n1gzd_plymouth Posted July 11, 2009 Report Posted July 11, 2009 Well, I am starting a new thread to narrow this discussion to one thing. As you know, I have been fretting about why my new drum/hubs don't fit. After further inspection today (took the day off to investigate) it has become obvious what the problem is. However, the exercise of trying to understand everything that there is to know about drum/hubs and axles was very worthwhile. I have been working on old cars long enough now to know that when you get a new part you should always be suspicious that it is the wrong part and also you should always be suspicious that the parts htat came with the car might be wrong. I did not follow my own advice and learned an expensive lesson. (so you can say, I told you so). MY NEW DRUM HUBS ARE THE PROBLEM. The drum part looks exactly like the old ones and at first glance the entire assembly looks the same. However, the depth of the hub is 1/4 inch longer. This is a LOT. Because of this, the hub could not be pressed all the way on to the axle or it pressed against the bearing dust cover (thus binding the bearing and the wheel could not turn). I drove this car once this way before I saw the light. As you can see from the picture below that my dust cover and the mating surface of the hub are both scored (not enough to be ruined but enough to make it obvious what the problem is. Today I compared the old drum/hub to the new drum/hub and the drums look the same but the original hub is 3 1/8 inches deep and the new one is 3 3/8 inches deep. The keyway on the new one is slightly tighter. Bioth of them have left hand threads on the left side. I was under the impression that plymouths started left threads in 1940 so this could not be a 1936 hub. Is this correct? Here are the casting numbers that are visible on the two hubs (new one is left side, not sure which one I grabbed for the old one): original hub: 32786-R new hub: 05936-R Does anyone have a book that lists which cars have a hub with this casting number on it? I need to figure out what is on my car and I need to figure out what I NOS part bought. If I received what I asked for then I really can't ask the person to take it back (it is a good drum that would be useful to someone assuming that they don't mind that it was scored a little on the backside of the hub (surface that touches nothing so this does not matter). I should also mention that I could not detect ANY axle shaft end play. However, this is not the cause of my problem but I need to find out where I can get shims so that I can add a little bit next time I have the backing plate off. As you recall, my orignal drum/hubs were separated by the previous owner. In addition to trying to find good drum/hubs, I am also going to try and put the original ones back to together (remove old ground off rivets and install new ones). Does any one know what rivets these are? Are they 1/4 inch round head solid rivets? How long should they be. Does anyone know of a known source. there is a machinists parts place near where I work that I am going to check out (called MSC). Here are a few pictures: Rebecca Quote
dezeldoc Posted July 11, 2009 Report Posted July 11, 2009 I think you got later drums and hubs, i found out that their was 2 different ones when i was trying to use later parts that i had. you knock the rivets out and good luck getting it trued up again, try'd that also! i doubt you will find the rivets, might be able to have a machine shop make you some. i think i would look around for the right ones complete, they are out there just gotta find them. Quote
RobertKB Posted July 11, 2009 Report Posted July 11, 2009 Drums do look later. Casting numbers are hard to deal with. There should be a parts number on the drums as well. This will be six or seven digits long depending on the age of the drum. Earlier ones would likely have six digits. Sometimes they are hard to see but I know my parts book lists them that way. ..........I just went out and checked some older front drums I have and I could not see a parts number that works. Best bet is to carefully measure your old drums and phone parts supply places and and give them the exact measurements and explain the fact you think you have a '41 rearend in your car. You could try these guys. Good luck!http://www.collectorsautosupply.com/ Quote
PatS.... Posted July 11, 2009 Report Posted July 11, 2009 Try this fellow!! I'll bet he knows exactly what you need. Quote
dezeldoc Posted July 11, 2009 Report Posted July 11, 2009 That just ain't right Pat, i seen that when it came out and started to have dreams of what might be, then i realized I got no money!! Quote
billwillard Posted July 11, 2009 Report Posted July 11, 2009 I would write all measurements down so you can find new ones. If you can't find new ones any good machine shop should be able to rerivit them for you and turn them down. I think you were sold the wrong drums. They be for a truck. Quote
james curl Posted July 11, 2009 Report Posted July 11, 2009 Would it be possible to have the drum and hub assembly chucked up in a lathe and the inside end of the hub turned down in length by 1/4"? If the back edge of the drum is not hitting the backing plate when the hub is tightened down you could use modeling clay between the backing plate and the edge of the drum to see if you can take the 1/4" off of the inside end of the hub. You could have the machinest measure the taper of both hubs to see if removing 1/4" from the inside end of the hub would work. Quote
