How To Machine A Prop Shaft Yoke?

[Lood]

A friend of mine gave me a box full of tooling. These include many, many end mills of different shapes and sizes, t-slot cutters, reamers, broaches, expandable reamers, etc, etc, etc. These are worth a fortune and to top it all, most have never been used!

In return, however, he asked me to try and fix his M/Benz Vito's driving shaft. One of the universals seized and these prop shafts are not made to be repaired. There are no cir-clips on the yokes to retain the universals. Instead, they are punched, after the universal is installed. So, basically, you throw it away and buy a new one, or you can cut the existing yoke off and weld on a replacement.
Both the above options are ridiculously expensive, especially buying a complete new prop shaft.

He found a universal that has the same length, but the end caps are slightly larger in diameter than the original. My job is to attempt to machine the yokes out by 1.5mm to be able to accommodate the larger diameter universal bearing, but this doesn't look to be that easy.

Doing only one wouldn't be too much of a problem, but my common sense tells me that the two holes need to be perfectly lined up and then machined precisely and at the same time. Doing one at a time might, or rather will probably result in the two holes being slightly off center from each other, which would wreck the yoke.

Is this possible, or is the way to go to buy a replacement yoke and weld it on? How do I mount the yoke and how do I indicate both holes. I do have a center finder, but not a DRO.
Should I end up getting the yoke mounted, which tool and method would be best to machine with? A boring head or should I try to mount it in a large drill and drill it out to size.

I'm looking forward to any opinions and advice.

 

[GK1918]

If I read this correctly you can't find cups that fit the yoke, and need to open up the yoke?
No DRO, but dro's were not invented yet in my day. Invest in a coax indicator . The big
deal is set up and clamping. Next why the coax is good you indicate the top now & get the
bottom, when the top and bottom is -0- clamp it. Have to have a boring bar long enough.
Thing is light cuts or you get into flexing. I forgot after clamping mark the bore with
sharpie and run the boring head around looking for an even scratch and on the bottom
too. I just did a F700 Ford front spindle that way. Does this help "if I'm on track"
sam :

 

[Bob Korves]

Before you bore out the yokes, make sure you have a way to retain the cups in the yokes at the correct radial dimensions. If I was doing the job, I would take it to the local driveline shop and ask them for their opinion on how to proceed. You might be able to fit a inch dimension u-joint in there after machining the yokes to fit with less modifications. They have no doubt dealt with your issue before, or ones much like it, and if they can do the work for less than the cost of a new driveline, they will have a customer. So, they might be able to help you and tell you what is the best way to approach the problem. They deal with problems like that every day. Sometimes the enthusiast forums on the internet are also a good source of information, after filtering out the Bozo advice...

Edit: I just noticed you are in South Africa. That might change things a bit, but the concept is still worth pursuing.

 

[Ed ke6bnl]

just a novice, BUT can you put the caps in the lathe and cut or grind them down?

 

[kamn]

Just a suggestion, but if you have never built a drive shaft then this might not be the one to learn on. The yoke needs to be centered on the shaft when welded and then rebalanced. And if you are out slightly with centering new u joints in the yoke onec you removed the 1.5mm...its possible the joint could be off centered and possibly bind. If it were me, I would bring it to a driveshaft shop and have them repair it, they can remove the u-joints that are staked into place and install new joints. My Honda Element has the same set up and I also need to replace the joints.
Just a thought

 

[FOMOGO]

Some pics of the part would be helpful in determining the best route to take. If you have a cutting torch you can cut out the center of the joint and knock the caps out from the outside of the yoke. Then you could bore the yoke to size for a new joint of an appropriate dimension or even see if the original bearing is available as an individual part and cut in slits in the yoke for cir-clip bearing retention. The cir-clips generally come with the bearing for most automotive applications. Failing this approach the advice on a drive line shop may be the way to go. In the U.S. many full service auto parts stores do drive line repair. Good luck with your project. Mike

 

[kamn]

These joints are staked in, you can use a dremmel and grind the staked points off to remove the u-joint

 

[chevydyl]

An easy way to line up two bores on the mill is with a piece of drill rod the same diameter as the cap bores, that can ensure its inline with your mill spindle, I do tend to agree that this might not be a good candidate to learn on, unless you have the proper tooling.
Also if you don't have the drill rod you could make your own Arbor on the lathe so it's concentric

 

[bollie7]

You could possibly line bore the yoke on your lathe if you can figure out a way to clamp the yoke to the cross slide or saddle. Some older machines have T slots in the saddle for that very reason.
peter