Control Problem

[JeffP]

I need some help on this one.
1975 CJ5 , AMC 304 , T-18 , Dana 20 , Dana axles, manual steering, manual brakes.
When I put this Jeep back together, we stripped it down to the frame but left it standing on it’s own suspension.(for portability) The springs, bushings, shackles etc. all looked good so they weren’t disturbed.
The gear ratio was changed fro 4.27 to 3.37. Front hubs rebuilt, new tie rod ends, new steering box, new shocks, (steering shock added also) new brakes, new tires etc.
I got the alignment almost dead on, but took it to “the master” for a professional alignment. He looked it over, tweaked it a little and gave his blessing. (Absolutely no question about the alignment guy or his work!)
So... here’s the problem... If I’m going straight & let go of the wheel, it continues straight as long as I don’t exceed 40 mph. Barely over 40, I don’t dare take either hand off the wheel! I’m fighting for control! It’s not a wobble, more like the feeling of an overloaded trailer that is fishtailing.
Don’t tell me “it’s a Jeep... they do that”.
The only component that isn’t new or rebuilt is the springs & bushings, but again they “looked” great, possibly recently replaced before I got it.
The only test I could come up with was to crank the steering wheel while watching the front end. Nothing loose, springs aren’t moving... again everything “looks” good. WTH?
Any idea what the problem is? Could springs, bushings or even mounts / shackles cause the problem?
I’m not being overly picky, it’s really bad! To the point I don’t dare let someone else drive it!

 

[Lumpy Grits]

Can you post up the readout from the alignment shop?
What size tires and wheels? How much off set in the wheels?
What air pressure in the tires?
Bet the toe-in needs some help, and question what the camber and caster is set at.
You want your caster to the upper end of the spec on a CJ with fat tires.
http://www.superstreetonline.com/how-to/wheels-tires/sstp-1004-camber-caster-toe-wheel-alignment/
LG

 

[jp360cj]

What was the caster when the alignment was done?


Sent from my iPhone using Tapatalk

 

[JeffP]

What was the caster when the alignment was done?

What was the caster when the alignment was done?

On the 75 CJ5 Caster / camber is preset and can’t be changed without serious modifications. All that can be “adjusted” is toe. I had that within a gnat’s *** before the ol’ pro checked everything.
When I checked it with my official Summit Racing alignment tool, both sides were identical so I’m reasonably confident neither knuckle was bent. I don’t remember the spec.
A note about the alignment guy. He’s been in the same spot since the sixties. I’ve taken him some real disasters before and they were perfect when I drove out! This time, the owner did it himself!
The only thing I can come up with is... all four shackles have been changed to slightly longer ones, lifting the Jeep somewhat. Could that change the geometry from the factory settings?

 

[JeffP]

Note: Tires are BFG All Terrain, 31 x 10.5 x 15. Same exact tires & wheels on several CJ5s. This is the only one with a problem.
One thing that is noteworthy... this is also the only one with aftermarket shackles.
I should have some factory ones on a donor Jeep, I can swap them out & go for a test drive.

 

[CJ]

On the 75 CJ5 Caster / camber is preset and can’t be changed without serious modifications. All that can be “adjusted” is toe. I had that within a gnat’s *** before the ol’ pro checked everything.
~~

Caster requires a spring perch change / Camber can be changed easily with camber shims. The shims are placed between the spindle and the control arm

 

[jp360cj]

On the 75 CJ5 Caster / camber is preset and can’t be changed without serious modifications.

This is not 100% correct. Camber shims have already been mentioned. Shims between the leaf springs and axle will adjust the caster. Not the best fix, but works for minor adjustments. And suspension modifications can change caster.

The only thing I can come up with is... all four shackles have been changed to slightly longer ones, lifting the Jeep somewhat. Could that change the geometry from the factory settings?

Unless you have also done a shackle reversal, longer shackles in the front will reduce caster. I you can get a ballpark number with a big socket on the upper ball joint and an angle finder, but I would take it back to the alignment shop and have it checked. Get an actual number, don't accept "it is fine".



Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

What was the caster when the alignment was done?

On the 75 CJ5 Caster / camber is preset and can’t be changed without serious modifications. All that can be “adjusted” is toe. I had that within a gnat’s *** before the ol’ pro checked everything.
When I checked it with my official Summit Racing alignment tool, both sides were identical so I’m reasonably confident neither knuckle was bent. I don’t remember the spec.
A note about the alignment guy. He’s been in the same spot since the sixties. I’ve taken him some real disasters before and they were perfect when I drove out! This time, the owner did it himself!
The only thing I can come up with is... all four shackles have been changed to slightly longer ones, lifting the Jeep somewhat. Could that change the geometry from the factory settings?

