upper control arm: why 2 different types?

[Imploder]

I have a 97 exploder with 4.0 I am replacing the upper and lower control arms.
why is the passenger side upper control arm different than the drivers side.?
I bought the 1 piece control arm for both sides can I replace the 2 piece upper control arm with the 1 piece?
Why would Ford put an adjustable upper control arm on one side and not the other??

 

[obie]

Yes, the one piece will be perfectly fine for replacing the two piece; that's what I did. The only advantage to the two piece is it allows for more caster adjustment, but to be honest I've never had a problem with the Explorer not being able to align perfectly, even with oversized tires and running a torsion twist.

 

[tgibbonsfordluv]

The multiple piece control arm is for caster adjusting that side. It doesn't allow for total caster adjustment, but allows it to at least make both caster readings match. Unless you do a lot of heavy towing or heavy loading, I wouldn't worry about. If you do heavy towing or loading, I would replace both uppers with caster adjustable control arms.

 

[FIND]

They are both adjustable, that one is just more adjustable. If you look at the uppers on the other side, you will note the cam bolts that hold it in place.

When I replaced my uppers, I had my passenger side set pretty much right in the middle, so I just got the one piece upper to replace it.

 

[1996BLKBauer]

Like mentioned above, it is to adjust Caster, Ford did it on one side, the passenger side to be exact, to setup the Explorer cheaply for what is known as Road Crown. Which is almost always happening on the passenger side... A single one will work just fine, but I highly suggest getting 2 sets of the caster/camber kits, and having a good alignment done afterwards.

 

[tgibbonsfordluv]

Like mentioned above, it is to adjust Caster, Ford did it on one side, the passenger side to be exact, to setup the Explorer cheaply for what is known as Road Crown. Which is almost always happening on the passenger side... A single one will work just fine, but I highly suggest getting 2 sets of the caster/camber kits, and having a good alignment done afterwards.

I'm pretty sure you're mostly right. I don't think caster has anything to do with road crown though. I might have to go fight my steering and suspension teacher from a decade ago (if he's still alive, he was old and still smoking 10 years ago) if it does. I'm pretty sure the purpose of having one is so the caster angles can be made to be the same. Caster does not cause tire wear or pulls. However, if they are not close enough together the truck will wander. To further that, if the truck is put under a heady rear load it will push towards a more positive caster angle on both sides rather than the desired negative caster. This will also cause wandering and less responsiveness in the steering wheel returning to straight after cornering.

The adjustments FIND was talking about are for camber only if I'm not horribly mistaken.

You can put eccentrics in the lower control arm bushing that will adjust both camber and caster. It's usually not necessary unless there's been some suspension modification or if you used a pressed balljoint in the lower despite what Ford says about doing so.

 

[1996BLKBauer]

I'm pretty sure you're mostly right. I don't think caster has anything to do with road crown though. I might have to go fight my steering and suspension teacher from a decade ago (if he's still alive, he was old and still smoking 10 years ago) if it does. I'm pretty sure the purpose of having one is so the caster angles can be made to be the same. Caster does not cause tire wear or pulls. However, if they are not close enough together the truck will wander. To further that, if the truck is put under a heady rear load it will push towards a more positive caster angle on both sides rather than the desired negative caster. This will also cause wandering and less responsiveness in the steering wheel returning to straight after cornering.

The adjustments FIND was talking about are for camber only if I'm not horribly mistaken.

You can put eccentrics in the lower control arm bushing that will adjust both camber and caster. It's usually not necessary unless there's been some suspension modification or if you used a pressed balljoint in the lower despite what Ford says about doing so.

I swear my teacher did a talk for 30 minutes on how roadcrown can be corrected by adjusting caster, I could be wrong, but I am almost positive. I know on my Explorer it had some sort of shims for aligment in the upper control arms. they where pretty bent on mine, which makes me think that is why I had sure a negative camber for so long. The eccentrics go in the uppers, and do both caster and camber. They really helped me out when I did my truck, but they SUCK to tighten to 100 ft. lbs. with the tire in the way.

***I grabbed my book real quick... It said that BOTH Camber, and Caster can be used to correct for Road Crown, But that Caster CAN ONLY correct road crown in SOME long arm, short arm suspensions. SO we are both right I guess, you are more correct for every car, I am correct for only some cars, and I believe the Explorer is one of them.

 

[tgibbonsfordluv]

I swear my teacher did a talk for 30 minutes on how roadcrown can be corrected by adjusting caster, I could be wrong, but I am almost positive. I know on my Explorer it had some sort of shims for aligment in the upper control arms. they where pretty bent on mine, which makes me think that is why I had sure a negative camber for so long. The eccentrics go in the uppers, and do both caster and camber. They really helped me out when I did my truck, but they SUCK to tighten to 100 ft. lbs. with the tire in the way.

***I grabbed my book real quick... It said that BOTH Camber, and Caster can be used to correct for Road Crown, But that Caster CAN ONLY correct road crown in SOME long arm, short arm suspensions. SO we are both right I guess, you are more correct for every car, I am correct for only some cars, and I believe the Explorer is one of them.

No kidding, learn something new every day I guess. I could swear from factory there are already eccentrics in the lowers.

 

[1996BLKBauer]

No kidding, learn something new every day I guess. I could swear from factory there are already eccentrics in the lowers.

There could be. But to be honest I have never looked. I do know there is for sure ones in the uppers though.

 

[Imploder]

Thanks for the replies. I have been holding off changing the upper control arms until I could determine if it was OK to replace them with the 1 piece. Yes it does suck torquing the adjustment bolts to 100lbs with the tire in the way ..... but it sucks worse to grind down a set of BF Goodrich KM2's Mud terrain's because of alignment issues.
Money is harder to come by than blood and sweat

 

[imp]

If road crown were to be considered, and alignment set to optimize steering with a crowned road, what the hell happens when you are driving on a non-crowned road, or a banked curve, or any of a zillion possible variations in road crown? Maybe ya wannba have constantly controllable alignment from within the cab? Ha!

The right-hand side upper control arm adjustment, with the screw and locknut, was incorporated to achieve as close to zero "caster split" from side to side as possible. The real key to excellent steering is having the caster identical on both sides. This was an expensive but very desirable feature, and I miss it on later Gen Explorers! imp

 

[tgibbonsfordluv]

If road crown were to be considered, and alignment set to optimize steering with a crowned road, what the hell happens when you are driving on a non-crowned road, or a banked curve, or any of a zillion possible variations in road crown? Maybe ya wannba have constantly controllable alignment from within the cab? Ha!

The right-hand side upper control arm adjustment, with the screw and locknut, was incorporated to achieve as close to zero "caster split" from side to side as possible. The real key to excellent steering is having the caster identical on both sides. This was an expensive but very desirable feature, and I miss it on later Gen Explorers! imp

That is EXACTLY what I thought. A road crown compensation would really bug me personally, I tend to drive the left lane of a divided highway a lot......

 

[imp]

That is EXACTLY what I thought. A road crown compensation would really bug me personally, I tend to drive the left lane of a divided highway a lot......

That is EXACTLY why I wrote it! Crowned road, my a$$! Do you drive much in Allegan Forest? imp