Hot Rods Crumbling Urethane Bushings

I’ve heard of this occurring but figured it was not something I’d see myself let alone today! Yet I found the Energy Suspension end link bushings are crumbling…
Is this still an issue & if so what brands are holding up? I hate repeating work twice (or more)!

 

The bushes in that design of end link take a real pasting.

how old are they/how many miles they done?

tbh I consider them a service part.

just throw some rubber ones back on there and have a second set on standby for when you next change your oil

 

I bought a set of summit brand rear tubular control arms with urethane bushings. After 10 years they basically disintegrated.

 

Rubber and polyurethane treat them as consumables. 5 years good, 10 years maybe, 20 years lucky.

 

You've probably heard the expression, "Rust never sleeps".
The same is true for poly-plastics...... or rubber bushings, for that matter. There's really no way to prevent and protect against the degradation to any great degree. Any type of lotion or treatment is a short-term solution.
Years ago when I was researching this very issue, I read an interesting article about how contemporary art museums were frustrated because many of their valued sculptures, which had plastic components in them, were degrading over time. And that was in ideal, weather-controlled environments, nothing like what vehicles are exposed to.
You have to think of the replacement task as 'quality time spent with someone you love'.

 

I have a independent front suspension from one of the suppliers and the poly bushings crumbled in about 1000 miles on the road. I had the car together for 5 or 6 years but it wasn't finished enough to drive it. I contacted the supplier and was given a story that the poly bushing with deteriorate if they are allowed to sit, but last forever it they are worked by driving. Didn't really buy that story. The replacement bushings they shipped me are derilin.

 

Wrong material for the application.
How long does OEM rubber last ?

 

I have a 20 year old truck with all factory suspension except for upgraded shocks. All the rubber bushings are still ok. The truck has never been inside overnight.
I also have a 19 year old car that has spent most of its life indoors. All the ball joint and tie rod boots are falling apart.
I guess I need to abuse stuff more lol

 

I should have said in my previous comment there is a world of difference between OEM and aftermarket moulded parts made of rubber or poly.

A lot of aftermarket rubber parts are made from reclaimed rubber, characterised by a strong tar smell. These are extremely poor quality and will fail quickly. Polyurethane parts need to be vacuume de-g***ed in the manufacturing process which is not done in cheap parts making a porous and weak part.

 

There is a reason the factory uses rubber.

 

Lots of excellent points! I use to think aftermarket was as good but learned over the years it’s not. Unfortunately the OEM’s were good I just thought I needed some poly for handling better. Thankfully they aren’t control arms on something difficult to replace & I probably have extras in my box of swaybar parts.

One of my kids cars is a 2011 Sentra from California but over the past two years lots of rubber failed. The front 2 rubber sub frame connectors broke, lower control arm rubbers cracking bad & all 4 motor/trans mounts were failing. Plus the rubber accordion looking hose from the air box to throttle body had split open.

I have heard Delrin does last a very very long time & due to that alone I may need to use Delrin bushings on my 89 Corvette’s bushings when I get around to that task.

 

All I know about this after 40 + years of working on cars is, the aftermarket stuff goes bad rather quickly. Like what was stated, spend some quality time with your pride and joy and replace them.

 

Are you racing these plastic bushing cars? If you aren’t, I can’t imagine why you’d want an almost solid feeling bushing. Use rubber.

 

Delrin is hard, no give.
The factory considers vibration, in street applications.

 

If I can get an oem style bushing etc in rubber thru a name brand manufacturer that's what I use, moog/Napa gold etc.

After 45 years in frame & suspension shop I prefer rubber when possible. Seen too many poly bushings fail in a short amount of time and customers complaining of stiff/harsh rides and road noise transfered into the cabin.

Been thru the poly bushing phase myself and ended up ripping it all back off and going back to high quality rubber....


...

 

At least rubber bushings (as well as rubber weather-stripping, etc.) respond well to treatment with silicone spray or a smear of dielectric silicone grease. Don't know what you might use to treat urethane bushings, and I suspect that there might be nothing that can done to treat Delrin.

 

Urethane will eventually degrade. I had a pair of Rocky brand insulated boots that I only wore 2 or 3 times a year. One year I picked them up and the urethane soles just crumbled. Pissed me off but they were about 10 years old. No reason to believe suspension bushings, which are subjected to a lot more stress, would be any different.

 

If you have a lathe, make your own bushings out of DELRIN plastic.
Much tougher than urethane. Look here:
is delrin platic toughter than urethane - Search
and here:
Solid Bushing Explained: Polyurethane vs Delrin vs Aluminum Bushings – Garagistic

 

Polyurethane oxidizes, so it will crumble eventually no matter what you do with it.

