Lack of proper lubrication is the most common cause of premature failure in u-joint kits and slip assemblies. Properly sized U-joints that are adequately lubricated at recommended intervals will normally meet or exceed fleet operational requirements. Inadequate lube cycles, and failure to lubricate the u-joints and slip splines properly, will not only cause premature u-joint kit failures, but may lead to other problems, such as slip spline seizures. Relubrication at recommended intervals flushes abrasive contaminants from the u-joints and slip components, helping to optimize the life of the driveshaft.
What type of grease should I use to lubricate my universal joints equipped with grease fittings?
- A good quality lithium complex soap based EP (Extreme Pressure) grease with a NGLI grade of 1 to 2 is recommended.
U-Joint Kit Lube Procedures
WARNING: To prevent serious eye injury, always wear safety glasses when lubricating or servicing a driveshaft. Failure to wear safety glasses could result in serious injury and/or partial or permanent vision loss.
Greasable u-joint kits contain only enough grease to provide needle bearing protection during storage. Prior to installing a new u-joint into the driveshaft, you must:
- Remove each bearing assembly and pack each journal cross lube reservoir with grease.
- Wipe a liberal coating of the same grease into the each bearing assembly, filling all of the cavities between the needle rollers.
- Apply a liberal coating of grease into the bottom of each bearing cup.
After installation into a driveshaft, and prior to being placed into service, you must (with the exception of Lube for Life U-joints) lubricate each u-joint kit in accordance with the following recommendations:
- Apply grease gun pressure to each u-joint until fresh grease appears at each bearing seal. This purging action not only assures that every bearing has been properly greased, but flushes out any moisture and abrasive contaminants that may have worked their way past the seals.
IMPORTANT: The seal design may, on occasion, prevent one or more bearings from purging. If that should ever happen, try one of these purging procedures to relieve seal tension:
- Push up on the driveshaft, from the side opposite the bearing that will not purge, while applying gun pressure to the lube fitting. This might create a slightly greater clearance around the bearing’s sealing surface and may allow the bearing to purge
- Using a rubber mallet and wearing safety glasses, sharply strike lug ear of the inboard yoke once to firmly seat the bearing against the retainer (retainer may be a snap ring, bearing plate or spring tab). Striking the yoke ear may relieve tension across the span. Rotate shaft 180 degrees and repeat procedure on opposite lug ear. Apply grease gun pressure. If the problem still persists move on to step 3
- Depending on the type of yoke design in your driveshaft, release pressure on the affected bearing(s) as follows:
- Release seal pressure by loosening the bolts that retain the non- purging bearing cap(s) in the yoke ear(s). Apply grease gun pressure to purge the bearing or bearings.
- If loosening the bolts does not allow purging, remove the bearing(s) to determine the cause of blockage.
Recommended Greasing Intervals
Spicer recommends greasing your U - Joints at the intervals indicated in the chart below:
Slip Assemblies Lubrication Procedure
- Re-lube slip assemblies at the same intervals, and with the same lube, as u-joint kits.
- Apply grease gun pressure until fresh grease appears at the pressure relief hole in the slip yoke plug.
- Cover the hole in the plug with your finger and continue applying grease gun pressure until fresh grease appears at the slip yoke seal.
NOTE: In cold winter months, new grease in a slip assembly can stiffen and cause the slip yoke plug to pop out of the slip yoke bore.
- Activate the slip spline by driving the vehicle enough to displace a little grease out of the pressure relief hole.
- Failure to complete this recommendation can lead to premature failure of the slip assembly if the slip yoke plug is lost.