I've replaced the 52' Ford F-1 front brakes with the Wilson Welding Lincoln brakes with Buick drums on my 34' Ford Nostalgia Gasser and since then cannot get the car to hold while doing my burnout. With the F-1 brakes the pedal was rock solid and never a problem, but with the Lincoln brakes I have a spongy pedal that I can't seem to cure. I've adjusted the brakes several times, bled the brakes, adjusted play in the pedal. The car runs a Bronco nine inch rear and an AMC master cylinder. Is it possible this master cylinder is a mismatch with the Lincoln brakes? What type of master cylinder has anyone else used with this set up? Thanks for any help. Art
Lincoln wheel cyl same type if as F1, maybe little different bore size but if the MC worked before it should work now..
spongy pedal, and not holding could be air in the fronts, but I'd want to pull both front drums to look at shoe contact first. if the shoe radius does not match the drum perfectly, it won't hold. And if it's way out, it can give a spongy feel because the shoes are actually flexing to fit the drum. less guesswork by just pulling the drums. on brakes like 39-40 car, if the lower adjustable anchors are way off, same thing can happen. .
I assume this is mainly a drag car, so if the shoe radius doesn't match, there is very little hope of the shoes seating in by just using the brakes normally. They will glaze first, "in the traps", before ever wearing in. A drag-only car would need to be 99-100% perfect match on shoe-to-drum radius. looking at all 4 front shoes for wear points right now, should help figure this problem out, or at least eliminate things if you have to dig deeper. .
If you can find someone that has an old brake shoe arcing machine, they can arc them to fit the drum perfectly. On a slightly different note, I have a 1930 Plymouth here in the shop (full restoration) and the drums are bolted to the (wooden) wheels so it's really difficult to adjust the shoes out close to the drums - I turned the wheel while I adjusted the upper rear adjustment cam until the shoe drug on the drum, turned it in just a little, then used a Starrett caliper to measure from the spindle bearing surface to the outside of the pad in that corner, then matched that dimension at the other 3 corners. Pretty much right on the money as far as I can tell.
It can't be just air bubbles, "unless" it was a dual circuit master with an OEM style proportioning/brake warning light valve. If it was a single system, a bit of air trapped in fronts could cause a spongy pedal, but the actual pressure to the front shoes will still be the same. An example of why/how that can be, is an oil pressure gauge that has many visible air bubbles in the clear tubing to the gauge itself. The gauge itself will still read the same pressure, even if you bleed the line at the gauge to get rid of the air bubbles. If it was that OEM style dual purpose valve, and enough air was in the front circuit, then that type of valve will block the bad side completely, which will give a low, spongy pedal. The quick way to test that system issue, is take a normal drive, then feel heat at all 4 wheels. If backs are hot and fronts are cold, then the valve is blocking. if all 4 wheels are hot, and fronts are not holding well, then it points to "lack of stopping friction grip" on the front shoes/drums. If a person used very tiny brakes in a front swap, the results would be the same as mismatched shoe/drum radius,... a lack of friction grip, but due to a lower "swept area" on those small brakes. .
Just a note on those early drums. Those might be? pressed steel drums, not cast iron. There is/was a difference in shoe material for pressed steel drums. Also, I believe all car makers with steel drums advise not to machine the drums. Of course, that was when a new drum could be bought .
There was a difference between the Wilson Welding and MT Lincoln brakes in that on MT's the top centering bolt was adjustable which made for a little better shoe adjustment, You loosened the stud then adjusted the shoes out to make full contact with the drums then re tightened the stud and backed off the shoes for clearance. Wilson may have addressed this? This is all discussed in the 32 pu rebuild on the HAMB done by Dennis Lacy.
F&J, yep, they are pressed steel - of course you can't find anything like them, but we had pretty good shoes on the car and the drums were within specs (finding 1930 specs is fun) I did find a set of NOS Firestone linings, but I doubt we'll ever need them - now where did I see that brake riveter machine?....................................
Wilson backing plates have had the slotted upper anchor bolt hole from the start. I have done a few Wilsons with the Buicks and they worked fine. There are a whole lot of Buick conversions that don't have the shoes positioned correctly in the drums. Some of the mistakes are cutting the brake surface for backing plate clearance and using a hub that moves the drum too far outboard.
You might find this interesting. I did, Bill http://www.jalopyjournal.com/forum/threads/mt-car-products-brake-shoe-issue.959903/
I must have been wrong but the Wilsons I've had didn't appear to have any adjustment on the top bolt????
I'll be pulling the drums and checking things out. Thanks for all the information and suggestions. Art
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