Bump Stop Misalignment

XCRN

XCRN

TJ Enthusiast
Supporting Member
Joined
Jun 1, 2020
Messages
494
Location
Springfield OH
How much bump stop misalignment is too much? I am showing about 1” offset. I think its mostly the necessary pinion adjustment for a double cardan drive shaft is whats doing it. Ill add the plans to move the perch later but I cannot do it right now. Would this be okay even playing in the dunes for a weekend where I will likely be hitting them? For what it’s worth, they are at least set up correctly to prevent shock bottoming out.

IMG_8313.jpeg


IMG_8330.jpeg
 
how do they line up with the jounce bumpers removed so it's just the cups and the lower pad?
 
XCRN said:
They might go closer, but those jounce bumpers do not compress all the way into the cup like a factory one. They might go in at most 3/4”
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ah. I haven't really used them quite like that. My Rockjock stops tend to come together at an angle but they're still more centered than that. I'm not sure that wouldn't push the bumper over and fold it out of the cup. I'm also a little surprised you can get the axle that far back without the track bar getting friendly with the gas tank skid. Mine LOOKS like they'll hit yet somehow don't, and my bump stop alignment suggests mine must be at least 3/4" farther forward. I do have an LJ though so my pinion doesn't have to be as high.

I like what you did with your e-brake cable retention there, basically reproducing the factory bracket. I have what looks like the same clamps and a length of 12ga flat bar to do the same but haven't gotten around to it, so mine are still on there with zip ties.
 
freedom_in_4low said:
ah. I haven't really used them quite like that. My Rockjock stops tend to come together at an angle but they're still more centered than that. I'm not sure that wouldn't push the bumper over and fold it out of the cup. I'm also a little surprised you can get the axle that far back without the track bar getting friendly with the gas tank skid. Mine LOOKS like they'll hit yet somehow don't, and my bump stop alignment suggests mine must be at least 1/2" farther forward.

I like what you did with your e-brake cable retention there, basically reproducing the factory bracket. I have what looks like the same clamps and a length of 12ga flat bar to do the same but haven't gotten around to it, so mine are still on there with zip ties.
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Thanks, just some aluminum strip and pipe clamps.

The LCA are about stock length. The track bar is apparently hitting the mounting plate at the top of the gas tank skid at full bump, but has pretty much self clearenced at this point and bent the tab over. I actually have a bigger problem with exhaust interference and its preventing the driver side from dropping. I only get 6” overall travel on that side and can get close to 12” on the passenger side if I had the shocks to do it. Moving axle forward would make it much worse but I also dont have much room to move it back either. Fun stuff!

IMG_8312.jpeg
 
I would snatch that back in a few turns, to get it a bit more onto the bumpstop.
That would also clear up 'most' of your track-bar/gas tank contact as well.

Then just re-dial your pinion angle utilizing the Upper Control Arms.

I just went through this same process 2 nights ago, while installing my rear axle.

Before I shortened the Lower Arms :
(Track Bar/Skid bind was preventing full bump. Note the Track Bar interference with the gas tank skid)
1707173182515.png


Then I turned the Lower Arms by 3 full Turns, and these were the results..
(again, note the track-bar contact in the second photo. It wasn't much at all, but just enough to allow full compression without hard contact)

1707173284529.png


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All it takes is a few turns of the lower arms to set fore-aft axle location.
Then utilize the Upper Arms for adjusting Pinion angle.
 
XCRN said:
Thanks, just some aluminum strip and pipe clamps.

The LCA are about stock length. The track bar is apparently hitting the mounting plate at the top of the gas tank skid at full bump, but has pretty much self clearenced at this point and bent the tab over. I actually have a bigger problem with exhaust interference and its preventing the driver side from dropping. I only get 6” overall travel on that side and can get close to 12” on the passenger side if I had the shocks to do it. Moving axle forward would make it much worse but I also dont have much room to move it back either. Fun stuff!

View attachment 497799
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that's interesting. What is that exhaust? Mine doesn't come close enough to the track bar for me to have even thought about it.
 
XCRN said:
3” Holley for LS swaps. Looking at pictures, it looks like the stock exhaust is close but clears. So I probably just need to notch it a little.
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or maybe just adjust some things to pull it forward a bit. Mine was contacting the shock recently and i noticed one of my clamps wasn't tight enough so the tailpipe had twisted out of its correct orientation.
 
freedom_in_4low said:
or maybe just adjust some things to pull it forward a bit. Mine was contacting the shock recently and i noticed one of my clamps wasn't tight enough so the tailpipe had twisted out of its correct orientation.
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At full bump, tube sits perfect in the bend. I can move it a bit forward I think.

IMG_8314.jpeg
 
XCRN said:
At full bump, tube sits perfect in the bend. I can move it a bit forward I think.

View attachment 497822
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What are you calling full bump? Is it squishy jounce touching axle pad? Steel cup touching axle pad? Or full shock compression?

The correct answer is full shock compression.
 
XCRN said:
Full shock compression.
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That being case, the steel cups in your first post ought to be extended some amount to make the jounces do their job of slowing shock travel speed prior to full shock compression.
 
jjvw said:
That being case, the steel cups in your first post ought to be extended some amount to make the jounces do their job of slowing shock travel speed prior to full shock compression.
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These poly jounces only compress like .75” unlike the factory ones. I got a set of the Metalcloak Jounces on the way which I know ill need to make some kind of extension for them.
 
XCRN said:
These poly jounces only compress like .75” unlike the factory ones. I got a set of the Metalcloak Jounces on the way which I know ill need to make some kind of extension for them.
Click to expand...

That's fine. Currie/Rockjock bump stops only compress about an inch. Use what you have, make it work, and return the Metalcloak garbage.
 
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