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Elite Veteran
Posts: 782
  
Location: Edmonton, Alberta | Brake Drums......
Can someone verify the maximum allowable diameter for a 11' Plymouth brake drum? I have a spec of 11.090. I'd like to get these turned, but need to verify the spec.
Brake Shoes
I need to get brake shoes re-lined. Does anyone know how thick the linings should be? Width is a no brainer from the old shoes, but I have no specs for lining thickness. After reading the manual, it looks like in the old days you had grind the new shoes .010 to .024 depending on drum diameter (assuming you used the Dealership's cycle bond process). But how much did you start with on the new shoes? Anyone know? |
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Expert
Posts: 1737
Location: Hay Lakes, Alberta, Canada | Gord,
I looked in the books...I cannot find a spec... |
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Expert
Posts: 3399
Location: Chestertown, NY ( near Lake George) | My 59 shop manual says .200. Drums size can be .090 over. Look in the specs in the rear of the manual.
Edited by Shep 2014-06-28 8:15 AM
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Expert
Posts: 3778
Location: NorCal |
Most drums have the max diameter dimension cast in
 (Drum Max Dia.JPG)
Attachments
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 Drum Max Dia.JPG (126KB - 115 downloads)
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Elite Veteran
Posts: 782
Location: Edmonton, Alberta | Unfortunately, no diameter dimensions cast in. Shep,...what manual do you have? Where did you find those specs? I have the '57, the '57&'58 Combined manual and the '59 Supplementary, and I can't find them. The good news is you say your manual shows .090 over, so that would support the 11.090 spec that I was given.
Edited by sconut1 2014-06-28 8:20 PM
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Extreme Veteran
Posts: 594
Location: Melbourne, Australia | I've found a spec of 0.200" for lining thickness in the orange fronted 57 Plymouth manual... It's listed in a table with torque specs and the like on page 34 , on the page that faces the main heading page for Brakes ! If you look at the main page and the ones after it, its not obvious; its actually on the back page of the last subject which is Rear Axle in my FSM !! It also states that there is/was an oversize lining available (0.030") but I'm not sure if that relates to radius or diameter..... If you propose turning them to 11.090", I would be inclined to use a lining thickness greater than the 0.200" listed. It is of importance; I had to have my shoes reground as the linings were too thick iniatially (nominal thickness provided by the shop were 1/4 inch - 0.250") and even with shoes set all the way in, the drums would foul. Good luck ! Colin |
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Expert
Posts: 3399
Location: Chestertown, NY ( near Lake George) | If the drums go to .090 the shoes need to arc ground for proper drum contact. |
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Veteran
Posts: 253
| .090 IS the limit -- period..... after that, you risk ths wheel cylinders "exploding" from being "pushed out" too far...............
I have some N.O.S. ++ Asbestos ++ brake shoes for the Plymouth (11" x 2"), the Dodge (11" x 2 1/2") and th Chrysler & DeSoto (12" x 2 1/2")...... that is the cheapest and easiest way to go...
(These sizes are not "etched in stone" as we know -- certain models used different sizes --- for those who want to "jump on my back".....)
Call me --- Craig -- 516 - 485 - 1935.... New York --- also have some BRAKE DRUMS and HUBS & DRUMS!!!!!!!!!!!!!!!!! Will be at Chryslers @ Carlisle, of course, H107 - H108..... |
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Expert
Posts: 3778
Location: NorCal | The shoe-to-drum clearance is adjusted at the bottom so, when properly adjusted, the actual movement of the wheel cylinder pushrods stays about the same no matter what the diameter of the drum.
The reason for a maximum oversize dimension is to maintain the structural strength of the drum i. e. thin equals weak.
Edited by 57chizler 2014-07-01 6:17 PM
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Elite Veteran
Posts: 782
Location: Edmonton, Alberta | Ok....thought I should finish this post. I had '61 12" Plymouth brakes on the car. The drums were badly warped (don't ask) and needed to be replaced. I decided to go with the proper '57 Brakes which both Jeff Nichols and Big M Helped me out with. Thank you to both.
I took the shoes to be re-lined. I found out, that I had a choice of lining materials. I chose to go with a non metallic lining, as Mobile Parts mentioned somewhere that metallic linings will be hard on my old brake drums. That made sense to me, thus my choice. They bonded new linings to my shoes, and painted the shoes. Prior to installing my brakes, I had the backing plates sandblasted. I primed and painted them. No rattle cans here.... 2 coats of ProForm epoxy primer and two coats of SEM Trim Black with my fancy new paint gun!
