Help with Axle Shims to Increase Caster - Diesel Forum

Pat Garcia · 12-15-2007, 01:28 AM

I finally got together the shims, the new u bolts and the nuts. I have only one problem now, which way do the shims go in to increase my Caster? They are 2 degree wedges. I have searched all over the forums to find this procedure but there is no information on which way to install them.

Thanks in advance for any advice offered.

I have a stock 2003 Ford Excursion 4X4 with 6.0 Diesel

Pat Garcia
Huntington Beach, CA

caryt · 12-15-2007, 10:46 AM

I would not use shims on a front axel. Get ball joint eccentrics at your local shop and have them do the alinement.

Cary

TomzToyz2 · 12-15-2007, 11:52 AM

To rotate the castor to positive (top BJ rotated rearward) put the thinner end of the shim toward the front. What issue are you having on a stock EX that it needs the shims for - Wandering? Return to center? See link below for good info.

http://www.superlift.com/library/caster-camber-toe.asp

Pat Garcia · 12-15-2007, 02:56 PM

I special ordered this 2003 Excursion. When it arrived at the dealer my wife and I went to pick it up. The only comment the dealer had was that there was a possibility that this model might have a slight steering problem. At that point I was not aware that any problem existed. One of the reasons I bought the Excursion was as a backup vehicle for my F350 Dually that tows a 30 foot travel trailer.

My Excursion ended up having a severe wandering problem, in a long gradual turn it was all I could do to keep the truck in its own lane. Going straight I would constantly have to adjust the steering wheel to the right and the left to keep in a lane.

The Ford dealer replaced all four of the ball joint and deemed the steering fixed.
This fix I would say was a slight improvement, but by no means fixed the problem.

I installed a sway bar on the rear.
This made a big difference but did not fix the wandering.

I tightened the steering box.
This made a bit of difference, the truck still wandered.

I had my brother in-law install adjustable ball joint eccentrics in an effort to get to the target alignment numbers. (The brother in-law has been doing front end work for over 30 years.)
This also helped some, but we did not get to the target caster

I installed air bag supplements in the back to help tow the 30 foot trailer in a pinch if needed. This was not meant to influence the steering under normal conditions and is included for informational purposes.

I installed new tires, Michelin XPS Tractions, love these tires.
Made some difference.

Next I plan to install the axle shims to increase the caster a bit. Drive for a while to note the results. Also, after I will remove the steering stabilizer to see if that has any affect.

While I am under the truck installing the axle shims I will check nut on the pitman arm.

I think that is everything, it has been a four year period.

By the way, I still love my Excursion; it’s a shame that Ford couldn’t or wouldn’t fix it.

I hope this answers any questions, thanks for your input.

rcpcanada · 12-15-2007, 05:17 PM

I would have sworn I wrote this post myself, I am having the exact same problems as you, I have also done the exact same repairs (and then some). My caster is set at between 3 and 3.5 on both sides. I am thinking of useing shims to increase the caster. I'm having wandering/poor return to centre on a 2004 f-350. Please keep me updated on your findings, this issue is driving me crazy.........Thanks in advance

Pat Garcia · 12-15-2007, 07:53 PM

I will keep this thread posted on any progress or lack of progress that I make.

coldair · 12-15-2007, 08:33 PM

I had to replace the tie rod end at the pittman arm three times already, there is a guy that makes a kit to replace them with Hiem joints and that seems to be the way to go. there is a lot of slop in the tie rod ends

fastersteve · 12-15-2007, 09:38 PM

So who's the guy?
FS

Pat Garcia · 12-16-2007, 10:12 PM

Installed Axle Shims Today

First I removed the steering stabilizer and did a test drive to see if there was any discernable difference. I did not detect any difference. For the moment I decided to leave the stabilizer off and maybe after I think that I am to a point that I am satisfied with the steering I would put on a new one. One less variable.

Then I checked the pitman arm connection, the side with the grease fitting, I could not see how to get a toque wrench on the other side. Everything seemed to be very solid. The nut I did check was at 90 lbs as my book said it should be. I had to back it off very slightly to get the cotter pin back in.

I then proceeded to install the axle shims. I ended up having 6, 2 degree shims; I thought I only had two. So I decided to go ahead and install 4 degrees of shims instead of 2 degrees. Initially I am using the old U bolts and nuts. I am going to test drive this configuration for a week or so to make sure I am satisfied with what I have done before I install the new U bolts and nuts.

I have done a brief test drive and I am encouraged by the addition of the 4 degrees of shims (thin side forward). My initial reaction is that it drives better than before. I live in Huntington Beach, CA so all of the roads by my house are straight and flat. Once I can get it out on the highway I will be able to get a better feel as to whether there is actual improvement.

I looked around for the actual alignment numbers but at the moment I can’t seem to find them. I know my caster was about at 4.5-5 and my target was 6.

I will post my drive test results next week.

I also want to thank you all for your comments and suggestion.

Soaggydogg · 12-16-2007, 11:10 PM

Why wouldn't you realign the front after any, every or all changes?

Pat Garcia · 12-17-2007, 08:10 PM

Thanks for the suggestion.

I have had the truck aligned several times, a couple of times at the Ford dealer. Each time the alignment readings are the same except for the last time when I had the adjustable ball joint eccentrics installed. I did not really see any point in taking the truck to an alignment shop if I installed new tires or put a rear sway bar in for example since these type of things would not effect alignment.

cobramoser · 12-19-2007, 01:20 PM

I am looking forward to your conclusions. I have had trucks that I lengthened the rear shackle for some extra lift and found that it also drove much better. I would rather have the truck drive better and wear the tires a little faster, than have the truck wander all over the road.

Mr_Roboto · 12-19-2007, 01:35 PM

Caster angle does not affect tire wear one bit, except in the case where uneven caster side - to - side would cause a pull.

Adding the shims will change the toe-in and camber, but only SLIGHTLY and not enough to warrant a re-alignment. The only reason it changes is because you are changing the relationship between the kingpin angle and the point at which the tires meet the ground (where alignment is measured from).

Stewey · 12-19-2007, 03:27 PM

After the New Year, I will be installing a Red Head Steering box in hopes of addressing the same symptoms. I'm keeping my fingers crossed.

rcpcanada · 12-19-2007, 10:14 PM

Pat Garcia,

can we please get an update from you,I milled a couple of shims at work today.I am very interesed in your results, your last post after your shim install didn't say much. Please let us know.I am also wandering (lol) if your truck did or now does return to centre after turns?