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Rock Krawler 3.5 Flex/Synergy Drag Link and Tie Rod Replacement

11K views 39 replies 13 participants last post by  MFerrell 
#1 · (Edited)
Ok guys and gals bare with my while I attempt to put together my first post as a JK owner.

I recently bought an 08 JKU X. The jeep had over 100K but I got it for a steal and everything looked to be in great condition. Looked being the key word. Shortly after I got the jeep it started to have the dreaded "death wobble" and the dealership wouldn't do anything about it. Basically saying, well sorry for your bad luck, hope you don't die. Needless to say I wasn't very happy. Being that they weren't going to help me out and that my fiancé and 1 year old would be riding in the jeep, there was no way that I was going to put them in it in the condition it was in. So I just took the plunge and ordered everything I could think of to basically replace the whole front end.

here is a pic of the beast. (hoping it shows up)

Land vehicle Vehicle Car Jeep Automotive tire


Shout out to NorthRidge4x4 for helping me out with everything.

Below is a list of everything that I ordered:

Synergy HD ball joints
Synergy Drag Link and Flip Kit
Synergy HD Tie Rod & Ends
Synergy Wheel Spacers
Rock Krawler 3.5 Flex Suspension Kit
- w/ Bilstein 5100 shocks
- TeraFlex Bump Stops (front and rear)
- Teraflex Spring Retainers
- Synergy Coil Correction Wedges

I was surprised at how fast the boxes started to come in. right now I am still waiting on one more box but hopefully it will arrive soon. That didn't stop me from starting the build however.

Since I was terrible and didn't take pictures before I started to tear everything apart I will upload some of the progress so far. (pics to come)

First thing I started with was changing out the ball joints. At this point I have the knuckles off and will be pressing them out this evening (after I barrow a press from a buddy). The top ball joints weren't bad, the bottoms ones on the other hand are in horrible shape. I'm surprised the didn't just fall out once I pulled the knuckle.

So far everything has went smoothly. I will try to post pictures of my progress this evening for those that want to follow along.

In the mean time anyone have any questions, concerns, or lessons learned that I should know about or any tribal knowledge to pass along? I'm all ears and excited to get this thing up and running again.
 
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#2 ·
You bought quality parts, good choices.

Curious though, since you bought all the synergy steering stuff, why not Synergy suspension stuff? Doesn't really matter, RK is darn good stuff but was just wondering.

Pay attention to your torque specs and torque when the jeep is back on the ground under its own weight
 
#6 ·
Honestly no real reason. I read reviews on RK, Tera, and synergy and it seemed like you couldn't go wrong with either of the 3. But the RK kit being a few dollars cheaper help the decision. Was going to do Rk steering components as well but the fact you had to take the tie rod off to adjust it raised a flag so I went with synergy.

Thanks for the torqueing info. I was just planning to torque things while I go.
 
#3 ·
Nice list of parts :)
 
#7 ·
Thanks, I also have a 78 CJ 7 Project jeep that's yellow, just something about standing out in the crowd with a loud color. Definitely not going to miss it on the trails.

I'm excited to get yall's product under the JKU and bolted up though. I've ready nothing but good things about yalls products.
 
#9 ·
Finally able to give an update. Between my kids birthday party and being sick this weekend I was able to complete the front end.

While waiting on the ball joint press I was able to drill the spring pad for the bump stops and spring retainers and install the springs. This wasn't to bad if you insert the bump stop into the spring and then install the spring and then screw down the bump stop. If you installed the bump stops first you would need a spring compressor to get the spring over the stop.

The ball joints were a pain in the butt to remove and then reinstall even with the ball joint press.

Here is a comparison of the old Vs. new. The upper ball joints were still in pretty good shape. The lower ones however were completely shot. I'm surprised they didn't just fall out when I took the knuckle off.

