YTread Logo
YTread Logo

The DOs and DON’Ts When Installing Polyurethane Suspension Bushings

Apr 29, 2024
What's wrong with this image? If you know, you know, if you don't know, you will know after watching this video. Hello Garage Fabbers, sweet man, here during my time as a

suspension

manufacturer. In some ways I became the fixer of other people's constructions. I repaired most of the

bushings

probably installed incorrectly. It's super simple, but just because it's simple doesn't mean it's common sense. I got some of these things completely wrong on my first build, so here's a quick guide on

bushings

for those of you planning to build. By the way your own

suspension

when

I say the word bushing I mean the entire bushing assembly the correct name would be rod end but I like to frustrate smart people.
the dos and don ts when installing polyurethane suspension bushings
There are five main components to a hub, the hub flanges. bolt on the inner sleeve, the bushing material, in this case

polyurethane

, and the outer sleeve, which will usually be welded to the end of a link rod or control arm. Hey, the tabs are not part of a hub. Oh yeah, well my friend might be building. The bushings on it are wrong. I like to think of bushings as two separate assemblies and I think you should too. You have the suspension component side that has the bushing material and outer sleeve and the chassis side that consists of the lugs, bolt, and inner sleeve.
the dos and don ts when installing polyurethane suspension bushings

More Interesting Facts About,

the dos and don ts when installing polyurethane suspension bushings...

When manufactured and assembled correctly, the side pieces of the chassis form one solid piece, there are no moving parts, the inner sleeve does not rotate around the bolt, are you surprised? I know it was

when

the bolt is tight, the tabs are held firmly against the sides of the inner sleeve the suspension component side the assembly consisting of the outer sleeve and the bushing material rotates around the inner sleeve stationary the outer sleeve technically could rotate around the bushing material but probably will not the inner sleeve is lubricated and the outer sleeve is not In many bushings you can see channels formed in the inner bore wall of the bushing material.
the dos and don ts when installing polyurethane suspension bushings
These are there to allow lubrication to reach all the important spots. Greece goes on the Zerk fit on the outer sleeve and forces a small gap between the two. bushing halves and works its way through those channels between the

polyurethane

and the inner sleeve to finally lubricate the outer edges of the bushings that contact the bushing flanges. There is no grease inside the sleeve around the bolt. Why because the inner sleeve does not move? Certified by Toyota to work on Toyota products for a living. From time to time we see trucks that have rusted through bolts stuck inside the inner sleeve.
the dos and don ts when installing polyurethane suspension bushings
If you want to cover the bolt and grease it in an attempt to prevent it from rusting, you won't. It hurts a little but it's not necessary now that we know how caps work, let's get one and then we'll do some eyelashes on it. I get my bushings from thorbros.com once again. I'm not sponsored, they're just really good products. I can consistently use two inch diameter ferrules, but the width of the ferrule varies depending on the size of the material I am using to make the link bar. If I use 1.5 inch tubing, I will order 2.5 inch wide ferrules.
Here's why I like them. having a quarter inch of the outer sleeve sticking out beyond the link bar as a shelf to place the weld bead on a quarter inch on both sides equals half an inch. Thorbros identifies their bushings by the overall width of the bushing, which is the width of the outer sleeve with both halves of the polyurethane bushings installed, the flares on the polyurethane bushings are a quarter inch thick, there are two, so add another half inch, half an inch of polyurethane plus a half inch of overhang equals one inch larger than the link bar now that We have a professionally made bushing, let's check it out.
Note that the inner and outer sleeves are not the same width. The inner sleeve is significantly wider. This is intentional and important. Place both sleeve halves on the outer sleeve and they are now the same width. When tightening the bolt, the inner sleeve prevents the link bar tabs from bending inward and crushing the polyurethane. If you are

installing

a grease nipple, check for a small gap between both halves of the bushing and make sure the gap is aligned with the threaded hole for the Zerk connector, if this gap is too tight or the polyurethane covers the hole you will not be able to Inject grease into the connector.
A quick side note on fat. Some greases corrode polyurethane or Delrin rubber, so be sure to make sure the grease you are using is compatible with the bushing material you are using. Next, let's make some link bar tabs that you've probably seen me tracing around the hub when creating link bar tabs. This is because the tabs must completely cover the sides of the socket depending on the application there can be a lot of force on the side of this socket a properly sized tab will support the side of the socket and prevent the outer sleeve from slipping off the material of the socket. bushing and we will also prevent the tabs from chewing on the sides of the bushing, lastly the holes, this one is really important, the through bolt must fit perfectly in both the inner sleeve of the bushing and the hole of the tabs, in other words the flange hole and the inner diameter of the bushing.
In other words, the sleeves are the same size again and I'm trying to make this clear because this is what I see done wrong more than anything else: the inner sleeve cannot fit through the hole in the tabs, if it does. ago, the bolt cannot pass. Hold the sleeve in place and the entire assembly rotates around the bolt, which is really not good. A quick side note about bolts. I always use grade eight bolts on the link bars, usually 9 and 16 inch bolts. My reasoning is simple, this is equivalent to the bolt size that Toyota uses on their link rods and control arms.
I once learned from Max Fish that the shank of a bolt, this unthreaded part, should extend the entire distance between the link bar tabs. The reason is that a bolt is more likely to break in the threaded area, so you should purchase a bolt with a shank long enough to span the width of the link bar tabs. However, this means that there will likely be excess threads sticking out that you will want to trim. If this is all good, you should be able to slap it all together. Together, tighten the bolt to the torque recommended by your Bolt and you'll be ready to move forward.
See you soon, my friends.

If you have any copyright issue, please Contact