So, I've done a lot of research, ripped apart my subframe and control arms, and since I didn't feel that this topic should go anywhere else, I figured I'd add on to the Suspension FAQ.
Q. Bushings... WTF are they?
A. Bushings are the buffers between your control arms, differential, subframe, and the chassis. They are rubber inserts that form a protective cushion between the metal, moving parts of your suspension.
Q. What do they do?
A. Their job is to absorb Noise, Vibration, and Harshness (NVH), while keeping your suspension geometry somewhat within spec while cornering or going over bumps. Being made of rubber they make the ride more bearable. Nissan of course made our cars to be "sporty", and rubber is slow to respond sometimes, which means they aren't the best for spirited or motorsports use. The problem with these bushings, is that, like anything else on a car, they wear out over time, when subjected to road-grime, heating and cooling cycles, vibration and all the other elements that our cars endure, not the least of which is the driver.
Q. So what are the alternatives?
A. Well, you can replace them. There are 3 main types of replacement:
--Rubber is the first. Now, these come in OE or Performance Flavors. These bushings are usually pressed in, which as a result means to replace them, especially with OE-hardness bushings, that you'll need a press or new arm. Performance Rubber Bushings are generally harder, like Nismo/Full Race/Megan. These provide a tighter feeling while still being very street/daily-driver friendly.
--Polyurethane is next. This is a plastic alloy (lol) that is more dense than rubber, but still has some give to it. There are more than a couple companies which make these types and the performance benefits are pretty sweet. You get to tighten up your handling to better than stock, your handling becomes more predictable and you STILL have a car you can use on the streets. The downside with these is that like rubber, they won't last forever, and ones that move, like the control arms, need periodic lubrication (depending on manufacturer/style) via Zerk-grease fittings or Dis-assembly. The big names here are Energy Suspension, Prothane, and Whiteline.
--Solid/Heim Joints are last. These are the fully adjustable units you see the racing/hellaflush guys running. These are usually spherical bearings (in the case of Control Arms), or Solid Metal Slugs (in the case of your differential or subframe). These bushings are the best for performance, because they allow very predictable handling, because they bearings will only move a certain amount, your suspension geometry remains more static as well. The bad is that all the NVH that was previously captured by the rubber, is going to get to you now much easier (a reduction in ride comfort). Heim joints also need periodic inspection to make sure the vibration isn't shaking bolts/nuts loose, they aren't binding.
Q. That was really long winded...
A. Not a question, but okay, here's the short version: Bushing replacement should be determined by your own sensibilities and what you plan to use the car for.
Rubber - Good for Daily, Not as good as others for performance
Polyurethane - Acceptable for daily, acceptable for performance, may be more maintenance involved
Heim/Solid - Great for performance, not as good for daily, Heims require vigilance/maintenance
Q. So... How do I install them?
A. I shall direct you to Project Car Magazine for a detailed How-To with our cars. And also
Here. Remember to say thank you when you get there.
Q. Anything else I should know?
A. There was some interesting discussion with Poly-bushings going on
here, and
over here we have some Subframe Bushing Install Tips.
Now, if you have clunks coming from your suspension, when cornering or going over bumps, it means your bushings are probably shot. The reason is because the suspension is contacting itself in ways it was never designed to.
Quote:
Originally Posted by SuperBlackS14
Quote:
Originally Posted by KendallH
Hope this is the right place to ask. I recently bought a set of brand new FA500s for my coupe, and I'm having an issue with one of them. The front passenger side is clunking on rebound(?) I believe. When going over bumps in the road/potholes/etc. When the wheel comes up in travel, compressing the coil, it's a strange bump/clunking sound. Also, on the same side I'm hearing a binding noise when turning the wheel stationary. I pulled the wheel and knuckle off to inspect it and the tophat will barely rotate at all which is causing the actual insert to turn instead of the tophat. I've tried shooting some silicon lube inside the pillowball but it's still very stiff and won't turn. This is only on the front passenger coilover, none of the others. Overall very happy with the 500s, the ride incredibly well, would just like to figure out if theres a way to correct those issues.
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Have you checked your bushings recently, they might be out to lunch. |
Links:
energysuspension.com | Welcome
Whiteline Performance Suspension – Activate More Grip
Prothane Suspension Parts - A Dealer of the Prothane Brand of Suspension Parts
Nissan 240sx - Suspension & Steering - Suspension Bushings - Enjuku Racing Parts, LLC
Well, that's it for me. Let me know if I missed or need to add anything to this.