De Soto Frank Posted January 2, 2007 Report Share Posted January 2, 2007 Actually, it's the hub that needs to be swapped... Scenario: '41 De Soto, front brake drum: outer bearing race now a loose fit in hub; apparently hub is "hogged-out" from the ill-effects of running a bent rim. Remedy: 1) Replace entire hub/drum assembly (anybody got a spare? ) 2) Swap hub good hub from a cracked drum already on-hand. I started looking at the cracked drum, and besides obviously having to grind the rivets away to liberate the hub, I became concerned about HOW the drum is centered on the hub: the drum is NOT a snug fit around the hub, as on late-60's early '70s GMs... it would appear that the "blank" drums were hot-rivetted to the hubs, then the drum was machined so that the braking surface was concentric with the hub... I am thinking about using hardened "button-head" allen screws to replace the hot rivets, but am still concerned about being able to get a used drum adequately centered on the hub, as I won't have a whole lot of lee-way to turn the drum "true" before it gets too thin... Has anyone been down this path before and have any helpful suggestions? Thanks, Frank McMullen Quote Link to comment Share on other sites More sharing options...
James_Douglas Posted January 2, 2007 Report Share Posted January 2, 2007 Frank, This a 11" or 12" drum ? Quote Link to comment Share on other sites More sharing options...
captden29 Posted January 2, 2007 Report Share Posted January 2, 2007 there is always a good reason why things are built the way they are. i would not fool with putting the hub together any other way, not even to sell it. gotta sleep at nite. there are plenty of sources for either a new or used drum, from $75 to $250 depending on how much you will spend and who you trust. i got one from a south dakota junkyard in hemmings for $175 plus shipping when the lug bolt holes in mine were destroyed by a loose rim. they included the lug bolts and the bearings. i got it cut and all is well. dennis Quote Link to comment Share on other sites More sharing options...
De Soto Frank Posted January 2, 2007 Author Report Share Posted January 2, 2007 James, I'm pretty sure they're 11" x 2". Frank Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted January 3, 2007 Report Share Posted January 3, 2007 I removed all of my drums from the hubs. You can just grind off the end till its flush with the hub and press the pins from the hub. They are really in there tight. I replaced all the pins with a "spring pin" thing that is a rolled up piece of spring steel. It is pushed in from the back side of the hub until it is nearly flush, what sticks out the drum side can either be ground off or used as guide pins. That was ten years ago and the drums have not moved any. Some have said this should not be done, but it seems to make no difference. Rear wheel brake service is a snap since I don't have to remove the hubs. Front wheel brake service does not require bearing removal. For legal purposes; I am not saying you should do this, I am only saying that I have done it with no negative results. It does promote regular brake checks since it is easier to do. I would suggest that if you decide to remove the separate the hub/drum assemblies, do not attempt to drive them out with a BFH, as you will crack the hubs. They must be pushed out with a press or a large vise. Once you have ground off the ends, you can remove the hub from the drum aking it easier to push the pins out. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted January 3, 2007 Report Share Posted January 3, 2007 years ago I saw this fixed by a shop..won't go any further than that except to say I saw it and it was not me...lol But!! the fix was taking out the race..using a sharp center punch and go around the entire hub where the race sits and punch little dents..this will distort the metal and actually shrink the ID so that the new race can again be pressed into place...may very well work for you and save you a lot of headaches..your car..your call...by the way this did work very well. Quote Link to comment Share on other sites More sharing options...
Tim Frank Posted January 3, 2007 Report Share Posted January 3, 2007 If you do remove the hub, could you not get the bearing seat hardchromed and machined back to a press fit? If you are swapping hubs, you should be able to make a 5 or 6 lug circular plywood template attach it to the hub, mount the whole assembly on a lathe and trim the plywood to an OD the same ID as the drum. The plywood will locate/centre the hub for reassembly. While I agree with the earlier comment/caution that there is usually a reason for the way things are built, in my experience it is often for manufacturing expedience and efficiency. Cars of this vintage could be repaired and often were by ordinary people if common sense and skill were blended. This forum is a running summary of both common sense and skill.....I think Walter Chrysler would be well pleased! Quote Link to comment Share on other sites More sharing options...
Young Ed Posted January 3, 2007 Report Share Posted January 3, 2007 Tim my trailer had spun wheel bearings in it and I did that exact same thing. Its made a trip to Madison WI and a few to the cabin with no issues. Oh and I put 2000lbs of gravel in it when I redid my steps. Quote Link to comment Share on other sites More sharing options...
De Soto Frank Posted January 3, 2007 Author Report Share Posted January 3, 2007 Niel, Once the rivets were out of the hub/drum, do you recall if the rivet-holes in the hub and face of the drum were the same size ? Yes, the original rivets would have been a very tight fit indeed: these were hot-rivets ( such as were used in structural steel building construction), which were heated red-hot ( or hotter) before they were installed: as the rivet was peened-over, the shank expanded to tightly fill the holes it was being installed in. ( If any of you remember the Bugs Bunny cartoon where he gets into a battle of wills with a construction foreman who insists on building a skyscraper right over top Bugs's rabbit-hole, I believe there's a Rube Goldberg sequence involving hot-rivets!). Guys, thanks for the various replies - lots of good ideas here. Frankly, I would love to just find another hub & drum, but my local yards seem to be "Fresh-out of" '41-'48 Chrysler/De Soto... and the thought of paying $150 or more for a junkyard drum is "sobering" to say the least... I think I will try the prick-punch method first, and see how that goes... Quote Link to comment Share on other sites More sharing options...
