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Rear suspension clunk after new lift components

Fergie

Fergie

NAXJA Forum User
Location
Flagstaff, AZ
Alright, rig specs for those that will ask later:

1995, 2-dr, 4.0L, AW-4, 231, 29-spline 8.25" with Auburn and 4.10s and front hp30 with 4.10s. I have an OME lift on, consisting of coils, leaves with RE shackle and OME shocks all around. I have raised shock mounts, BPEs, no degree shims/sye/or cv ds.

Problem:

When going over a swail, concrete drainage section in parking lots, or over speed bumps, the rear suspension makes a "clunk" after passing over said bumps. This happened when I had RS9000s on, but went away with the stock shocks, and now it appears to be back. I have RRO BPEs on the shocks, just to reiterate.

Question:

What in the hell is causing the thud/clunk/noise? Everything is tightened and I dont know what else to check or look into. Please, does anyone know what I am talking about, and how to solve it? Thanks

Fergie
 
I would suggest taking those RRO BPE's off and throwing them in the trash. They turn the upper part of the shocks 90* in the wrong direction, which will cause severe bushing wear and damage, especially with more lift height. Get some quality BPE's like JKS that keep the shocks turned the correct direction.
That is where I would start.
 
Well, I am going off of what the previous owner of the lift told me, and tend to think that his knowledge is correct.

Besides, the JKS BPEs will not fit OME shocks, so that is why I am not using them.

The part that baffles me is that the noise was there with RS9Ks which had bar pins, but went away with the stock shocks that also had bar pins. Why is it there with BPEs is what is killing me.

Fergie
 
Fergie said:
Well, I am going off of what the previous owner of the lift told me, and tend to think that his knowledge is correct.

Besides, the JKS BPEs will not fit OME shocks, so that is why I am not using them.

The part that baffles me is that the noise was there with RS9Ks which had bar pins, but went away with the stock shocks that also had bar pins. Why is it there with BPEs is what is killing me.

Fergie
Click to expand...


That is strange that it comes and goes, but, the JKS BPE's will work with the OME shocks. :thumbup:
 
A little tough to see because of all the dirt, but here is my proof on my wife's XJ.

http://www.imagestation.com/picture/sraid92/p031df5c761ca07464cd0777060c75776/fa58df0c.jpg

fa58df0c.jpg
 
Start with the easy/obvious common problems!
The shackle is hitting the tailpipe.
The shackle is hitting the bumper bolts.
The exhaust is hitting something(mine hit the receiver).

Then look at the possibilty that you are bottoming out the shocks.Since you moved the mounts thats a good possibility.
 
RCP Phx said:
Start with the easy/obvious common problems!
The shackle is hitting the tailpipe.
The shackle is hitting the bumper bolts.
The exhaust is hitting something(mine hit the receiver).

Then look at the possibilty that you are bottoming out the shocks.Since you moved the mounts thats a good possibility.
Click to expand...
I'll check those out, but there didnt appear to be any issues when we had it flexed out on the forklift.

Any other suggestions folks?

Fergie
 
had a similar problem...checked every bolt, bushing...make sure your 9000's are mounted with the shaft up. turned out to be my problem. they tend to get a small amount of air in the valve and this causes poor damping characteristics when mounted upside down.
-g luck
 
As for rotating the shocks, it is a non issue with OME shocks as you can spin one end of the shock 53 times and it won't bind, it's just how they are made.
The lift in question is exactly as it came off of my Jeep, except that I took out the OME AAL to keep it.
I never had any problems, but I would look to the shackle, the exhaust, and make sure those RRO BPEs are snugged tight around the bushings to give them a bit of preload. I used a vise to clamp the BPEs tight around the shock bushings, and make em tight.
Are the BPEs secure in the body?Exhaust on shackles would be my guess.
Listen to the 'tone' of the clunk, and determine what type of metal is making the noise and look there.
I don't know how to describe it, but after Jeeping for awhile, you can listen and identify noises by their tone.
HTH, and good luck.
 
