My repair book says that I should pack grease in the rear bearings of my 1990 f-350. I have never done this to any other rear axle that I have worked on and was wondering if this was accurate. It is a Ford full floating axle, and there appears not to have any grease in the bearings now. Also any tips on how to reassemble the hub would really help.

Thanks Ken

 

sounds like you need a real repair manual. coat it with the proper gear oil then after reassembley park so that oil runs down hill to the side you were working on.

 

dro
It's a FF axle - the diff oil doesn't lube the wheel bearings. It's like the front hubs on a 4WD.

Get a Haynes manual and a bearing packer (2 plastic cones). You might also find that info here.

 

well thats a new one on me, i am gonna pay close attension next time one of these come into our shop for repair.

 

Thanks for the replies, I think, the manual that I'm using is a Haynes. I,m still stumped, because there is no grease packed in the bearings now.


Thanks again,

Ken

 

Grease is the primary lubricant, but gear oil does flow into the bearings. You would be suprised how many people dont grease them, and they seem to last pretty well.

 

Thanks for the info. I just took the hub apart and found that the bearing rollers are rough, so I will replace them. The bearing races (sp) seem to be rough also so I will replace them too. My question is can I replace them by myself or should I have them pressed in at a machine shop?

There was no grease in the bearing when I took them apart, and I think that is part of the reason they are shot now, so I will pack the new ones with grease. Is it all right to use synthetic grease even if the diff lube is not synthetic?


Thanks for all the help.

Ken

 

You can do it yourself, but you'll need a slide hammer with a GOOD bearing puller attachment, and a good bearing drift would help keep them straight as they go in. I don't think the type of grease matters as long as it's rated for use in wheel bearings.

 

Thanks for all the help. The job is going well, a little bit more than I wanted to do, once I got the brake drum off I found the brakes were shot and the wheel cyl leaking. Should be good for a while now with new brakes, new bearings and races, new seal, and new brake cyl.


Thanks again.


Ken.

 

On a full-floating axle, the the wheel bearings are more-or-less "outside" the axle- very similar setup to front wheel bearings on front-drive or 4x4. "Regular" front wheel or trailer bearings are also similar; major difference is that the spindle is solid. So, on full-floating rears the differential fluid does NOT lubricate the wheel bearings, and you need to grease them like front wheel bearings or trailer bearings.

If you didn't see any grease, suggest you replace the inner and outer bearings while you've got it apart. Remember that each assembly has rollers and an inner & outer race- you want ro replace all parts on each assembly.

On semi-floating axles, the bearings are inside the axle tube, and there is an oil seal outboard of the bearing. The axle shaft protrudes through the seal. Oil from the differential partially fills the axle tube, and that's what lubes the bearings. Hence the comment to let oil run into the bearings on assembly.

Pulling bearings on a full-floating axle shouldn't be too bad if you've got good puller attachments for your slide hammer. Not sure of the exact setup, but if you're lucky, both inner races might just slide off the axle. If not, they are exposed and should be fairly easy to get at. You should be able to tap the hub races out with a drift & hammer if you can't get a slide hammer puller behind them.

Pressed-in bearings on semi-floating axles can be a pain. Did the rear bearings on my S-10 last year, and couldn't get the slide hammer jaws to stay behind the race. Ended up cutting through the races with a Dremel tool then tapping them out with a cold chisel. Would have been easier to drive them out from the backside with a pipe or rod run through the axle tubes and differential from the the opposite side of the truck. But, we didn't have the right piece of steel, or enough room.

 

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