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Poor stopping power.

21Scott

New Member
Hi, I recently bought a 1921 T, well she has disc in the front, and drums in the rear. The prop valve is under the seat, or mid way on chassis. The master cylinder is a Delco single reservoir. I didn't get a chance to drive it much, but it's very hard to stop. It's not spongy, you just push your brains out. Is there an up-dated master cylinder? Thanks
 
There are many things that will cause a hard pedal and poor stopping. Your mismatched master cylinder is most likely a major factor. Disc/drum systems are supposed to have a dual reservoir master cylinder with the larger reservoir feeding the front discs as they use more volume than drums. In any case, single masters are outdated and potentially dangerous (if you have a leak anywhere in the system you lose ALL your brakes) and should always be replaced by a dual. It's certainly not matched with your setup.

Without knowing your exact setup, it's hard to tell which one to get. On mine (GM front disc/S-10 rear drum) and many others, the replacement for a mid 70's Mustang and similar models is used . For front disc conversions, the Corvette master is popular also with street rods and full size cars, but may not be so good for a T as they are very large compared to the Ford unit.

I would go through the entire system, because anyone that would use a single master with your setup is not very savvy with the way braking systems should work.
 
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There are many things that will cause a hard pedal and poor stopping. The mismatched master cylinder is most likely a major factor. Disc/drum systems are supposed to have a dual reservoir master cylinder with the larger reservoir feeding the front discs as they use more volume than drums. In any case, single masters are outdated and potentially dangerous (if you have a leak anywhere in the system you lose ALL your brakes) and should always be replaced by a dual. It's certainly not matched with your setup.

Without knowing your exact setup, it's hard to tell which one to get. On mine and many others, the replacement for a mid 70's Mustang and similar models is used (GM front disc/S-10 rear drum). For front disc conversions, the Corvette master is popular also.

I would go through the entire system, because anyone that would use a single master with your setup is not very savvy with the way braking systems should work.
Thank you, I thought that was odd, (single cylinder) I'll look into a Corvette master cylinder. The car was built 25 or 30 years ago, or longer, so I suppose that explains the antiquated parts.
 
I agree with what bobs66440 said. What you presently have is an accident waiting to happen!

Jim
 
Take a look at one and make measurements before you buy. My bucket uses a dual reservoir MC from the later drum/disc Mustangs. As mentioned above, the Vette MC is much larger, no way would it fit in mine.

Jack
Thank You, I will do some checking on that....
 
I use the one that Spirit sells. I have disc and drums, and it works fine. I did change my leverage point about 1/2 inch to lessen the pressure that I had to apply to the pedal.
Lee
 
I use the one that Spirit sells. I have disc and drums, and it works fine. I did change my leverage point about 1/2 inch to lessen the pressure that I had to apply to the pedal.
Lee
Thanks, Lee, can you tell me Spirits complete name?
 
Thanks, Lee, can you tell me Spirits complete name?

Look at the top of the page and you'll see Spirit Industries, click on it and you'll get to their site as they are one of the sponsors of this forum.

Jim
 
Hey Jim and everyone who helped! I wanted to up-date my progress. I put the new duel master cylinder, and 2psi and 10psi residual valves on, and the brakes work perfect! I took it out for my 1st drive and the 350 turbo trans is junk! I'm rebuilding it now, Thanks again to you all!!!!!
 
Disc/drum systems are supposed to have a dual reservoir master cylinder with the larger reservoir feeding the front discs as they use more volume than drums.
Is this universally true? My MC has the smaller reservoir feeding the front discs. Is this another builder error I'll need to fix?

Jack
 
This is nuts. Every time I go in to fix one new symptom, it turns into multiple repairs. Sometimes I think I should pull the body, strip down the frame and start from scratch. :confused:

Jack
 
This is nuts. Every time I go in to fix one new symptom, it turns into multiple repairs. Sometimes I think I should pull the body, strip down the frame and start from scratch. :confused:

Jack

Sometimes that helps! When building mine, I had it together and apart more times then I can count.

I would not say start from scratch, but if you have the body off and full access to everything, makes finding/fixing things much easier.
 
This is nuts. Every time I go in to fix one new symptom, it turns into multiple repairs. Sometimes I think I should pull the body, strip down the frame and start from scratch. :confused:

Jack
Fixing other hack's crap is a right of passage for many rodders. :eek: Been there/done that so many times I want to cry...the last car I bought (still have, '55 Chevy 210) was virtually all new from front to back, but I still spent a month fixing all the screwed up messes. I've had a lot of different cars and there was only one I can think of that wasn't a complete disaster under the skin.

Stripping it may be drastic, but it may end up being less work if the problems keep coming . In any case I would use it for a while first to shake out all the hidden gremlins.
 
Has anyone tried to tighten body mount bolts, and they just spin? I can't tell what is in the frame for a nut.
 
Generally, yes it's true. I would switch it around.
OK, it's on my list. Just so I know, is this an issue of braking efficiency? Is the applied system pressure different between the two reservoirs? If the only real issue is reservoir capacity, I won't have to do this right away. Capacity is only an issue when I'm bleeding the brakes.

Jack
 
If your bucket is a T.P. build it probably has rubber "well nuts" in/on the frame . If they're turning , they're probably "bottomed out" . I never cared for the setup , but WINTEC most likely has replacements... bad thing is you''ll have to lift the body off the frame to get at them.... as an aside.. just because they're turning doesn't mean they're bad.
dave
 

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