 

Relatively soft materials (urethane, delrin, rubber, etc.) deteriorate whether they are active or p***ive. I put a Pete & Jakes four-bar suspension on the front end of my '29 Model AA back in the '90s. The 16 urethane bushings eventually crumbled in place without ever being subjected to road use. For $60 or so I replaced them last spring. Easy peasy. Stuff wears out and/or deteriorates because everything - even the pyramids - breaks down and erodes eventually.

 

I swore blind years ago to never ever use polyurethane bushes in any thing, rubber will eventually wear, but it doesn’t totally disappear like poly.

 

I got sick of the chinesium dust boots falling apart, went with some ES polyurethane tie rod boots... those cracked as well.

 

Using harder materials like polyurethane on sway bar end links are a good application for it. It makes the sway bar work better as it has less give in the connection but doesn't impact ride quality. On the control arms and parts that actually affect the ride though? No thanks.

 

I used poly on my sway bars too, for a while.

I always said/say I drive my cars so with that said. On my 68' firebird and 71 G.P. I kept popping the heads off of the sway bar link bolts. I used Curtis 5 grade originally then switched to Curtis grade 8 bolts and still kept popping the heads of the bolts off, went back to oem rubber and cured it.

Anyone that's been in the hills of s.w. Missouri roads know how curvy they can be and taking 40mph curves at 60+ was a little hard on sway bar bushings and tires !!

My boss used to ask me if I ever thought about buying a pro rally car as a daily driver....

....

 

One thing I learned over the years and I was/am as guilty as anyone else is our penchant to overtighten suspension pieces and squash the bushings causing them to break down faster. That taking the impact and rattling the nut or bolt down until it quits hammering and calling it good and tight and a year later see the bushing start showing cracks around the edge on rubber bushings.
I don't have a lot of Poly bushing experience except for helping a buddy change his suspension link bushings out on his 4x4 and they didn't seem to last that long but he seemed to view it as part of the deal that you replaced those bushings on a fairly regular basis. He did take the truck to the hills all the time and it wasn't a boulevard cruiser in the least bit. More wood hauler and huntin rig.

 

I disagree. I had Delrin bushings in a suspension one time. They have no lubricity at all. After the grease wipes away, they squeak and squawk like mad. The suspension bushing people abandoned that decades ago. I've had much better luck with today's polymer bushings, particularly Energy Suspension's. YMMV.

 

Real Delrin contains Teflon.

 

Polyurethane bushings are not indestructable and are vulnerable to road crud, chemicals, and U.V. just like rubber.
When it comes to sway bar polybushings they need to be lubricated, treat them more like bearings than bushings.
Rubber will squish and compress, poly wont. Excessive torque/clamp will distort and damage poly. Rubber forgives much more.

Endlink washers are cupped for strength, not to contain the bushing. If the sway bar seems to be stiffer after installation(properly lubed/torqued) flip the cupped washers 'out'. Sway bar funtionality will be better.
Snapping bolt heads off is just an indicator that the bolt was being bent cyclically. Weakest point would be the bolt head to shank interface.
Polyurethane endlink bushings need to funtion as a sperical bearing. If the fastener is cranked down tight then the endlinks will just bind.
With poly endlink bushings the nut only needs to be snugged down, best to use polylock type nuts, with the car on the ground/level the swaybar should not be preloaded. One should be able to rotate the bushing with your fingers.
Contrary to what rice rocketeers believe, a car needs to roll for proper weight transfer for grip.

If one keeps driving said vehicle, surprisingly a long time.
As long as U.V., chemicals(oils/road salts etc), or excessive abuse are not applied to the bushings they will last hundreds of thousands of miles. The exception is sway bar/end link bushings as they are physically worn down from friction between the sway bar and bushing. They are treated more like a bearing surface. Control arm bushing rubber is bonded to the shell and crush sleeve, rubber twists which self lubricates internally keeping it pliable. Walk away from a vehicle with even fresh rubber bushings they will fail and dry rot if not exercised regularly.

 

That's not exactly true. Delrin does not contain PTFE (teflon). Delrin AF contains PTFE fibers which improve wear characteristics and lubricity.

 

One thing I learned over the years and I was/am as guilty as anyone else is our penchant to overtighten suspension pieces and squash the bushings causing them to break down faster. That taking the impact and rattling the nut or bolt down until it quits hammering and calling it good and tight rather than tightening them down just so has cut life short for a lot of bushings.