Rear Spring Isolator Size?

Kugellager · **Posted:** Wed Apr 29, 2009 11:00 am

So I am one of the early Frankenlift adopters and lifted my 2005 at about 2800 miles. I am now at about 17k miles and the front has never completely settled down. The front at the center of the fender well is 36" and the rear measures 35". There has always been a noticeable slope toward the rear as seen in my rock rails and body lines.

Troy suggested awhile back to add a spring isolator to the rear to level it out. I am now ready to add a 1" isolator to the to the rear springs to accomplish this.

What dimensions/size for this isolator do I need and is it best to replace the upper or the lower? I would assume the upper would be better due to the length of the bump stop. I have seen 1" isolators from various places but they are of various dimensions. Making correct measurements from my KJ has not been very accurrate (springs get in the way).

Any help (or links to correct part) would be appreciated)

Click the thumbnail. The current state of the front to back disparity is not as bad as in this photo which was taken not long after the lift but there is still a F/B slope.

John
];')

jeepkj02 · **Posted:** Wed Apr 29, 2009 11:14 am

Go to your local dealership and ask for a upper isolator pad. Its a stock/oem item that you add to the existing pad. Its about $12 ea.

Kugellager · **Posted:** Wed Apr 29, 2009 11:30 am

jeepkj02 wrote:

Go to your local dealership and ask for a upper isolator pad. Its a stock/oem item that you add to the existing pad. Its about $12 ea.

Aren't they only 1/2" thick? Not sure I want to put 3x 1/2" pads in there to level it out. I think I should just replace the stock one with a single 1.5" isolator. It would be safer.

John

jeepkj02 · **Posted:** Wed Apr 29, 2009 12:26 pm

There are a few people on here that run 3 isolators (1 existing, 2 additional). You are correct, they are 1/2" thick so you need 2 per side.

tjkj2002 · **Posted:** Wed Apr 29, 2009 12:51 pm

Your safe adding 2 extra upper isolators per side(for a total of 3 per side).Each isolator gives you 1/2" of lift.

Kugellager · **Posted:** Wed Apr 29, 2009 12:56 pm

tjkj2002 wrote:

Your safe adding 2 extra upper isolators per side(for a total of 3 per side).Each isolator gives you 1/2" of lift.

Would I want to silicone them together so they don't slip around when flexing? It all just sounds so ghetto-rigged doing it this way.

Is there a single solid rubber/polyurethane isolator that is available ? I would rather go this option if there is.

John
];')

tjkj2002 · **Posted:** Wed Apr 29, 2009 12:58 pm

Kugellager wrote:

tjkj2002 wrote:

Your safe adding 2 extra upper isolators per side(for a total of 3 per side).Each isolator gives you 1/2" of lift.

Would I want to silicone them together so they don't slip around when flexing? It all just sounds so ghetto-rigged doing it this way.

Is there a single solid rubber/polyurethane isolator that is available ? I would rather go this option if there is.

John
];')

I know USAFCOP has one,can't remember where he got it or if they still make it,might try PM'ing him.Otherwise no need to glue the isolators together,just make sure they are clean and they will stick to each other anyways since they are rubber coated.I had to add 2 per side(level out lift) and they make no noise or move at all and mine are not glued.

Kugellager · **Posted:** Wed Apr 29, 2009 1:21 pm

Ok thanks for the help/suggestions guys.

John
];')

SweepnChoke · **Posted:** Wed Apr 29, 2009 1:32 pm

I had the same issue, rear end sat low with the amount of gear I keep in the back. Added 2 extra stock upper iso's to level out (about $75 @ the dealer), not glued, no slipping around, no issues.

Kugellager · **Posted:** Wed Apr 29, 2009 4:10 pm

Ok. You all convinced me. I ordered 4 from the Jeep dealer closest to my work for $13 a piece. They will be in from their warehouse tomorrow morning.

Thanks again.

John
];')

dieselenthusiast · **Posted:** Wed Apr 29, 2009 6:24 pm

BjBnet · **Posted:** Wed Apr 29, 2009 8:14 pm

mine is sitting the exact same way..... I was going to wait for it to settle but you've done that for me, so I guess I know what to expect.
Thanks for posting pics guys

ATXKJ · **Posted:** Thu Apr 30, 2009 12:49 am

There used to be a small spacer for the rear called a trim packer -
never seen one - but I remember it mentioned a couple of times
check with All-J's.

Kugellager · **Posted:** Fri May 01, 2009 12:13 am

I picked up the isolators from my Jeep dealer after work and put them in today. Took me about an hour to do each side using my two screw-type spring compressors (this included a lot of putzing around with other things). I first removed the lower bump stops that were added with my Frankenlift. Next I just compressed the spring enough to pull it out and then compressed it some more once it was out to compensate for the thickness of the isolators. I added two new isolators on top of the original isolator and replaced the spring. I uncompressed the spring making sure it seated properly and then replaced the lower bump stop. I needed to use the Jeep scissor jack under the shock mount to lift the axle up high enough to get the tire back on.

The thickness of adding two isolators comes to almost two inches before they are compressed by the spring. They add roughly 1.5" of height to the rear after they are installed. The back definitely looks higher and the slope is almost completely gone. The remaining slope I can perceive is most likely from the slope of the driveway or the slant of the moulding. Both the front and the back lift heights now measure just over 36" from the ground to the center of the fender well and 22.5" from the center of the fender well to the center of the wheel hubs.

Thanks for all the suggestions on the quick fix. It was really easy and on the fun side of Jeep wrenching.

John
];')

Kugellager · **Posted:** Mon May 04, 2009 6:04 pm

Ok, Here it is after I finished leveling the lift using two extra OEM rear spring isolators. Definitely worked.

Before spring isolator installation. Click the thumbnail.

After the spring isolator installation. Click thumb for larger size.

John
];')

tommudd · **Posted:** Mon May 04, 2009 6:21 pm

Wow I need some of those since it even made your KJ look cleaner :shock:

Rear Spring Isolator Size?

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