Question

When greasing a U-joint on a driveshaft, grease only exits from three of the four journal seals on the trunnion. What should you do first?

a) Heat the trunnion with a rosebud.
b) Leave it; three of four journals are good enough
c) Loosen the journal cap and try again.
d) Replace the U-joint.

Answer 1

First, try loosening the journal cap and re-grease the U-joint. If grease still doesn't exit from all four seals, further inspection is required for potential blockages or damage that may necessitate replacing the U-joint.

Option c.

Step-by-step explanation:

When greasing a U-joint on a driveshaft and grease exits from only three of the four journal seals, the first course of action should be to loosen the journal cap and attempt to grease it again.

This is because not all seal passages may align correctly, and loosening the cap can help grease to distribute evenly.

If after retrying, the grease still does not come out of the fourth seal, further investigation is needed to determine if there is a blockage or if the U-joint components are damaged and require replacement.

Option c.