Lift Shaft Bushings

I had a similar experience as JimNC, I broke my lift cover in the process of removing the rockshaft from the cover. However, my mistake was not understanding that one of the bushings (which ever side the rock shaft comes out) must come out with the rockshaft because the middle splines of the rockshaft are bigger in diameter than the outer splines that rest inside the bushings. Had I realized this when using a hydraulic press to get the rockshaft out, I would not have busted my lift cover. I thought the rockshaft was the same diameter as the ends where the lift arms attach (but it is bigger on the inside where the rocker arm fits). The FO-4 manual did not make this fact clear.

Anyway, Zane is correct (as usual) in that once I got a new (used) lift cover and finished the job, the difference in the slack and movement of the rockshaft inside the new bushings were not that much; although, it was a valuable learning experience. HTH. Rick H. Ga.

My 2¢
Jim

There is really no practicle reason to replace the bushings anyway unless the lost motion is really big and sloppy. Water can enter through the bushings even when the bushings and felt seals are new if left out in a lot of rain.

The operation of the lift is not much affected by the loose bushings on the rocker shaft. If the cam is worn down badly it would be advisable to built it up by brazing or welding in place and regrinding to the correct shape in place.

I have taken the lift arms off and the rocker out of Ns before but only if the rocker itself was broken and there was no other choice.

Zane