So, some play in passenger side rear wheel prompted the bearing replacement, put in a new Timken & thought everything to be ok. Couple of days later, noticed with the car on the lift that there is about 1/16" play in & out at top and bottom of wheel when wiggling it with hands placed at 12 & 6 o'clock. No play at all with hands placed at 9 & 3 positions. Peeking in to the CV joint while the wheel is worked up and down confirms the hub is working up & down a bit.
Is the carrier oval maybe? This is a clean, /6 trailing arm, but there was some scoring on the inside of the carrier where a previous bearing extraction had encountered a burr. Anyone seen this sort of thing and what's the remedy?

Sounds like the inner mount for the trailing arm may have worn into an oval shape. I'd remove the trailing arm at it's pivot and take a look. I think most people can weld some reinforcement and redrill the hole, or the inner mount is available as an assembly to be welded in place.

Yeah, checked that....no play at the front pivot mount area....it's all in the hub area...

I don't think the bearing could be installed cocked, so the only other spot I could think of is the actual bearing itself. If you rotate the wheel, can you get the mivement to occur in another location? Are the bearings new or old?

Sounds like the bore is worn in the direction of the load (up and down).

A previously spinning bearing maybe? It might be time to find a new trailing arm ...

It's a brand new Timken bearing....play is only in the up/down direction, no play at all in the 9 o'clock/3 o'clock direction. Tried it in multiple rotations of the wheel...the brake disc wobbles with the wheel, but only in the up/down direction.

Was your old bearing total trash or just a little noisey? It would take alot to oval out the trailing arm. That's usually only happens if the old bearing was spinning in the housing. Possibly the nut didn't get torqued down to spec's? It's 220-240 ft pounds. Does the stub axle sit the same as the other side? the amount of axle showing past the nut should be real close. Did the hub draw into the bearing real easy? It should take some force to pull them together. If you have a wear problem on the hub, I'd think it would have been pretty easy to see it when you had it apart. Mike

Old bearing wasn't noisey....it had the up/down play, so I replaced it. It was hard to get the old one out, hard to get the new one in, even with freezing it 48 hours and using heat on the housing, still had to crank it in with the allthread rod and appropriately sized huge sockets to press on the outer rim of the bearing.
I'll check the stub axle protrusion--that's a good idea.

It is possible for the bearing bore in the trailing arm to become slightly oval. I haven't personally seen this on a 914 hub, but I know that older 911s are known for this. You might as well try cranking down on the stub axle nut to see if that gets rid of the wobble. It's a little odd that you get up-down wobble, but no side wobble, but at this point it can't hurt to try cranking on the stub axle nut to see what happens.

Scott

Are you sure it is just the hub moving and not the arm?

You can oval the hole in the suspension ear which will alow you to move the whole arm up and down but not side to side!

OK, pulled it apart today...red herring about no play front to back...the caliper was inhibiting that movement, duh! Looks like somehow I screwed up the new bearing on installation, or got a bad Timken (unlikely). Absolutely no play or ovality in the trailing arm mounts or bearing recess. Gonna be real careful on installation of the new bearing....no hammering, I know--press the bearing in & draw the hub in...