Ujoint grease turned black

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Hey folks.

I replaced one ujoint a while back, and today replaced the other. These Moog joints came with this greenish-blueish grease, which the Moog instructions said was only shipping grease. So I got all I could out with my finger and replaced it with Lucas Red N Tacky.

The one I replaced a while back bolts to the rear yoke with straps so I was able to easily pop a cap off and see how it looked. It was greased good, but the grease had turned black and thinned out a bit. This ujoint had also failed to loosed up and had a bit of the initial bind in it from install, so I replaced it with another Moog which I did a much better job at, with no bind this time. Do you think the heat from the bind turned it black, or do you think the Lucas may be incompatible with the shipping grease?

On another note, one of the caps will slide nearly all the way into the ear and doesn't need tapping in until the last couple millimeters. Think it will hold without spinning?

Thanks,
Mike

PS this is the rear shaft on a Chevy Trailblazer 2wd.
 
Originally Posted By: heynow
Redline CV grease makes it a point on the label that it may turn dark after use.


Do they say why?
 
The shaft ears bend easily in these and cause the new joint to bind and feel tight, it can also cause snap rings not to fit properly.
You can fix this with a simple home made spreader.
The heat from the binding joint probably overheated and started to wear the joint, contrary to popular belief a binding/tight joint does not "loosen" up with use they loosen by excessive wearing, the ears are not bending themselves back.

If the cap is not tight in the ear bore you can use loctite 660 on the outside of the cap when installing it, make sure its 100% clean before using it.

https://www.amazon.com/Loctite-442-66010-Retaining-Compound-Silver/dp/B000O03DK0?&tag=rnwap-20


Before I start working on a joint I measure the distance of the ears with a caliper, that way if it needs a slight spreading I know right where to put it back to. Very slight binding (free moving with just a hint) can usually be cured with just a couple of raps with a hammer on the ends
To make and use the tool get..
A piece of hardened 3/8 or 10mm bolt thread (cut the head off a full threaded hardened bolt) about 4- 5" long, 2 thick washers 4 nuts and 2 short pieces of dowel (wood or nylon it doesn't matter) that fit inside the holes of the ears.

Drill a 3/8 hole through the 2 short pieces of dowel, this is just to keep the tool straight and so the threads don't score up the machined surface.
Put and nuts and washers on the threaded rod and place it inside the ears 2 nuts on each side, put the dowel through the holes on the rod on both sides.
If one ears is more bent than the other lock the 2 nuts on the opposite side together against the washer and tighten a nut against the bent ear till it pushes it straight. You get the idea.
 
The grease turning black is normal. Both farm equipment and my heavy trucks always turned the u-joint grease black in short order.

I've talked with Dana reps at truck shows and they always say to think of greasing a u-joint like an oil change. Always make sure to grease until fresh grease is coming out of all four "corners" so to speak.

Now I have a new truck with sealed u-joints that I can't grease, and can only hope that they still last a long time. It's hard to get used to not greasing them.
 
I'd take anything Lucas and throw it in the trash .. their oil stabilizer product for engine oil should tell you anything you need to know about Lucas oil co.
 
Every universal joint I've ever had that was equipped with zerks has turned the grease black between lubrications on pickups, tractors & equipment...just one more reason to grease them until you see fresh grease from all 4 ends of the joint.
 
I use moly lithium grease (Valvoline synpower), it turns everything black!
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