Andydodge Posted July 11, 2009 Report Posted July 11, 2009 To reattach the drums onto the hub, just use some countersunk allen screws.......when I adapted vented disc brakes onto the mid 50's plymouth rear brake hubs I had the hubs machined a few thou to slip inside the disc "hat" and then drilled between the wheel studs and put a couple of the allen screws thru into the hub......in my case the original large axle nut then just held a disc brake instaed of a brake drum onto the axle but the procedure is the same..........andyd Quote
dezeldoc Posted July 11, 2009 Report Posted July 11, 2009 Andy, on the drums their is nothing to locate the drum on the hub, it is centered by the reivets. James, the keyway is also bigger on his replacement ones so maching it down would not work. Quote
james curl Posted July 11, 2009 Report Posted July 11, 2009 A good machinist should be able to center the hub into the drum and secure it with a couple of countersunk machine screws. Quote
dezeldoc Posted July 11, 2009 Report Posted July 11, 2009 Sure but is it cost effective? why not just get the right parts. Quote
RobertKB Posted July 11, 2009 Report Posted July 11, 2009 Sure but is it cost effective? why not just get the right parts. Ditto. Get the right parts. Quote
james curl Posted July 11, 2009 Report Posted July 11, 2009 So far the right parts have not appeared, I am sure if she could she would get the right parts. Now can either one of you help her find the right parts? All that I am trying to do is give her some ideas to use if she cannot find the information to locate the right parts. Quote
dezeldoc Posted July 11, 2009 Report Posted July 11, 2009 I had a bunch till the scrap price went up last year! scraped out at least 6 of these things, still don't know why i did not keep the drums, to lazy to pull them i guess. i have a friend checking to see if he has some,he is pretty sure he does, i will let her know. Quote
RobertKB Posted July 11, 2009 Report Posted July 11, 2009 I have a set on my '48 spare axle housing along with the axles and differential. Unfortunately, I said spare as in for my own car. I recently sold two sets of spare rear drums so they are out there but sometimes the search can take a while. I agree machining is an answer, but perhaps one of last resort. Quote
n1gzd_plymouth Posted July 12, 2009 Author Report Posted July 12, 2009 I would write all measurements down so you can find new ones. If you can't find new ones any good machine shop should be able to rerivit them for you and turn them down. I think you were sold the wrong drums. They be for a truck. I will continue to try and get the right drum/hub (preferably a nice one like the one that did not fit - it is really nice - too bad). However, in the mean time I have given it to a machine shop. They are going to try and get the rivets out without damaging the hub. the will tell me what size rivets to get. I still will need to find a wheel centering pin. that does not look like an off the shelf part. However, I could remove it from a bad hub if i need to. I will let you know how I make out. Rebecca Quote
n1gzd_plymouth Posted July 12, 2009 Author Report Posted July 12, 2009 Would it be possible to have the drum and hub assembly chucked up in a lathe and the inside end of the hub turned down in length by 1/4"? If the back edge of the drum is not hitting the backing plate when the hub is tightened down you could use modeling clay between the backing plate and the edge of the drum to see if you can take the 1/4" off of the inside end of the hub. You could have the machinest measure the taper of both hubs to see if removing 1/4" from the inside end of the hub would work. I though of that too. However, I am not sure how this can be done because I think that this won't work because the drum will hit the brake linings. Rebecca Quote
billwillard Posted July 12, 2009 Report Posted July 12, 2009 What is a wheel centering pin? If you mean the pin on the drum to line the wheel up with lug bolts it ant necessary. Quote
TodFitch Posted July 12, 2009 Report Posted July 12, 2009 What is a wheel centering pin? If you mean the pin on the drum to line the wheel up with lug bolts it ant necessary. The pin is not necessary. And my 1933 never had them that was a nicety that was introduced later. It does mean a bit more futzing when mounting the wheel, especially on the front where rotating the wheel to line up the lug bolt holes rotates the drum too. Got to pull the wheel off, rotate it a little, then put it back on again and see if you are close enough to start a lug bolt. Using a screwdriver with a long large diameter shank to guide the wheel on can help. Quote
dezeldoc Posted July 12, 2009 Report Posted July 12, 2009 Put the wheel on the hub, hold the hub and turn the wheel, done deal. or better yet drill out the lug holes and install studs! Oh Yeh someone has 2 rearends for sale in the classifieds for 75.00. Quote
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