Well it looks like my rear axle is leaking- again. It's axle oil, not brake fluid. And jacking up the rear and giving it a shake I can feel some play which says I wore out the rear axle again. In case you haven't run into this prob yet, Ford axles roll straight on the bearings without an inner race, and they're prone to wearing down the axle itself so just replacing the bearing may not help. When the axle has enough slack to move around inside the bearing it will leak oil right out the axle seal.

Just how I could wear this out after 6 yrs has got me. I have changed the rear diff oil, not really frequently, but I don't drive a lot. Maybe 50k miles or so since then, I'd say the diff oil's been changed twice in that time. I changed it sometime last year and saw some sparkly flakes in the oil which disturbed me some, although I took pics of the diff and people said the wear marks looked basically normal.

That was a new axle, so there's a space I could install one of those Axle Saver bearings. Now just what is the best way to get one of these in there? I know a slide hammer will take out the original bearing. I recall the instructions said to install with a hydraulic press which sounds absurd, I don't know what press which could grip the axle housing on the vehicle and I certainly don't have one.

When I installed the previous "axle saver", I used a block of wood and hit it with a sledgehammer to drive it in. I thought I had it in to the right depth and the saver appeared to be undamaged. Then again, that Saver failed in under 1000 miles so I may not have done it right. Is there a better way to do this? Does AutoZone have a tool they can rent out to press these in?

 

Say, how much play is acceptable when you have it jacked up and you lift the wheel?

I mean, I can feel it move inside the housing a bit, but it's hard to gauge whether this is "a lot". I'm just wondering if there's any possibility that it's just a defective axle seal, something I can replace cheap and be done with.

Or do we have a spec on what the smallest diameter worn into the axle is acceptable? I have a caliper and can measure it when I pull it, I have to pull it to replace the bearing or seal anyways. But I need that spec with me before I start taking it apart so I don't have this thing strewn across the driveway awaiting a decision.

 

Are you talking about an 8.8"?

 

IIRC yeah; it's a stock rear end for the '87 E150.

 

Well, I spoke with a Ford service center and they said there's no spec to gauge axle wear, just look for pitting. IMHO that's quite an oversight. Be nice to just caliper the part and see if it's in spec just like everybody else in the machine world!

He did suggest that if it's 50k, the axle's supposed to be good for 90k so he'd just slap in a new std wheel bearing and be on your merry way. Sounds good to me.

Now those bearings don't use any bearing grease, right? It's only the rear end oil that lubricates them?

What type of gear oil did the std Ford 8.8 non-limited slip use? What was the capacity?
What was the synthetic oil option I could try?

I probably won't try the synthetic until I give this a thou miles or so and know for sure the repair is good. That stuff's 'spensive.

 

OK found the capacity and oil type, and got the grease I needed.