PDA

View Full Version : Using Chrysler rear drums for Stude front drums?



John Kirchhoff
10-14-2006, 09:44 PM
I was rumaging around through some parts today and came across a Chrysler rear brake drum that looked an awful lot like a finned front drum on a Stude. I took it to the shop, mounted an assembled spindle and brake assembly in the vise and compared it to a Stude 11 inch drum. I must admit I was quite surprised at how close it fits. First of all, the rear Chrysler drum doesn't have the hub and bearing pressed onto the drum, but I had a Stude hub without the drum to compare with. The Chrysler drum is 1/4" wider with a 1/4" wider friction surface. The Chrysler drum rubs slightly against the backing plate of the brake assemble when mounted on a Stude hub, but with thin (.065") washers, it clears and everything seems to fit perfectly. The stud holes are the same size and the bolt pattern is the same as a Stude drum, so with new studs it should fit like a glove. While the drum is 1/4" wider overall, the outer lip actually extends past (to the inside) the backing plate 1/8" less than the Stude drum. The extra width it on the outside around the outside circumference, which gives it more of a square shoulder than the Stude. I haven't tried a Stude wheel to see if it will fit a Chrysler drum, but I use Chrysler rims on my car anyway, so I know the Chrysler rim will fit either (naturally). It appears the only thing necessary to make it work would be to either cut .065" off of the inner lip (the lip on the friction surface, not the outside of the drum) or make up a spacer with the appropriate holes to mount between the drum and hub. The inside diameter of the particular drum I have is maybe .020 more than the Stude drum I was comparing to. However, I haven't measured either accurately to determine what's what. The maximum ID on a Stude drum is 11.060" and the Chrysler says 11.090, so it may be just a touch wider. I believe the Chrysler drum is off of a '81 Plymouth V-8 Fury, but not 100% sure. It MAY be the same drum used on a '77 or later D150 pickup, but haven't went so far as to check that yet, so not sure. I have a the rear axle off of an '81 6 cylinder Chrysler and it's a 10 inch but haven't compared it to a 10" Stude drum. The Chrysler drum does feel heavier than the Stude. I don't know if anyone out there has a Chrysler parts book, but the drum # is L-36860. Is this potential interchange something known to every one out there but me? If not, I know the Chrysler drums would be very much easier to find than good Stude drums.

stuvw2mny
10-15-2006, 01:19 AM
Sound very interesting.

I am especially interested from the standpoint of a replacement front drum for the 2R trucks, with supposedly 11" brakes and drums. Sure, it is a different wheel bolt pattern (4 1/2") than the truck 5" bolt pattern, but I sure as heck would like to use one wheel pattern for both the cars and the truck. Another benefit would be to get me away from the awful truck front drum that few wheels will fit.

I had been thinking of transferring my 56 President brakes to the truck, but I suspect they are 10" rather than the 11", and thus might not have the same braking mechanical advantage. More info, particularly the identification of the Chrysler Corp wheels, as soon as you can get it, please. Is the L-36xxx number on the Chrysler drum?

Of course if I change the truck front drums I will have to do the rear drums also. Thanks for your insight.

sbca96
10-15-2006, 02:57 AM
5 on 5 is a common GM full size truck size. It was also used on mid
90's Caprice cop cars, and also the Impala SS.

Tom

'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: 97 Z28 T-56 6-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

Neal in NM
10-15-2006, 10:31 AM
I have machined odd things like this before in my shop. It should take very little time to do but, some machine shops might not like the idea because of a liability issue. As far as hole patterns in drums, I have welded the holes closed in drums and axels and drilled a new bolt pattern it does take some time but you would never know that it was done:D! Neal

r1lark
10-15-2006, 12:55 PM
quote:Originally posted by stuvw2mny

Sound very interesting.

I am especially interested from the standpoint of a replacement front drum for the 2R trucks, with supposedly 11" brakes and drums.

Stu,

Go here:
https://www.studebakerparts.com/studebakerparts/parts/html/pages/trkdrum.html
for information on using readily available (and cheap<G>) Chevy truck drums in place of the Stude 11" 1/2-ton brake drums. This will allow you to use other wheels without adapters. Also, if you get some late ('63/'64 8E) champ backing brakes and associated parts, you can use the self-energizing brakes on your truck that are MUCH more effective.

I used the late Champ brakes on my '55 V8 1/2 ton, and they worked great. I have not tried the Chevy drums yet, but I know that several other people are running them.

Hope this helps you out!

Paul

Visit The Studebaker Skytop Registry website at: http://hometown.aol.com/r1skytop/myhomepage/index.html

stuvw2mny
10-15-2006, 07:10 PM
Hey guys

I had no intent to divert this thread to truck wheels. There are many threads on this, many stating that Chevy truck wheels will work - Not entirely true!! I have tried several of them and some aftermarket wheels. Most fit on the rear wheels but I have yet to find one that allows complete nut tightening on the front drum with its wierd "bump". One thread says only SOME (again not all) Chevy van wheels fit the Stude truck front wheels. I am just fed up with the 5 on 5 bolt pattern and Stude truck wheels issue. I particularly don't want to go spend several hundred dollars on new aftermarket wheels for a presently non-running truck. Since I have several other cars and several Stude cars I am interested in limiting the number of wheels around, hence the desire to use the 4 1/2" bolt pattern.

So please, let's go back to the original subject of this thread - getting some Chrysler (or Ford) wheels that fit the truck. I know there are some Chev drums that can be installed on Stude trucks with a little machining. I also know there was some stuff on this from Dick Datson way back in the 60's, but I haven't had time to dig it out.