Caster is easy to adjust with angled shims under the axle's spring pad.
Still wait'n for those specs.
LG

 

[CJ]

This is not 100% correct. Camber shims have already been mentioned. Where where this mentioned?Shims between the leaf springs and axle will adjust the caster. Not the best fix, but works for minor adjustments.

Mentioned where?

 

[JeffP]

Caster requires a spring perch change / Camber can be changed easily with camber shims. The shims are placed between the spindle and the control arm

And for that Sir... you win a cookie!
I’ll go up against the best when it comes to building engines but obviously not up to par with suspension & steering. It makes things nice to have a group who knows more where guys like me can ask questions. Pretty sure you nailed it.
It’s hotter than a Tijuana outhouse here today so I’ll put some stock shackles on tonight and go for a ride. The extra height wasn’t doing any good anyway.
Thanks!

 

[CJ]

And for that Sir... you win a cookie!
I’ll go up against the best when it comes to building engines but obviously not up to par with suspension & steering. It makes things nice to have a group who knows more where guys like me can ask questions. Pretty sure you nailed it.
It’s hotter than a Tijuana outhouse here today so I’ll put some stock shackles on tonight and go for a ride. The extra height wasn’t doing any good anyway.
Thanks!

I’ll go up against the best when it comes to building engines

AMC 401 kB, custom Crower, Iskey, Hilbrrand and more. Looks ugly in the pic. Sequential FI in a Jeep.

 

[jp360cj]

Mentioned where?

You mentioned them in post #6.

OP, the stock shackles should help. But sometimes lift springs themselves can also change the caster


Sent from my iPhone using Tapatalk

 

[JeffP]

Changed the front shackles to stock and while it only dropped 2”, it make a huge difference. I ran it up to 55 mph briefly and while scary, it was driveable. I just wouldn’t want to try it for long.
Something is still obviously wrong but on the right track. I’ll do the rear tonight & see if that has any effect.
I also have a 76 CJ5 and noticed the springs were much wider than all the older Jeeps I have. The ‘76 is very stable at any speed with identical tires & wheels.
One huge benefit of lowering it back to the stock height is that the front driveline is perfectly aligned now. I expect the same when I do the rear.
At this point almost everything is new (200 miles on it) so nothing is loose or worn, it’s got to be adjustment(s).
After finishing up the rear if I still have issues I’ll get a actual specs on the alignment & go from there.
Thanks guys! Big help!

 

[JeffP]

Update...
Just came back from a VERY enjoyable test drive.
Apparently both front and back both need to be right. I ended up making new shackles rather than taking them off a parts Jeep. 1/4” steel plate, drilled on 2.75” centers and some 7/16 bolts it’s back to factory height.
I was only able to run it up to 60 mph in town but I could let go of the wheel until time to turn! The road wasn’t great either. It’s actually more stable than the one I drive daily!
I couldn’t have solved this one if someone put a gun to my head so I really appreciate thehelp! Thanks guys!
I’ll get the actual alignment specs for referance on future projects. All that is left on this one is to reupholster the rear seat add another grab handle and it’s ready for a new loving home. I’ll be kind of sad to see this one go.

 

[jp360cj]

Glad you got it figured out! I'm surprised the rear shackles affected the steering/handling that much, but that's good to know.

I think it's a good idea to get alignment specs for reference.

 

[JeffP]

Glad you got it figured out! I'm surprised the rear shackles affected the steering/handling that much, but that's good to know.

I think it's a good idea to get alignment specs for reference.

Yeah right... “I” figured it out lol. I’m still astonished over how such a simple thing could cause such a major problem.
The P.O. didn’t notice that it wasn’t driveable after that?
Also surprised that my alignment guy didn’t mention it. Just agreed with my belief that caster / camber couldn’t be changed. I thought he knew everything there was to know about steering.
Anyway another CJ5 is reborn. Hopefully the next owner will take good care of it. It’s showroom perfect and a real pleasure to drive now.

 

[Lumpy Grits]

JeffP-Are there any CJ Jeep clubs in your area?
They would be a good source for knowledge and references for who to see and avoid.
LG

 

[JeffP]

JeffP-Are there any CJ Jeep clubs in your area?
They would be a good source for knowledge and references for who to see and avoid.
LG

I’m sure there are but I haven’t bothered to look. This was the first timeI was really stumped.
There have been some compatibility questions I’ve had but was able to figure them out on my own.
Jeeps are by far the easiest vehicles I’ve ever worked on. And parts areeasy to come by.
For major stuff it takes minutes to remove the entire front end... then it’s like having your engine on a stand! I put extra connectors on my wiring just for that. Not that I’ll be taking them apart again anytime soon but when it’s necessary it sure will be handy.