You won't believe this

[rficalora]

Made some good progress this weekend on exhaust and misc. other things.  Then took my wife for a quick ride.  Chirped the tires going from 1st to 2nd, then clunk, clunk, clunk...  

[mgb260]

Rob, Man, If that is the way those axles were built, I would take them both off and redo them. The "pin" should be 3/4" tool steel and both sides of the axle chamfered 45* and the gap built up with weld. I prefer one piece axles and am planning on using a VW Vanagon axle cut in half and resplined. Makes two 1 3/8" super strong one piece axles about 11" long and then VW Type 2(Transporter/Vanagon) CV's with Microstub and Dodge Intrepid hub(33 spline 5X4.5 Ford bolt pattern). The axle pictured is 14" for Datsun 510.

[Bill Young]

Looks like Todd needs to do some redesign in that area. I'm sure he'll come up with something that will hold up better. No self respecting V8 MGB owner should be restricted to not chirping the tires now and then. ;-)  Maybe something like the way Jim Blackwood spliced the axles on the Roadmaster rear end. Those have taken some abuse already in the parking lot at Indy and no problems so far.

[74ls1tr6]

Hi Rob,

I went through the same thing with my CV axle. The CV blew out with just spining tire acceration. I had to do it to make sure they would hold up to some power, and not wanting to be stranded somewhere. When this blew out, the car wouldn't move under its own power.

I was lucky that Richard Good stood behind his products, and sent me some new axles that were better made.

Good luck!

[mgb260]

Bill, The stub ends inside a tube welded on each end like the Roadmaster would be an excellent fix.

[rficalora]

Anyone know what page of the roadmaster project this was dealt with?

In the interest of time I might have to order new ones but I'd like to fix the ones I have if I can.  Seems like where the current welds are, a sleeve would need to extend through the hub side boot so I'd need to find:
 - the right size tube for the sleeve -- what material/wall thickness?
 - a replacment boot with the same big side & bigger diameter on the shaft side -- where would I go about that?

Once welded, does the 1/2 shaft need to be heat treated or otherwise treated?  Anything special in the welding process?  I don't think I want to attempt the weld, but there is a great welder nearby who I could probably enlist to do the welding.

[Bill Young]

Rob, there isn't much detail on the forum in the Roadmaster section. On page 19 Jim described it like this:

" Good enough for the uprights, at least for now, we next turned our attention to the half shafts. First we rough turned the shafts to 1.020" and then set up for finish turning and polishing, cutting both shafts to 11-7/8" x .997", which gave us.0005 to .001" of clearance with the tube.We precisely cut the tubes to length, squared and chamfered the ends, and cut the shafts to exactly fit the length of the tubes. On assembly the fit was dead on, so close in fact that the parts slid together easily but snugly, trapping the air inside and bouncing before being shoved home. They snugged up just right as they seated, but still could be rotated. I don't think we could have gotten a more perfect fit for this application. Once welded the internal shaft will provide full support for the tube to help resist wrinkling under torque, and the slip fit will allow the torque to be absorbed by the full length of the tube rather than a short section between the ends. Given the weight of the car I think they will hold up well. "

I found some thick wall DOM tubing that was close to the required size of the original half shaft and Jim cut the half shaft into, narrowed it and then chucked it in the lathe and turned it down to a very close slip fit in the DOM. He then welded it in place on both ends. So far so good as we chirped the tires repeatedly at Indy. Granted those were old hard as rocks tires that came on the wheels that Flying Circus donated, but they're wide and still have a bit of traction left in them.

[rficalora]

Custom axles are looking like about $425 each side -- and early estimate is anywhere from 3 weeks to 90 day turn around.

If I've got the roadmaster approach right it is basically to turn down the sections to be joined; snug fit DOM pipe over that; & welded at each end of the DOM sleeve.  That sounds like it's not much different than what I had snap already --- the weld is only as thick as the DOM tube; maybe a little more.  I must be misunderstanding something?  What will keep that weld from breaking the same way -- or the DOM tube from twisting?

