Steering, Suspension, & Brakes

No, Rob, You would have matching stubs on both ends and go full length with the DOM tube. Look at the red lines in the drawing. It would replace the entire center of the axle. Believe it or not the hollow tubing is probably stronger than the solid shaft.



Edited 1 time(s). Last edit at 03/23/2011 08:44AM by mgb260.

My new CV axles only have one moving CV joint on the inner CV joint. My old CV axles had a floating axle that both CV joints moved.

There is an adapter from 5 bolt to 6 bolt at the diff R200 like yours Rob. I don,t know if your diff are 5 or 6 bolt flanges. Richard Good has those adapters from 5 to 6 bolt already made up if that helps.

[quote]The concern I have with the DOM approach is that the shaft is not the same diameter for the full length. Unless I'm thinking about this wrong, the DOM would only go from about the 10 1/4" mark to the about the 11 1/2" mark in the pic I included above -- at least unless the entire length of the longer piece were turned down to make it uniform size? Is that what you're thinking?

What I was going to suggest last night is to go from the 2 inch mark to the 11 1/2 inch mark having equal stubs as Jim pointed out, snugly fit and rosette welded and then welded around the end of tube to stub.

Tube is stronger torsionally than solid.



Edited 1 time(s). Last edit at 03/23/2011 11:47AM by flitner.

Even if you were to have the stubs turned down to 5/8 od to fit into 5/8" id x 1" od DOM tube it would be strong!
edit, you could go deeper this way and closer to the flange, also bevel the end of the tube and step in the stub for best weld penetration.
Sorry for the crude drawing ;o)



Edited 1 time(s). Last edit at 03/23/2011 12:18PM by flitner.

Yep,

As long as it's in the lathe I would make the DOM tube go the full length.
Just like the rest of the guys are saying.
Much stronger and better appearing.

Cheers
Fred



Edited 1 time(s). Last edit at 03/23/2011 03:03PM by DiDueColpi.

One last question, then it's decision time... is there any value to the existing axles/CV's that I might recoup on ebay or the like? E.g., if new axles are on the order of $775 to upwards of $1k, are there folks out there who'd see these as a bargain - either for parts or to make to the size they need by cutting/turning & using DOM like above? If there's a market for them, any idea what I'd likely be able to get back?

Rob, I can;'t see that they would have any value to anyone else as they are built for your particuilar applicatiion and IRS. I don't know what Todd has to say, but if it were my car I'd use the existing axles and some DOM and try it, really don't have much to lose for now and the cost would be small even if they didn't hold up. You'd have plenty of time to try them out before taking off for Townsend. I'd use some DOM that was just small enough OD to clear the shocks and other suspension bits with an ID just smaller than the OD of the smaller of the two stub axles you're working with. If you need a source for a small length of DOM at a reasonable price let me know, we have a good store here in KC that sells stock by the inch. That's where we got the stock for the Roadmaster rear axles. I can get it and ship it to you. Check out their website to get an idea of the sizes available and the cost. [www.metalbythefoot.com] Same goes for anyone else that can't find stock locally as long as the quantity is small enough to ship by UPS or parcel post.

Yeah, I checked ebay & nothing but parts for OEM cars - nothing that looks like they're catering to the hot rod crowd.

Looks like I'm going to have to remove the passenger side & measure before I finalize dimensions because I'm confused. I put the car back on the ground & measured from the diff flange (where the axle bolts up) out to the bearing where the outer CV meets -- it's 17". I then put the axle back together & measured it from the same places & it's only 16" -- even with the inboard plunge part fully extended to the very end of the plung housing. I measured twice & got the same result. It's almost like there was a 1" piece welded in the middle that broke loose & got lost when the axle broke -- honestly, I can't imagine that could be the case but I haven't been able to think of another explanation. Before I can close on either machining or the drive shaft shop I need to sort out what the right measurement is.

