buggy spring rear suspension????

Hey, just wondering if anybody has any info that can help me out? I have a 34 ford pu with a 8" rearend, buggy spring with a triangulated ladder bar set up and a pan hard. My problem is when I step on it hard it wants to change lanes and feels like the rearend is twisting, it handles good around corners and rides okay. I do not have any preload on the pan hard bar. I run regular shocks aswell. Is there any way to keep this from happening? Thanks

 

SHOW US SOME PICTURES TO SEE WHAT YOU GOT. Knuck From Indiana.

 

x2, pics will tell the tale of why the rear is steering the car.

 

The first thing that rings a bell is a panhard rod with a buggy spring... Not that it is right out bad, just not necesary and could be putting things in a bind under acceleration.

 

Do you have a locker in it ?

 

Or a spool?

 

Check for worn parts.

 

no spool or locker, everything seems tight and it was worse with no pan hard bar.

 

Sorry, these are the best pics I got right now and it does not have the pan hard bar installed in these pics. Thanks

 

How much squat does it have under hard acceleration?

 

Are you sure the rear end is "twisting"? It may be squat aggravating bump steer.

 

Not sure on the squat, I assumed it was twisting and that was why it seemed like it was changing lanes. Does the look of this set up look okay? What should I check? Thanks again

 

carefully put a jack under the rear diff yoke, and slowly jack upwards and see if there is any obvious deflection (simulating some axle wrap up) I would start there. And a pic of your spring perches on the axle may help us out as well...

 

I will get better pics tommorow and I will check that.

 

does it change to the right lane? or the left?

 

It wants to go to the right, it does not shoot to the right but it seems to twist to the right. It's hard to explain, and probably hard to diagnos over the computer. Thanks

 

make sure panhard bar is as long as possible. short bar causes the rear end to travel in a circular motion while going up and down.

 

How about your rear shackles? Are they hanging at a 45 degree angle or more 90 degrees to the spring and mounts? Lots of questions, I know! 'Nother thought, which side is your panhard rod swung from? Right framerail or left?

 

Left frame rail.

 

Sounds like a torque reaction thing. Have you got any torque numbers for your engine? What's your first gear ratio? converter stall? rearend ratio? What sort of spring stiffness have you got at the back?

Lots of torque, low first, high stall, short rear, and soft rear spring, and it could be engine torque is trying to twist the entire car clockwise. More roll stiffness at the back will fix that, but then you'll need more roll stiffness at the front to trim out the resultant oversteering tendencies, and ideally some frame stiffening to get that to work.

 

I find with my O/T daily work truck, if the rear tires are lower pressure than the front, it feels as though the rear end is braking loose. you could try lowering the front tire pressure to see if it helps.

Squat is the rear end of the body/chassis dropping on acceleration, raising the pivot point of the ladders can give you anti-squat, or even lift, which increases rear traction, if you raise it enough, but to much anti squat can cause brake hop.