I installed the pinion conversion on my 404 axles and bolded up the drive shafts. I noticed that when I grab the drive shaft there is a fair amount on play between the new yoke and the splines on the pinion.

I would like to reduce this and wonder if anyone has had the same issue.

I’m thinking about welding the yoke to the pinion? Has anyone done this… good / bad idea?

Welding the Yoke to the pinion will only work for so long, either it will just break cause the flange is mild steel and pinion is harded or it will cause the pinion to fail..
I did my pinion conversion and dont have this issue you are..

I got mine off ebay http://www.ebay.com/itm/220784850955?item=220784850955&viewitem=&vxp=mtr
they come undrilled and are good quality ..

Matt

midog:
first, I am not familiar with the kits or who builds them.

The yoke is intended to be an interference fit on the pinion shaft... not a slip fit. It should tight, either taped or pounded on. There should be No Slop/Play.
I think the yoke was not correctly machined. Return it and get one that matches the shaft.

Many of the conversion flanges are very loose. Most of them use a set screw on the sides to lock them down.

Or you can drill and tap the end of the splines and run a bolt through the center of the flange into the splines.

Ok, to update, what I decided to do was; I ran a quick weld on the "high" spline of the yoke that slides onto the pinion. I had to get my file out and make sure it was cleaned very well and it did not take much at all. I did not want to weld anything to the hardend steel on the pinion.

All the work is on the yoke and it worked out great and a tight fit!