Auto part Vehicle


Auto part Tire Automotive tire Rim


After Installing the new ball joints I was able to finish installing the tie-rod and drag link. Since I was doing the synergy drag link flip I had to drill out the knuckle with a 7/8 drill bit. It took a couple tries to get the adapter to fit right but I finally made it happen. Here is a quick snap shot of everything going together.

Auto part Vehicle Chassis Suspension Tire

Auto part Suspension part Suspension Vehicle brake Disc brake


Once I finished up installing the drag link and tie rod I moved on to installing the lower control arms. These things are a chunk compared to the stock arms.

Auto part
 
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#11 ·
Yeah I figured I'd just dive on in and see how far I got and cross my fingers it wasn't gonna be too much. With the exception of replacing the ball joints the build has been pretty fun and has gone smoothly. I'm going to jump back on it tonight and see if I cant finish the rear up. Well, at least as far as I can get. I'm still waiting on one more box that has the extended brake lines, sway bar brackets, and rear track bar bracket.
 
#13 ·
Ok, I forgot to take pictures of my progress so far on the rear end so I apologize in advance, but I will try to get them up tomorrow. I ended up getting the springs, spring retainers, shocks, and bump stops on yesterday evening in the little time I had. Everything went on very smoothly and looks good. IDK if its just me though, but the rear springs seem to be a good bit stiffer than the front ones, could be wrong though.

I have to give Teraflex a thumbs up on their spring retainer for the rear. The tool they supplied to install the nut that goes on the bottom side of the spring pad is clutch. It makes installation a breeze. If they didn't supply that tool it would have taken more like an hour and a whole list of choice words instead of 5 minutes lol.

At this point in time I am kinda dead in the water without the other parts. I will probably call RK today to see what the ship status is on the last few pieces. Once I get those in and the jeep buttoned up its off to the alignment shop. Whoop.
 
#14 ·
WOOHOO my last box came in yesterday afternoon which contained my brake lines, Rear track bar bracket, and sway bar links and I didn't waste any time continuing with the build.

The track bar bracket was a breeze to install, but I do recommend having a small drill to drill the 10 mm hole needed for the top bolt. I had a full size dewalt and it was a tight fit trying to drill the hole. I probably could have lowered the rear axle a little more to get more clearance but I didn't want to stretch the old break lines too much. Once I got the track bar mount mounted and the track bar re installed I installed the new break lines, which again was a breeze. However, it did end up being a little messy.

Once I got the brake lines installed I put the tires back on, bled the brake lines, and took it for a little spin before I put the new sway bar links on. Let me tell you it is a handful trying to control the jeep without any sway bars front and rear. Even after installing the rear it was still dicey to drive. This evening when I get home from work I will be installing the front sway bar links and taking it for another short test drive, then the ol' lady is taking it to the front end shop to get it aligned Thursday.

Soo close to finishing it up and I can't wait.
 
#16 ·
Thanks, Had to modify some pictures so they could all fit but here are a couple of the finished product.

My fiancé was nice enough to take the jeep yesterday to get a new replacement steering stabilizer and get the front end aligned. Unfortunately the front end alignment shop didn't have a printer or the printer was broken so I didn't get a spec sheet. Might take it somewhere else just to get the numbers.

Anyways, after I got home from work I installed the new steering stabilizer and took it for a drive. The jeep does a little walking, but not too bad. Since I didn't get a spec sheet from the alignment I couldn't see what my caster was to check that. But from what Ashley was telling me everything was in factory specs. Any suggestions as to what can eliminate this completely? It drives straight down the road, but sometime I feel if I accelerate it pulls to the left and when I let off it sometimes feels like it pulls to the right.

All in all I am very happy with how everything came out. The jeep looks awesome, not god awfully tall, the ride quality is very good, and the whole system was fairly simple to install.

