9 Inch Rebuild/Gear Setup
Copyright © 2000 James Oxley
NOTE:
IF YOU ARE A BEGINNER, THIS IS THE REAR YOU WANT TO START WITH. THE 9"
FORD REAR IS A MODEL OF SIMPLICITY FOR ADJUSTMENT OF PINION DEPTH AND SETTING
BACKLASH
NOTE:
TO PERFORM THIS REBUILD, YOU SHOULD HAVE A SHOP MANUAL THAT LISTS TORQUE
SPECS, A FULL SIZE FLOOR JACK , TWO (3 TON MIN) JACK STANDS, A DIAL INDICATOR
WITH MAGNETIC/STATIC BASE, A VIERNER CALIPER, GEAR PATTERN GREASE,
"RED" GRADE THREAD LOCKER. INCH-LB TORQUE WRENCH, AND 150+ FT-LB
TORQUE WRENCH
1. REMOVE WHEELS AND PLACE REAR AXLE ON JACKSTANDS. I LIKE JACKING BETWEEN
SHOCK MOUNT AND CENTER SECTION. JACK STANDS SHOULD BE PLACED BETWEEN SETS OF
U-BOLTS, DIRECTLY UNDER LEAF SPRINGS.
2. RELEASE EMERGENCY BRAKE. REMOVE BRAKE DRUMS.
NOTE:
BACKING OFF ON INTERNAL SHOE ADJUSTING STAR WHEEL (ACCESSED
THROUGH HOLE IN BACKING PLATE) AND/OR HITTING BRAKE DRUM WITH HAMMER BETWEEN 2
STUDS IN AXIAL DIRECTION MAY BE NEEDED TO REMOVE STUBBORN DRUMS. WHEN HAMMERING
DRUM, KEEP WHEEL NUTS ON STUDS TO AVOID THREAD DAMAGE.
3. ROTATE AXLE TO LINE UP HOLE IN AXLE FLANGE WITH ONE AXLE RETAINING BOLT.
REMOVE AXLE RETAINING BOLT. REPEAT THIS 3 MORE TIMES TO REMOVE A TOTAL OF 4 AXLE
RETAINING BOLTS. REMOVE AXLE BY PULLING STRAIGHT OUT. AXLE MAY REQUIRE
SUBSTANTIAL FORCE TO BE REMOVED. ENSURE SMALL PAN IS UNDER END OF AXLE ASSY TO
CATCH ANY LEAKING REAR END FLUID. USE MASKING TAPE TO MARK AXLE AS TO DRIVER OR
PASSENGER SIDE.
4. INSPECT AXLE BEARING AND RACE FOR PITTING, CORROSION, OR WEAR.
CAREFULLY INSPECT AXLE SEAL FOR MISSING RUBBER. IF RUBBER IS SHOT, NEW SEALS
WILL BE NEEDED. REINSTALLING AXLE AND LOCATING MISSING PART OF SEAL ON TOP OF
TUBE AND/OR USING GASKET SEALER WILL NOT WORK CORRECTLY. I TRIED THEM BOTH.
REPLACING AXLE SEALS MAY REQUIRE NEW BEARINGS (DEPENDING HOW THEY PRESS OFF) AND
WILL REQUIRE NEW BEARING RETAINER RING. ENSURE BEARING RACES ARE CHANGED IF NEW
BEARINGS ARE INSTALLED.
5. REMOVE 10 NUTS FROM 3RD MEMBER ASSEMBLY. REMOVE 10 BRASS WASHERS FROM
STUDS TAKING CARE TO NOT DESTROY THEM. BENDING THEM SLIGHTLY TO GET THEM OFF IS
OK. PICTURE SHOWS 3RD MEMBER ALL READY OFF STUDS.
6. USING RUBBER HAMMER OR BOTH HANDS, CRACK GASKET, PULLING UPWARD ON 3RD
MEMBER ASSY. ENSURE LARGE PAN IS UNDER 3RD MEMBER TO CATCH OIL. SMALL
SCREWDRIVER CAN BE PLACED AT BOTTOM BETWEEN 3RD MEMBER AND HOUSING TO ALLOW
THOROUGH FLUID DRAINING. DRAIN FOR 1 HOUR MIN TO ENSURE ALL OIL IS OFF 3RD
MEMBER.
7. REMOVE 3RD MEMBER. JERKING UP/DOWN AND SIDE/SIDE MOTIONS MAY BE REQUIRED
TO GET 3RD MEMBER OUT. SOMETIMES STUDS ARE ANGLED SLIGHTLY, MAKING 3RD MEMBER A
TIGHT FIT. PLACE 3RD MEMBER ON CLEAN RAGS/SURFACE. SOP UP REMAINING FLUID IN
BOTTOM OF CASE. CHECK FOR HEAVY/LARGE METAL PARTICLES ON CASING BOTTOM.
8. SETUP 3RD MEMBER ON BLOCKS AS SHOWN. A 6 X 6 AND 2 -2 X 4’S ON
EITHER SIDE WORKS WELL FOR THE CORRECT HEIGHT.
