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5mike5

U-joint greasing problem

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I've been trying to grease new half-shaft u-joint bearings in my '71 240z. Using GMB bearings from Motorsport Auto and using Red 'n Tacky Lucas grease with a pistol grip 14 oz. grease gun.The problem is grease is only coming out of 1 of the 4 bearings. All suggestions appreciated and I love this forum.

Thanks in advance

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Welcome to the forum Mike.

You don't need to keep pumping until it comes out the caps. Just a little inside the spider and centrifugal force will do the work for you. It will work its way out to the ends of the spider when the uni is warm and turning.

Its not good to pop the seals each time you grease them. They can stay dislodge and allow dust and grime to get in and destroy the uni-joint.

I have used the GMB uni-joints on half shafts before. They came with an extended zerk fitting, but no plug to cap the uni-joint after greasing. I replaced all four zerk fittings with grub screws. Probably wouldn't effect vibrations, but one less source the better. That was my theory.

Chas

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Hi Chas,

Thanks a lot for replying.That info makes me feel a lot better about driving it soon.Still up on jack stands installing new rubber bushings on t/c rods. I also appreciate the suggestion on replacing the zerk fittings. Have a good one.

Mike

11/70 240Z stock. Painted silver by previous owner. I'm the 3rd owner

Edited by 5mike5

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Welcome to the forum Mike.

You don't need to keep pumping until it comes out the caps. Just a little inside the spider and centrifugal force will do the work for you. It will work its way out to the ends of the spider when the uni is warm and turning.

Its not good to pop the seals each time you grease them. They can stay dislodge and allow dust and grime to get in and destroy the uni-joint.

I have used the GMB uni-joints on half shafts before. They came with an extended zerk fitting, but no plug to cap the uni-joint after greasing. I replaced all four zerk fittings with grub screws. Probably wouldn't effect vibrations, but one less source the better. That was my theory.

Chas

 

Great advice.  I added a link to this post from my page.  Half-shaft rebuild.

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Greasing bearings or ball joints or steering racks is not a perfect science. There is no flow path through and past each set of bearing cups, other than through a seal, and when you break a seal, any more you add goes straight out that seal. The best you can do is put JUST enough in until just before it breaks a seal, which is of course impossible to do. Like bolt torque. Torque it until it breaks then back it off a quarter turn. Do the best you can and add the least you dare.

 

BTW, grease does not move in a joint due to motion or heat. It is designed to do exactly the opposite, stay in place. It only flows when frictional forces at the metal contact surfaces get the pressure/temp up enough to make it move/flow to lube the surrounding area. yes, putting grease in your front wheel bearing cover/caps to supply extra grease if the bearings run dry is silly. It just sits there in the cap.

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