Spring Shackles Won't take Grease

[Chuck W.]

The shackles on my 1964 CJ3B won't take grease. I took them apart, expecting to find old, hard grease, but they were really pretty clean. I did notice that the outer bushings that have the grease fittings were tight against the end of the shackle, completely blocking the grease hole. The service manual didn't help much,
 
"Holding the U shackle tightly against the frame, start the upper bushing on the shackle.... Screw the bushing on the shackle about half way. Start the lower bushing , holding the shackle tightly against the spring eye, and thread the bushing in approximately half way. Then, alternating from top bushing to lower bushing, turn them in until the head of the bushing is snug against the frame bracket and the bushing in the spring eye is 1/32" away from the spring as measured from the inside of hexagon head to the spring."

I am not quite sure I understand this procedure. I plan to reinstall my old shackles (in their original positions) with new grease retainers and grease seals and want to make sure the shackles will take grease properly. If the bushing is tight up against the end of the shackle, there seems to be no way it will take grease. I'm thinking the shackle should be a thread or so away from bottoming out when the head of the bushing tightens up against the frame bracket/spring eye bushing. Am I over complicating this?!

[Rus Curtis]

Chuck,
With your new shackles out, have you attached a grease gun to see if grease will go through the zerq and into the bushing?  Are there holes visible where the grease can come out onto the threads?

To me (having only one vehicle (and a trailer - if I can ever get it painted!), that install description wants the "C" part flush against its mating surface before screwing in the bushing from the other side.  Once both are in, I interpret the instructions to alternate (to keep them as closely aligned as possible) but only one (the top one against the frame) gets screwed in snug.  The spring has a gap so that there can be movement and also to avoid binding.  At least the verbiage states binding could cause spring breakage.

[Bruce_W]

  You’re right, the bushing will tighten up against the shackle, not only preventing grease from entering, but also preventing the shackle/bushing from moving as they need to do. When I install new (or used) shackles I tighten the bushing until it stops and then loosen it about a wrench flat, maybe a bit more. This gives them room to work and room for grease to enter. Usually, the bushing-to-spring fit and bushing-to-bracket fit are tight enough that the bushings won’t back out. Keeping them greased helps.
BW

[Chuck W.]

Thanks, guys!

Are there holes visible where the grease can come out onto the threads?

That's the problem, there are no holes in the end of the shackle, when the bushings are screwed in tight, they butt up against the ends of the shackle and block the grease fittings.  I thought about milling a slot across the flat ends of the shackle to give the grease a path to get to the threads.

When I install new (or used) shackles I tighten the bushing until it stops and then loosen it about a wrench flat, maybe a bit more.

That's what I am thinking I will try first, there has to be some clearance for the grease between the end of the shackle and the bushings.

[Chuck W.]

I put the front shackles back on today, everything went together beautifully EXCEPT, with the bushings tight, the grease passage is blocked by the end of the shackle, same as before. I backed both bushings out about 1/2 turn, then was able to pump grease into the cavity between the shackle and the bushings. I slowly tightened the bushings up until it forced grease out around the seal.