However, this morning while driving to work I became very disappointed. I hit a rough patch in the road and the DEATH WOBBLE IS STILL PRESENT!!! What the heck!!! I did all this work to eliminate that and it still there. Fortunately it isn't as bad as it was, probably due to having new ball joints. but WHAT DO I DO? I still need to weld the new track bar mounts to the axle housing, which I plan to do this weekend, but is not having these welded contining to cause that? When I replaced the track bar with the RK one I didn't notice the holes being wallowed out, but maybe they are just enough? And maybe I need to get new hardware for the track bar? I read a few threads where the factory hardware runs on the small side and allows for some slop. Definitely looking for some help here guys so if anybody has any suggestions please let me know.

Land vehicle Vehicle Car Jeep Automotive tire

Vehicle Auto part Car Automotive exterior Bumper
 
#17 ·
Getting the 9/16th bolts for the front track bar eliminated my DW issue.
 
#19 ·
Regarding your DW, you still have some lose component(s). I would do some research on DW. There are some great threads on this site on DW.

I personally think the 9/16" bolts are a gemmick. If parts are bolted to torque they should stay in place. But many think otherwise.

Good luck. I had it too, but after laying under the jeep and having someone turn the steering wheel I finally figured it out.
 
#20 ·
Thanks guys for all the input. Friday I made a run to the local hardware store and grabbed a couple 9/16 bolts for the track bar and installed them. Everything has been torqued to spec with the vehicle sitting on it's own weight. The track bar was torqued to 125 ft/lbs.

Holy Cow jvandy50 that had to have gotten really interesting really fast when that happened!

Plan Man has an excellent write up on DW and Shimmies, which I have read on watched the videos on multiple times. I've went through his checklist while having someone turn the wheel and I didn't see anything loose, clunking, or worn out. which I hope nothing would be worn out since I just replaced everything.

I drove it a good bit this weekend after replacing the bolts and making sure everything was tight under the jeep and haven't had another issue. So I have my fingers crossed that it has been eliminated.
 
#22 ·
Thanks, It definitely was a task but well worth it.

I wish I could tell you the specs. The alignment shop told my fiancé that they either didn't have a print or theirs was broken. So, Needless to say I wasn't very happy when she told me. I'm going to call a couple other places around town just to see how much they would charge to just run the numbers. That might tell me a lot. The only thing I got as far as confirmation is they told her that everything was "within spec".

I've check and double checked everything just to make sure. One of the only things I'm a little concerned with is the height of sway bar where the link connects. Since doing the flip kit, which relocates the factory link, and adding the lift with the extended sway bar links the sway bar ends where the links connect seem to be pretty high. Does the angle of the sway bar matter?
 
#24 ·
I measured the entire link when I got home and it measured around 12" with the disconnects and jam nut all the way bottomed out. A measurement from bottom of the thread to bottom of the thread on the center pins was around 8. Don't know if that helps you identify which center pins I have. Guessing there's about and inch of thread on each side so you'd be right on the money with them being the 10" ones.

I'm going to get on the horn today with yall and see about getting 2 of the shorter ones on order.

Thanks for all the help!

Update on the wandering issue... Ashley is taking the jeep back to another alignment shop to run the numbers and see about adjusting the caster to somewhere around 5* if it's not already. From what I have been reading between 4.5-5* is ideal. Any more than that and you run into drive shaft issues.

Slowly but surely we're getting closer and closer to dialing everything in.

Up next will definitely have to be a regear. Pulling my duck boat this weekend with it was somewhat of a task with the 3.27's. 5th and 6th gear were just about worthless. I'm thinking 4.56 or 4.88 gears. What do yall think?
 
#27 ·
You have to keep in mind gearing is very subjective. What may be perfect gearing for one guy may be not so great to another. You also need to take into account your final tire size and gear to that. Will you be staying with your current tire size indefinately or moving up to a 35 or 37 tire? The general consensus for the 3.8 engine with a manual is 4:88s for 35s and 5:13s for 37s. I would imagine 4:10s or 4:56s would be fine for 33s. There is a great chart to get an idea of your rpm speeds with your current engine, tranny and tire set up somewhere on this site
 
#28 ·
I agree completely that it varies based on each individuals set up. I should have stated that I will be switching to 35" tires. from what I was reading the 4.88 is very popular while running 35's, however I haven't heard very much about people running 4.56's. Seems like it would be a good gear set to run? Not too tall but gives you a little bit more than the 4.10's.
 
