The Stovebolt Site Forums The Shop Area Engine Shop Rear End Question

I've been reading everything I can on my '51 Chevy 3/4 Ton, and have a sorta goofy question to ask.

3 different times, the right rear wheel has frozen up on me, (won't turn, have to really give it gas to get going, then it loosens up and runs fine).

This always happens at the same location at my work, same parking spot. And always after the truck has sat there 8 hours.

At first I thought the brakes were locking up, as I have to make a tight turn into this spot, all while coming up a short steep entrance driveway, and have to jam on the brakes pretty good to stop. My plan was to open the bleeder valve on this tire the next time this happened, to see if the breaks were not releasing.

The last time I pulled in real careful and slow, no hard action on the brake pedal, and still it was locked up.

The space I am using has a slight slant, the right side about 4-6 inches higher than the left, and it is the right wheel that locks up.

So my new theory is that the gear lube is draining from the right side of the rear axle, and leaving the bearings just dry enough to lock up.

Sound plausible?

My solution was to top of the rear end, thinking maybe it was low.

No such luck, as I put fluid in an equal amount of fluid comes out, of course the old stuff is black, but I assume still working.

Now as I was putting rear end fluid in, I realized that the fill plug was on the lower half of the rear end. This doesn't seem right to me, is it at all possible that someone put the rear end cover on upside down? According to the shop manual the rear end on this puppy should hold 17 1/2 pints, I just don't see how this is possible with the fill bolt being that low. Can't find any pics of one of these rear ends on the net, so I thought I would ask.

Thanks

Frank

1951 AD Chevy 3/4 Ton, daily driver, and darn proud of it.

Well, I think this truck has the same rear axle as my 61, but i don't know for sure (check the link for pics). If it does, the fill plug in the rear cover should be below the midpoint. I think the theory is that as the gears spin, they will sling the oil all over the place, and lube everything. On mine, I don't see any way how all the oil could drain out of the hubs and back into the differential. It would have to flow up hill, which, last time I checked, doesn't work too well. Maybe somebody with a 50's era truck could back me up on this???

Do you use the e-brake? Are the temps cold? I have heard of cables freezing up, not letting the truck move. Try backing into your parking space. Does the other wheel lock up? Could the brake shoes be adjusted too tight? Just a few thoughts.

If it's a 51 3/4, does it have Huck or Bendix brakes? If they're Hucks, possibly the rear shoe is adjusted too tightly. Reversing out of the stall may just be enough to grab the shoe and bind. These brakes are not self adjusting, and have two adjusters per side, turnung in opposite directions.

Gooid luck!

Thanks for the replies guys,

I tried backing in to the spot friday, had no problems when leaving. However, my shift is a little different on fridays, so truck only sat there 5 hours instead of usual 8. Will find out tuesday when it has all day to sit.

Has been cold and wet here lately, but I haven't been using the parking brake at all, so I don't hink that is it.

About fluid draining from the hubs, I was only thinking this could happen because the truck was parked with the right side higher than the left by about 4-6 inches.

I believe she still has Huck brakes, that would have been standard for '51. With the 3,000 thnigs that need to be done on her, and the brakes having worked great from the time I got her, pulling the drums to check the brakes hase not quite made it to the top of the "to do" list, yet. I think that will be my next project, pull the rear right side apart, and see whats up with the braks.

Once again, thanks for your input.

Frank

The design of the axle doesn't allow all the lube oil to drain from a rear wheel bearing. There is a pocket that holds the lube around the bearing, and the axle extends past the bearing, which is on the outside of the axle.

As far as capacity, the 3/4 ton differential holds less than one gallon of gear lube. I can't remember the exact amount, somewhere around 3 quarts. If your lube is black, it could use changing.

The wheel locking problem sounds a brake sticking, either from a broken return spring or adjusted too tight.

Dag Nabbit Fred you beat me to it.

I recently had a similar problem with my 51 1-ton, with huck brakes, due to a broken return spring. My brakes weren't completely locked, but there was considerable drag. I think Fred pegged it.

Chevy Duty sells them for $8 ea. You can probably get them at NAPA too but I bet they make you buy them for both sides for $15-18.

OK,

And the winner is . . . . . .

Brake return spring.

NAPA did not have, neither did either of the brake supply businesses I visited,

fortunately I found one at the antique auto ranch, came off the rear end of a 1/2 ton, so it is not quite as stiff as the 3/4 ton one, but it will do until I get the new one in the mail.

Where did I get 17 1/2 pints, I coulda swore I read that, but of course when I checked both books they said 6 pints. I must have been thinking the amount of fluid in radiator, or something.

Anyway, all attempts at locking it up anymore have failed, so I think I am good to go for now. And I found a great cab, at the auto ranch, that may just find itself a new life on my truck, come this summer.

Frank