Front Upper Shock Bushing Failures

[steveroche]

ADMIN NOTE:

This discussion has come up before in random threads. This will become the definitive thread on the failure of aftermarket lift upper shock bushings.

I suppose this should probably be replaced soon...

strut bushing.jpg (193.15 KiB) Viewed 19501 times

[boog2006]

Is there a top washer?

[steveroche]

that is the Markmc 3in kit, It has all the components that normally come with it.

[v7guy]

I suppose this should probably be replaced soon...

strut bushing.jpg

That's what my upper strut bushing looked like a couple weeks ago, they take quite the beating

[The Roadie]

Since Mark's 3" *and* the BDS upper bushings seem to be disintegrating at a regular rate, it seems to be time for washers that exceeds the size of the bushings, or limit straps to stop the shock on extension.

[navigator]

good call James on the separate thread James.
I think my top washer (from RC) looks a good bit larger than the one from the earlier pic.
I expect mine is ~1.5".

[fishsticks]

good call James on the separate thread James.
I think my top washer (from RC) looks a good bit larger than the one from the earlier pic.
I expect mine is ~1.5".

I checked my RC bushings the other day. Even after all the punishment I've handed out to them they haven't significantly deformed.

[steveroche]

My driver side bushing is fine still, i'm actually rather surprised that the passenger side bushing deformed so much. I only upgraded to Mark's lift from the BDS lift less than 6 months ago. I do bash on my suspension because of the trails I encounter, but still a little surprised it happened so quickly.

[v7guy]

Since Mark's 3" *and* the BDS upper bushings seem to be disintegrating at a regular rate, it seems to be time for washers that exceeds the size of the bushings, or limit straps to stop the shock on extension.

I was thinking about this the last couple days and wondering if a larger washer would help some. It seems like the movement of the shock during suspension movement just wiggles the washer around until it cuts down through the rubber. If the outer edges of the washer were outside the bushing after we compress it, there probably wouldn't be the cutting action we see.
I was also starting to wonder if maybe the spacer that goes through the bushing should be longer to give less compression on the bushings themselves. I know I have a good 3/4"+ of threads on the shock showing above the nut. It shouldn't give any additional lift and it might reduce stress on that upper bushing that bulges when it's all tightened down. It also might result in the shock topping out more violently (not enough compression on the bushing to keep the shock valve slamming into the top of the body) , or maybe it would cushion the shock topping out a bit better (the bushing having more room to compress before the shock valve hits the body). Or maybe it wouldn't make any difference at all.

[Trail X]

This is my 4-year old bushing (the worst looking of the two). Still looks great.

I'm wondering if the extension distance is a contributing factor in all of this, since the sleeve design prevents 'overtightening' of the bushings. We've already seen how much destruction an 89 spring can have on a shock internally. If not enough extension is built in, this could be a result. Anyone seen this issue and not have a higher-rate spring?

[bartonmd]

I also suspect it could have something to do with geometry, as you go more toward topped out. Not a lot of rotation as you're around stock height, but the farther the control arm rotates around its axis, the more rotation there is at the top of the strut. I suspect that the coupling of rotation and topping out hard can cause the washer to eat into the bushing pretty good.

Mike

[The Roadie]

Anyone seen this issue and not have a higher-rate spring?

Greg, Michael, and I all had the issue with OEM springs. My prediction: it's all in how much you jump the front end and go off the ground after full compression with heavy tires. Desert trails lend themselves to this sort of abuse. Yours may not.

[Trail X]

I feel like mine top out fairly often when on the trails, but maybe you're right. I did put the washers under my mount, for an extra .7 or so of travel. I can't see it making that much difference.

Still, 6 months vs 4 years... you'd think mine would have caught up by now.

Bill, I recall you saying you had some good data or pictures on this topic, did you post that somewhere? If I missed it, I can merge it in.

[fishsticks]

I'm wondering if the extension distance is a contributing factor in all of this, since the sleeve design prevents 'overtightening' of the bushings. We've already seen how much destruction an 89 spring can have on a shock internally. If not enough extension is built in, this could be a result. Anyone seen this issue and not have a higher-rate spring?

I believe you and I are the only two (of the folks involved in this discussion) who have extended our shaft lengths via washers. Correlation?

The front end of my TB has seen some serious bounce. Not high frequency washboard style (a la the desert crew south of me) but tires hanging whoopsies at too high a speed bouncing. Sometimes I like to pretend I'm in a prerunner.

The RC spacers are similar enough to the BDS spacers that I don't think it's a design issue.

[v7guy]

I do believe you guys are the only two that have used the washers. I had considered it, but I don't necessarily need the extra height, and I fear being close to the limits of the CV. My upper bushing is far more buldged than James when I first put it in.




It may be as simple as the heavier spring exerting more force. But i would also think all the armour a lot of guys are using would put more stress on the bushings as well.

[bartonmd]

It may be as simple as the heavier spring exerting more force. But i would also think all the armour a lot of guys are using would put more stress on the bushings as well.

With this type of failure, the extra weight would stop it from topping out as much, so would be easier on the top bushing.

Mike

[Trail X]

I'm not sure the extra weight is entirely relevant. Other than the 1/4" of ride height it may consume - which may give the shock a LITTLE more room to absorb a few more bumps.

Bill, I see that you said Greg has a failure? I didn't recall that. He wasn't running any special springs was he? I don't remember his setup. Did Michael's failure come before or after heavy springs?

Are you all seeing ONLY failures of the top bushing? Or also failures of the lower? I would assume washboard roads would erode both.

What are the symptoms of the bushings failing? Is there excess movement of the arm? Or is it only evident by looking at the bushing itself?

[bartonmd]

I'd think that we'll only see top bushing issues. I suspect it's from topping out, where nearly all of the jolt force is dealt with by the upper bushing (and the one on the control arm, to some extent), but bottoming out would be on the big, soft rubber bump stop over the rod.

Mike

[v7guy]

James - My lower bushing was pretty good looking with very little wear. The upper was destroyed though. At that time I had no armor and 89 springs so I was topping out regularly. I also do end up on some truly horrible roads. I don't think calling them semi-washboard would be a stretch.

My thought on the sleeve through the rubber bushing being longer purely came from my experience that tightening down the shock nut compresses the bushing significantly more than it is when I take the compressors off.

[JCrayton99]

Could the bushing be getting cut because of the washer? If the washer was the other direction (bowl up) it might chaff on the bushing less....