Have you just purchased some new poly bushings to replace your old worn rubber bushings? Polyurethane suspension bushings need to be greased before installing them to prolong life and keep it from squeaking. There is a right way and a wrong way to do this. The type of grease you use is crucial. A Poly bushing if greased properly will outlast a rubber bushing.
To begin let’s talk about the grease you should use. You should only use lithium based grease on polyurethane. Petroleum based greases will actually eat a bushing away so this is why it is so crucial to use the right grease. You can actually be doing more harm than good by greasing your bushings with the wrong kind of grease. A lot of moving parts (control arms and shackles) have grease zerks to ensure that the grease you are putting on gets reapplied from time to time as it washes out from the elements. This is a great feature so you do not have to take them apart every time to reapply grease. But what happens all so often is you will take your vehicle in to get it serviced and someone will be under the vehicle pumping grease into all the joints. They see these fittings on a control arm or shackles and think let’s put some grease in there. Most of the time they have petroleum based grease in the gun and while thinking they are doing a good job they are actually ruining your bushings. Make sure you inform any and all technicians working on your vehicle, doing this sort of work not to use petroleum grease on your poly bushings.
When you receive a new part (body mounts, leaf springs bushings, etc) with poly bushings already in them they usually were installed in the part for shipping. They will need to be pulled back out and greased before being installed on the vehicle. One benefit to poly bushings is they do not need to be pressed into the part. They are usually a two piece bushing making them easier to install.
- Pull the bushings out of the part.
- Make sure to keep track of where the bushing came from or do one at a time. Often there are different bushings in opposite sides of a part
- Apply a generous amount of lithium based grease to the bushing
- Make sure to apply grease to all surfaces of the bushing inside and out
- Reinstall the bushing into part and the corresponding sleeve if applicable.
- Install part on vehicle
- Reapply as needed depending on weather and driving conditions