LJ Rear springs solution

glockman

I hate Jeeps
Location
Pleasant Grove
#21
I'm using a JKS adjustable rear track bar, the non CV one. It clears everything. But just barely. Speed bumps would be way cool but I'm petty sure they are too long for my 3 inch lift. I think I'd have to give up some uptravel to use them and I don't want to do that.
- DAA
Oddly enough, I picked up a Teraflex dual rate sway bar off KSL today. The guy I bought it from was outboarding rear struts on his TJ with a friend. Turns out the friend works at Teraflex. We got talking and I told him I just bought speed bumps. He said you can use the bracket for the front speed bumps and a hole saw to recess the bump into the frame rail and custom tune the height of the speed bump for lower lifts.

Spent a couple more minutes mentally planning on the jeep today.

I couldn't figure out why my Falcon's were so close to bottoming on compression. I have TF lower shock mount relocators that allowed the 9550s to clear the lower spring perch. Like these
1546742683629.png

This places the shock farther back away from the axle and up higher. The Falcons lower bolt hole mount is off centered so even though the shock body is larger they clear the perch in the stock location.

Damn the engineering in these things is sweet. Now I have about an inch of exposed rod. I am not only clearing the lower spring perch but also the exhaust that was contacting the shock body before.

Full droop without the re-locating bracket.
20190105_143250 (480x640).jpg

Fully compressed at current bump height.
20190105_143119 (480x640).jpg

The dark spot is where the 9550s were contacting the exhaust.
20190105_143024 (480x640).jpg

I'm leaning towards this Metal Cloak rear sway bar to resolve the contact with the cross member. I'm curious if anyone is running that setup and how they like it. I have a CV driveshaft and the bracket on the CV shaft version is tilted forward to move the track bar away from the crossmember.

https://metalcloak.com/tj-lj-wrangler/tj-lj-rear-durotrak-track-bar.html
 

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glockman

I hate Jeeps
Location
Pleasant Grove
#22
I picked up my speed bumps on Tuesday and commenced to install them. The kit is really easy to install and it was mocked up and installed in a couple of hours including removing the stock spring perches.
Here is what you get for the rear of a TJ.
20190108_123045 (640x480).jpg

Here is my setup mocked up and centered over the axle. I used the washer from the original lift bumps as a landing pad/spring retainer for the speed bumps since they don't include one for the TJ kit. The JK kit has a rubber bumper for the axle side. More on that later.
20190108_135734 (640x480).jpg

Her is the kit installed. Looks pretty sweet right?
20190108_175050 (640x480).jpg


Here is the rub. Teraflex claims this kit works with a 4"-6" lift. With no one in the jeep and a 1/2 tank of fuel I have less than 1" of free travel before the bump hits.


Put two adults in the jeep and it is sitting on the speed bumps. Teraflex claims it takes 4200lbs to bottom each speed bump. Put two of those together and remove all free travel and I have resolved my bottoming issue. I think I could get 10' of air and not bottom. However, it rides like a 1 ton truck from the 70's now. Also since there is no rubber landing pad, it sounds like there is an ADHD 8 year old with a ball peen hammer and a piece of 1/4" plate in the back seat. Needless to say, I'm not thrilled with the design on these for a TJ. It looks like Teraflex designed these for a JK and then threw together a bracket to make them fit, not work, on a TJ.

My options now are-

1. Find a way to use a hole saw to cut a hole in the bottom of the frame so the speed bump can be recessed into the frame rail and get me 4" of free uptravel before the bump contacts and starts to do what it was intended. This will be difficult with the bracket in place but may be possible with an extension and a hole saw. I will still have to find some way to get a rubber landing pad to eliminate the noise. It is loud when these things smack bare steel.

2. Cut them off, order some new upper perches and get different springs and the metal cloak track bar and mount.

3. Cut them off, weld on new upper perches and MC track bar and mount. Then see where I am with correctly set bump stops and a track bar that clears. I am leaning this way. Should have gone this way to begin with but I thought I had a perfect excuse for the cool speed bumps.

I contacted Teraflex by phone. They wanted me to send them some pictures and they were going to send them to their "TJ Guy" and see if he had any suggestions. Having already spoke to the Teraflex guy last week who told me you can recess them with said hole saw method, I don't have much hope for an alternate solution.
 

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Hickey

Rusty Girdle
Premium Member
#24
I definitely think you want some sort of rubber bump pad, no matter what you choose. My fronts are nearly silent on my JK. I really have to pay attention to hear them touch. My rears are very close to touching all of the time though. It doesn't sag and touch unless I put significant weight on the hitch.
 
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