Hummer H1 Service Manual page 602

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VERTICAL (SIDE VIEW) MEASUREMENT
1. Select a hard and level surface area 1-1/2 times the size of
the vehicle.
2. Raise vehicle at four points until all four wheels are off the
surface.
WARNING: When using shim material with jack-
stands, the shim material must be placed squarely and
firmly under the jackstand. The vehicle could be
knocked off the jackstand resulting in personal injury
or equipment damage if shim material is placed on top
of jackstand.
3. Measure the distance from the floor to the bottom of the
frame near each jackstand. Place shim(s) under jackstands
as necessary until the floor-to-frame distances are equal at
each jackstand.
NOTE: Measurements must be taken at identical locations on
the left and right frame rails. Failure to do so will result in a
faulty indication.
4. Select, measure and record the distance from the floor to
the frame rail at several different points on either frame
rail.
REAR SUSPENSION
REAR CROSSMEMBER
REAR BUMPER
OUTER MOUNTING
BRACKET
RIGHT
REAR-REAR
TIEDOWN
BRACKET
RIGHT
REAR-FRONT
TIEDOWN
BRACKET
RIGHT INTERMEDIATE
BODY MOUNT
BRACKET
05745159
Axles, Suspension, and Frame
5. Measure and record frame rail height at corresponding
points on opposite frame rail.
6. Compare
Measurements from comparable points deviating more
than 1/8-inch (3 mm) for each 2 feet of linear distance
indicates a vertically bent frame.
7. Lower vehicle from jackstands.
HORIZONTAL (BOWING) MEASUREMENT
1. Position vehicle on a smooth level surface.
2. Measure height of frame rails at each end near center of
crossmembers. If heights vary by more than 1/8-5/16-inch
(3-8 mm), raise frame rail and install jackstands to bring
frame to level.
WARNING:
stands, the shim material must be placed squarely and
firmly under the jackstand. The vehicle could be
knocked off the jackstand resulting in personal injury
damage if shim material is placed on top of jackstand.
3. Hang a plumb bob at the corner of one frame rail where
the frame rail intersects the crossmember. Tape a piece of
paper to the floor under plumb bob and mark location
where plumb bob stops moving. Repeat procedure for
each corner of the frame (Figure 9-154).
REAR SUSPENSION
FRONT CROSSMEMBER
LEFT
INTERMEDIATE
BODY MOUNT
BRACKET
CROSSMEMBER
TRANSMISSION
CROSSMEMBER
RIGHT FRONT
BODY MOUNT
BRACKET
RIGHT FRONT
SPRING SEAT
Figure 9-152: Frame Components
measurements
When using shim material with jack-
LEFT FRONT
BODY MOUNT
BRACKET
LEFT
TRANSMISSION
SUPPORT
BRACKET
ENGINE
MOUNT
BRACKET
RIGHT SPLASH
SHIELD BRACKET
9-65
from both frame rails.
FRONT
SUSPENSION
REAR
CROSSMEMBER
AIR LIFT
BRACKETS
FRONT
SUSPENSION
FRONT
CROSSMEMBER