NOTE:
IF THIS IS YOUR FIRST GEAR SETUP/INSTALL, YOU MAY WANT TO PERFORM A REFERENCE
CHECK ON BACKLASH AND A PATTERN CHECK ON DRIVE AND COAST. THIS WILL GIVE YOU A
GOOD IDEA OF WHAT BACKLASH YOU WILL NEED AND WHAT THE GEAR PATTERNS LOOK LIKE
UPON RE-ASSEMBLY. SKIP 9, 10 AND 11 IF YOU ARE SEASONED GEAR INSTALLER.
9. INSTALL DIAL INDICATOR AS SHOWN. MAKE SURE DIAL INDICATOR IS EXTREMELY
RIGID, OR RESULTS WILL BE SKEWED. ENSURE DIAL POINTER IS SET SO IT TOUCHES THE
TOP OF ONE GEAR TOOTH AND IS TANGENT TO THE OUTER ARC OF RING GEAR TEETH. HOLD
PINION FLANGE SOLID AND ROTATE RING GEAR BACK AND FORTH, ENSURING PINION/FLANGE
DOES NOT MOVE. PLAY SHOULD BE EVIDENT AND THE AMOUNT OF BACK AND FORTH PLAY IS
CALLED BACKLASH. IT SHOULD BE AROUND .008 TO .012 INCHES.
10. PAINT ALL RING GEAR TEETH, BOTH SIDES, WITH GEAR MARKING COMPOUND (USUALLY
A WHITE TYPE OF GREASE). PUT FORCE ON RING GEAR IN EITHER DIRECTION (SMALL
RUBBER PAD PRESSED AGAINST RING GEAR TEETH WORKS WELL FOR THIS). SPIN PINION/FLANGE
BACK AND FORTH, 10 OR 20 TIMES, ENSURING 5 OR 6 RING GEAR TEETH MESH WITH PINION
GEAR TEETH. RELEASE FORCE ON RING GEAR AND ROTATE IT TO A POINT WHERE PREVIOUSLY
MESHED TEETH (PATTERN IN GREASE) CAN BE SEEN. PATTERN SHOULD LOOK LIKE CORRECT
MESH PATTERN IN DIAGRAM BELOW.
11. REPEAT PROCEDURE, FORCING RING GEAR IN OPPOSITE DIRECTION. CHECK
PATTERN AGAIN. BOTH PATTERNS SHOULD BE IN CENTER OF TOOTH AND NOT RUNNING OFF
THE EDGE OF ANY TEETH. PATTERN CAN BE CHECKED AT VARIOUS LOCATIONS ON RING GEAR
TO ENSURE PATTERNS ARE THE SAME OVER ENTIRE RING GEAR. DOING THIS WILL ALSO
ENSURE RING GEAR IS SEATED CORRECTLY ON DIFFERENTIAL AND RUNOUT ON RING GEAR IS
ACCEPTABLE.
12. REMOVE DIAL INDICATOR IF INSTALLED AND LOOSEN 4 CARRIER BEARING CAP BOLTS.
MAKE SURE BEARINGS CAPS ARE MARKED IN SOME WAY SO THEY ARE INSTALLED AS THEY
CAME OUT. THEY ARE NOT INTERCHANGEABLE. REMOVE CARRIER BEARING CAPS. REMOVE
DIFFERENTIAL/RING GEAR, ENSURING BEARING RACES/THREADED SIDE ADJUSTERS DO NOT
FALL ON FLOOR.
13. USING LARGE ADJUSTABLE WRENCH, HOLD PINION FLANGE AND REMOVE PINION NUT.
REMOVE 5 BOLTS HOLDING PINION, PINION BEARINGS AND RETAINER TO MAIN CASING.
14. REMOVE PINION ASSEMBLY. CARE SHOULD BE EXERCISED TO PREVENT DAMAGE TO
RUBBER O-RING ON PINION ASSEMBLY. ENSURE METAL SHIM(S) BETWEEN MAIN CASING AND
PINION RETAINER ARE ACCOUNTED FOR AND NOT DAMAGED. SLIDE PINION OUT OF RETAINER
(MAY NEED TO BE PRESSED OUT) AND PRY OFF PINION SEAL ON END OF RETAINER.
15. PRESS OFF AND REPLACE REMAINING PINION BEARING. REPLACE BEARING RACES ON
BOTH SIDES OF PINION RETAINER. REINSTALL PINION INTO RETAINER.
16. INSTALL NEW CRUSH COLLAR ON PINION (SEE PICTURE BELOW). INSTALL
REMAINING PINION BEARING, PINION FLANGE, AND NEW PINION NUT. HOLDING PINION
FLANGE WITH VERY LARGE ADJUSTABLE WRENCH, TORQUE NUT TO 175 FT-LBS. ENSURE
ROTATIONAL FORCE OF PINION GEAR DOES NOT EXCEED 5-8 IN-LBS FOR NEW BEARINGS OR 8
IN-LBS FOR USED BEARINGS. IT IS BEST TO CHECK ROTATIONAL FORCE OFTEN WHILE
TORQUEING, AS THE ROTATIONAL FORCE WILL GIVE YOU A BETTER INDICATION OF PINION
BEARING PRE-LOAD THAN THE PINION NUT TORQUE. TORQUING CLOSE TO, BUT NOT EXACTLY
TO, THE SPECIFIED TORQUE MAY BE REQUIRED IF ROTATIONAL FORCE LIMIT HAS
BEEN REACHED.
