1986 Rear stub axle/hub problem
 

I have a 1986 944NA, I have replaced both L & R axles and wheel bearings. The left side went together perfectly, but I am having a problem with the right side.

I put the wheel bearing in the freezer overnight and heated the Aluminum trailing arm with a torch to the suggested temp and the wheel bearing slid right in and the snap ring installed against the bearing no problem. I pressed the hub into the bearing and it appeared normal, turned easily without any play.

When I installed the new axle for some reason the hub then had a lot of play in it. I could move the top and bottom of the hub in and out and as I did the CV joint and axle would move up and down...a lot. I put the old axle nut and spacer on and tightened it down with a long handle 1/2" rachet with a long breaker bar holding the lug studs, I tightened it firmly but not near the 350+ ft-lbs required. As I did the hub moved inward until it was rubbing on the trailing arm and no longer would rotate freely. I took it apart and as you know it ruins the bearing when you do so ordered a new bearing. I installed the bearing as before and carefully checked everything. I had the exact problem with the new bearing. Stupid me I ordered another bearing and did the complete install again with the exact same results. Yes, I am certified crazy!

I am at a loss, the bearing has an interference fit and there is no slop at all when the temperatures normalize. The hub is also a pressed fit with no slop at all. So why does it have slop when the axle is installed?

The only thing I didn't check is fitting the stub axle into the hub before assembling the axle.

How can the hub be sloppy when there is no play in the bearing and no play in the axle when they are pressed in?

I have my 4th bearing on order and I cannot figure this out. I need help!


http://forums.pelicanparts.com/uploa...1659663505.jpg

http://forums.pelicanparts.com/uploa...1659663505.jpg

http://forums.pelicanparts.com/uploa...1659663505.jpg

Can you post a pic of the backside of the hub with axle installed?

If you didn't install the backing plates on the back of the boot flange and/or the six bolts are too long, you might be pulling the inner race out of the wheel bearing causing the slop.

It's all I can think of...

onZedge, btw cool name!

I think you have solved my problem; it is the only thing that makes sense. The outer CV joint to hub does not have backing plates on either side.

This has been a fairly long term project I had to let go for almost a year because of other obligations, and with my weak mind I didn't remember if the backing plates went on both ends. The axle kit I received only had 3 backing plates per axle, I had photos showing the backing plates on the trans end so that is where I put them. I had trashed the old bolts and backing plates. All my error.

I will find backing plates someplace and let you know if it cures the problem. Thank you for replying so promptly, I was beginning to look for a rust razor blade so I could slash my wrists.

This will not be helpful (sorry) - but I just have to say...spectacular undercarriage!

The part that doesn't make sense about your description is that you "pressed" the hub into the bearing. How? Normally that happens when the stub axle is tightened.

I think you're assembling in the wrong order. Install the bearing, then assemble and tighten the hub and stub axle. That is the only way to "press" the hub into the inner bearing race.

Above what....

You can easily press the hub into the bearing bur make sure you hold the inside race so the hub seats fully. If you push the inner race out even à bit and the hub isn't fully seated your going to have problems.

I've never frozen a bearing in my life and have changes 100s maybe 1000s of wheel bearings on anything from bikes to cars to trucks bolts etc.

Something isn't seated together... and your forcing on something.