98 Navigator - suspension height measurement method

[Stan]

Hi there,
As I'm still trying to figure out how the suspension works in the Nav, here is my question - how to properly measure the vehicle height and how to compare front to rear? I found that by tightening the torsion bars I can make it level left to right, but I have an impression that front is too high now.

The rear - when fully inflated, seems to be just ok in height (I have about 3-4 inches distance between top of the tire and the fender arch).

The front distance is about 4-5 inch. Looking from outside the vehicle it seems to be ok, looking from behind the wheel, I have the impression I'm in the plane that is about to take off

So - how to perform the measurement and how to compare front and rear.
Should the front distance and rear distance be even? For that - I would have to lower the front - about 1.5 inch - by loosening the torsion bars.

I'm not asking for exact values at these depends on what rims/tires are on the vehicle, but I have to find the way to level it.
Thanks in advance

 

[Stan]

Hi again. I'm still having problems with my suspension

On the uneven surface, the ride is very 'bumpy' up and down... My mechanic played with torsion bar adjustments, and now i'm not sure how this shud be set.
Thing is that when torsion bars are stiffer (upper) the air suspension is inflated less (to keep the vehicle overal height)... When I loose the bars a bit - it inflates more (height is similar)... So where is sweet point ? What setting gives appropriate height and comfort ride (no bumping) ? The suspension works fine. Inflates, deflates, no leaks and so on...
Any ideas please ? Thank you

 

[Mediamonkey11]

If I remember right, the only adjustment you should do with the torsion bars if you have air suspension is left to right. front to back can be adjusted by adjusting the rear sensor as outlined in the thread below.

http://www.expeditionforum.com/f47/rear-height-adjustment-12812/

As far as measuring goes, after I converted to coils, I just measured on flat ground from the ground to the highest point on the wheel side lip of the wheelwells. Seems legit and rides wonderful!

 

[Stan]

Well, thanks for the response

About the measurment - i know where to measure - I just do not know how to undestand the measured values. Does the distance measured for front and for the rear needs to be even ?

Regarding torsion bars - I know, in time (and the car is almost 'adult') metal gets softer and less stiff than the factory wanted. I have second car - Isuzu Trooper, also with torsion bars but no air suspension, and there i needed to make a few turns for each torsion bar key so the car was up again

But there is no air... here we have torsion bars (adjustable) and air bags insuspension (also adjustable)...Point is that I do not know how high (or rather how low) should i put the car on torsion bars (with air system deflated) so after engine is on, air system inflates itself just alright. Too low is wrong as the air system will be overloaded... Too high is also wrong as the air system will be thinking car is up so no air is required...
I'm a bit confused...
And angry as I have to replace my pitman arm and have no idea how... have no Autozone here in Poland so I have no place to rent the reght tool...

 

[Mediamonkey11]

Aah, completely understood.

What year trooper? I owned a 93 and a 96! Both had multiple torsion bar adjustment sessions during my ownership

But, I've thought the same thing and I'm pretty sure there's no way to really do it per factory specs but best as I can tell, is the air suspension does a lot of the load handling or else it wouldn't flatten out when failed and springs at factory positions, so at factory height, I'd let the suspension settle, then put it to where you want with the bars with the ignition off, take that measurement, then adjust the ride height sensors to that height again once the airbags begin to try and correct due to the new height you've set with the bars. That seems the most logical way to me....


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[Mediamonkey11]

When I converted to coils - which is the preferred method as the airbags are known for failure - the set replaced the front bags with more coils so the torsion bars are merely an assistance in the first place but obviously the source of any adjustment. Interesting though, if I remember correctly, the front has ride height sensors on each control arm - one per side - and for it to be off sides like you stated at first I'd check to see if it's in place correctly...


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[Stan]

Well... The Trooper is green, long 2000 3.0 TD...
And as far for the height sensors - My navi has 2 - rear (mounted in the middle of the car, between the frame and the axle) and front (driver side, mounted to the frame and upper control arm).. right side has no sensor at all.

 

[Mediamonkey11]

Gotcha. Then the adjustment referred to in the above link would work for the rear, and an adjustment of the torsion bars combined with a sensor adjustment in the from would work...

Are you on PlanetIsuzoo? If so what's your username? Your rig sounds familiar...




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[Stan]

Well... I'm not... We've had a fev Fronteras and Troopers but here in Poland that's rather common 4x4 car so we do have forums... On the other hand Expy or Navi are super exotic... No information locally whatsoever... If I've had dodge ram or ford explorer/ranger - that would be easier... but not for these cars..
I may sound familiar as I left 7 years of my life back in Ireland... People I work with (US, Japan, India) are laughing that I should have a red hair to fit my irish accent