Comparing Heights, Spirit Level, Attitude Adjustment Information
FIGURE 15:
CHECKING BY COMPARING HEIGHTS
This check consists of comparing the heights of the front or rear sidemembers (H), one side in relation to the other side (Fig. 15). A 4-post hoist is required for these checks.
Using The Adjustable Spirit Level
The level is used twice for this check:
^ First to check the attitude of the vehicle in relation to a flat floor surface.
^ And second, to check the difference in height between pairs of sidemembers (front or rear).
Adjusting The Attitude Of The Vehicle
The purpose of this operation is to level the vehicle underframe.
Leveling may not necessarily be related to a horizontal line but to any theoretical centerline related to a known undamaged section of the vehicle.
^ Adjustment of the attitude will be made between the center and rear on a front damaged vehicle.
^ And between the center and front on a rear damaged vehicle.
FIGURE 16:
Adjusting The Attitude Of A Front Damaged Vehicle
^ Insert the stepped tip of the straight pointer (A) in one of the floor frame jigging holes (A-B, Fig. 16). Make sure that the jigging hole is undamaged and free of corrosion protection material.
FIGURE 17:
^ Choose any reference point at the rear of the vehicle (the same for the right as for the left) and clean it so that pointer (B) contacts bare metal (Fig. 17).
FIGURE 17:
ATTITUDE ADJUSTMENT (Cont'd.)
Setting The Adjustable Spirit Level
^ Turn wingnut (C) to adjust the level so that bubble (D) lies evenly between lines (E) (Fig. 17).
FIGURE 18:
ATTITUDE ADJUSTMENT (Cont'd.)
Without disturbing the trammel gauge settings (level, pointers and length), measure the opposite side of the vehicle (Fig. 18).
The vehicle attitude is correct if the bubble lies between lines (E) (Fig. 18).
If the bubble is not between the two lines, use the vehicle jack to correct the attitude.
FIGURE 19:
ATTITUDE ADJUSTMENT (Cont'd.)
NOTE: The jack should be placed under one of the rear jacking points if possible (Fig. 19).
Recheck the first measurement A-B and adjust the spirit level as necessary. Now check the other side A'-B' and use the jack to adjust until both sides of the vehicle are leveled.
The vehicle must not be moved nor the hoist raised or lowered after attitude is correct, unless the height difference has been checked.
FIGURE 20:
FIGURE 21:
CHECKING SIDEMEMBER HEIGHT DIFFERENCE
^ Insert the straight pointer with stepped tip in one of the jigging holes in the floor frame.
^ Choose any reference point at the forward section of the front end (the same for the right as for the left) and clean it so that pointer (G) contacts bare metal (Figs. 20 and 21).
FIGURE 21:
CHECKING SIDEMEMBER HEIGHT DIFFERENCE (Cont'd.)
^ Turn wingnut (C) to adjust the level so that bubble (D) lies evenly between lines (E) (Fig. 21).
FIGURE 22:
^ Without disturbing the trammel gauge settings (level, pointers and length), measure the opposite side.
The sidemembers are the same height if the bubble lies between the two lines (Fig. 22).
Depending on how great the height difference, the vehicle may have to be repaired on a repair jig bench.