James_Douglas Posted January 3, 2007 Report Share Posted January 3, 2007 Everyone should note that in the MOPAR Master Parts Books for 1946 -1948 (and no doubt others) that the hub and the drum could be ordered as separate items. Now, I doubt very much if a local dealer had the tools to preform a hot rivet operation. I ran a drum on a hub on my Suburban with button head hex grade 5 (don't use grade 8) bolts for over a year without any issue. The suburban out tips the scale over all the other cars on the forum for this period by the way. Frank. If your brakes happen to be 12", give me a call. Best, James Quote Link to comment Share on other sites More sharing options...
De Soto Frank Posted January 3, 2007 Author Report Share Posted January 3, 2007 Thanks James... I measured my drum last night: 11 x 2. I'm curious: why Grade 5 as opposed to Grade 8 ? Also, what size & thread bolts did you use ? Actually, there might be a machine shop near me that could do hot-rivets: Steamtown National Historic Site... they still use them for resto of steam locomotives... I'd just have to make friends with one of the shop monkeys and figure-out a way to disguise a brake drum as part of a PRR K-4 Pacific... ;-> Quote Link to comment Share on other sites More sharing options...
TodFitch Posted January 3, 2007 Report Share Posted January 3, 2007 Are you sure they were hot rivets? Someplace I have an automotive trade magazine from the late 1920s or early 1930s that showed the process of riveting a new ring gear onto a differential carrier. They specifically said that the rivets should be set cold. The claim was that a hot rivet would shrink as it cooled and not give as tight a radial fit as a cold set rivet. I have seen footage of Chevrolet frames being manufactured in the late 1930s and the rivets appear to be installed cold. It would seem to me that a cold set rivet would have to be made of pretty soft steel. Even hot set rivets would not be cooled in a manner that would reliably harden them. So I wonder about the need for grade 5 (or grade 8) hardware when substituting for rivets. Granted, those are different applications than holding brake drums onto axle spindles. I will also grant you that the one time I tried to set a large rivet (repair and replace a spring shackle perch on my 1933's frame) I could not make any head way on setting the rivet until I used a lot of heat. Quote Link to comment Share on other sites More sharing options...
james curl Posted January 3, 2007 Report Share Posted January 3, 2007 At our only auto parts store that turns brake drums Mo Par and Studabaker products have to have the rivets drilled out so that the drum can be mounted on their turning lathe. They can not turn them with the hub in place, front or back. As far as I know only Mo Par, Studabaker and possibly Packard are the only companies to rivet the hubs to the drums. I was told that I would have to remove the hub from the drum if I wanted the drums turned, I declined their offer. Quote Link to comment Share on other sites More sharing options...
captden29 Posted January 3, 2007 Report Share Posted January 3, 2007 you absolutely do not have to remove the hub to turn a drum. the machine that turns them uses a cone shaped piece to hold and center the drum. the rears are the problem as they do not have a hub and require a special adapter to center it for a proper cut. i don't have anyone in my area that can turn rear drums. dennis Quote Link to comment Share on other sites More sharing options...
1just4don Posted January 3, 2007 Report Share Posted January 3, 2007 "IF" I had a hub I absolutely had to keep in service, our local blacksmith would get the job of welding the hogged out part back with a bead of good steel weld. Then have him stick it in the turning lathe and turn it to exactly the right size again. I have used the peening method discribed before, here, with varied success in agricultural settings. Sometimes it works well,,,sometimes NOT. Depending how much was hogged out. IF severe the weld job for sure. IF not too bad I would peen severely and dimple the heck out of that race seat. Have to use good judgement here to peen enough and IF excessively peened makes driving the race in VERY hard! Otherwise other way might be to have it lathed straight, so its even all the way across and use some sleeve material to get the race 'tight'. My favorite shim substance for this is a wrap or two of aluminum pop cans. It compresses well and has held 'some' bearings 'here' for years and years with NO signs of giving up!! In the applications used in its NOT life threatnening to have a failure,,,just another 'fix-it' job!! (Ask my rider mower front wheels) Otherwise WAY to expensive to replace all that it would take to make it 'right'! Tin cans, like bean or soup cans can work too,depending on thickness required. Napa makes shim stock too,,,but considerably more expensive and no better materials. Welding and lathing would probably be my 'first' choice for your situation,,,any good machinist/blacksmith can advise!! AND if the first one doesnt like it ask a few more!! Quote Link to comment Share on other sites More sharing options...
Niel Hoback Posted January 4, 2007 Report Share Posted January 4, 2007 DeSoto Frank, the rivet holes in the hub and drum are exactly the smae size. That is why I can use a roll pin to hold the drum in the exact same position as the rivets did. I noticed in a junk yard that 70's AMC rear drums and hubs were held together with a couple of small flathead screws. Quote Link to comment Share on other sites More sharing options...
greg g Posted January 4, 2007 Report Share Posted January 4, 2007 How about replacing the lug bolts with studs and then leave the drum loose ala most modern rear drums, then let the wheel lug nut combo clamp and center the drum on the hub. just take the hub and have the threads drilled out and press in some nice new regular thread studs. this seems to work well on rear wheels, and the drums just flloat when the lugs are off. Quote Link to comment Share on other sites More sharing options...
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