Knuckle Leak

I've got a leak on the driver side knuckle of my 1966 CJ5. My jeep never really has anything major break, just blows a seal or two every time we take it to the hills.

The knuckle was leaking (blue arrow) and I replaced the seal around the knuckle with the cork backing and rubber seal etc. Then I filled the knuckle with gear oil (up to the filler hole on top), capped it and went for a drive.



I stopped about 10 miles later and oil was just pouring out of the kunckle... but in a new spot (red arrows).
It runs down and drips off the bearing cap (other red arrow).



Anybody know what seal(s) blew and what I have to do to replace it?

Was I wrong to top off the knuckle with gear oil?

How important is the gear oil when in 2 wheel drive?

 

Most people fill the knuckles with a mixture of oil and grease locally called "knuckle pudding." If you search for old posts with this phrase, yu'll find lots of discussion. http://www.google.com/search?q=site...fficial&client=firefox-a&source=hp&channel=np

 

So there isn't really a problem then?

 

Other than it drips oil? If it's empty and the hubs are locked out, the axles don't turn. So I'd guess it would be ok. But it sorta defeats the purpose of a Jeep if you can't lock in the hubs.

 

It drips oil, so I think a seal is busted somewhere. I thought maybe you were suggesting that knuckle pudding wouldn't leak b/c it would be much thicker. Thank you for your quick reply!

 

mine leaked when the inner axle seal went out they are, inside the pumpkin.

 

Thanks for the input Chuck... but that really isn't what I wanted to hear! Pulling axles don't sound like fun. I'll check my diff fluid level and if it has drained out that means it must be leaking through there.

Thanks again!

 

The bolt on the bottom of the knuckle that one of your arrows points to goes all the way through on my 69. It leaked there as well until i put some RTV on the bolt and reinstalled it. No problem now.

 

yea it isnt the funnest part of wrenchin,but it only took a day to change out an I did the annual wheel bearing greasing at the same time, like you said keep an eye on the diff it may take awhile to notice any fluid loss especially if you not using it or running on a slope.

 

I'll try the RTV trick and then fill the kunckle (mostly full) back up with this knuckle puddin' slurry... we'll see what that does.

Like you said chuck, I'll keep an eye on the fluid level in the diff.

The way that gear oil POURED out of where the kunckle and drum meet there must be a blown seal there... but I'll give the puddin' a shot first.

 

Those knuckles from 1941 thru about the early 60's were always spec'd to be serviced with #2 chassis grease. Kaiser changed the spec to gear oil in the 60's. Most folks do not run the same gear oil they use in their diffs in their knuckles. This is good because then when an inner axle seal starts leaking gear oil you will know it's really from diff and not the knuckle just from the smell. The original service program called for a periodic opening, cleaning and hand repacking of the Pivot (King Pin) bearings and then a filling of the knuckle with #2 chassis grease. If this is adhered to per the schedule you will never need to play with wild concocted brews from the Witch's Den! The old wives tale was the gear oil was better because it slings oil up on the top pivot bearing. Well that's just not the case. What gear oil does is leak past the spherical ball seals which were never designed to hold back thin gear oil. Also the steel ball surface needs to be kept like new smooth and clean.

The value of a thinner lube comes out when you drive your jeep in northern climates where zero and lower temps are common in the winter. The #2 chassis grease becomes so thick if you start driving in 4WD on a cold morning the first mile you can let off the gas and the grease in the hub will slow and stop the jeep for you without using the brakes. I believe it was this phenomenon in the 40's that led to folks experimenting with gear oils in the knuckles. If you are operating up here in the winter I have used the 600 weight Ford straight gear diff oil with very little leakage and the corn machine oil from the implement dealers is often tried as well.

 

Packing with Grease

Thanks a lot Wes. How difficult is it to access the king pin bearings and pack them? Is this an annual event?

 

Wheel, hub, back plate and knuckle get removed and disassembled. It's an all day job for the hobbyist. About 4 hours for the seasoned mechanic. If you thrash the jeep about and get her in water a lot then annual makes sense otherwise just follow the manual (I use SM-1046) which says disassemble and lube each 12000 miles. The same time limit as the wheel bearings.

 

Knuckle Schedule

Ok, I think I'll stick to the 12,000 mile interval. (We're surrounded by sagebrush so you can imagine we don't get much water up here)


Thanks again Wes!

 

My Knuckle Leak Plan

After reading through the shop manual for my 1966 model, I think I'm going to fill up the kunckle with 140 wt gl4 gear oil. I like the idea of kunckle pudding because it sounds like it wouldn't leak, but overall I think I'm going to stick with what the manual suggests (which is actually 140 wt GL3, but I guess GL4 replaced/exceeds/supersedes gl3).

So I'm going to put RTV on the bottom of the kingpin bolts and fill with 140 weight GL4 (which I hope is thick enough not to leak).

 

Wb, can you buy gl4????? The only gl4 I have is what is left in a 5 gallon pail,my oil guy says no more to be bought?

 

they've got 140 wt gl4 down at the local napa, $30 a gallon.

 

Interesting.....I'am gonna call my oil guy .......

 

Here is a place to get 140 wt gl4 online

http://shop.advanceautoparts.com/we...vance-Auto-Parts_7070502-P_N3242_T|GRP2035___

 

run 85w140 on mine with no leaks. I do recommend polishing the ball area with some fine (400 grit) emory paper to get rid of the scratches (where most leaks occur). I've found that using permatex form-a-gasket works better than rtv on the bolts and king pins to seal them up.