LS swapped XJ destroys shock bushings

[notAhoser]

I've been running my LS-swapped XJ for a year and have put lots of on and offroad miles on it. It eats front upper shock bushings. I mean eats them. I've tried poly, they last about a day on the trail. I've used many rubber bushings from different auto parts stores and they are clearly made of some cheap junk rubber. I've bought other stocks just to use their bushings. Sometimes they last a day on the road, sometimes they last an hour on the trail, no kidding. I have resorted to too many half-ass fixes to this. I haven't ordered any "factory" bushings to try yet. The shocks are not at their limit, and this happens on the street, too. They are correct-length brand new Doestch shocks with lots of rebound damping, so they pull the top bushing through and the lower bushing lives 5 times longer.



Am I the only one with this problem? It has to be due to the extra heat, every square inch of sheetmetal is too hot to touch.

[SlowXj]

Dumb question that I'm sure is irrelevant, but is your caster super funky and causing the bushings to not be square thus causing premature wear....? Or control arm bushings being loose effectively causing the same issues? I have probably 30k on doetsch tech shocks and the bushings are like new... this is a super strange problem...

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[notAhoser]

Nope, straight up and down in the hole, not pushed to the side or anything. Very odd, but it gets very hot under there.

[Anak]

It sounds like you need to get the heat under control.

What sort of exhaust are you running? Headers? What material and what coating? If mild steel and header paint it may be worth your while to invest in ceramic coating.

[old_man]

Pretty much the only things that will kill bushings are:

1) Maxing out the shock travel (bump stops and limit straps?)
2) Heat
3) Mis-alignment / binding (visual)
4) Chemicals

[SlowXj]

Redneck heat shield maybe?

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[notAhoser]

It's the heat doing it, geometry is perfect and it happens just driving down the highway, not just bouncing all over the place on a trail. I tried some redneckery - aluminum foil, towel, etc. The fenderwell sheetmetal just gets hot and there they go.

[SlowXj]

Header wrap, hood/ fender venting, and heat shields sound like the only way then...

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[MJ4BTA]

It may only be a bandaid over other heat related problems, but the JKS upper shock conversions will get the bushings out of the engine compartment. There are better weld in versions, but quick bolt in would give you quick answers. I had to do them with my Cummins 4BT Comanche when I had the single turbo on it because the exhaust housing was nearly touching the top pin on the shock.
If there is enough heat in your engine compartment to degrade rubber or poly shock bushings daily, you are going to have other things melting soon. Do you have any vents in the hood? What type of exhaust? As in converter, restrictive muffer?
With no intentions to be rude, are you very sure its not the coils just pulling them to death? Bushings will soften with heat, but they shouldn't fail that quick.
The reason I ask is my L33 powered XJ never has horrible heat in the engine compartment. Now granted, I have a cowl hood, but i have headers, converter, huge flowmaster muffler and full exhaust to the rear bumper. My PCM is just as close to the passenger header as the shock mount hole is, with my coolant overflow rubber hose thru the hole and my air locker line, which is plastic, is thru the drivers shock upper mount hole. In fact, I have A/C hoses running 2 inches closer to the header on the right side than the shock mount hole, with no heat shielding, for over a year. And, thats with a lean running factory tune.
If you have enuff radiant exhaust heat to kill upper shock bushings, that are 4-5 inches away, you should nearly be able to see heat degradation on the spark plug boots by now.
I hope you get this figured out. This is a strange failure, Please keep us posted on what you find.

[notAhoser]

I am 1000% sure it's not at the limits of the shocks, I measured it.


I destroyed the bushings that came with the shocks
OEM-type replacements from the auto parts that came with Monroe shocks
Literally 15 sets of the rubber Dorman replacements


I found a dusty old package of Energy Suspension poly bushings at the local Autozone and have had them on for a couple weeks now with no sign of failure. It hasn't been really hot yet, but they have not degraded at all yet. All the others were failing by now.


I still hate poly bushings, though. The new sway bar bushings are worn out. The bushings on the Novak motor mounts are all squished now and keep getting worse.

[MJ4BTA]

Yeah, the Novak motor mount bushings around the carriage bolts didn't last two thousand miles for me.

I looked in to using high duramometer urethane barstock to replace the rubber, but I dont think the keyhole shape in the frame side of the mounts will let any type of isolator last very long.

I just rebuilt the mounts using a basic ureathane thru bolted, double shear style when I put the 6.2/6L80 in. Its has only been test fired, not driven yet, so i cant say how they are for noise.

Any updates on the shock bushings?

[notAhoser]

Hey just for the record:


I installed Energy upper front shock bushings, in stock at Autozone, and zero issues at all. Boy I feel stupid, but in most other applications poly is the wrong material. Perfect here for almost a year.


I replaced the bushings on the motor mounts with perfect-fitting heavy duty ones from McMaster-carr. The plates seem to be designed for these parts, there is even a male bushing that fits perfectly into the big hole in the bracket. I'll get the part numbers this weekend and post them. Rock solid for a year.