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Excursion Steering and Wander


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#1 ghovis

 
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Posted 25 May 2010 - 01:29 PM

Hello,

I recently bought a used 4x4 Excursion PSD. The front end was very tight, so a front end check revealed that the ball joints were shot and the steering box had been overtightened for too long. Long story short, the steering box and ball joints have been replaced. The road feedback at the steering wheel is now great, but the truck still "wanders". By wandering, I mean on a straight and level road, with the steering wheel in one position, the truck will drift quickly to one side or the other, and it requires constant correction to keep it between the lines. The front-end shop checked all the joints and linkages up front and found a tiny bit of play in the steering column and pitman arm/drag link, but he doesn't think it's enough to cause this issue (in fact, he didn't even want to do the work and charge me for something that he didn't think would correct the issue). The truck was aligned after the ball joint install, again after the steering box install, and was recently re-checked on a second machine by another shop. Each time the alignment was shown to be within Ford specs. Tires are fairly new (stock size 265 Firestones).

Reading about this issue on other forums across the Internet reveals that I'm not alone in this issue. Some say it's weak springs allowing rear-steer and recommend an F250 spring swap and/or aftermarket radius rods. Others say increase caster to +3.5 to +4.0 otherwise it's like driving a "shopping cart". Some say tighten the gearbox, reduce tire pressure, toe-in, toe-out, change bushings, etc. etc. Reading all this madness is just more confusing.

So, I wanted to ask the Ford experts what you think and what your experience has been with this. Thanks for reading my long post, and I welcome any comments/suggestions.

#2 Karrpilot

 
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Posted 25 May 2010 - 04:51 PM

You say the tires are fairly new. What do you mean by that? New as in time wise, or mileage wise?

If the front end was worn out with the old ball joints, it is possible the tires were hunting all over the road as well. And quite possible you have shifted belts internally in the tires.

That is one suggestion. Another one is the steering stabilizer shock. If it even has one. If i remember correctly, many Excursions did not come from the factory with one installed. It was part of a suspension / handling package. Which many dealership stores failed to order due to the high cost of the vehicle itself.

I remember installing said steering stabilizer shocks both on the Excursions and the F-250's and F-350's to fix that issue. I think Ford even had a TSB out on it. But i can not remember it right now.

And one more thing. Even if the stabilizer shock is indeed already on your vehicle, it could be worn out. That shock was not exactly the best quality shock i have seen. The aftermarket ones use a bigger piston then Ford did.

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#3 Warren Johnson

 
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Posted 26 May 2010 - 09:08 AM

What kind of firestones are on the truck. If they have week side walls you will get a wonder. bump the tire pressure up to about 85 all the way around and see if the wander goes away
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#4 ghovis

 
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Posted 27 May 2010 - 03:01 PM

Thanks so much for the replies, sorry for the delay in getting back. Here are some answers to the questions:

You say the tires are fairly new. What do you mean by that? New as in time wise, or mileage wise?

If the front end was worn out with the old ball joints, it is possible the tires were hunting all over the road as well. And quite possible you have shifted belts internally in the tires.

I'm not certain about the tire age/mileage because they were put on by the previous owner. I made my remark based on minimal wear and lots of tread. Good point about potential belt shifting; hadn't thought of that.

That is one suggestion. Another one is the steering stabilizer shock.

Yes, mine does have one and I replaced it a couple of weeks ago with one from NAPA. This was a direct replacement part requiring no 'universal' brackets or anything like that.

What kind of firestones are on the truck

They are Firestone Transforce HT LT265/75R16. Max pressure listed on the tire is 80psi. I've been experimenting with tire pressure and I can only make the truck close to drivable by keeping the pressure near door-sticker values (38/45), but I'm running 40/45 right now. What I've found is that when I was running 65 psi all around, the wandering was more pronounced. At this lower pressure, it seems to 'dampen' the motion, almost like it gets stretched out over longer distances, but it's still there. The downside to the low pressure is that it increases steering force, which can be a pain (literally) over long trips.

Are these tires right for this truck? If not, what do you recommend? Again thanks guys.

#5 Karrpilot

 
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Posted 27 May 2010 - 09:00 PM

We use those exact same tires on our fleet trucks. They wear pretty good as far as life expectancy goes. But that is about it. Handling and ride quality are not those tires strong points.

Basically, they are cheap tires that last along time. Perfect for fleet operations like we have now. However, there are much better tire makers out there. I like BF Goodrich, Cooper tires, Michellin. But every mechanic out there will probably give you a different opinion.

What i can say for certain is to STAY AWAY from Generals, Continentals, and Hankooks. All 3 of thease have been put onto Ford vehicles, and all 3 gave us nothing but grief. I never understood why Ford went from bad to worse with their tire suppliers.

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#6 Jim Warman

 
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Posted 29 May 2010 - 04:25 AM

Hello,

I recently bought a used 4x4 Excursion PSD. The front end was very tight, so a front end check revealed that the ball joints were shot and the steering box had been overtightened for too long. Long story short, the steering box and ball joints have been replaced. The road feedback at the steering wheel is now great, but the truck still "wanders". By wandering, I mean on a straight and level road, with the steering wheel in one position, the truck will drift quickly to one side or the other, and it requires constant correction to keep it between the lines. The front-end shop checked all the joints and linkages up front and found a tiny bit of play in the steering column and pitman arm/drag link, but he doesn't think it's enough to cause this issue (in fact, he didn't even want to do the work and charge me for something that he didn't think would correct the issue). The truck was aligned after the ball joint install, again after the steering box install, and was recently re-checked on a second machine by another shop. Each time the alignment was shown to be within Ford specs. Tires are fairly new (stock size 265 Firestones).

