Front suspension on a 2004 suburban?

[AxelBruijnis]

Today i have my 2004 suburban 2500 "quadrasteer" in for its annual test.
The mechanic responsible for the test discovered that the vehicle looks normal, but that the front suspension appears to rest on the end stops ( see pictures )

Can anyone compare this to their suburban , please ?
There are not many of these vehicles around in holland to compare in person.

your effort will be appreciated !

[overlander63]

There are adjustment bolts for the torsion bars near the transmission. Your mechanic will need to tighten them up somewhat until the lower control arms no longer rest on the stops. He needs to make sure he turns each bolt, one per side, the same number or rotations, or your truck will sit at an angle.

[richinny]

this adjustment might also require the front tires to be realigned. keep an eye on the tire edges for excessive wear.

[dznf0g]

Trim Height Inspection
<A href="#ss1-745583">Trim Height Measurements

Trim height is a predetermined measurement relating to vehicle ride height. Incorrect trim heights can cause bottoming out over bumps, damage to the suspension components and symptoms similar to wheel alignment problems. Check the trim heights when diagnosing suspension concerns and before checking the wheel alignment.
Perform the following before measuring the trim heights:

• Make sure the vehicle is on a level surface, such as an alignment rack.
• Remove the alignment rack floating pins.
• Set the tire pressures to the pressure shown on the certification label. Refer to Vehicle Certification Label in General Information.
• Check the fuel level. Add additional weight if necessary to simulate a full tank.
• To ensure proper weight distribution make sure the rear storage compartment is empty.
• Close the doors and hood.

<A href="#ss2-745583">Z Height Measurement

Important: K models only the Z height must be adjusted before the alignment.
The Z height dimension measurement determines the proper ride height for the front end of the vehicle. Vehicles equipped with torsion bars use a adjusting arm in order to adjust the Z height dimension. Vehicles without torsion bars have no adjustment and could require replacement of suspension components.

1. Important: All dimensions are measured vertical to ground. Cross vehicle Z heights should be within 12 mm (0.47 in) to be considered correct.
   <LI type=1>Place hand on the front bumper and jounce the front of the vehicle. Make sure that there is at least 38 mm (1.5 in) of movement while jouncing. <LI type=1>Allow the vehicle to settle into position.
   
   
   <LI type=1>Measure from the pivot bolt center line (2) down to the lower corner (5) of the lower steering knuckle (1) in order to obtain the Z height measurement (4). <LI type=1>Repeat the jouncing operation 2 more times for a total of 3 times. <LI type=1>Use the highest and lowest measurements to calculate the average height.
2. The true Z height dimension number is the average of the highest and the lowest measurements. Refer to Trim Height Specifications .

<A href="#ss3-745583">Z Height Adjustment

1. 
   
   <LI type=1>For vehicles equipped with a torsion bar suspension turn the bolt (1) that contacts the torsion arm as needed. One revolution of the bolt (1) into the nut increases the Z height by approximately 6.0 mm (0.2 in). <LI type=1>For vehicles without torsion bars, replace damaged or worn components as necessary.
2. If these measurements are still out of specifications after adjustment or are not equipped with torsion bars, inspect for the following:
   • Sagging front suspension. Refer to Torsion Bar Replacement in Front Suspension.
   • Collision Damage

The spec is 4.3" - 4.8" with the preferred Z height set at 4.5"

[dznf0g]

Sorry, the drawings won't copy over. Draw an imaginary line (use string or a straight edge) from the center of control arm pivot bolt (at the frame attachment) through the center of the torsion bar end in the control arm. Extend this line out to the hub.

Measure the distance from this line to the bottom most, inner edge of the steering knuckle where the ball joint mounts. This is the edge (circular) where the ball joint stud bolts to the knuckle. Raising the truck, by adjusting the torsion bar increases this "Z" spec.

[dznf0g]

CORRECTION: The drawing is deceiving. Take your string from the ball joint mount, on the hub, at its lowest most inner point. Set this string so it is parallel to the ground. Measure the distance from the center of the control arm/frame pocket pivot bolt. This distance shoud be close to 4.5". Sorry for the confusion.

