Topic: slingshot

[geturbig1]

Hey i just installed the rough country 4inch lift on my 1994 jeep yj also with 33 inch super swampers by interco. My problem is that my jeep rocks and
Shakes violenty ... When i go on bumps and on tracks etc.ss. Its almost like a slingshot effect. does any one know if this is common. I love my jeep and this is killing me. Please note before i installed these it still did the same thing. Thanks alot

[FourbangerYJ]

Welcome to the board 
Are the shocks new too?
How tight are the bolts that hold the springs to the shackles?
Do you have a drop pitman arm?
Are the tires balanced?
 Bias ply or radials on the Swampers?

[sharpxmen]

x2 on the shocks and make sure they are proper length

also, did you angled the rear axle (the rear leafs should have come with angle shims) and did you install a t-case drop or SYE?

[geturbig1]

Yeah bud i replaced the leaf springs drop pitmn arm shakcles shocks bolts  Steering stabilize ret. Tires are balanced And radial. 

[geturbig1]

I had every thing installed pro style. Shocks every thing new. 

[Jeffy]

That probably means they over-tightened everything! 

I'f go back and check the shackles and spring hangers.  Then remove the rear track-bar and possibly the front.  it will probably ride 100x better.

[sharpxmen]

what about t-case drop or SYE and pinion angle?

does it do the same if you have the clutch pressed in?

[Jeffy]

If he's saying, "When i go on bumps and on tracks (train tracks?)" then I suspect his pinion angles are the least of his worries.

[sharpxmen]

If he's saying, "When i go on bumps and on tracks (train tracks?)" then I suspect his pinion angles are the least of his worries.

i had the same thing when driving over bumps and on the gas pedal would start vibrating and jumping up and down, turned out to be the pinion angle and d/s (had to do a t-case drop), that's why i was asking. it would settle if i pressed the clutch.

[Jeffy]

4" RC lift will come with T-case shims.  I'm betting on the overtightening of everything and the track bars though.  The bouncing he's getting is because the suspension doesn't move.  Seen it way too many times.  There is even a YJ in town that I occasionally see bouncing over every little bump.  Newbie driver doesn't know and is living with it. 

[sharpxmen]

4" RC lift will come with T-case shims.  I'm betting on the overtightening of everything and the track bars though.  The bouncing he's getting is because the suspension doesn't move.  Seen it way too many times.  There is even a YJ in town that I occasionally see bouncing over every little bump.  Newbie driver doesn't know and is living with it. 

imo - it comes with poly bushings so should move freely. the track bars might have been tightened with the Jeep lifted and that's something to look at but for the leafs i don't see how it can happen, maybe the shackle bushings on the frame in case those were not replaced with the poly ones

[FourbangerYJ]

geturbig1    take one the nuts off that hold the spring to the shackle. Go to the hardware store and match the nut with either a nylock or stover nut. (they lock when tightened) then replace all of them with your new purchace. (cheap) when you put them on don't crank them down. Just run them until they are snug and you have a bit of the bolt sticking thru to make sure they lock.
Also ditch the track bar front and rear. Then report back. Pretty sure this should fix the problem.

As far as spring bushings if the kit was new it should have come with a new set. Just make sure you added some grease to them. Or install greaseable bolts.

[sharpxmen]

i guess i'm missing something - i thought what you're saying is true when you have the stock bushings where the rubber is vulcanized to the sleeve, once you go to poly which are to be greased when installed the shackles would set on the inner sleeve when you tighten the bolts but you should be able to move them by hand - isn't this the case?

there are still the ones in the frame which i'm not sure if he replaced or not

[FourbangerYJ]

i guess i'm missing something - i thought what you're saying is true when you have the stock bushings where the rubber is vulcanized to the sleeve, once you go to poly which are to be greased when installed the shackles would set on the inner sleeve when you tighten the bolts but you should be able to move them by hand - isn't this the case?

there are still the ones in the frame which i'm not sure if he replaced or not

I think the biggest issue is the bolts holding the springs to the shackle are to tight. Most people either gun them on till the gun stops spinning or spot torque them by hand (torque them until you see spots)
There could be issues with the bushings as well.