#29 ·
Alighment spec sheet

Ok guys I finally got an alignment spec sheet after my fiancé took my jeep to have the front end aligned again to see if we couldn't eliminate my wandering issue.

Unfortunately even after tweaking the caster a little bit I still am having wandering issue.

Since I have ran out of space to add pictures here are a few of the specs:

Caster: Left - 5.10*
Right - 5.09*

The initial castor on the spec sheet said 5.11* and 5.12*. However the guy at the shop told Ashley that he changed the castor angle by 1.41*. So I don't know why the initial says one thing and the guy is saying another.

Toe: Left - .08*
Right - .13*

Camber: Left - .57*
Right - .58*

I triple checked all the bolts last night and still haven't found anything loose or worn. However, one thing I did notice that around the side wall of the tire there are a few places that have indentions all the way across the side wall, kinda like inverted ribs. Probably not the best way to describe it but only way I can think of at the moment. I'm wondering if the death wobble I previously had damaged the tires in some way?
 
#32 ·
one thing I did notice that around the side wall of the tire there are a few places that have indentions all the way across the side wall, kinda like inverted ribs.
I dealt with death wobble for a while with my 09 2 door. After replacing the entire front end, it still didn't seem right. I noticed my tires, which were the factory Goodyears, had those same "ribs" that you are talking about. They still had decent tread left on them but I ended up buying new tires anyways because I had just lifted my jeep at the time and wanted to go a little bigger. After buying the tires I noticed my jeep to ride a lot better.
I remember doing a lot of searching about those factory Goodyears and if I remember correctly, I did read that in some cases (not sure how common it was), the plies could seperate causing the vehicle to ride like crap and potentially have death wobble-like symptoms. It was about 2 years ago that I was dealing with this so I couldn't give you every detail about it, but I'm sure I'm not the only one that's had that happen.
 
#31 ·
Tires are 255/75/17 Goodyear Wrangler SR-A's and I'm running 30 PSI all the way around.
 
#33 ·
Thanks for the info, makes me feel like a little bit better and not like I'm loosing my mind. I feel like I have done everything to help the steering and I'm still having issues. Not as much DW anymore, but just steering stability now.

The steering seems super tight, as it should since I just replaced everything but you name it and it does it. Floating, Darting, wandering, etc. Wonder since my sway bars aren't exactly parallel if that has anything to do with it?

I just went out and took two magnetic levels to check the drag link and track bar parallel-ness and they are dead on. so I don't think its a geometry issue as far at the drag link and track bar goes. I think I'm going to try to adjust the steering box a little and see if that tightens up anything.

Driving to work today I also got a feeling that the back end was floating or moving as if the axle was moving laterally under the jeep. Could just me being paranoid.
 
#34 ·
I was definitely paranoid for a long while after dealing with death wobble and shakes and bump steer my Jeep was having, even after fixing it. I'd cringe over every bump I'd hit lol. I went through 2 sets of factory tie rod ends on the tie rod and drag link, then I decided F this, and finally dropped money on good stuff. I'm currently running Synergy ball joints, tie rod, and drag link setup and I love it. It tightened up the steering a lot and I have zero complaints. My Jeep doesn't drive like a caddy by any means, but I'm content with how it feels driving.
 
#35 ·
I'm in the same boat, I do the exact same thing. The bumps still get me nervous but so far so good. I'm running the same synergy set up and really like it so far. I let my tire pressure down a little more and took a touch of slack out of the steering box by tightening the allen screw, which I know they don't recommend, but It has really improved the walking issue I was having. It drives 95% better, but still not perfect.
 
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