XJ D44 axle play

[blistovmhz]

I wouldn't normally ask this, and instead would just go tear it all apart again, but I'm real pressed for time and need to be back on the road in a few hours, so hoping someone has the actual answer.

My D44 (xj rear) has KJ discs. Setups has worked fine for years. I swapped to some chromoly shafts with new Set10 bearings and seals a few months ago.
It's been absolutely destroying new pads and rotors for as long as I can remember. Several brands, none especially good brands. This may be the hint. I'm not sure.

Last night I pulled the brakes off to replace with some new centric premium rotors and greenstuff pads, and noticed probably a 1/4" of play in the passenger shaft, so I pulled to inspect. Found that the retaining plate had bent pretty good, which explains the play, so I cut off the retainer plate and spacer and built a new one with 1/4" steel. Once the plate was done, I cut it and the spacer in half, slid it into position, and welded it back up on the shaft, and stuck it all back into the housing. Once in the housing, it's much tighter, but still have a very small but obvious amount of play (can tell just by pulling the shaft in/out). Seems to be around 0.05 or so.

I've looked all over and can't find tolerances for this axle. I figure because it's a roller bearing, the tolerance should be 0, otherwise you'd have no preload, but just can't find any actual data on this.
I've still gotta fab up the other retainer plate for the passenger side in the next hour or so, so I'll have wheels to get to a doc appt, but I'm hoping someone can throw out a theory as to why I still have play on the drivers (and presumably, on the passenger as well).

When I had the shaft out for inspection, I didn't see any evidence of the bearing retainer collar backing off. I marked it when it was installed. The seal doesn't look crushed, but I suppose it's possible it may be. What really gets me is that with 1/4" play, I wasn't leaking any oil. WTF?

Now I know I could just pull the shaft again and fab up a thicker spacer, but the spacer that's in there was the right thickness when I put it in . All I can think is the bearing is somehow worn (not visibly) and my spacer/backing plate is just bottoming out on the caliper backing plate. Thoughts?

 

[89eliminator]

my MJ D44 has always had a small amount of play. I too made my own retaining plates out of 1/4" plate because i was bending the stock ones almost every trip. it "sounds" like you are ok.

 

[blistovmhz]

Yea, and SOUNDS okay based on other people also having some nominal play, is okay for now, but I want the definitive answer. Any play absolutely has to mean there is zero preload on those tapered rollers, and that's gotta be very bad. Plus, with any play, your seal is moving in/out of the housing, which will lead to fluid loss (or water intrusion). I wanna solve this once and for all .

I just remembered that my passenger side isn't actually out yet, so I can just throw the new pads/rotor on it and get to my appt., and just pull the axle tonight. Damn I wish I had a big press. Gotta take my shafts to the axle guy just to install bearings *le sigh*.

 

[cal]

If I had *any* play at all, I would be pulling the axle apart to figure out what is wrong.

There should be no play. None at all.

 

[blistovmhz]

That's what I figured (cause tapered roller bearings require preload).
I'll stick the new pads/rotor on now, just to get me by, but I sorta wonder if my race didn't spin at some point, and grind itself back into the tube a little. I can't think of anything else other than the new bearings have somehow worn a tonne in only a few months.

 

[cal]

I would be looking at a retaining plate problem, or incorrect axle shafts. (If the shafts were built around set 20 bearings, you'd get about 1/4" of end play).

 

[blistovmhz]

When the shafts went in, they were tight. Torqued bolts to 45ft/lb. Zero play as far as I recall. They're set 10 and definitely the correct shafts. Strongly suspecting that the driver side bearing is a little worn due to the retainer plate bending and allowing play. That'd also explain why I've gone through two sets of pads on the drivers side in 6-7 months. Driver side pads wore at an angle, and they went real fast. Either way, it's definitely in better shape now that it was, and I've got the new rotors/pads in and took it for a quick test drive. Seems good.
I'll definitely be pulling the shafts again to replace the bearings/seals again in the next week or so. The new 1/4" retainer plates aren't going to bend out again, but I do want to have the correct bearing pre-load on there. Thanks for the input guys.