[DiDueColpi]

Hey Rob,

Do you have an end shot of the broken pieces.
From the pictures that I've seen the break looks odd.
Jim's method for shortening the 1/2 shafts should work just fine. If it's a concern you can drill and plugweld the DOM tube in several spots to lock it in better.
Another option is a friction or spin weld. Basically the same build up but instead of welding. The shaft is spun inside the DOM tube on a large lathe. The tight fit causes the shaft to sieze inside the tube creating a very strong joint.
CV boots are very pliable and will accomodate the larger shaft size without a problem.
When you have the outer CV joints out, do not put the cars weight on the wheels. The wheel bearings are held together by the CV joints and they will be destroyed if they are not clamped together.
Any way, hang in there.
Stuff like this happens and it gives us good stories to tell down the road.

Cheers
Fred

[Six0GTO]

The difficulty here is the shafts are of two different diameters. The GM shaft has a 1.250" shaft and the Nissan shaft is closer to 1.75". These shafts were made using a method that has worked well in other units be it a lower HP  but just as much torqe. The shafts are center drilled, tapped, machined down with a 45deg angle to a minimum of 1/2" the thickness of the shaft. The dowel is a tool steel grade bolt that is threaded about 1" into each end of the shaft. This is a method that was tought to me by an Army machinest that repaierd broken hummer axles this way.for years.

I have moved away from this method. Hawk also has had many failures with this same issue. Rob's build was uniqe in that we needed a 5 bolt hub that would work with the wheels that he purchased. The S-10 Hubs had the right peices parts

. There is a fix that I have to solve Rob's imediate needs. I will machine down a stock shaft to fit into the stock Nissan yolk and weld the yolk to the shaft. The Nissan yolk is rebuildable by replacing the 3 smaller cylindrical bearings that slide in the hub. This allows a treamnedious amount of  weld to be put on the yolk and not effect its operation. The shaft will be macined infront of the yolk to allow for maximum penitration into the shaft. It then will be sent for cryo treatment to make sure the shaft will not break or twist at the weld.

Any new IRS units are built with porsche CVs that have adapters for almost every hub and differential configuation imaginable.

[DiDueColpi]

Hey Todd,

I knew you'd be in there taking care of things.
It's as heartbreaking for you as it is for Rob.
If I can be of any service PM me and we'll see what we can do.

Cheers
Fred

[flitner]

I dont want to hurt anyones feelings, but the way it was set up was fairly weak and I dont see much penetration of weld into the joint, If you pick up some DOM tubing and turn the stubs to fit inside snugly and trued, staggered rosette welds and a final weld around the joint will get it strong to last long,  using the components you have will save alot of coin and get you running again.

[Bill Young]

Rob, the secret to the DOM success is size. Just like a drive shaft the larger the diameter of the tubing the greater the torque capability is even with a thinner wall. On the Roadmaster the DOM ID was almost as large as the original half shaft diameter. Just small enough to clear the coil over shock. Then the half shaft was turned down it wasn't much to slip fit inside the DOM. Jim Nichols posted a photo on page 10 of the Roadmaster threads that shows a stock Jag half shaft, one that is spliced with small DOM tubing and one that is spliced with a larger diameter DOM tubing, the later is the way Jim B went. According  to Jim N the use of the larger tubing made the part 4 times stronger than the  smaller tube shaft.

[rficalora]

Ok Jim, Fred, & others with experience with this stuff -- I think I may be in better shape than I thought but not sure it really changes the decision points...  For a while I was thinking I had tripod type CV's but now that I've taken them apart, they appear to be regular Rzeppa 6-ball type (see the pic below).  When I thought they were tripod style I was concerned I'd be throwing good money after bad if I put money into the the axles (I got some input that the 280Z crowd seems to find that to be the weak link when they do Ford or Chevy V8 swaps & some quick internet research seems to support that).

