OK, I'll start by admitting that I know very little about steering geometry!

I fabbed a dropped drag link about a month ago and have been running it with NO problems. Made a 4" bend in it to get my drag link parallel because of my 4.5" lift.

This weekend I finished my matching 4" dropped panhard bar and installed it. Both bars are now parallel to each other and my axle is once again centered.

Problem is, since installing the panhard, I get HORRIBLE bump steer, which goes against any little knowledge of this that I have. WTF!!!

With stock panhard and dropped draglink all was well. I install the dropped panhard, and my steering goes to hell. Doesn't make sense.

Tonight I'm reinstalling the stock panhard just to make sure, but nothing else was changed. My only guess is perhaps the panhard is flexing some during travel and causing the bumpsteer. Could that be it? The panhard is made from 1" steel with 3/16" wall. Too thin?


~~~~~~~~~~~~~~OS Insert~~~~~~~~~~~~~~~
http://pics.montypics.com/Old_Scout/2002-09-23/arms1.jpg

http://pics.montypics.com/Old_Scout/2002-09-23/arms2.jpg

http://pics.montypics.com/Old_Scout/2002-09-23/arms3.jpg

post a pic
or send one to me.

Originally posted by roverhybrids
post a pic
or send one to me.
I would like a stab at this as well.

j

First is from P/S 3/4 view, second is from head on, and third is from D/S 3/4 view. Would flex in the panhard cause this? My steering feels a bit more "vague" as well. Before, it was more precise whereas now it is more mushy and less responsive.

a "drop" in the panhard does nothing, all you need is a longer unit to center the axle under the truck again. you could have a panhard rod with three S bends in it but it wouldnt matter, for geometry purposes you have to invision a straight line between the two.

for the drag link, basically what you have accomplished is correcting the angle at the tie rod ends, so they have full travel in all directions before binding. this is beneficial, however it COULD lead to other problems, such as a bent drag link because you have now created a weak link in the unit by putting the bend in it.

what material did you make the DL out of?

fab work looks great (as always).

OS, thanks for posting those.

Adam, material is seamless mild steel. But again, all was well with just the DL installed . Everything went to hell when I installed the panhard. :confused:

And thanks for the fab work compliment.

As I see it the problem is that the distance between either end of the new panhard rod is greater (I assume the new rod is longer, if not this could be the problem) and at the end of an arc. the ends need to be as close to the same plane and possible. The further they are away from the same plane the greater the sideways movement that will result as the suspention cycles. I think that you need to raise and or lower either end of the rod, or both to get them closer to the same hight.

Well that's my shot at it... anyone else?

Also, what type of bushing did you use in the ends? Bushings are finicky pieces of crap that do more than we give them credit for. If the resonant vibration is not absorbed or quelled, that could be the issue. Different bushings will transmit/absorb different amounts of vibration.

j

My guess is this.

As 9V said having the bends in the bars doesent change the steering geometry cause the mounting points are still the same.

Now when you put in the first bent bar it drove OK. And when you ran both bent bars you get bump steer. In terms of steering geametry by adding the bent bars you have made the links a lot more flexible and I would guess this is the cause of the problems.

What you should do is bind up the front end into a rock and get somebody to move the steering wheel so that the wheel leavers against the rock I think you will be amaized how much the bent links will flex.

You would need to make the bars out of something bigger or go back to running the straight bars.

Sam

I would at least gussett the bends for rigidity both sides as the 1" matl you used has no tensile strenght, not that that matters....when you put them 36"ers on there, beware...better sell that new shiatt and get something older.....

First off, I don't want to sound like an ass, but you really should research your mods before doing them. You wreck that thing and the crash inspection will surely see those beautiful bends and you'll outta luck for insurance coverage.

Putting all the bends in the world in the drag link etc won't do anything for your handling. It's the same as running a straight shaft, except you lose all the strength.

If you want to eliminate bumpsteer, you can build a drop steering arm, which sucks because it increases strain on your steering box, or you can raise the mounting on the swivel ball, which is illegal in most states and provinces.

I run a freak rover with 1990 Rangie ABS axles, converted to leaves. Sorry about the quality of the pics..

http://riverport.org/JL/P0003625.JPG

This raises the track rod's attachment on the swivel ball, so it is parallel, and I have no bumpsteer. BTW, I figure I've got about 6" of lift. It's 1" thick mild steel, milled and welded by myself. I got it hot dipped afterwards. It's tied into the caliper mounts, both swivel pin bolts and the turning stop boss.

Of course, as well, you'd have to make the other suspension link parallel to the newly fixed track rod geometry.

In my opinion, it can be done, but it's not easy to do it right. Hope someone else has a better idea for you...

J-L

Yes the tube you have used is way t o small.
90 degree bends as you have used have no strength at all.
Remove and refit std items. use some thing like dom tube 38mm by 6mm wall thicknes wityh cranks at ends to realine ball joints.
Michael.

Greg,

If you kept the panhard rod straight but a little longer, would this, therotically, solve your problem? As others said it, you prolly lost your rigidity by the bends and the bumps aren't transferring to the steering damper. The bent drag link shouldn't induce bump steer I suspect. Only thing you'll see is how much the link bends under lots of load but it'll bend back, theoretically!

My .02 cents

OK, thanks for all of the input. I replaced the straight stock panhard last night and today all my problems are gone. I will also be reinstalling the straight stock drag link as well. I will then make new bars from heavy wall SS material and keep them both straight.

By the way, the ends on the panhard were 3/4" heims, so yes, vibration transfer could also have been a problem. I really think that the main culprit was flex, though. I guess I really underestimated the amount of forces that are transferred through the panhard.

Oh well, nothing ventured, nothing gained. At least I can chaulk this one up to experience and just be grateful that nothing or no one was damaged.:)

Thanks again for all of the advice. Damn, one of these days I'll get it right!:D

Originally posted by Greg Davis

just be grateful that nothing or no one was damaged.:)



That's my favorite type of learning!

If a D90 drop arm has the same splines it would get you an inch or two drop on the drag link.

Ron

Anyone care to measure the splines on their D-90 steering arm? I'd greatly appreciate it. Then, you wouldn't have to keep hearing about all of my steering (self-inflicted) problems. :rolleyes:

Originally posted by Greg Davis
Anyone care to measure the splines on their D-90 steering arm? I'd greatly appreciate it. Then, you wouldn't have to keep hearing about all of my steering (self-inflicted) problems. :rolleyes:

WHAT?

And take all the fun out? It's been too slow around here....

j