My 30 roadster hops some when driving so I set the back on stands and let it run. The rear right backing plate stays just as it should but the drum and wheel wobble. My guess is I have a bent axle but before I take it apart to figure out, can anyone think of anything less demanding to repair that might cause the wobble? I have never disassembled the rear end so I have no idea what I am in for!
Sounds bent but remove the drum and see if the key is broken or sheared off. If you do have to take it apart it's not that bad.
We haven't either. Need to tell us what kind it is so we can look it up in the manual. I'd pull the wheel and make sure it's the axle flange wobbling. Could be a bent wheel. Are a loose wheel.
First off, thats a wicked roadster! I am guessing by the pic of your car that you have a Banjo rear end in there. You may have a sheared or twisted key way or a problem with how the drum is mated to the axle. If its a newer read end under there it may have a bent flange. First thing you need to do is remove the wheel and drum. You may see a problem right away. If its a Banjo, the drum should be hard to remove with out a puller, if it just pops off then you may have found your problem. The banjo has a tapered axle shaft with a keyway to hold the drum in place. Using a dial indicator, place it on the axle shaft (if its a banjo) or axle flange (if its newer) and rotate it by hand and measure the run out. If its realy bad you may not even need the dial indicator to see the issue. If you have a banjo, the entire diff needs disassembled to replace an axel, anything else is very easy. The only issue will be getting the right one with out knowing exactly what its out of. Axels dont just bend with out hitting something, did it just start doing this?
I guess a little more detail would be good. I bought the car as a rolling wreck two years ago. I went through everything on it and just got it on the road. I thought before that the rough ride was tires and wheels so to date all tires and wheels are replaced, all new brakes, backing plates, rear hubs, drums, etc. I never did open up the banjo rear beyond the hubs but the shims, key, etc are all new and in good shape. So it sounds like there is nothing left but a bent axle.
You can see what I wrote below but it has been doing it before I did a frame off on the car. I always thought it was wheels or tires and I replaced them, along with all brakes and the rear hubs, so I think the axle was bent when I picked up the wreck I started with. Thanks for the input. I guess I will be pulling it apart after Hot August Nights!
If you replaced the drums, did you check how they seated on the taper before installing them? Sometimes you have to lap them in like valves before installing them. Did you torque the rear axle nut to spec? If not, its possible that it was not seated properly and has loosened off some. With the wheel off the ground, grab the top and bottom of the tire and see if there is any movement in it. Shouldnt be any. That will help give you a bit of direction. It would suck if you have to replace an axle, but, it might be a good excuse for a quick change if you dont already have one and wanted one
Woodz pretty well gave about as good a batch of suggestions that anyone could come up with. I'd pull that wheel with it up on the stands and run it just as you did before and see if you can see the end of the axle wobble or just the hub/drum. I'd lean towards the axle being bent though.
Mount another wheel and see if it wobbles. Might have to rule out the out of roundness of bias tires? Cool car!
MO. Do not drive it till you sort it out, If you have a bent axle, ( which I doubt) the drum, would not be correct on the backing plate, Jack it up, take off wheel, block other wheels , put in gear, watch drum, How the heck could you have a bent axle without distorting the backing plate and flange of axle housing? Be aware when jacking up, wheel might FALL Off, you may have a broken axle. Does the wheel and brake drum wobble on the same plane? I am assuming, (a word I hate) you have a early Ford rear end.. I subscribe, want to be here for report.... Bob
I will perform the check you mentioned. I have another rusty Model A rear end sitting outside my garage so I may have good parts there for the repair. It would be great to not have to change out the axle though as it sounds like a lot of work. The backing plates do appear flat seated. I had to do a lot of modification to the front hubs to get those seated but the back plates bolted right up to the after market hubs designed to space them out.
The axle is basically a floater on a banjo as the bearing is on the hub ...I would think if you are seeing movement between drum and backing plate , the drum or hub flange is bent...
The backing plate and housing stay perfectly still and the wheel and drum wobble. I suspect it is the axle but have no experience with this problem.
If the axle is bent there will be radial runout at the end of the axle. With the axle off the ground, just rig up a simple fixed pointer (framing nail thru a piece of 2x4, or something similar) set up so its pointed at the center of the axle end. Then, when the axle turns, it'll be real obvious whether or not the axle is bent. If you want to know how much its bent, just replace the nut temporarily with a nut whose OD has been turned round. Then you can use a dial indicator against the OD of the round nut to measure the total indicated runout. The actual amount of the bend at that measuring point would be half of the total indicated runout.
I posted video to show what is happening. Strange for sure but again, all wheels, tires, the hubs, brakes, backing plates have all been replaced. It did ride bumpy before I did all of this and I always assumed I had a bent wheel. So it seems all that is left is the axle.
The drum is running out in sync with the wheel and tire, so either the axle is bent or the drum/hub isn't seated properly on the axle taper. Since you've checked the fit on the axle and found its good, that leaves nothing but a bent axle as your problem. If you check the end of the axle like I outlined above, you'll know for sure that its bent and that its not some wierd thing where the tapered bore is machined crooked relative to the hub centerline.
only thing i have to say is I would not drive that car untill that is fixed that could cause you or the guy behind you a very bad day
OK, we see the drum moving, how about a similar video with the wheel and tire off and something close to the tip of the axle for reference?
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