Assuming the CV's are regular Rzeppa 6-ball, then I should be ok strength wise right?  So I'm back to 3 options --

a) Least expensive answer is sleeving & welding them.  Note, DOM would only extend about 1" over the existing axle on the hub side.  Any more than that & it would limit the CV angles by the yoke (if thats the right term).  On the other side it could cover the smaller diameter portion of the 1/2 shaft to the point where it gets bigger.  Anyone care to give odds on them breaking again if I go this route?  Cost for this is pretty minimal.  Todd will fix the broken one but wants me to pay to do the same to the other side since it's not broken -- ~$150.

b) Next most expensive is replacing just the axle shafts.  Two downsides on this are 1) turn around is longest -- 4 weeks to 90 days depending on which supplier and 2) I'm not sure I can disassemble/reassemble.  Most of it looks pretty easy but there's a retaining clip of some sort holding the CV inner collar to the shaft on the hub side.  I don't know how to remove or replace that or if special tools are needed?  Or if the collars need to be pressed off/on.  If I have to have a CV rebuilding shop do that stuff, the cost of this option & the next start to get pretty close.  1/2 shafts alone are about $550 from The Drive Shaft Shop in NC.

c) Complete replacement axle assemblies.  The Drive Shaft Shop in NC offered this solution:
our axles would use a billet plate to bolt to the inner flange (6 bolt)
 to convert it over to a porsche 930 CV joint and the outer would be a
 Chromoly one we use for the kit car market. i would need dimensions
 from the flat of the inner flange to the back of the inner race of thw wheel bearing
 (where the CV touches the inner race)
Turn around for this option is 1 week which is good.  Of course, cost is the highest @ $750 (& I'd have to verify that it's the same to do a 5 bolt flange instead of 6 bolt).

I'm leaning toward option C since that should be a do it once & be done answer & the turn around is as good or better than the other options.  But if option A really has very low odds of breaking again I'd be throwing away a lot of money.

What do ya'll think?

Rob

[flitner]

I drove ( flogged) the heck out of my B until a rear wheel suddenly had a different vibe to it and wobbled to boot, come to find out the axles(9"ford) were welded and not even in the correct place, I went ahead and got new axles from Mark Wms.

 DOM done the right way and well thought out would be plenty strong, I see the problem with the dual 6 ball type, there would be minimal or no slip action causing binding at extreme travel, like putting a solid shaft in a 4x4 with no slip yoke, unless the geometry is dead on its gonna break.

If you have the coin and more things to finalize on the B during the down time, go for opt. C for the piece of mind

[mgb260]

Rob is the diameter on the unbroken side the same as the broken stub? If so I would cut it off about the same,clean it up, use 1/4" thick DOM tube full length to replace the fat center part. Tig weld and plug weld twice on both ends. This pic is for a u-joint shaft but you get the idea.

[mgb260]

John is right, you have to have plunge on the CV's at least on one end as the suspension moves up and down. The VW/Porsche type slide on splines on both ends. Can you compress the end with the bell?

[mgb260]

Here is a picture of the Driveshaft Shop setup. The adapters look just like mine except mine are for VW Type 2 Transporter/Vanagon. Porsche CV is 108MM/28 spline. VW Type 2 is 100MM/33 spline. Both, If done right should be good to 600HP.

[DiDueColpi]

Hey Rob,

To start with only your outer joint is a Rzeppa joint.
The inner is a plunging disc joint that allows the 1/2 shaft to change length with suspension movement.
So no real worries with what you already have.
They should be easily able to handle your toque ( oops.. Canadian slip) torque needs.
Your present axles modified with some DOM tubing will hold up just fine as well.
Turning the inner axle to the same dimension as the outer stub and joining them per Jim's description will work well.
Be carefull with the VW/Porsche CV joints. They come in two flavours. A true fixed Rzeppa joint and a double offset style.
They aren't intended to slide on the splines.
If however, your pockets are deep enough.
Option C would be prefered and would be the most reliable fix
Not to mention they probably look the coolest.
It's your call.

Cheers
Fred

[rficalora]

Thanks guys.  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?

[mgb260]

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.

[74ls1tr6]

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.

[flitner]

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.

[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)

[DiDueColpi]

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