2 piston calipers ( 4 piston if you have the $$$ ) and high performance brake pads.

 

well, this is my plan, im getting rebuild my current brakes now until i found the 13" discs and all necessary stuff required for the mod