U joint wont take grease

I replaced all 3 u joints in the driveshaft last week with Spicers and it's been riding smooth.

However, when i greased them before putting the shaft back on, one channel on the middle joint wouldn't take grease. The two caps which are inline with the zerk did just fine but the other two, no matter how much grease i pumped in there, they wouldn't spit any. I figured I'd drive on it for a few days and try again, thinking maybe things would settle. Tried to grease it again today and still no joy. Am i going to have to take this thing off again and reinstall it?

 

take a small punch or a nail or something similar and push the ball on the end of the zerk in. it should free it up to accept grease.

 

When you put the u joints in did they rotate smoothly after install or were they kind of stiff?

 

The valve ball is frozen. Free it up and then grease. Did you pack them on install? Don't drive on dry bearings

 

The zerk is taking grease ok because it's filling both cups that are in line with it, its the two that are perpendicular that won't grease.

They were all pretty free moving when i installed them, i tapped the knuckle lightly with a hammer to make sure they sat ok and that helped loosen up the movement

 

Go to a shop with a pneumatic grease gun and explain it, they should give it a few shots under pressure and that should clear things up.

 

You really should buy a pneumatic grease gun. They are not expensive and they make this job much easier. The pressure pulses also help free any hardened grease. It could be that your U-joint is bad though. Maybe there is an obstruction in the grease galley?

Years ago I bought a brand new Spicer U-joint. Before installing it I just turned all the caps. One of them felt funny, so I pulled it off. The cap was only machined on one side! The other half of the cap looked like it was cast. Lesson: Just because something is brand new, doesn't mean it is good. I have found 6 or more items over the years that were fails right out of the box. One item that is particularly bad is thermostats. I always measure the opening point before installing. The last one I bought for my 460 Ford, I had to return twice. The first two did not open at the specified temp.

 

could have a joint that is clogged

 

On infrequently grease bearings I've run across in commercial settings I could grease most of these using this ....

$26 Lincoln Industrial 82784 Needle Nozzle with Extension and Locking Sleeve

https://smile.amazon.com/gp/product/B0002SR7QA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

I wonder if there is a way to plug off the two caps that are inline, or otherwise keep the grease from spewing out of them... this will help force the grease pressure into the perpendicular caps.

 

Lightly tap the caps with a hammer. May be caps not centered. Grease taking easiest path pisdible.

 

This

 

Tap the knuckle on the driveshaft or the cup itself?

 

Counterpoint: use non-greaseable u-joints next time. I've always replaced u-joints with the non-greaseable type. They say they are stronger because they don't have the internal grease channels, but I use them because I have lazy-greasegunitis.

 

If all else fails then pull the ujoint off and swap the cap with the zerk fitting inline with the side you suspect is not getting any grease.

 

People are too gentle on u joints. Get a big hammer and after a joint install bang the shaft to seat the corresponding cup outwards. Do this for all 4 cups. This allows the cross and the cups to have some clearance and flow grease. If I have time tonight I will post a video to show what I mean. I do this no matter the size from small 1” shafts up to 8” dia shafts. Otherwise if the cups are tight to the cross it won’t always flow grease. Sometimes all 4 are tight and sometimes only one.

 

The knuckle.

 

That is the only way I install ujoints.