I blasted the center planes with wd-40 and let them sit. Hit them with WD 40 again. Let them sit a little more and everything loosened up nicely. Once everything was moving freely, I blasted them again with Brakeclean and cleaned them up again. Everything still moves nicely and is lubricant-free. I boted the new backing plates on with the centerplaness installed and torqued to spec.
The manual recommends a thin coat of lubriplate on the area of the show that fits inside the centerplane and on the area where the adjuster contacts. I did so. Went to put on the left hand drum and........
Dammit.... the drum doesn't fit.
If you look at the service manual, it says that re-lined shoes need to be ground to fit the drum. I assumed this was a '50's thing. It's also a 2014 thing. If you're getting shoes re-lined, you must do this step. Off came the shoes, and I delivered them (and the drums.... you need them too when the shoes are ground). They ground my shoes. I put them back on the car and low and behold.... the drum fit perfectly. I adjusted the brakes and they felt good.
While I was in there, I took a look at the brake hoses. They were in really bad shape with a crack nicely hidden from my view. I would not have noticed this crack had I not had to pull the wheel cylinder assemblies from the car when installing the new backing plates. I changed both front hoses.
I bled the brakes with my handy dandy one man brake bleeder and a vacuum pump. Brake Peddle felt good.
I didn't really have a chance to test drive the car before heading to a car show, so it was trial by fire. I was careful driving out of the subdivision and the brakes seemed great, so it was off to the show. No more peddle pulse!
So..... things I learned....
1. (This is just me....) The more I put my car back together the way it's supposed to be instead of all these silly mods the PO did, the better it seems to work. Funny how well parts made to work with other parts fit and work so well.
2. 11" drums.... spec is 11.080 max. The drums I got from John at Big M were in fantastic shape and after sandblasting, needed very little turning. I'm told that that there's lots of meat left on these drums.
3. Rebuilt pads are fine. It's how they used to do it in the 50s, (RTFM) and it's fine today. Expect to wait a day or three. Pad bonding results in a the shoes taking a trip to a large oven, and brake rebuild places don't run the oven until they have enough stuff to go in it. Also, bring your manual....the specs can be useful for the rebuild shop.
4. You must have your re-built pads ground. They don't fit otherwise. The manual says to do it. Funny how that orange book is always right..1957 or 2014. Not doing this step may result in the consumption of copious amounts of Budweiser and involuntary use of the F word.
5. Specs in the manual call for brake shoes to be .200" thick, with an option to go with .230. What's available these days (at least here), is friction material that is .250. This probably compounded my brake drum fit problem. What I can tell you is that .025 friction material will work if the shoes are ground to fit the drums.
6. Check your brake hoses. If in doubt, change them. They're cheap and were available locally in town. Hint: As I discovered, if your brake hoses are quite hard and inflexible, cracks or not, they probably should be changed. I was shocked at the difference with the new hoses.
7. In Canada anyway, it's not legal to use Asbestos to re-line brakes. Asbestos concerns therefore, weren't an issue with the new pads. You may wish to check into this and specify non-asbestos linings if you so choose.
All in all, I'm pleased. I hope someone can use some of this info some day.
Edited by sconut1 2014-08-07 1:18 AM
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Elite Veteran
Posts: 782
Location: Edmonton, Alberta | LOL....just re-reading this whole post. Y'all told me about the need for grinding and I missed that totally. Duh. Reaching for Budweiser.....
And Colin..... you were spot on with everything!
Edited by sconut1 2014-08-07 1:26 AM
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Board Moderator & Exner Expert 10K+
Posts: 13050
Location: Southern Sweden - Sturkö island | Right on Gord, RTFM and do what it says solves most problems |
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Extreme Veteran
Posts: 594
Location: Melbourne, Australia | Glad it worked out for you Gord ! I still love my Asbestos brakes: it was banned here in Oz in the late 90's IIRC but they still show up at swap meets and ebay.... just not available in a business enviroment. My schoolmates dad was a brake mechanic and he blew out each job for 30 years before succumbing to Asbestosis.... so i've been extra careful to not repeat those mistakes ! Colin |
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Board Moderator & Exner Expert 10K+
Posts: 13050
Location: Southern Sweden - Sturkö island | I'm just doing the brake service control after a longer roadtrip - I use a vacuum cleaner with Hepa filter and a brush. Just carefully brush the dust into the nozzle and be careful when changing the dust bag. Yes, the asbestos brake shoes works really well as they are made to work with the drums - everything else is just a compromise. That said, many suffered and died working with the asbestos - we just didn't know back then.......... |
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Brake shoe and drum questions
