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TABLE OF CONTENTS I. Description and Operation A. B. C. II. General Description Operation Operation Instructions V. 2 2 2 A. B. C. D. E. Wheel Bearings Universal Joints Kingpin Bearings Differential Carrier Steering Tie Rod Ball Joints 3 3 3 4 4 Ill. Axle Adjustment A . B. C. D. E. F. G. H. IV. General Wheel Bearing Adjustment Kingpin Adjustment Steering Stop Adjustment Camber Adjustment Caster Adjustment Toe-In Adjustment Brake Adjustment 5 5 5-6 6 7 8 8 8 Steerable Drive End Disassembly A. B.
I. DESCRIPTION & OPERATION A. General Description The Fabco Steerable Drive Axle consists of four major assemblies. The axle housing is the structural backbone. Steerable drive ends are attached to each end of the housing. A differential carrier assembly bolts into the center of the housing. A steering connecting tie rod joins between the right and left steerable drive ends. A steering arm is provided (usually on the left steerable drive end) for connection into a vehicle’s steering system.
II. LUBRICATION Recommended Lubricants LUBRICANT ABOVE 32° BELOW 32° Gear Oil MIL-L-2105 B SAE 140 MIL-L-2105 C 80W-140 MIL-L-2105 B SAE 90 MIL-L-2105 C 80W-90 Chassis Grease MIL-G-10294 MIL-G-10294 Wheel Bearing Grease NLGI Grade #2 NLGI Grade #2 Wheel Bearing Oil Use same as recommended for differential A. Wheel Bearings Wheel bearings require cleaning, inspection, packing with grease or an oil change at each brake re-line.
II. LUBRlCATlON D. Differential Carriers Differential carriers should have the lubricant changed at the same intervals as the rear axle on the vehicle, or at 10,000 mile intervals. Drain while lubricant is warm. Clean the magnetic drain plug when it is removed. Remove the fill plug to ensure quicker drainage. Allow housing to drain completely. Install the drain plug and fill the housing with the appropriate gear oil to the bottom of the fill plug hole. Check for leaks.
III. AXLE ADJUSTMENT A. General C. Kingpin Adjustment 1. The front of the vehicle should be raised and properly supported. The front wheels should be taken off the axle. Adjustments may be necessary after an accident, in response to and to correct steering problems, tire wear problems or as a part of the reassembly process after a thorough inspection. 2. The lower kingpin jam nut should be loosened and the lower kingpin ball should be backed down until it stops. B. Wheel Bearing Adjustment 1.
III. AXLE ADJUSTMENT 6. Place a stack of feeler gauges in the gap between the lower kingpin bracket and the suspension yoke. The gauges should fit snugly. Continue to screw the lower kingpin ball stud upward untill the feeler gauge begins to fall (move downward). (See fig. 6D.) Fig. 6 7. Fig. 7 Remove the feeler gauge from the opening and back off the lower kingpin ball stud ¼ turn. You have now seated the lower kingpin. Tighten the jam nut to 400 lb. ft.
III. AXLE ADJUSTMENT Fig. 11 Fig. 9 Fig. 12 Fig. 10 E. Camber Adjustment 1. Refer to this section, part B, steps 1 and 2, 2. Adjustment is made by the addition or subtraction of shims. 3. Loosen the four bolts at the upper kingpin bracket, loosening bracket from the spindle yoke. Remove only the top two bolts. 4. Remove or install shims as necessary to achieve the desired camber. (See figs. 11 and 12.) 5. 6.
III. AXLE ADJUSTMENT F. Caster Adjustment H. Brake Adjustment Caster is set by the vehicle manufacturer and can be adjusted only by shims between the axle spring seat and the spring. Changing the caster will change the pinion angle and may affect the operation of the front drive shaft. Brake adjustment is made automatically. Make the initial adjustment by driving the air braked vehicle forward and applying the brakes. Continue applications until the shoe to drum clearance is between .015” and .030”.
IV. STEERABLE DRIVE END DISASSEMBLY A. General Precautions for Disassembly 6. IMPORTANT: READ THIS SECTION BEFORE STARTING THE DISASSEMBLY PROCEDURES. 1. The flange should be loose enough to remove by hand. If not, use suitable bolts in the extractor holes to remove the outer axle shaft. (See fig. 15). Note: If oil is used for wheel bearing lubrication, care should be exercised to protect brake linings, etc. Follow each procedure closely in each section, making use of both text and pictures. 2.
IV. STEERABLE DRIVE END DISASSEMBLY 9. Lift the hub (or hub and drum assembly) off the spindle (See fig. 17) using care to avoid damage to the bearing surfaces and to the threads. Wipe off any oil that may have reached the brake shoe before it reaches the lining. 10. Do not remove the axle shaft studs unless replacing them. 11. Remove the hub seal from the hub and discard. 12. Remove the inner wheel bearing cone and protect it from dirt. 13.
IV. STEERABLE DRIVE END DISASSEMBLY D. Spindle Yoke Removal 1. Perform steps B and C, page 9 and page 10. 2. Disconnect the steering rod by removing the cotter pin, castle nut and then while prying between the tie rod end and the tie rod arm, sharply strike the side of the tie rod arm radially to the tie rod end tapered stud. Disconnect the brake hose. 3. Remove four capscrews (See fig. 20) that retain the universal joint cross and bearing to the outer drive yoke. 4.
IV. STEERABLE DRIVE END DISASSEMBLY 5. Disconnect the steering tie rod by removing the cotter pin, castle nut and then, while prying between the tie rod end and the tie rod arm, sharply strike the side of the tie rod arm radially to the tie rod end tapered stud. 6. Disconnect the brake hose. 7. Remove the four bolts that hold the upper kingpin bracket to the spindle yoke. 8. Lower the transmission jack about two inches and roll the outer section of the steerable drive end away from the axle. F.