I had a thunk and it turned out that my ome shocks didn't have enough travel and the noise was the shock stop hitting at full extension. I had to switch 'em out for the ome long travel shocks.
 
Well, I doubt it is a lack of travel, in any direction.

I'll check the tightness of the shocks in the BPEs, and the BPEs against the body.

After looking at it last night, the exhaust hanger is clsoe to the shackle, so that may be the culprit.

I'll report back in when I figure it out, so thanks for the insight.

Fergie
 
could it be with the longer shocks your getting more flex and you are hearing the slip joke going back in after it flexes?
 
89xj said:
could it be with the longer shocks your getting more flex and you are hearing the slip joke going back in after it flexes?
Click to expand...
That is not something that I have thought of checking. I wouldnt think that just going over swails and sppedbumps would cause that much suspension travel, but I'll check it out too.

Hopefully I will get this resolved this weekend.

Fergie
 
I'd be curious as well to find out what the mystery clunk is, as I have it as well. Mine seems to occur a relatively slow speeds while placing "force" on the right side (turning into a driveway, etc), when the right rear flexes up a bit. It's sort of sporatic as well.... :shrug:

I have some JKS BPE's I'm going to throw at it in hopes that might mitigate the problem, but I'll keep watching this thread to see what else pops up...

Ivan
 
Ivan said:
I'd be curious as well to find out what the mystery clunk is, as I have it as well. Mine seems to occur a relatively slow speeds while placing "force" on the right side (turning into a driveway, etc), when the right rear flexes up a bit. It's sort of sporatic as well.... :shrug:

I have some JKS BPE's I'm going to throw at it in hopes that might mitigate the problem, but I'll keep watching this thread to see what else pops up...

Ivan
Click to expand...
I had a similar clunk usually when turning right as well and traversing normal driving bumps. Drove me nuts. Replaced all all kinds of stuff. It was my slip yoke flexing in and out. I put in a AA SYE and new shaft.....noise gone instantly.

just a thought.

david.
 
Ivan said:
I'd be curious as well to find out what the mystery clunk is, as I have it as well. Mine seems to occur a relatively slow speeds while placing "force" on the right side (turning into a driveway, etc), when the right rear flexes up a bit. It's sort of sporatic as well.... :shrug:

I have some JKS BPE's I'm going to throw at it in hopes that might mitigate the problem, but I'll keep watching this thread to see what else pops up...

Ivan
Click to expand...
Those are the BPEs that I had, but never used except for the front. I bought them originally for the Ranchos, but put the stock shocks in before those, just to see.

How far out should the SY be, in stock form? I noticed that is was out farther than before, more shiny metal showing than before, so that may be it.

I want to try other methods before I drop money on the SYE and shaft.

Fergie
 
Okay, had a look at the XJ this weekend to figure out what the noise was. First off, everything was tight, so I know it wasnt something that was just loose.

It is not the bumper bolt hitting the shackle, during comp or droop.

What it appears to be is the exhaust hitting the shackle bolt. I say this for several reasons, least of which being the metal to metal contact marks on the exhaust pipe. There is only about 3/8 of an inch between the exhaust pipe and the end of the shackle bolt(the one that goes through the spring eye).

I can pull the pipe over to make it contact the shackle so I see no reason why a good bump wouldnt do the the same. I am going to rig up some kind of pad on the bolt tomorrow. If this dampens the noise, then I know the problem, if not....back to the perverbial drawing board.

So, does anybody have any good/safe/practical solutions to solve this prblem, or is it something I need to learn to live with when I hit bumps? Thanks

Fergie
 
Stick a three-four foot pry bar in your pipe and inch it over towards the exhaust a bit, worked for me at a total cost of $0.00. Send me a PM with an e-mail and I'll attach some before and after pics for you if you'd like.
 
Yeah, I plan to get some pics up that show how close it is. I'll have to go to the shop to get a prybar bar tomove it though. We'll see how it goes.

Fergie
 
Here are two pics of the exhaust pipe and the shackle/leaves. Lemme know if you think that the noise isn't the two connecting when going over a bump.

Fergie

lightpic2.jpg


lightpic1.jpg
 
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