brake issues on 1936 with '39-42 setup

Freoway

Freoway

Member
I've got a '36 Ford roadster (factory RHD) that has a '39-42 juice brakes. This is the first car I've had with this setup. I've changed the front hoses, replaced the master cylinder (which is a later tandem PBR unit). Although the brake pedal is hard, the stopping power is lousy. The shoes have plenty of meat on them and the pedal isn't spongy. I've bled the system through.

I've noticed that all four have the adjusters on them and they work fine, but only the rear brakes have the lower anchor pins that are also adjustable. Should the front brakes have adjustable anchor pins, because they don't?

Cheers.
 

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The '39-'42 have the lower and upper adjusters. Later '46-'48 only have the upper.
You may have the wrong size master cyl.
 
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If you have a short pedaltravel and it takes both feet on the pedal to stop my bet is also on a to large bore mastercylinder.
It´s a bit tricky to fit a dual master and get it to work good, pedal travel has limitations.
A lot of folks stay singe master for this reason.
Next is if you got the wrong friction material you can have problems to...or glaced drums...
Sorry for bringing more questions then answers....
 
How do your brake shoes fit in in the drum? If you shoes are new and the drums have been turned to the max, you will only have a small amount of contact between the two. If that's the case, the shoes should be ground to match the curvature of the drum.
 
do you know the bore size of the master cylinder? Do you know the size of the front wheel cylinders? Are they sized 1 3/8 or they 1 1/4
 
Just got home. Thanks for all the quick and useful replies.

It's strange that my front brakes don't have lower adjusters. I can see that they're available online.

Sounds like I ought to check out my master cylinder too. I'd happily replace it with an original single pot master if that fixes it. I replaced it like for like, so I can measure the bore on the old one. It's in a shed down the road, so I'll measure it tomorrow (it's late evening now here).

The shoes are fairly old. I haven't check to see if they're radius matched. The car has only done a couple of thousand miles in 30 years. Runs like a top though.

Cheers and thanks, Lloyd
 
Was watching Fantom Car Woks and they could not get the brakes to work on an old Army Jeep. Turned out the drums were out of round. I hate these shows because that should have shown up when they adjust them, which they did 3 times. Jack the vehicle up and have someone step on the brakes. Check each wheel to see if it locks up. Rarely driven might mean frozen wheel cylinders. The other suggestion above are also spot on. This is a simple setup. Good luck.
 
You did not mention in your description of the system on the car if a '39 peddle assembly was used, or is it some kind of an after market affair.
The '39-41 brakes with the lower adjusters are problematic at their best, very difficult to get the shoes centered so that they make good contact with the drum.
The front backing plates with the fixed anchors are much easier to work with.
I would suspect that the shoes are old and hard, having lost many degrees of friction. I would also suspect that the wheel cylinders and brake lines are all "gunked" up from age and moisture intrusion.
When I first put hydraulic brakes on my '36 in 1952 I used '41 brakes and drums with a '41 master cylinder mount that was cut down to fit where the original battery had been. I had to fabricate a longer rod attached to the stock peddle assembly to engage the master cylinder. I moved the battery behind the seat on the right side.
I used the '41 system for many years, however, I was not to pleased with it. In reality the the stock mechanical brakes, which had a very rare power booster worked better.
In 1962 I converted the brake system to a '42-48 system with '39 drums a '39 peddle assembly, and stock wheels. This system worked much better.
 
your front are the later ones that self center like my 46 had

it may be just the picture but the lining looks thicker than i remember, perhaps the drums are large

look at the shoes to see if they are wearing all around, or just in a small area, this will show if the arc of the shoe matches the drum---the wear areas get polished, the non wear areas just get dusty---no full shoe contact no full braking

also there could have been a fluid leak on the shoes that was "cleaned off", but the friction is changed in the lining----been through this with the 39,46, the brakes wern't dependable, now have the A, and mech brake 36 because of the reliability----the only cars I have had total brake failure is hyd brake cars, even some dual mcyl ones, but never with mechanical brake car
 
Sounds like I better check out the linings and replace them. I'm not sure how they age or deteriorate with time, although I understand that they can become glazed. Hopefully there's someone local here who can reline them. Thanks, Lloyd
 
flatheadmurre said:
If you have a short pedaltravel and it takes both feet on the pedal to stop my bet is also on a to large bore mastercylinder.
It´s a bit tricky to fit a dual master and get it to work good, pedal travel has limitations.
A lot of folks stay singe master for this reason.
Next is if you got the wrong friction material you can have problems to...or glaced drums...
Sorry for bringing more questions then answers....
Click to expand...
Hi flatheadmurre. Thanks for your advice. The bore is 1" diameter, not sure what it's meant to be. The shoes do look glazed, so I'll deal with that first.

Thanks, Lloyd
 
For those interested, my front shoes were glazed (no sign of wear). The brake specialist told me he reckoned they were at least 20 years old, so I'm having them redone and the brakes skimmed. Hopefully that should fix the problem.
 
Freoway said:
The bore is 1" diameter, not sure what it's meant to be.
Click to expand...

A 1" master cylinder bore is actually a little on the small side for the early Ford brake systems, so it should be fine. The smaller the bore the higher the braking force at the wheel cylinders, and the larger the bore the lower the braking force. There are other factors that come into play such as pedal travel and fluid volume, but pressure wise you should be fine.
 
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