How to grease the U-joints?

[wxm]

I have searched for instruction of greasing the u-joints. Got a lot of valuable information about what grease to use, but still not sure how actually to do it. It sounds silly but I have never done it myself. So here is what I figured, please let me know if it is not incorrect in anyway.

(1) find the zerk fittings (according to FSM, there are three on each side), and clean up the fittings with brake cleaner.
(2) connect a grease gun on the zerk fitting (I plan to use Mobil 1 red bearing grease).
(3) Pump the grease gun until see some expansion from the shaft end (How far should I go, if I don't see any expansion?)

Thanks.

 

[antichrist]

The key is that a little bit of grease goes a long way. Do not over load the cups with grease. the seal can be compromised plus the real fun grease slinging action that will likely ensue at higher shaft speeds that'll coat all that you own under the truck.

 

[john_eckels]

I usually pump until I see new grease come out of all 4 seals. Is this bad?

The key is that a little bit of grease goes a long way. Do not over load the cups with grease. the seal can be compromised plus the real fun grease slinging action that will likely ensue at higher shaft speeds that'll coat all that you own under the truck.

 

[firetruck41]

I pump until new grease comes out of the u joints. You do not want to over fill the driveshaft though. You don't want hydraulic pressure in the drive shaft, so I usually do just a couple pumps on that one.

 

[wxm]

Upon further check the FSM, I notice that our truck actually has 4 spiders (u-joints) which I assume should be greased as discussed. In addition, the FSM also mentions to grease the two slide yokes. How do you guys grease them? Just smear a layer on the surface?

[Edit] Never mind, found a couple of threads that well cover the issue. Many thanks for 89GASHOG too.

 

[Devils Paw 80]

The 4 u joints have grease fittings, as do the two slide yokes (driveshafts). Look for the nipple and ye shall find.

 

[Cruisin']

The goofy thing about the slip yokes is that the grease goes into the hollow void at the end, and not on the splined section of shaft where it needs to be. In order to get grease there you'd need to fill the hollow section completely which would then lead to the 'hydraulic' problem discussed above. I had the driveshafts out a little while ago, and greased up the splines really good by hand. I've since been not putting any grease into the slip yoke nipple.

I'd be interested if anyone has figured out a better way to keep the splined section of the slip yoke greased.

 

[Squash]

After greasing the two splined yoke shafts you could remove the zerks...if grease forces it's way out you know the system is locked and requires some cleaning.

Use a crayon, chalk or paint to mark the orientation of shaft/shafts before removal.

I have had good luck spraying cleaner or favorite areosol penetrating fluid into zerk fitting and retesting "later"

Tremendous pressure is exerted on drive train components when these splined shafts are plugged and over greased. If you want to feel this pressure just undo the shaft and try moving it in and out with the zerk in place and then with the zerk out.

 

[wxm]

OK, Just finished re-greasing the u-joints. I ended up using the same moly that was left over from knuckle repack (Valvoline Palladium). it is quite straight forward for the spiders. For slide yokes, I pumped until it starts to move, I then pushed down the center of the zerk fittings to let out some of the air/grease. Not sure it actually helps to prevent the hydraulic problem. Hopefully it is OK...

Thank you all for the info.

 

[greentruck]

Sounds About Right

For the slip yoke, it sounds like you got it about right. Once the slipjoint on the shaft starts move, you're there.

The first time I did this on my first LC, a '76 FJ55, I just kept pumping.

Went to drive it and it sounded like the transfer case was going to explode. I consulted the "braintrust" of guys that I ate lunch with at work and eventually we figured out what I'd done wrong. I took the slipjoint zerk out, loosened one end of the shaft and pressed to expel the extra grease. Problem solved.