Thanks

Roscomacaw
10-15-2006, 07:52 PM
I understand what you're saying, but it seems rather drastic to me to have a goal of having the same bolt-pattern wheels fit cars and trucks for convenience!
I've got a set of 15" wheels here from a '75 Lincoln town car that fit the Stude drums nicely. I'd like to find them a new home. Are you willing to pay for dismounting the tired tires that are on them and paying the shipping as well??? MAybe throw in a few bucks for my time and travels to see them on their way?

Miscreant adrift in
the BerStuda Triangle!!

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe

John Kirchhoff
10-15-2006, 10:14 PM
I ground down the offending lip on the Chrysler drum today with an offset head grinder, really took very little to get it to clear, at least on this particular drum and backing plate. I got some studs for the rear of an early '80 Chrysler that have a little longer shoulder that will center the drum nicely. I still have to get them pressed in and I hope to put it on the Hawk later this week and try it. By the way, I'm still using a Stude hub so there's no problem with having to change bearings and so on. The guy at NAPA told me to bring the drum in and he should be able to compare dimensions and #s and tell me what model vehicles it fits. More on that later when I have more.

John Kirchhoff
10-16-2006, 10:25 AM
Yes Mike, I know what you mean. Some people can screw up a free lunch. Like when I first got my Hawk and the Chevy engine was setting on the tranny crossmember unattached and the front motor mounts were torched off pieces of generator adjusting bracket with one tiny weld holding everything in place.

I do keep an eye on safety matters because as I get older, I realize I'm not as indestructable as I thought I was as a teenager. For anyone out there interested, fear not. I swapped engines in my motorcycle this spring. Quite an ardous task and definately not a job for the faint hearted with having to aline the driveshaft, build motor mounts and all that. However, three days after I got it all together I took off on a 2,800 mile trip and nothing uneventful happened. If I didn't trust myself I sure wouldn't have been that brazen! Thanks for the reminder though.

John Kirchhoff
10-16-2006, 10:31 AM
One other thing, does anyone know why the Stude drums crack? From my own experience, it always seems to be front finned drums. Is that the experience of others? I wonder if it's the placement of the fins that distorts the drum when it's hot or if maybe it was just the material they were made from. My dad talked about some of the camshafts on the '51's that would experience accelerated wear on just one or two lobes. The dealer told him it was from using scrap metal and some of the different materials just never mixed well in the molten mix. Anyone know if that's true or not?

stuvw2mny
10-17-2006, 04:45 PM
Yes the 1951 V8s did have a soft camshaft problem (not serious, but it existed). I would be much more inclined to believe the story current at that time - It was the first year of a new engine and all the valve train loading problems hadn't been fully worked out. Camshaft science at that time was nowhere as good as it is now. You have to admit the Studebaker V8 did turn out to be a darn good engine for 15 years. Another possible contribution to the rumor (God I hate rumors, because they get amplified out of all proportion) is that there were problems getting lots of materials for consumer products in the late 1950's thru 1952 because of the outbreak of the Korean War. By the way did you know the Korean War still exists - there was never an armistice or surrender - just a truce.

John Kirchhoff
10-18-2006, 09:17 AM
Hmmm, just a truce. I had a marriage like that once........

John Kirchhoff
10-23-2006, 10:41 PM
I tried out the Chrysler brake drum this evening. It works fine and I can't see any problems with it. I used a Stude hub, replaced the studs with Chrysler studs from an early 80's. They have a shoulder that fits the holes in the brake drum correctly. I did have to grind down the inner lip slightly to clear the backing plate. The advantage of this set up is since the drum and hub are seperate, you can fiddle with the brakes without the greasy job of removing the hub and bearings. I need to talk with the local dealer and see if they can tell me what Chrysler vehicles used that particular drum. It would surely be easier to find than good Stude finned drums.

sbca96
10-24-2006, 01:12 AM
John, thats why most new cars since the early 90's have had separate
floating rotors on hubs. Thats how I was able to mount the Cobra
rotor on the Studebaker hub! Much nicer design. I found during my
adventure setting up the rear discs, that the tapered axle hubs get
distorted over the years from being pulled off the axles. To install
the Dodge wheel studs I found, it was necessary to drill the hubs to
the correct size for the proper interference fit. You dont want too
much interference, or you can over stress the hub and possibly crack
it over time. It was simple to do with a drill bit from Home Depot.
I wonder if the studs you found are the same knurl? These are a few
pictures that should help explain what you did to your hubs :

http://hometown.aol.com/sbca96/images/avantibrakeproject/HubsforCobraRotors/hubs_001a.jpg

http://hometown.aol.com/sbca96/images/avantibrakeproject/HubsforCobraRotors/hubs_008a.jpg

http://hometown.aol.com/sbca96/images/avantibrakeproject/HubsforCobraRotors/hubs_016a.jpg

http://hometown.aol.com/sbca96/images/avantibrakeproject/HubsforCobraRotors/hubs_018a.jpg

http://hometown.aol.com/sbca96/images/avantibrakeproject/HubsforCobraRotors/hubs_023a.jpg

But I went huge disc instead :

http://hometown.aol.com/sbca96/images/avantibrakeproject/cobra_install/cobra_install007a.jpg

http://hometown.aol.com/sbca96/images/avantibrakeproject/cobra_install/cobra_install023a.jpg

Tom