Rob the weight of the car compresses or plunges the axle slightly. Maybe the axle was slightly too long and bottomed out is why it broke. You would think at normal road height it wouldn't be compressed very much. Tape it up and have somebody push down on the fender and see if it bottoms. A lot of times the axles are different lengths to center the pinion. If the control arms are the same length both sides, the axles are probably the same. Also on my R230 the output flanges are different length from the diff.



Edited 1 time(s). Last edit at 03/24/2011 12:36AM by mgb260.

Actually what I'm seeing is just the opposite Jim. The [broken] axle is measuring 16" from diff flange to hub bearing mating surface -- that's with the axle plunged "out" to where the CV balls would be at the very outboard edge of the collar -- any more out & the axle would fall out of the collar. That's why I was saying it's like a piece is missing.

I get it after rereading. Long day at work. The wheel is just moved out with the axle out. Jack up that side and I bet you can push the wheel in and bolt up the taped axle. Put the car back down on the ground. Then try pushing the fender down and see if it bottoms. Then you can measure both axles and see if they are the same.



Edited 1 time(s). Last edit at 03/24/2011 01:44AM by mgb260.

Quote,,,,,,,, The wheel is just moved out with the axle out. Jack up that side and I bet you can push the wheel in and bolt up the taped axle. Put the car back down on the ground. Then try pushing the fender down and see if it bottoms. Then you can measure both axles and see if they are the same.

Take a measurement with the car jacked up then with the suspension compressed and make sure the travel is correct with the travel in the cv joints.
If need be wind the spanners on the coilovers back to get a few extra compressed inches of travel for any unforseen circumcisions.

Rob, I was just reading through the Roadmaster build posts and found where I posted the size of the DOM tubing we used. It was 1.5" OD with a .250" wall thickness.
If your axle did indeed reach the end of the travel in the CV joints that would explain some extra stress placed on the welded area. Add the torque plus some linerar stress could easily result in a stress failure.
In the Jag rear the half shaft acts also as the upper control arm so it has to be able to handle both rotational and linerar forces. So far there are a lot of Cobra kit cars and hot rods running around with axles narrowed using DOM that seem to be doing quite well.
Todd, hope you know we're not trying to out engineer you, just offering ideas to both you and Rob on how to fix his problem and get him on the road towards Townsend without worry.



Edited 1 time(s). Last edit at 03/24/2011 10:10AM by Bill Young.

These links are very informational on axle length: [www.rorty-design.com] [www.swayaway.net]



Edited 2 time(s). Last edit at 03/24/2011 01:31PM by mgb260.

Good info -- I'd read portions of it before... what's the deal with unwinding? The pic @ that link sort of looks like the break in mine. Do I need to worry about being sure the axles are spinning the right way if they're being cut, turned & DOM sleeved? If so is there any way to determine if they're on the right or wrong side already?

Rob,

I have never heard of "un winding".
Possibly this is an old wives tale resulting from the twist that some forged axles seem to have.
This twist appearance is caused when the axle is run through a rolling forge to strengthen it.
If this was an issue you would think that the axles would have a direction printed on them.
I've been wrong before but all the witnesses have disappeared.

Cheers
Fred

Basically the axle has to be shortest when level(straight across) and longest at full droop without bottoming either way to determine length. I wonder if you were a little short and when you adjusted your coilovers for ride height extended the distance even more.



Edited 1 time(s). Last edit at 03/24/2011 08:56PM by mgb260.

Rob, I don't know about the unwinding thing, but it shouldn't be difficlut to just do one axle at a time and keep track of what side they each came from and reinstall them on the same side. Most of the problems associated with changing axles from side to side relates to the splined area where the axle fits into the side gear in the differential. I suppose that could also be the same for splines on CV joints as well, so just keep them seperate side for side.

ordered new axles from "The Drive Shaft Shop" in NC. By the time I added up cost of machining, DOM, welding, etc. I was at about 1/2 or more compared to DSS price for complete new axles

And probably some peace of mind.