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28 worm drive brake drums

Posted: August 11th, 2017, 10:36 am
by birdacre
are these originally steel? will later cast iron drums fit a worm drive. i have heard that steel drums are prone to fade. will woven linings help with this? thank you for any input. i get my brakes nice and then after a few miles heat up and fade even when pumping conservatively on long hills.

Re: 28 worm drive brake drums

Posted: August 12th, 2017, 6:20 am
by njcar757
All model A's and AA's came with pressed steel drums, cast iron drums are now available only for the model A cars and pu's. Model A car's and pu's had 11" drums. The AA's had 11" drums on front only but are different from the cars and will not fit AA trucks, because of there shape and lug pattern.
If you removed the hub-drums and had them turned and replaced the woven lining and installed a shim between the shoe and the woven lining, that might help. They sell a brake drum reinforcing band that is pressed on to steel drums to help with heat distortion but I don't know if they will fit the front of AA's 11" drums.
carry on nick c

Re: 28 worm drive brake drums

Posted: August 12th, 2017, 9:03 am
by drtrcrV-8
The steel drums are already on the thin side : DO NOT TURN THEM!! The original woven linings will help. The fading you describe sounds like a material or adjustment problem: heating up after a few miles sounds like "Brake Drag" from being too tight or possibly weak return spring or a bind in the system?

Re: 28 worm drive brake drums

Posted: August 12th, 2017, 9:11 am
by Bob C
The Judging Standards state that cast iron drums for the Model A came out in September 1931, not sure about the AA.
Also see Vince's site. http://www.fordgarage.com/pages/3132frontbrakedrums.htm
http://www.fordgarage.com/pages/1931rearbrakedrum.htm

Bob

Re: 28 worm drive brake drums

Posted: August 12th, 2017, 11:44 am
by birdacre
thank you for your input. i was wondering if the drums could be out of round and not contacting. you do bring up an important part about being thin in the first place. brake drag is a good point too. i think i will start with the woven linings like you suggest and go from there. thank you, kevin

Re: 28 worm drive brake drums

Posted: August 12th, 2017, 6:38 pm
by flatford39
You need to arch your shoes to the drum. I just sand them.

Re: 28 worm drive brake drums

Posted: August 13th, 2017, 7:18 am
by birdacre
does the arching make up for an out of round drum. some say not to turn these drums at any cost. so... if they drum was perfect there would be no need to arch the shoes. i have never had to arch shoes on other makes. sounds like this is the protocol for model A's. i appreciate your help. when i got the truck it had all new on front, non braided, new old stock braided on rear. sat for many years. nice clean drums, no ridges. so you suggest arch first, then replace lingings if not better. thank you, kevin

Re: 28 worm drive brake drums

Posted: August 13th, 2017, 6:13 pm
by KimVanOrder
Just went through that process on mine. Arching matches the drum ID to the lining OD. That is all it dose. this gives 100% contact area so there fore more / better breaking action. If the drums look good, then match the linings to them via checking for contact area. Once all the "high" spots are gone that is as good as it gets..

Re: 28 worm drive brake drums

Posted: August 14th, 2017, 7:53 am
by birdacre
i saw several ideas about paint, tape, etc. on the shoes. what did you finally find worked best. are your shoes braided or smooth? and then did you apply a small bit of pressure and have someone turn the drum by hand for contact. thank you for your help in advance. kevin

Re: 28 worm drive brake drums

Posted: August 14th, 2017, 2:40 pm
by dhetch
Kevin,

You might also look at play between the hub and the axle housing. It is not uncommon to have the bottom of the wheel bearing surface on the axle surface worn down (you can see it with the hub off) along with worn rear wheel bearings (often caused by the irregularities in the bottom of the axle housing) and also check the bearing surface on the inside of the hub. Stacked together, these can account for a lot of play in keeping the hub/drum centered on the axle housing/brake. I have 3 out of 3 1928 axles with this problem.

If you really want to reline your own shoes, I may have NOS linings and shims depending on what you are looking for.

Dave

Re: 28 worm drive brake drums

Posted: August 14th, 2017, 5:43 pm
by KimVanOrder
birdacre wrote:
August 14th, 2017, 7:53 am
i saw several ideas about paint, tape, etc. on the shoes. what did you finally find worked best. are your shoes braided or smooth? and then did you apply a small bit of pressure and have someone turn the drum by hand for contact. thank you for your help in advance. kevin

I used masking tape first then switched to chalk. 4" side wheel grinder to rough it in then switched to chalk and electric sander to get the final ' fit '.
My linings are woven. Put the chalk on the lining, assemble drum on and turn in the adjustment screw until you feel it touching. Back out the screw, pull the drum and sand off high spots. ( Where the drum made contact). This will take many, many, times to get near 100% contact area. Once you have that done, work your way back through the linkage making all the adjustments as required. Do not skimp on any step. They are all important. I'm now in the process of making an arching machine. ( I just want to see if I can do it)! Good luck..