I went out last night to block up the 26 touring last night for the winter & discovered that the right rear wheel was loose at the hub. I pulled the wheel (I've never had the wheel off since I bought the car) to find the chewed up remains of a shim which had been on the tapered portion of the axle & a key that had grooves worn along both sides where it had been "worked" because of the loose fit. I cleaned it all up (everything else doesn't appear to have suffered any damage) & made a new key.
How does one go about determining how thick the new shim material should be to get the hub in the correct location?
Try a tin can. Or you can order from one of the vendors.
Here's a link to the shims from an ACCESSORY OF THE DAY post a while back.
Axle shim of .005" usually works fine.
For those ugly looking taper hub bores, then I have made .010" shims....
The ideal shim thickness is .000, zero. If your axle and/or hub is worn out, replace them. You will only find that in a short while, your wheel will be loose again and you'll have another chewed up shim that sometimes migrates up the shaft, through the seal and into the Hyatt bearing.
Mike, You can use a shim quite successful. If you put on one shim and then retighten it a couple times after driving it wll not loosen up anymore. One benefit of using a shim is that the hub comes off easier next time you pull it. Mike
The name of the game is having the hub/brake drum covering the entire brake shoe but not rubbing on the backing plate. The "how thick a shim" part depends entirely on what you're working with.
The most important thing to remember is that the hub and axle taper must mate completely. That's what keeps your wheel turning, not the key.
Once you're back together and on the road, remember to check those axle nuts. You're not done with this project until you can't tighten them up anymore.
Even then, it's a good idea to check them check them once in a while.
Thanks for the input. I sorta figured that if nothing else, I'd use the backing plate as a gage to determine the best fit for the brake drum.
I was shocked to see how loose the wheel was. I remember shaking all 4 wheels when I first discovered i had loose spokes in 2 of the wheels (this particular wheel is tight) on the car.
The left rear wheel is tight at the hub, but I think I'll pull it off while I've got the car jacked up to see what's in there.
On a side note, this car was give an amature restoration probably 20 or so years ago. The cap on the end of the axle tube looks to be a replacement. the thing that got my attention are the nuts which hold the brake drum on the wheels. They have been worn nearly half of their thickness from rubbing against something (I asssume they were rubbing on the brake shoe spring or the area of the backing plate that is part of the axle). There are no similar wear marks on the end of the axle. I figure either the wheel, or axle tube, are replacements & weren't originally mated together.
DO NOT use aluminum, brass, for a shim. It is too soft. Yes, in a perfect world, fixing the worn parts and having no shim is the best, but if you have to use a shim, make sure it is steel, and carry the torque wrench with you and check that axle nut at 5 miles, then 25 miles, then 100 miles, then every 250 miles, or as often as you can after that. Even a real nice shaft & hub combination can be good and tight for thousands of miles, then be a little loose one day for what seems like no reason at all (well, actually: heating & cooling cycles, side loads, wheel imbalance, heating from use of rear brakes, lubricant creeping down the key way and around the taper, rough roads, etc, etc...). The hubs on my T have always been good and tight, but that doesn't stop me from checking them during the season in the course of other regular maintenance. I probably drive about 5,000 miles per year and figure I probably spend about two eight hour days each year taking care of "regular maintenance" on the T.
The nuts you are referring to are in fact thin compared to standard nuts. They did not likely wear themselves thin even though it is not uncommon to see those nuts kinda shiney from rubbing on the brake shoes at some point.
One thing concerns me. You say you made a new key (or did you mean to say you made a new shim?).
I think the axle key is harder than a lot of standard keys. Just a thought.
I did make the new key from regular key stock (I ground the taper to match the old one). Isn't it odd to have a hardened key??? I don't ever see a situation where the joint would be in a big bind, but shouldn't the key be softer than the hub & axle?
I also made the shim from some steel stock I had (I have my own machine shop here at home). .005 seems to put the hub where it belongs.
Yes, I knew the brake drum nuts were supposed to be thinner than normal nuts, but these are obviously damaged from rubbing against something (the surfaces are very uneven and all 6 match).
I agree that in a perfect world, you would not use shims in this manner. But axles and hubs wear, and they do not always wear alike. Wheels and axles get mixed and matched over the years. Definitely, do not use soft metals like brass or aluminum. But the shim acts as a sacrificial wear point. It will wear and hammer down where the "high spots" between the axle and hub meet. That is why you must tighten the hub nut several times over the next thousand miles. A mildly hard steel is best. The heavy mass of the axle and hub will hammer down the harder, but thin shim material.
The easy way to make a shim from scratch. With the wheel off (presumably rear end on a jack stand), wrap a piece of paper around the axle. Squeeze your hand around it to crease in the keyway and small end of the taper. Since there is no sharp edge on the large end, use a pencil to draw it. You now have a simple pattern to cut out and trace onto your shim material. Check the fit after cutting it out. Some additional trimming may be necessary. I like to use the sheet metal from an empty rattle can.
Happy Holidays, and drive carefully, W2
Locktite makes a bearing lock fluid, would that help keep the shim from moving?
Loctite Bearing Mount 680
A farmer friend of mine who is also into T's, swears by Locktite Quickmetal when making repairs to farm machinery which has had flogged shafts/chain sprockets etc. You assemble the parts as usual, with a liberal coating of the product to each component, and they stay where they are put!
I was skeptical at first. When I rebuilt his rear end, he had me use the stuff on each rear axle to compensate for worn keyways in the axles and one worn hub.
He came back later with a brake shoe problem, requiring removal of both rear wheels to check/fix the problem. I was not looking forward to pulling the wheels. Heat is the answer, and all we had to do was warm the hub, not enough to blister the paint, and off they came! They were certainly still well seated before we applied the torch, and the ease with which the came away surprised me.
We replaced them with the same stuff. That was years ago and they are still holding up. There is no substitute for doing the job properly, but this stuff certainly buys plenty of time until a rebuild becomes necessary.
I have not used it on my T's as yet, but it has worked wonders on a Case harvester on the shaft of the fan which propels the chaff through the rotor. Saved a heap of down time and money having the shaft rebuilt and re-machined.
Allan from down under