Bushings rarely lead to clunk noises until they get really bad. Clunking is usually links. But even partly worn bushings can lead to excess noise and poor handling. My front end was making a groaning noise (more like a soft graunnch) going over sweeping bumps when the front suspension would move together as a unit. This is the situation where the sway bar rotates in the bushing instead of the bar torquing when only one wheel would go over a bump.
I replaced my bushings with Moog K80774 (actually the NAPA relabelled version) and the noise is gone. The existing bushings were okay but the lack of lube created the noise. They were urethane bushings and needed lube, but I just cannot bring myself to unbolting the bushings every year and regreasing them on the inside. (Trying to do it from the outside would be useless.) Urethane bushings are notorious for making noise unless greased regularly.
Note that there are three types of bushings available for our platform:
- Rubber (usually black, but sometimes blue) They may or may not require greasing, but grease must be designed specifically for rubber bushings, or it will rot prematurely.
- Urethane (may be black, red, blue) They will usually tell you they are urethane and it feels like a very dense and stiff rubber. They add control to the front end but MUST be lubed with the special (included) lube. They must be re-lubed regularly or they make noise such as I experienced.
- Polymer (Moog calls it thermoplastic) These are the latest bushing design. They have the stiffness of urethane but without the need for lube. The thermoplastic is a self-lubricating bushing and are supposedly much more resistant to wear, weather and road grime than the other two. Note that they are sold under several brand names: Moog K80774, NAPA 2652632, AC Delco professional 45G1557, Raybestos professional grade 5501557 etc. They are all blue and all look the same. (Probably made in the same factory and relabelled for all.)
These should NOT be lubed.
So care must be taken to ensure urethane bushings are lubed at install and re-lubed regularly, and that the new thermoplastic design is NOT lubed. The way to tell if your new bushings should be lubed is simple - if they come with lube, install them lubed. If they don't; then don't lube.
To me, sway bar bushings are cheap and easy to install. They should be replaced with every sway bar link or shock replacement, or if you are like me, at least every 3 to 5 years.
