Front end hop

Has anyone a diagnosis for this problem? When driving my '75 CJ5 above 40 mph, if I hit a rough spot in the road the front will start hopping uncontrollably. I don't think it is wheel balance because if the road is smooth, it will go 50-55 with no problem. Has anyone else experienced this? Any input is appreciated.

 

I would check ball joints and tie rod ends. Sounds like you may have some worn steering parts.

 

search "death wobble" on here. Its been covered extensively.

short story: worn steering parts somewhere.

 

To me "HOP" is up and down and "wobble" is sideways. Which is it?

 

Yes, I'd say hop is up and down.

It's a resonance, which could be exacerbated by a wheel out of balance or worn shocks. A resonance will only happen at a specific speed and/or over a spcific type of surface. Other worn parts can contribute.

 

What kind of wheels do you have? Aluminum wheels that use locator washers and non acorn lugnuts are easy to put back on off-center.

 

Spackard stated 'when he hit a bump' the hop started. My CJ5 did the same thing after I put my lift on.... combination of zero caster, badly worn tires, bad ball joints, and broken motor mounts. All better now with all of the above fixed and 6 deg of caster.

Have you done any new mods to your jeep recently or has it just developed this problem overnight?

 

I've had the Jeep for about 3-years now; when I got it, it had a 4-inch Superlift (professionally installed), it came with giant Bogger tires which I subsequently sold for a set of original style steelies with 7.50-16 MT tires. Yes, it does hop up and down but only if I hit a bad spot in the road (pot hole, asphalt-ripple, etc.) When it starts hopping, it quickly intensifies to near loss of control. There is no "wobble" as would be felt in the steering wheel. This is a fairly recent problem and may seem to be getting worse (easily hopping on smaller bumps); and it could either be the left or right side depending on which side hits the pot-hole.

 

What do the shackles look like? if you jack up the frames there should be no slop.

 

You're right! its usually a caster problem. I have an aftermarket steering and suspension mfg co. We've been fixing the "death wobble" for years in Dodge and Ford pickups. Some lift kits, sagging springs and/or worn bushings will cause the caster to to end up out of spec. Even a completely worn out steering system will not have the death wobble if the caster is right. Loose steering components just enhance the original caster problem.
Regardless of what the factory says the deg. is supposed to be set at (Dodge says 0 for their pickups) if it wobbles-add more caster til it quits!
I've had some as high as 16 deg, but they finally quit!