CVD's and Dogbones

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mulepic

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Yesterday at the track I broke a cup on my cvd:


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I managed to fix it by boring a hole in a bolt and welding it to the cup:


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It sounds like others are having the same issue. Let's post up the best solution to this. I see some have switched the cvd's to dogbones (part # 50032 & 50034). RCDAD suggests using a piece of fuel tubing in the cups to keep the bone centered in the cup to prolong it.


What have others done to keep the cups or dogbones from failing? What about sleeving the cups? Has anyone tried it?


My goal it to enter the DR in a race in February which will go several days. As of now I can't keep it together for more than 60 minutes of runtime.
 
Does the DR only have issues w/ the cups/dogbones for the axles at the wheels or do the center shafts/cups have issues too?

Does the fronts fail more then back?
 
My center shafts are mushroomsing where the pin rides but I didn't grease / boot them so that's probably my issue. After some of the issues I sure do love the dune runner
 
rampagemt said:
My center shafts are mushroomsing where the pin rides but I didn't grease / boot them so that's probably my issue. After some of the issues I sure do love the dune runner
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What if you use shrink tubing? You could pack the cup w/ grease then slide the tubing over it and shrink to fit.

I have not greased mine every. I guess that's something I should be doing along w/ the fuel tubing.
 
Hey Mulepic...

Seems like several platforms have issues...I have had 1 CVD blow up and have busted a cup on my MT and a cup on my XBe and I know of one guy that has only busted the front center diff cup.

The suggestions that many have done is harden the cups with some map gas.

Many others have sleeved them...I am in the process of that category.

Some have used chromoly, BigFol shared a link with supplier of CF tubing.

I got some 20mm ID tubing and cut up 14mm sections, sanded and sealed with nail polish. I plan on using locktite 680 to install them this weekend.
 
I think sleeving will be the solution. Right now I'm trying to fit a 19mm box wrench over top of the cup. The 19mm opening is just .005" less than the cup outer diameter. I'm going to try heating up the wrench and cooling the cup and slipping it over the cup.

The only issue w/ this is that it's permanent. The only way to separate the axle from the cup would be to cut off the wrench collar. This approach is for those to use w/ common hand tools.
 
mulepic said:
What if you use shrink tubing? You could pack the cup w/ grease then slide the tubing over it and shrink to fit.I have not greased mine every. I guess that's something I should be doing along w/ the fuel tubing.
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I think the shrink tube will eventually come off, I used shrink tube a while back to keep the pins from coming loose. All but 2 eventually tore off.

I'd still use Fuel tubing to center the bone.
 
krashkrieg said:
I think the shrink tube will eventually come off, I used shrink tube a while back to keep the pins from coming loose. All but 2 eventually tore off.I'd still use Fuel tubing to center the bone.
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Thanks, only my front center shaft has enough play in it for me to consider doing this. But I would like to grease up all the cups but not if it is just going to get flung out. We need a solution.
 
I finished up the box wrench approach. I think this is much better than my nut approach. It only requires the use of an angle grinder. I put the stub axle (assembled w/ the axle) in the freezer for a couple of hours. Then I heated up the 19mm box wrench w/ the torch.

The wrench slid over the stub axle easily. You only have a second before everything seizes together. I wish I would have lined up one of the teeth of the wrench w/ the pin.... oh well. Then I cut off the rest of the wrench w/ the angle grinder. Then I put the stub axle in the drill press (very low speed) and used the angle grinder to take off some of the diameter of the wrench so it doesn't hit the knuckle.

I think I will do this for my rear stubs as well. Of course hopefully I didn't just cut up a $50 wrench ;) I suspect I can get some from harbor freight for a buck or two.

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This requires no welder or milling machine. I hope it works.
 
Here's a way to keep your dogbone/cup joint covered and grease in. I'm using a bicycle tire from a racing bike. The type of bike where you put over 100 psi in the tubes...700c I think it is.

This was a pain to get on the cup but that's probably why it would work. I had to use needle noise pliers to get it on and I'm pretty sure it'll last a while.

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RCDAD said:
That looks crazy strong! The wrench makes for one beefy cup sleeve.
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I really like the wrench approach b/c it's quick and simple to do. But I wish I had a way to drill it so I can have an access hole to the pin.

Do the pins fail much?

The only downside to the wrench is that they are $9 at auto store. Maybe harbor freight has them for less.
 
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