Well, isn't this interesting. I knew the old rear wheel cylinders were upside down and had been for a very long time. This is an age-old way of adapting '40-style brakes to Model A rear axles, but what I failed to realize is that they seem to be unbleedable in this position. I got good front brakes but the rears just won't pump up. Used a Mighty Vac and speed bleeders. Neither seemed to work. I've done the searches and all I see is "maybe this and maybe that", but no solid info. Anybody out there who has solved this problem PERSONALLY?
Just dealt with the same issue last week. I swapped the cylinders side to side. Had to break out a die grinder and raise the hole in the backing plate till the bolt holes lined up but no big deal. First time in 25 years I feel like I got good pedal.
Maybe wasn't clear enough, swapped the cylinders to get the bleeder on top. Side to side since when my buddy put the juice brakes on back in 58 he just swapped the plates, left the cylinders technically backward, big bore to the rear.
Swapping wheel cylinders from left to right was part of the "traditional" setup instructions. I have the same setup on my Model A now and it works fine.
Yes, the backing plates get swapped side-to-side so that the emergency brake tubes point in the right direction, but did you also turn the wheel cylinders upside down so that the bleeder is on the top?
Just the backing plates and shoes get swapped side to side. The wheel cylinders need to stay on the same side they are suppose to (right on right side, left on left) and flipped over so bleeder on top.
Could you bend up a piece of brake line and screw it into the wheel cylinder. Then move the bleeder screw to the top of the brake line you bent making it the top point in the system at the top of the backing plate? Just an idea.
Take a squeeze container like gear lube comes in fill with brake fluid attach a hose from bottle to bleeder open bleeder and loosen brake line . Squeeze bottle until air quits coming out line fitting tighten line and bleeder.
I have the same situation. I bled mine by taking the drum off and using a hand held pressure bleeder to keep slight pressure on it, I stuck a .003 feeler gauge past the rubber piston cup at the top. I was able to get the air to burb out. I now have a good solid pedal.
It is confusing. The plates are switched side to side and rotated so the emergency brake tube is forward. The old way of arranging the shoes must be changed so instead of all big stuff forward, it is now to the rear. Long shoes to the back and big ends of the cylinders to the back. The cylinders are also switched side to side so the blenders are on top and the big end to the back. They bleed like normal then.
Okay, so I now have the backing plates positioned so that the emergency brake cables come out at the top facing forward. I also have the bleeders at the top, accomplished by slotting the mounting holes and switching them side to side and upside down from where they were on the origial '40 Ford application (see photo). But... The big end of the wheel cylinder faces forward, not to the rear as you said it should. Is this important? Also, the long shoes now go on the rear, the short shoes on the front? Is this correct?
Wow! I thought I was the only guy who ever had to solve this problem. For me it was in 1960 and there was no H.A.M.B. to appeal to. Ar the time I found some soft plastic tubing that looked like heat shrink but wasn't. I chose a size that was a snug fit in the hole under the bleeder. I assembled the wheel cylinder with a length of this tubing that started just inside the bleeder, went into the bore, and curved up the side of the wheel cylinder to the top. Opening the bleeder allowed the air at the top of the cylinder to flow down the tube and out the bleeder. Worked very nicely until the flathead was superseded by a 283, Buick trans, and Pontiac rear. (Pontiac?? Hey, it was 1960. And besides, the rear was a 4.10.
The big ends of the cylinders need to be at the back. Forget about the emergency stuff and just think about the cylinders and shoes for a moment. If you turn the whole assemblies 180* the big stuff would change from the front to the back. That is the correct assembly orintation. You then just move stuff around so the plates and the cylinders are right. Plates and cylinders swap.
Okay. Why does the big end of the wheel cylinder need to be to the rear? I read somewhere that it really doesn't make any difference, but I want to do it right.
And then there's this other tiny little problem... When I swapped the wheel cylinders side for side and rotated them so that the bleeder is at the top, the pistons no longer align with the shoes. That certainly won't work...
If you attach wheel cylinder with flexible brake hose you can have the whole backing plate and cyl/shoe assembly assembled held as close to stock [cyl up] and bleed brakes.. once set rotate whole assembley to cyl down position, bleed will maintain....
Yep, been there. Have it on my Roadster Pick-up with bleeder on the Bottom. I've said it many times here on the H.A.M.B. I don't think like normal people. I bled mine different than mentioned above. I learned a long time ago, Air will always rise to the top. In my case for the rear lines that would be the Master cyl. So I bled the rear lines the best I could with a helper doing the Brake Pedal dance then let it set an Hour with the rear tires on the ground and the Front axle about 2 feet up in the air. Then I did some light taping on the brake lines starting at the wheel cyl all the way to the master. Then with the lid off the Master watching the fluid I pushed the pedal lightly and slow just about 1/8 of it's travel. You can see the tiny bubbles come out the vent hole inside the master. When the bubbles stop you have all the Air out. Repeat the pedal movement several times. This is also called back bleeding. I also have a very solid pedal. Of course I'm using the Stock early single master Cyl. I still have faith in that Old system. I find this to be much easier than all the other things mentioned. The Wizzard
Yay! I've got brakes! Thanks to metalman and his posts above, I finally have '40 brakes on the rear of the 'Banger Roadster that can be bled normally! The secret, as he said, is to mount the brake cylinders with the bleeders up by raising the big hole with a die grinder until the bolt holes line up. Then bleed 'em like normal. Simple.
As the old guys "retire" some of this old information is getting lost. Here's a "bump" for the late-comers. Enjoy!
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