Quigley Front end handling question.

[katoom400]

Let me clarify that I do not believe the the SS will cure DW, however in my case it certainly prevented it from occuring. I changed nothing else initialy but the SS and the DW was gone! That being said, I don't believe that it cured the DW but masked it! When the SS began to wear out I suspect it would return, which is my reason for persuing the root cause (track bar bushings/caster) to make sure it doesn't come back.

I'm going let the shop correct the alignment and see if I can free up the hanging left brake caliper. Then take it from there.

I also thought that +caster relaxed the feel and bringing it closer to 0 would make it more "twitchy/sensitive" but it was quigley's advise and I went with it!

 

[truck mechanic]

you said someting a few post ago, feels to tight.. Has anyone checked for a frozen ball joint, tie rod end , or axle shaft u joints ? None of this will kive you dw, but will give you the chase the steering down the road feel. Just a thought. I have fixed more then 1 steering problem by replacing front u joints.
Paul

 

[ujoint]

you said someting a few post ago, feels to tight.. Has anyone checked for a frozen ball joint, tie rod end , or axle shaft u joints ? None of this will kive you dw, but will give you the chase the steering down the road feel. Just a thought. I have fixed more then 1 steering problem by replacing front u joints.
Paul

Good point.

 

[Photog]

........I also thought that +caster relaxed the feel and bringing it closer to 0 would make it more "twitchy/sensitive" but it was quigley's advise and I went with it!

You are confusing caster with camber.
Edit: You are correct, that caster closer to zero will feel twitchy; but +caster may not feel relaxed. It will feel more stable. I may have been confused by the terms being used. Appologies if that is the case.

Camber at zero (on a straight axle vehicle) is what you want.

image from Lancerevoclub.com

Think of caster just like that on an office chair caster wheel.the vertical axle that the whole assembly revolves around is the caster shaft. If you project a line through that shaft, down to the floor, it is inches in front of the center of the wheel. When you push the chair, the wheel will follow that spot on the floor, as if beeing dragged behind that imaginary line.

On your vehicle front suspension, the ball joints or king pins set up the same effect. Project a line from the upper ball joint, through the lower ball joint, and to the ground (straihgt line). This line should intersect the ground, in front of the center of the tire's contact patch. The larger this distance between the line and the center of the contact patch, the more caster you have. When turning a corner, if you let go of the steering wheel, the tire will try to return to a point directly behind that imaginary line. The smaller the caster angle, the less leverage it has against the tire, and the less stable the steering will be at high speed, and during braking.

Caster is actually measured in degrees angle, not inches. It is the angle of the imaginary line and a vertical line. Positive (+) caster is an angle leaning back at the top, or forward at the bottom. If you look at the picture above, you may notice that if the tire were larger diameter, the distance between the contact patch and the steering axis gets larger too. That is what makes steering more difficult with larger tires, they have more leverage against the steering. increases as the axle rises further from the ground.

 

[ntsqd]

I'd add that you want, if anything, a little negative camber, not positive (it may not be possible to get it to zero with the limited adjustment in your front suspension.) Positive will make the tire want to roll over on a higher speed turn when the suspension is compressed. Negative camber will flatten the tire out on its tread in the same situation.

I do not know why, but a very seasoned alignment guy (had been doing alignments for nearly 50 years at the time of my question) told me that live axle's do not behave well with negative camber. I asked because I noticed that on a live axle vintage sports car that we were working on had positive camber and I thought that it should be negative.

Another symptom that I have seen called DW is when the front tires oscillate back and forth at high speed (the oscillation, not the vehicle speed). The axle isn't moving, but the steering system has been excited. An SS will help with this, but if the movement doesn't require movement of whatever in the linkage that the SS is attached to then the wobble will happen regardless.

 

[Stumpalump]

While on the caster subject... I put an angle finder right on the upper ball joint to read the angle. The angles always seem to be different from side to side by about 2 degrees. I was told thats because the welding of the tubes causes some twist but have also heard they add the twist to compensate for crowned roads. At any rate don't try and force once side to be the same as the other by loading control arms or adding angled leaf spring pads to try and get the discrepancy out of it. Its the axle not being perfect from side to side. Any info on this? Is this built into the axle on purpose or is it just a tolerance issue? They all seem to have some twist in them.

 

[kjp1969]

I do not know why, but a very seasoned alignment guy (had been doing alignments for nearly 50 years at the time of my question) told me that live axle's do not behave well with negative camber. I asked because I noticed that on a live axle vintage sports car that we were working on had positive camber and I thought that it should be negative.

