HO52 fluid ???
 

HO52 fluid question....I recently replaced rear brakes and inner and outer wheel bearings and didn't do a proper brake adjustment. I installed axles and refilled the rear diff fluid. I then drove the truck about 30 miles and removed the axles again to adjust the brakes properly but this time there was no gear oil on the new bearings. The first time I removed the axles fluid was leaking from the axle tubes. I made sure to fill it up as much as possible. Sorry if this is a stupid question I just see full as full. Should I jack one side of the truck up and pour more in there? or is there a fill port on top that I cant see? I thought I looked it over pretty well.

Thanks in advance
Aaron
1972 k20
1968 c10 SWB in progres LS swap
1968 c10 Step side

Re: HO52 fluid ???
 

The bearings should have been packed with wheel bearing grease as per the service manual.

Yes, some fluid does make it down the axle tubes to the bearings but if you look at the level of the fill plug it ain't much. I noticed aftermarket covers have higher fill plugs and some people turn the factory one upside down to increase the fluid level.

Re: HO52 fluid ???
 

There was no grease when I removed it and full of fluid, so I assumed with the setup the gear oil lubed the bearings. It was a lot of fluid. The bearings I removed wasn't in bad shape but cheap enough to replace while torn apart.

Re: HO52 fluid ???
 

Sorry to bring up an old thread, but...

This is absolutely true. The HO52 / HO72 oil level as governed by the cover fill port IS BELOW the axle tubes.

How do I know? Well, I completely rebuilt my '71 HO52 and then filled the diff on a level surface to the port. I drove it about a mile and realized I had a brake issue. To fix the brakes, the axles and hubs had to be removed. When I pulled the axle, I was shocked to find the axle flanges were dry! There was no oil at the hubs! Good thing I "sorta" packed the bearings with grease.

To fix the issue, I jacked up the axle so I could add 1/3 liter additional fluid, then parked the truck sideways on a hill, both directions.

Anyway, BE WARNED!!!! Do pack the bearings with grease and do tilt your truck to get some oil out to the hub bearings during the initial break-in period.

I assume the design oil level is low so as to reduce oil foaming and heat build-up. The Engineers assumed the oil would eventually flow to the hubs due to centrifugal force when cornering.

Re: HO52 fluid ???
 

These diffs take a gallon plus in them after you tip the tubes. Pack them light with grease. Fill with 90 to the plug. Jack up one side and walk away for 1/2 hour. Fill to plug, repeat for other side.

Re: HO52 fluid ???
 

Why when the service manual is pretty clear?

Re: HO52 fluid ???
 

That's good advice. I'll top the oil level again once I have 500 or so miles on it. I assume it will take a few drives to dissolve the grease enough to permit oil to flow through the outer and into the inner bearings.

You know the original HO52/72 service manual (circa 1946) simply said to soak the bearings in engine oil before installation. I wonder if the oil level changed over the years?

Re: HO52 fluid ???
 

There are some videos done by Gale Banks on youtube, with a clear differential cover, that show what happens under the cover.

Like this this one

Re: HO52 fluid ???
 

Because everybody has a service manual at their disposal??? Liberally packing the bearings with todays grease is different than 60 years ago.

Re: HO52 fluid ???
 

That is good stuff. I suspected the level was below the tubes to help reduce air entrapment and heat.

I'm impressed with Banks. Most aftermarket crap is exactly that, but after seeing the video, I'd use Banks components. They actually Engineer their product.