Reading about this issue on other forums across the Internet reveals that I'm not alone in this issue. Some say it's weak springs allowing rear-steer and recommend an F250 spring swap and/or aftermarket radius rods. Others say increase caster to +3.5 to +4.0 otherwise it's like driving a "shopping cart". Some say tighten the gearbox, reduce tire pressure, toe-in, toe-out, change bushings, etc. etc. Reading all this madness is just more confusing.

So, I wanted to ask the Ford experts what you think and what your experience has been with this. Thanks for reading my long post, and I welcome any comments/suggestions.


When someone says an alignment is "within specs", I shudder. You can have a car that is "within specs" with no regard for the delicate interrelationship of the angles involved and have a foul driving, white-knuckle ride.

When someone says "I put new ball joints in a SuperDuty based 4X4" - I shudder. There is a specific wat to tighten these ball joints. If this procedure isn't followed (hell, even if it is followed) the chance for assembling the knuckle with the ball joints "in bind" is very real. This type of memory steer will be preceived as wander on the highway.

Insufficient toe in and high rear axle loading can induce wander... but without any memory component to the "feel".

While caster is considered to be a "stability angle", increasing it on a beam type axle can be looking for "death wobble". You should have access to a printout of your alignment readings... post those and let us consider the results.

As for my take on things? I get paid to be sure that we have "anal" in "analyze".

Jim Warman
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#7 Karrpilot

 
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Posted 29 May 2010 - 08:06 PM

I agree with Jim. You have a specification area to set the alignment angles. You can be anywhere in the ballpark, and still have an ok alignment. Sometimes the mechanic has to tweak them a little to make the vehicle track correctly. Most techs today throw on the alignment heads, move the angles around until they show "GREEN" on the screen, and ship the vehicle. Sad......

And since i have been doing it for so long the correct way, i had completely forgotten about "Memory Steer". Memory steer is when a steering / suspension part is installed and torqued down just as the part is installed without the installer caring or sometimes even knowing how to install said parts.

The right and correct way to install any steering / suspension part is to have the steering wheels facing straight ahead and the weight of the vehicle on the suspension. Along with doing the final bolt torque. This is certainly not an easy task to perform sometimes. Especially with the tires installed and or on a frame type vehicle lift with the suspension hanging.

What i have even done in the past was use bottle jacks, wood blocks on a floor jack, whatever combination of "red-neck" skills etc. i needed to make sure i had access to the fasteners with the vehicle in the correct position. Straight ahead tires, vehicle suspension not hanging. It take a whole lot of work to do this. But it is justifyable in the end.

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#8 Bob K

 
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Posted 30 May 2010 - 10:37 AM

I agree with Jim. You have a specification area to set the alignment angles. You can be anywhere in the ballpark, and still have an ok alignment. Sometimes the mechanic has to tweak them a little to make the vehicle track correctly. Most techs today throw on the alignment heads, move the angles around until they show "GREEN" on the screen, and ship the vehicle. Sad......

And since i have been doing it for so long the correct way, i had completely forgotten about "Memory Steer". Memory steer is when a steering / suspension part is installed and torqued down just as the part is installed without the installer caring or sometimes even knowing how to install said parts.

The right and correct way to install any steering / suspension part is to have the steering wheels facing straight ahead and the weight of the vehicle on the suspension. Along with doing the final bolt torque. This is certainly not an easy task to perform sometimes. Especially with the tires installed and or on a frame type vehicle lift with the suspension hanging.

What i have even done in the past was use bottle jacks, wood blocks on a floor jack, whatever combination of "red-neck" skills etc. i needed to make sure i had access to the fasteners with the vehicle in the correct position. Straight ahead tires, vehicle suspension not hanging. It take a whole lot of work to do this. But it is justifyable in the end.



What I use is a set of frame machine wheel stands to load the suspension. I know most tech don't have access to a frame machine. But it wouldn't take much to make yourself a set of stands. Below is a link to a set of stands. It will give you and idea what would be required to make them.

http://www.chiefauto...p?PartID=232274


HTH

Bob

#9 ghovis

 
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Posted 31 May 2010 - 03:25 PM

More great input!! Thanks to all. Here is some additional info:

1) I will try to get the alignment info and post. Thanks for the suggestion.

2) Regarding the ball joints and front-end components: The ball joints and gear box were installed by a basic auto repair shop, not a front-end specialty shop, and I may or may not end-up regretting that decision - remains to be seen. However, after those components were installed, the handling issues caused me to search for a specialist, and I found "THE front end guy" in town (who probably should have done the work in the first place, but we all know how good hindsight is). I learned that he's the guy that local shops send their 'problems' to, and has a great rep. He uses no frame lift and works in a pit. I took the truck to him, and he went through the front end piece by piece, unbolting what he had to in order to test each component for binding and/or play. He checked from the steering column all the way down to the ball joints and everything in between. While I can't be certain he knows the proper way to torque things back down, I assume he does since that's his specialty. He said the ball joints and rod ends were good and operating freely. He's the one who found the small play in the pitman arm/drag link area, but he wasn't 100% sure that was enough to cause the problems, so he was reluctant to do the work. He did check the alignment (the third check) and he said that the toe was on the high side (i.e. borderline too much) but that was his only comment about alignment. He agreed that the truck was a handful to drive, but he was not able to nail-down a concrete solution.

I'm not sure if all of this fully answers the issue of "memory steer", but hopefully it helps in answering that question. I'm thinking I'll get the specialist to go through it again and fix ALL play and re-align. That would at least eliminate that as a contributor.




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