So I had a 3-1/2" Rubicon Express lift done at 4Wheel Parts. It has made a big difference offroad but on the highway the Jeep wants to jump "sideways" with any pothole encountered. It is not to the point of OMG sideways, but it is noticeable and annoying.
Someone suggested track bars for the rear. So, ur, what are track bars, their purpose, and will this solve the issue?
Running 33" tires set at 38 lbs.

 

What components came on the lift? Post a link to the exact kit you got is possible?

 

In addition to the above request, is the jumping a steering wheel type issue or feel more suspension related like not soaking the bumps up at all?

The three likely possibilities (could be one or all together): bump steer, low caster, tire pressure too high. The kit is not a compliant ride, so to some extent it may never react like a stock Jeep over bumps.

 

38 psi sounds very high. It's probably not the direct cause for the 'bump steer', but it can definitely increase it, not to mention very hard ride and increased tire wear.
I'd try 30 psi, then do a chalk test to find the best pressure for the specific tires & Jeep weight. The result will not be far from 30.

 

Oh, good catch. I didn't see he listed that. Yeah, lower the PSI for sure and that alone will help.

 

RE7142 Rubicon Kit
RE1157 Rear Sway Bar
RER1371/RE1376 OR (whatever that is)
RE1380 Bump Stop 2"
RE1387 Rear Bump Pad
RE1474 Frt. Lower Cam Bolt
RE1477 JK Rear Upper
RE1607 Rear Lower track
RE1673 Front Track
RE1508 Rear Brake Line
other bits and pieces

 

2 door or 4 door? Also I have RE 3.5 on 4 door with 35's and can easily put 37's in. That lift gives you extra lift like over 4" so 33's may look small. 2 things I would do is lower psi and try RE control arm drop brackets. They will help with giving you a stock ride and absorb bumps in the coils.

 

I agree control arm drop brackets do help soften up the front during compression.

I would speak with a qualified installer to decide if a drag link flip kit would help or hinder the steering performance based on the geometry of the track bar and drag link.

I run 28PSI in my 37" toyos on a 4 inch lift with evo plush rides and king 2.5 shocks, flipped drag link and it rides great. At some point any large bump in the road will test the design of the suspension and its ability to absorb large abrupt impacts.

 

Agree with what has been said. Your caster will be way low and that makes for a really crappy drive, especially over bumps. I had the same problem long ago and drop brackets fixed it. And definitely lower the PSI. I'd say 34 at the max.

 

You have caster correction. Did they print out an alignment sheet? If not, find a shop that does free checks and post the numbers for us. (not saying to pay for a full alignment, some shops will print the 'before' specs for free)

Stock caster is a bit over 4*. After a lift, that number goes down, and causes the steering to get worse. Find out where you are at before spending money on parts.

When you lift, both axles shift to one side. (one tire will be tucked into the wheel well, the other side will stick further out) Adjustable trackbars, or trackbar relo brackets, will center the axles from side to side.

RE1673 is a front adjustable trackbar
RE1607 is a rear trackbar bracket - this relocates the stock trackbar to shift the axle