IV. STEERABLE DRIVE END DISASSEMBLY I. Upper Kingpin Removal M. Outer Axle Seal Removal After Section IV-E, remove locknut from the bottom of the upper kingpin. Use a jack or jack screw to pry between the stud and the lower portion of the suspension yoke to force the ball stud from its tapered hole. After IV-D or E, Page 11 use a standard puller to remove the seal or refer to IV-O. J. Steering Arm Removal N. Outer Drive Yoke Roller Bearing Removal 1.
V. CLEANING AND INSPECTION A. Choice of Cleaning Methods C. Inspection 1. Steam may be used for external cleaning of completely assembled units. Care must be taken to ensure that water is kept out of the assembly by tightly closing breather caps and other openings. 2. Rough parts such as housings, which are too large to conveniently clean with solvents, may be immersed in a hot solution tank containing a mild alkaline solution.
VI. STEERABLE DRIVE END ASSEMBLY A. General Precautions for Reassembly IMPORTANT: READ THIS SECTION BEFORE STARTING THE REASSEMBLY PROCEDURES. 1. Gaskets — Use liquid sealant per Service Bulletin 738 407, Page 22. 2. Differential Mounting Bolts — To prevent oil leakage, use Permatex form-a-gasket #2 pliable setting sealant or equal on all threads. See torque rating chart for recommended torque, Section VIII. 3. Assembly — Refer to the parts section as a guide to reassembly. 4.
VI. STEERABLE DRIVE END ASSEMBLY 4. Apply a bead of liquid sealant to the axle housing flange. (See Service Bulletin 738 407, Page 22.) Install the suspension yoke with hardened washers and locknuts. Tighten to specified torque. 5. Install a new o-ring and a new upper kingpin bearing (if needed) into the upper kingpin bracket. Apply a light coat of lubricant to the inside of the socket and to the ball section of the upper kingpin ball stud.
VI. STEERABLE DRIVE END ASSEMBLY D. Spindle Yoke Assembly 1. Pack the roller bearing with the proper lubricant and press into place in the spindle yoke. (See fig. 35.) 2. Coat the outside circumference of the outer drive yoke seal with liquid sealant. Press the seal into place in the spindle yoke. (See fig. 36). 3. Rest the spindle yoke with its inboard side down. Install the lower kingpin mounting studs. E. Lower Kingpin Bracket Installation 1.
VI. STEERABLE DRIVE END ASSEMBLY H. Wheel Hub Assembly 1. 2. Assemble the wheel bearing cups and the outer axle shaft drive studs to the wheel hub. 1. The outer drive yoke should be complete with a bearing race pressed on its hub. This race should not have been removed at disassembly unless either the yoke or race were replaced by new parts. 2. Lubricate the seal and bearing surface of the outer drive yoke and put the yoke in place in the bearing and seal that is in the spindle yoke. (See fig. 37). 3.
VI. STEERABLE DRIVE END ASSEMBLY Fig. 41 Fig. 40 J. Universal Joint Assembly M. Tie Rod Assembly Install the universal joint cross and bearing assembly with two bolts in each of the bearing caps. (See figs. 27 and 20, Page 13 & 11.) Rotate the wheel hub to rotate the universal joint while the end is turned against the steering stop and check for positive clearance. Install the steering connecting tie rod. Tighten the castle nuts to the specified torque and use new cotter pins. N. Final Assembly K.
VII. DIFFERENTIAL CARRIER A. Removal of Differential Carrier from Axle All service of the differential carrier assembly requires removal of the assembly from the axle housing. 1. Remove the drain plugs and drain lubricant from axle housing. 2. Disconnect propeller shaft at pinion yoke. 3. Refer to Section IV-E (Page 11), and remove both inner axle shafts. 4. Attach differential carrier to a suitable roller jack. (See fig. 42). 5.
TORQUE SPEClFlCATlONS SIZE LB-FT 1-1/8 - 18 320 Min. 7/16 45-55 3/4-16 250 1-14 250 5/8-18 125 Spindle, Brake Spider to Spindle Yoke 9/16-18 150 Upper and Lower Kingpin Bracket Mtg.
REVISION A SERVICE BULLETIN NO. 738 407 Fabco SUBJECT: FORMED-IN-PLACE-GASKETS FOR PRODUCTION AND SERVICE USE AFFECTS: ALL FABCO AXLES EFFECTIVE: JUNE 1985 I. Formed-In-Place-Gasket compound has been phased-in as the standard gasket material on all Fabco axles. The paper gaskets will not (and should not) be used. II. Service gaskets will not be available. Fabco offers gasket compound as a service replacement. FABCO NO. LOCTITE PRODUCT NO. 6 ml. tube 728 232 001 51517 50 ml.
REVISION A Page 2 Service Bulletin #738 407 C. Loctite product 515 Gasket Eliminator is available through Industrial Bearing Suppliers. III. The compound listed above may be used to mount the differential carrier to the axle housing or to assemble the differential carrier itself. The following materials may also be used to mount or assemble the differential carrier: A. General Electric 1473 Silicone RTV “Silmate”. B. Dow 732 Silicone RTV “Silastic”. C. Loctite 504 “Gasket Eliminator”. D. Loctite 510.
SERVICE BULLETIN NO. 738 407 USE ONLY LOCTITE PRODUCT 515 GASKET ELIMINATOR APPLY AS ILLUSTRATED 3/32 TO 1/8 DIAMETER BEAD. DIAGRAM ILLUSTRATES SDA-20 - SDA-9, 12, 16, 18 ARE SIMILAR.
