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Category: Technical
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u-joint hitting standard zerk

Ground off grease zerk

The axle u-joint knuckle has ground off the top of the grease zerk on the lower ball joint.

I'm somewhat of a newbie to Jeeps by purchasing a used 2008 Rubicon Jeep Wrangler JK in September of 2018. I have owned a 1997 XJ for many years now but I really started learning about Jeeps with the purchase of the Rubicon.

There have been a number of servicing and repairs I have had to make to get the Rubicon in top working order. Here's something I have learned about servicing lower ball joints.

In the first year of owning my Jeep, I have had a number of repairs made on it. One of those repairs was replacing my rear axles with some heavy-duty G2 rear axles. I found out the hard way that slipping sideways in the mud on a steep incline and having a rear tire smack a hard bump, sliding sideways, with over-sized tires (35s) bends the stock axle flange that the wheel bolts to. You'll know one is bent when you hear the repetitive brake squeak and you look in your rear view mirror and watch the rear wheel wobbling.

With a bent axle, I figured that it was time to go to a 4x4 shop and have them repair it. They did a great job but in the process said I needed ball joints. So in a couple of months, I returned to get the ball joints replaced. Given this is a 4x4 specialty shop I figured they would put the best ball joints or give me some options on the joints. They didn't give me any options but upon inquiring they twice assured me that the lower ball joints would be serviceable. Greasing the lower ball joints was something I couldn't do on my Jeep with the ones that were currently installed. So this was the most important thing that I requested to have. I knew Terra Flex had great ball joints with wonderful placement of zerk fittings but I didn't insist on TerraFlex... looking back I wished I had of.

A day after the ball joints were replaced I climbed under the Jeep to have a look. Check out the photo to see what I found. There were grease zerks sticking out of the top of the lower ball joints and they were ground off from being hit by the rotating knuckles of the front axle u-joints. Nice.... not really.

After contacting the shop they offered to replace the joints for the price of the TerraFlex joints but they said they would have to be knurled because they put knurled joints in. The idea made me nervous that I would end up getting the whole front axle replaced if the knurled joints didn't hold tight. So I opted to keep the ball joints I had. At least I would get some mileage out of them before I had to replace them. But how do I service them? If I could figure out how to service them I may get a few more years out of them. Hmm...

Here's what I ended up doing that works great.

On Amazon, I found some low profile zerks and a 90-degree needlepoint tip for my grease gun. I turn the wheel as far as it would go outward on the side I'm working on and jacked the tire off the ground on that side. Carefully I would turn the wheel to rotate the knuckle of the axle u-joint so that I had just enough room to remove and replace the zerks. Then with the help of my son squeezing the grease gun handle, I held the 90-degree needle tip in place on the zerk. Take a look at the photos and it should give you a better idea of what I did as compared to me trying to describe it.

Low profile zerk clearance

Low profile zerk clearance

Low profile zerk clearance between the lower ball joint and the knuckles on the axle u-joint.

In the process of looking at the photos I took of the ball joint I can read MAS on them. I'm pretty sure my invoice and what the shop told me that what they installed was Moog brand. Hmm.... are Mas and Moog the same company? It's hard for me to tell online.

Hopefully, I am able to get a few miles on these joints before they need to be replaced. 

For all I know the shop may have not pressed in the bearings as far as they should have been and this may have decreased the amount of available space for a zerk as well.

I really like the 4-Wheel Parts store that replaced my ball joints. I have been back there a couple times since buying tire chains and gear oil. I do think that part of being a Jeep guy is that you do the research of what you want before you go to get something replaced and you ask to get the parts that you want. Jeep people tend to know their stuff and what they want. I'm still learning. Love my Jeep!

Mas lower ball joint with low profile zerk.

You can read "Mas" on top of this ball joint.


Needle nose grease zerk fitting

This is the 90-degree needle-nose grease fitting I use to service the lower ball joints.