[AxelBruijnis]

thank you !!

I did not know i could sag trough my front suspension , I guess I will need to watch what I eat more..

Axel

[dznf0g]

OR, you could measure from the ball joint lower, inner edge knuckle mount to the ground. Then measure from the pivot bolt center to ground and subtract the two measurements to get your 4.5" This should really be done on the alignment rack or known DEAD LEVEL surface, such as an "in floor" body repair rack.

[dznf0g]

Springs will settle as they age. That's one of the reasons for the adjustment. This also allows for things like snow plow weight. If your Burb is loaded ALL the time, you may want to perform this adjustment and alignment with the load applied. This is done all the time in fleets where they ALWAYS carry tools and equipment. Up to you.

[overlander63]

Originally Posted by dznf0g

Trim Height Inspection
<A href="#ss1-745583">Trim Height Measurements

Trim height is a predetermined measurement relating to vehicle ride height. Incorrect trim heights can cause bottoming out over bumps, damage to the suspension components and symptoms similar to wheel alignment problems. Check the trim heights when diagnosing suspension concerns and before checking the wheel alignment.
Perform the following before measuring the trim heights:

• Make sure the vehicle is on a level surface, such as an alignment rack.
• Remove the alignment rack floating pins.
• Set the tire pressures to the pressure shown on the certification label. Refer to Vehicle Certification Label in General Information.
• Check the fuel level. Add additional weight if necessary to simulate a full tank.
• To ensure proper weight distribution make sure the rear storage compartment is empty.
• Close the doors and hood.

<A href="#ss2-745583">Z Height Measurement

Important: K models only the Z height must be adjusted before the alignment.
The Z height dimension measurement determines the proper ride height for the front end of the vehicle. Vehicles equipped with torsion bars use a adjusting arm in order to adjust the Z height dimension. Vehicles without torsion bars have no adjustment and could require replacement of suspension components.

1. Important: All dimensions are measured vertical to ground. Cross vehicle Z heights should be within 12 mm (0.47 in) to be considered correct.
   <LI type=1>Place hand on the front bumper and jounce the front of the vehicle. Make sure that there is at least 38 mm (1.5 in) of movement while jouncing. <LI type=1>Allow the vehicle to settle into position.
   
   
   <LI type=1>Measure from the pivot bolt center line (2) down to the lower corner (5) of the lower steering knuckle (1) in order to obtain the Z height measurement (4). <LI type=1>Repeat the jouncing operation 2 more times for a total of 3 times. <LI type=1>Use the highest and lowest measurements to calculate the average height.
2. The true Z height dimension number is the average of the highest and the lowest measurements. Refer to Trim Height Specifications .

<A href="#ss3-745583">Z Height Adjustment

1. 
   
   <LI type=1>For vehicles equipped with a torsion bar suspension turn the bolt (1) that contacts the torsion arm as needed. One revolution of the bolt (1) into the nut increases the Z height by approximately 6.0 mm (0.2 in). <LI type=1>For vehicles without torsion bars, replace damaged or worn components as necessary.
2. If these measurements are still out of specifications after adjustment or are not equipped with torsion bars, inspect for the following:
   • Sagging front suspension. Refer to Torsion Bar Replacement in Front Suspension.
   • Collision Damage

The spec is 4.3" - 4.8" with the preferred Z height set at 4.5"

Thanks for giving Axel the additional info. I was heading out the door to work this morning, and didn't have time for a lengthy post.

[ticki2]

The rubber stop that you are refering to as a stop is actually called a jounce in the manual . It is supose to be in contact with the lower control arm , it is part of the suspension and is not a stop. Chances are there is nothing wrong with your suspension

[AxelBruijnis]

I'll have to bounce on the bumper, i guess.. to see if there is some room for suspension travel.
It always seemed somewhat lower on the front axle, but i always figured that was part of the "2500" rated suspension.