Steering knuckle lubrication

[welder]

I have the right side steering knuckle apart to fix a leaky axle seal. I have a question about the lubrication on the steering knuckle. Does the knuckle get grease from the fitting on top of the upper trunion bushing? Or am I missing something. I need to know before I start putting it back together. Any help would be apreciated. Thanks

[Charles Talbert]

I have the right side steering knuckle apart to fix a leaky axle seal. I have a question about the lubrication on the steering knuckle. Does the knuckle get grease from the fitting on top of the upper trunion bushing? Or am I missing something. I need to know before I start putting it back together. Any help would be apreciated. Thanks

Notice the 1/8" npt plug in the bottom of the ball area on the axle tube. Remove that plug, remove the fitting on the top bearing retainer & install the fitting where the plug came out. When the joint is fully assembled, pump grease through the fitting until you see it come out the retainer hole you removed the fitting from on top. The housing is now full, it holds about 2 1/2 lbs. of grease; reinstall the fitting at the top & the plug at the bottom. In future greasing, remove the plug first, pump grease in at the top until you see grease coming out of the plug hole; let any excess bleed off, reinstall the plug. This method will eliminate over greasing & seal damage. Use a high quality NLGI #2 grease that has anti-bleed properties, otherwise oil in the grease will separate & bleed past the felt knuckle seals in hot weather.

[Tom Petroff]

Yes, you grease it from the top fitting. There is a small plug on the back of the "ball". remove it with a screw driver and pump grease until you see it there.
Pack as much as you can in there before you put it back together now it makes it easier.
Most use good quality chassis grease.
TGP

[Charles Talbert]

Respectfully disagree

Yes, you grease it from the top fitting. There is a small plug on the back of the "ball". remove it with a screw driver and pump grease until you see it there.
Pack as much as you can in there before you put it back together now it makes it easier.
Most use good quality chassis grease.
TGP

I disagree with this post for these reasons. I simply don't like to try to assemble the parts with grease all over everything as has to be dealt with when putting grease in the knuckle prior to full assembly. Having grease present also adversely affects sealant application when installing the spindle onto the front of the housing. Pumping grease in is easy when using the bottom plug hole as you aren't feeling the resistance in pumping that is felt when pumping in at the top because of the grease having to be pumped through the bearing. Greasing after the fact enables a much cleaner, better sealed assembly in the end.

[welder]

Thanks so much for the detailed directions. I was wondering about the plug. Now I know, and should have no problems with this. I am trying to get the Truck going to make it to the Rally in June. Welder

[Cav Trooper]

Knuckle greasing

I just decided to top off the grease in the front steering knuckles on my M37. I bought a cheap Harbor Fright pneumatic grease gun and 6 tubes of grease just in case. I removed the to zerk fitting and put it in the bottom hole and started pumping grease. The problem I found was that the small size of the zerk fitting hole would not allow much grease to pump with any volumn. I removed the zerk fitting and installed the flex hole from the grease gun directly into the lower plug hole, the hose had the same 1/8 in. threads. Without the restriction of the zerk, the fill up took much less time. Turns out I needed 3/4 tube on the left and 1 1/2 tubes on the right. I watched the top port and stopped pumping and let it purge, then I pumped a little more to vent any air. I let the pressure bleed off of both the top and bottom ports installed the plug and zerk, easy as pie.

CT