So the 40 drums on the front of the model A have seen the end of their life. the drums are cracking and warped. I did some research about 58 buick aluminum drums and realised it was a do-able combo. However i chose a different path as to set up and modification.. I bought a set of drums.. and set about observing all the things i would need to modify..I will try to explain what i did.. they are working fabulously . first off.. most of the post ive seen show mounting the drum behind the hub. since the ford shoes are1.75" and the drum surface is 2.25" I figured if i could just get all of the shoe in contact with the drum it should be enough stopping power.. I chose to keep it simple and keep the 40 brake shoes. (albeit a new set with modern brake linings.) So the first step was removing the 40 drums from the 40 hubs.. the drum is swedged to the lug studs. I cut off the studs flush with the drum . Ground out the swedge then punched all of the studs from the hub removing the drum from the hub. Next the buick drums i purchased came with the buick hubs. i chizzled off the rivets holding the aluminum drum from the hub. They are pretty soft so a sharp chisel and a few solid wacks with a large hammer will do the job. The whole center in the buick drum is larger than the ford hub. and i preferred to mount the drum on the outside of the 40 hub. so i machined a small aluminum concentric ring. so i could center and mount the drum on the hub.
that went fairly easy.. now i had to modify the buick drum to fit.. So i marked and machined the Ford 5x5.5 bolt circle on the drums and drilled them for the Ford bolt pattern. Now since i want to mount the drum on the outside of the hub. i had to machine the back (inside) mating surface so it would sit flush to the hub face. Now the buick drum will fit flush onto the 40 Ford hub and after the wheel is installed the lugs will hold the drum in place.
They are not '53 model.........either a typo or mis-information... A further braking improvement can be gained by adapting the Buick backing plates and wider shoes. It has been done. Ray
Now the more difficult part.. mounting the drum on the outside of the hub moves the drum farther out from the backing plate. Which is what i wanted.. however the shoe sits very close to the 40 ford backing plates and a portion of the shoe would be behind the braking surface of the drum. "the shoe will stick out past the drum on the inside. So i needed to move the shoes away from the backing plates so they will ride inside of the drum. to do this i needed to move the shoe about 3/8" away or off the face of the backing plate. to do this i had to move the wheel cylinders inside of the backing plate. since the wheel cylinders hold/register the shoes in place. moving it will effectively move the shoe out into the center of the drum surface. So i removed the wheel cylinders and ground out the window where it mounts on the backing plate to make clearance for the bleeder valve and brake hose. then i machined a 3/8" piece of aluminum to fit the back of the wheel cylinder and relocated the cylinder 3/8th forward inside the backing plate. this picture shows where the shoe sits after the modifications..
not to side track but i was told they where 53.. if your confirming them to be 58 ill change the title.
I am....but it's no big deal....happens here all the time. The main thing is you are making an improvement and have shown how it was done. Ray
So this registers the top of the shoe.. now i have to register the bottom of the shoe. on the back side of the backing plate where the cam adjusters sit there is a thick piece of steel reinforcing the backing plate. It is spot welded on .. i drilled the spots welds and chizzled off the piece of steel. cleaned it up and reinstalled it on the inside of the backing plate. this moves the cams and adjusters inside the backing plate. and makes up the difference i needed to keep the shoes centered. and forward inside the drum. this picture ^^^^ shows the piece of steel spacer now mounted on the inside of the backing plate. this picture^^^^ shows how it was (factory) before i moved the steel plate from outside the backing plate to inside the drum/ inside of the baking plate and became a spacer moving the shoes out. while still remaining a support.
the mid section support of the brake shoe is held in position by a stamped steel clip. that is swedged or spot welded to the backing plate. this is what grasps and i suppose locates the brake shoe mid way between the wheel cylinder and the lower cam adjuster pivot. I chiseled these off and fabricated new ones that hold the shoe the correct distance off of the backing plate. i measured and machined these .. then i drilled and tapped them for mounting screws .. located where they need to sit and drilled mounting holes in the backing plate to accept and secure these new retainers..
