Fulltext TSBs

Technical Service Bulletins

TSB
98-23-21
  • SUSPENSION – FRONT OR REAR – SIDE-TO-SIDE LEVELING PROCEDURES AND ATTITUDE SERVICE KITS FOR F-53 RV BASIC STRIPPED CHASSIS
Publication Date: NOVEMBER 16, 1998

LIGHT TRUCK:
1989-1999 F SUPER DUTY, F-53

This TSB article is being republished in its entirety to include the latest level parts and to add 1999 model year vehicles.

ISSUE:

Service procedures and Vehicle Attitude Service Kits have been developed to assist customers and vehicle modifiers with side-to-side leveling concerns related to weight distribution. The service procedures involve adding spacer(s) to the springs of the low corner of the vehicle.

ACTION:

If service is required, use the appropriate service procedure and/or leveling service kit to properly level the vehicle.

NOTE:IT IS THE BODY BUILDER’S RESPONSIBILITY TO DESIGN THE VEHICLE SO AS TO PROVIDE PROPER SIDE-TO-SIDE WEIGHT DISTRIBUTION INCLUDING CONSIDERATION OF THE CUSTOMER’S STORAGE OF PERSONAL BELONGINGS AND/OR EQUIPMENT. INSTALLATION OF SPACER BLOCKS AND/OR ADDITIONAL SPRING LEAVES ON THESE MODIFIED VEHICLES IS NOT COVERED BY FORD FACTORY WARRANTY.

NOTE:IT SHOULD BE NOTED THAT THE SPRINGS USED IN THIS APPLICATION ARE EXTRA LONG, 102mm (4″) WIDE TAPER LEAF SPRINGS. UNDER NORMAL LOADING, THE SPRINGS WILL APPEAR FLAT AND/OR HAVE SOME REVERSE CAMBER. THIS CONDITION IS CONSIDERED NORMAL.

Determine which corner of the vehicle requires the addition of spacers by weighing each corner.

  • If weighing equipment is not available, measure the distance from the top center of the axle adjacent to the spring pack to the bottom of the frame
  • The weight method is preferred because rear side-to-side differences can affect the appearance of the front, regardless of the front side-to-side weight differential

Refer to the following Spacer Requirement Chart to determine the number of spacers to use.



SPACER REQUIREMENT
MethodFront DifferentialRear DifferentialSpacers Required
Weight68-125 kg (150-275 lbs)91-181 kg (200-400 lbs)1
    
 125-181 kg (275-400 lbs)181-272 kg (400-600 lbs)2*
    
Height6-13mm (0.25-0.50″)6-13mm (0.25-0.50″)1
    
 16-22mm (0.625-0.875″)16-22mm (0.625-0.875″)2*

(*) TWO 3/8″ SPACERS MAXIMUM

FRONT VEHICLE LEVELING PROCEDURE

If the weight (height) differential is in the front of the vehicle, use Vehicle Attitude Kit. The following procedure is to be performed on the heavy (low) side of the vehicle only.

  1. Jack up the front of the vehicle until the wheels are 102mm (4″) off the floor. Install floor stand under the frame, rearward of the front spring’s rear hanger, Figure 1.


    Figure 1 – Article 98-23-21

  2. Remove U-bolts, flatwashers, and nuts. Throw them away.
  3. Install a C-clamp on the spring and tighten it to hold the leaves together, Figure 3.


    Figure 3 – Article 98-23-21

  4. Remove the center tie bolt and nut and discard.

    NOTE:TO GAIN ENOUGH CLEARANCE SPACE TO REMOVE THE CENTER TIE BOLT, IT MAY BE NECESSARY TO LOOSEN THE U-BOLT NUTS ON THE OPPOSITE SIDE OF THE VEHICLE.

  5. Install spacer(s) using the new center tie bolt and nut included in the kit. Tighten the center tie bolt to 108 N-m (80 lb-ft).

    NOTE:IF THE SPRING ORIGINALLY HAD A WEDGE INSTALLED BETWEEN IT AND THE AXLE, BE SURE TO INSTALL THE WEDGE BETWEEN THE SPACER(S) AND THE AXLE WITH THE THICK SIDE OF THE WEDGE TO THE REAR OF THE VEHICLE.

  6. If only one (1) spacer is used, cut off excess length of the center tie bolt so that only two (2) screw threads are visible. This is done to ensure the bolt will not interfere with the frame during full jounce. Remove the C-clamp.
  7. Install new U-bolts, flatwashers and nuts included in the kit. Tighten U-bolt nuts to 380 N-m (280 lb-ft).
  8. Recheck torque on the center tie bolt and be sure it is at 108 N-m (80 lb-ft).
  9. Remove jack stands and lower the vehicle to the ground.
  10. Recheck U-bolt torque and tighten if necessary.

REAR VEHICLE LEVELING PROCEDURE

If the weight (height) differential is in the rear of the vehicle, use Vehicle Attitude Kit. The following procedure is to be performed on the heavy (low) side of the vehicle only.

  1. Jack up the rear of the vehicle until the wheels are 204mm (8″) off the floor. Install floor stand under the frame, forward of the rear spring’s front hanger, Figure 1.
  2. Support the axle on the side to be worked on using either a tire wheel jack or a floor jack positioned under the axle to the inside of the U-bolt lower bracket, Figure 2.


    Figure 2 – Article 98-23-21

  3. Remove and discard U-bolts, nuts, and flatwashers.
  4. Install a C-clamp on the spring and tighten to hold the leaves together. It may be necessary to loosen the U-bolt nuts on the opposite side of the vehicle to accomplish this step, Figure 4.


    Figure 4 – Article 98-23-21

  5. Remove the center tie bolt and nut. Throw them away.
  6. Install spacer(s) using the new center tie bolt and nut included in the kit. Tighten the center tie bolt to 108 N-m (80 lb-ft).
  7. Remove C-clamp.
  8. Install new U-bolts. Use new flatwashers and nuts included in the kit. Tighten U-bolt nuts to 380 N-m (280 lb-ft).
  9. Remove the jack stands and lower the vehicle to the ground.
  10. Recheck U-bolt torque and tighten if necessary.



    SUGGESTED LABOR TIMES
    OPERATIONSUGGESTED TIME
    Install One Spacer In Front Axle1.4 Hrs.
    Install Two Spacers In Front Axle1.3 Hrs.
    Install One Or Two Spacers In Rear Axle0.8 Hr.



PART NUMBERPART NAME
F7TZ-5K648-AAVehicle Attitude Kit (For Front Leveling)
F7TZ-5A581-AAVehicle Attitude Kit (For Rear Leveling)

OTHER APPLICABLE ARTICLES:

NONE

SUPERSEDES:

96-24-13

WARRANTY STATUS:

Information Only

OASIS CODES:

303000, 304000, 305000


Copyright © 1998 Ford Motor Company