My alignment experience is all on IFS/IRS cars, and its limited at that. Given the choice of believing the experienced alignment guy or the yahoo on the internet, I would choose the former. Even if the yahoo is me. :sombrero:

While on the caster subject... I put an angle finder right on the upper ball joint to read the angle. The angles always seem to be different from side to side by about 2 degrees. I was told thats because the welding of the tubes causes some twist but have also heard they add the twist to compensate for crowned roads. At any rate don't try and force once side to be the same as the other by loading control arms or adding angled leaf spring pads to try and get the discrepancy out of it. Its the axle not being perfect from side to side. Any info on this? Is this built into the axle on purpose or is it just a tolerance issue? They all seem to have some twist in them.

Compensating for crowned roads? I dunno, that sounds like a screwy answer to me- how does the factory know what side of the crown you're driving on? Driving in the left lane of a crowned divided highway would be the opposite of the right lane. I would bet that bubba the welder just had an 'off' day, or its within the tolerances of their manufacturing. But maybe you should ask the alignment guru, above!

 

[Photog]

The axle knuckles, tubes, differential and mounts, are welded up in a jig. The knuckles should be very close to the same angle. The angle is set, relative to the pinion axis. The control bars or leaf spring pads will control the pinion angle relative to the transfer case. One of the ball joints (upper or lower) will have some type of eccentric adjustment, to correct any small tollerance problems of the assembly, and provide a nearly perfect alignment.

You could have a problem with a lifted vehicle or custom transfer case intallation. Either of these cases may require the pinion angle to be adjusted. On the front axle, if the axle is rotated to aim the pinion more directly toward the transfer case, you will lose caster angle; possibly more than the alignment adjustments can account for.

 

[ntsqd]

My alignment experience is all on IFS/IRS cars, and its limited at that. Given the choice of believing the experienced alignment guy or the yahoo on the internet, I would choose the former. Even if the yahoo is me. :sombrero:



Compensating for crowned roads? I dunno, that sounds like a screwy answer to me- how does the factory know what side of the crown you're driving on? Driving in the left lane of a crowned divided highway would be the opposite of the right lane. I would bet that bubba the welder just had an 'off' day, or its within the tolerances of their manufacturing. But maybe you should ask the alignment guru, above!

I'm not convinced that he was right for every single possible application, but I would definitely head the advise of an old timer alignment guy over whatever I happen to think is right.

I have heard of the differential caster being to deal with crowned roads, but always in the context of a SLA front suspension, never with regard to a live axle. A pretty sharp friend of mine cut loose and rotated the 'C' brackets when he corrected the pinion angle for his lift. He set the Caster to be the same on both sides and having followed that truck over numerous roads and highways on several different long distance trips I can say that it behaves as it should. I see no reason to not set the caster as identical as you reasonably can.

 

[katoom400]

The shop straightened out my alignment, and I also put new rotors/pads up front which cured the hanging pad issue which was causing it to pull to the left.

The alignment seems very straight and true. I still feel that the van is a little "hyper or sensistive".

I am starting to think that it is more of a sway issue and may try a rear sway bar and/or rear wheel spacers.

Also I believe that the shocks are stock/quigley Monroes and with 57k on the van I'm sure it's time for new ones. can anyone give me the part numbers for Bilsteins to fit the quigley?

 

[truck mechanic]

What did they do ?

 

[Photog]

The Monroes should have a part number on them. You may be able to do some cross referencing to get a Bilstien replacement.

 

[katoom400]

What did they do ?

they had the toe numbers @ +.10, quigley calls for max of +.01

 

[ujoint]

Also I believe that the shocks are stock/quigley Monroes and with 57k on the van I'm sure it's time for new ones. can anyone give me the part numbers for Bilsteins to fit the quigley?

Call Shane Casad at Bilstein in CA. He'll make sure you get the right shocks.---

 

[Beynham]

I have an E350 Quigley that had a terrible case of DEATH WOBBLE. I looked underneath, and noticed that the sway bar connector bushings had walked up the bar and out of the I-Beam.

I replaced them at home by first removing the sway bar (easy), cleaning the holes out, and then pounding in new ones with the end of a 2x4 and a 12lb sledge hammer while dad laid under the van and held it in place... and applied a liberal application of saliva. I then used a similar technique to get the sway bar into the now tight holes in the bushings. Worked a treat!
I also replaced the sway bar bushings while I was at it. Parts were MOOG brand: K80222 for the sway bar ends, and K8690 for the sway bar bushings. $60 in total.
The advantage of the K80222 bushings is that they have a back grommet on them to hold them in place.

I also plan to replace the steering stabiliser bar, too, just for good measure, but the bushings ended up solving the problem on their own. Happy wife = happy life.