the adjuster cams in this picture are to set the shoe depth and set the wheel cylinders. these just press against the flat part of the shoe. on the back side metal portion that the brake liner is installed on. after these modifications i did not need to modify these cams.. there is plenty of shoe in contact with the cams . so they function the same as before. Once this was accomplished i purchased new shoes with modern brake linings..(not shown) and cleaned up the drums with a soda plaster and then sent the drums with the hubs mounted to have the drums brake surface turned and true'd. then i gave them a few coats of high temp clear.. and mounted them up. Next was reassembly and new brake hoses and bleeding the brakes.. pretty straight forward.. but getting the brakes bled.. you will need to have the shoes as close to "home as possible" i found moving the upper cams clocked to the widest setting helped in getting the initial pressure .so i could bleed out all the air. on the rear of the backing plate is all of the the adjustments.. its difficult to remember which adjuster turns which way.. so i took an electric etcher and imprinted directions on the backing plates to keep it all straight. i also drilled dimples on the adjusters to highlight where the high side of the cams are.. so you can keep the relationship clear while you adjust. (the factory put dimples on them.. but they are hard to see after 80yrs of rust ) i just took a drill and made the dimples proud enough to see them. Then i had to adjust the brake shoes so they would ride in the center of the drum.. this can get tricky. i just followed the directions based on the Ford Manual.. and since it was fresh shoes.. after i adjusted.. i spun the drums and checked the witness marks on the shoes.. then again after a short drive to bed in the brakes.. i removed the drums and looked at the wear marks and adjusted them based on the where the shoes were riding. They stop great.. in fact exceptionally well, the combination of a thick ,true drum .. the modern brake liner and confirmation that the shoes are riding property in the center of the drum made a huge improvement. and i didnt have to scrounge for buick baking plates.. or modify the system for larger shoes. or even turn the back of the drum and remove material to clear the backing plates.. its worked out pretty well. If it didnt i was fully prepaired to keep modifying and go to the next step. but they work fine.. i recently made a drive with speeds up to 80mph.. and when i applied the brakes they stopped the car very well.. its a super simple solution.. but it is one way of many ways that it can be done.. fwiw. now if i could just figure out how to change the title to 58 drums.. it will be even more clear what this thread is about...
Good work Duster, I have one safety concern and one machining option for you. When you spaced the wheel cylinders outwards by 3/8" you've lost the critical cylinder registration spigot engaging the backing plate. You are now only relying on the two 1/4" screws to stop the cylinder from shearing/rotating on the backing plate. If you remake the spacers out of steel with a male spigot on the backing plate side and a recess on the cylinder side you will regain that critical support ....... the bolts are only intended to hold the cylinder flat against the backing plate. Though not as critical, I generally machine an angled bevel on the hub mounting surface to clear the unmachined drum area you reworked. I believe that some drums could get too thin in that area when they're done your way. I'd also like to publicly thank Rich B for helping me out many years ago when I entered into the Buick/F2 Bendix brake conversion.
i agree on the wheel cylinder.. was thinking of that..i just put arp bolts in it.. and the hub is the thin part.. the drum was pretty thick . if i machined the hub it would have been knife edged..
Next time, just use '53-'56 F-100 hubs. You will wind up with the same configuration (drums captured between the hub flange and the wheel) and you don't have to do all that shimming. Tom
Thanks for walking us through your method. My questions/suggestions have already been answered (wheel cyl index and hub vs drum machining) Very cool. I like the look of the old Ford backing plates, especially with the Buick drums. Hotcoupe; could you expand on the conversion using the F100 hubs? or is it already in a thread somewhere?
@bchctybob The flange on F-100 hubs is 3/8" closer to the backing plate than the O1A hubs; this would do away with the ..... spacing; but require the aluminum to be turned away from the iron liner as done when using "outside" flange hubs, Buick drums, and Lockheed brakes in the common manner.
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