16. REMOVE AND REPLACE EXTRA SMALLER PINION BEARING FROM MAIN CASE.
RETAINING RING CAN BE PRIED OUT AND USUALLY REUSED IF NOT DESTROYED.
ENSURE CASING AROUND THIS BEARING IS NOT CRACKED (SEE SECOND PICTURE, LEFT
SIDE). IT IS A COMMON PROBLEM, ESPECIALLY AFTER HARD USE. IF IT IS CRACKED,
YOU MAY WANT TO CONSIDER UPGRADING TO A NODULAR CASE AND/OR A PINION
HOUSING THAT ACCEPTS LARGER BEARINGS.
17. USING CALIPER, MEASURE THICKNESS OF METAL SHIM THAT WAS REMOVED WHEN
PINION ASSEMBLY WAS REMOVED FROM MAIN CASE. INSTALL PINION ASSEMBLY. ENSURING
THAT O-RING IS NOT DAMAGED AND THAT METAL SHIM IS ALIGNED PROPERLY (SEE PICTURES
AFTER STEP 14). IF YOU ARE INSTALLING NEW PINION (GEARSET), YOU MAY WANT TO
CHECK AND SEE IS END OF OLD AND NEW PINIONS HAVE MARKS LIKE +1 OR -2. IF THEY
BOTH HAVE THIS MARKING, THIS WILL ALLOW YOU TO ADD OR SUBTRACT PINION SHIMS IN
THOUSANDS (.001) OF AN INCH. IF OLD PINION WAS +2 AND NEW PINION IS -1, YOU WILL
NEED TO SUBTRACT .003 INCHES FROM THE ORIGINAL SHIM. THIS IS OPPOSITE WHAT YOU
WOULD DO ON MOST DIFFERENTIALS, AS PINION SHIMS ON A FORD 9 INCH CHANGE PINION
DEPTH IN THE OPPOSITE DIRECTION COMPARED TO MOST DIFFERENTIALS. THIS WILL
GIVE YOU A GOOD STARTING POINT FOR PINION DEPTH
18. IF DIFFERENTIAL IS TO BE REPLACED/REBUILT OR NEW GEARSET IS TO BE
INSTALLED, REMOVE RING GEAR BOLTS, TAP RING GEAR OFF WITH PLASTIC HAMMER. USE
AXLE SHAFT INSERTED INTO ONE END OF DIFFERENTIAL TO AID IN REMOVING RING GEAR
BOLTS. IF RING /PINION AND DIFFERENTIAL ARE TO BE RE-USED, MARK RING GEAR SO IT
CAN BE REPLACED IN THE EXACT SPOT IT WAS TAKEN OFF FROM.
19. REBUILD/REPLACE DIFFERENTIAL. REPLACE BEARINGS IF DESIRED
BY PRESSING OFF AND BACK ON. REPLACE RACES IF BEARINGS ARE REPLACED. ATTACH RING
GEAR AND TIGHTEN BOLTS IN A CRISS-CROSS PATTERN. TIGHTEN IN
INTERVALS TO ASSURE CORRECT RING GEAR SEATING. FINAL TORQUE SHOULD BE 65-85
FT-LBS. TIGHTEN BY REVERSING PROCEDURE FOR REMOVAL SHOWN ABOVE.
20. MOVE MAIN CASE WITH PINION ATTACHED ON IT SIDE. ENSURE PINION
ROTATES FREELY. GET BEARING CAPS READY AND SET UP MAIN CASE ON THE BLOCKS
METIONED IN PART 8.
21. INSTALL RING/GEAR AND DIFF ASSY, INSTALL BEARING CAPS. LEAVE
BEARING CAP BOLTS LOOSE FOR NOW.
22. SCREW IN SIDE ADJUSTERS INTO SIDE OF MAIN CASE/BEARING CAPS.
IF IT GETS HARD TO TURN THEM YOU CAN USE TWO PHILLIPS SCREWDRIVERS TO ROTATE
THEM.
23. SET UP DIAL INDICATOR AS DESCRIBED IN PART 9. ROTATE
ADJUSTER, OPPOSITE RING GEAR TEETH, UNTIL RING GEAR IS TIGHT AGAINST PINION GEAR.
ROTATE OPPOSITE ADJUSTER UNTIL IT IS TIGHT. LOOSEN AND TIGHTEN EACH ADJUSTER
UNTIL THEY ARE BOTH TIGHT, BUT YOU HAVE .008 INCHES OF BACKLASH AS DESCRIBED IN
PART 9. SNUG UP BEARING CAP BOLTS.
24. PAINT ALL RING GEAR TEETH, BOTH SIDES, WITH
GEAR MARKING COMPOUND (USUALLY A WHITE TYPE OF GREASE). PUT FORCE ON RING GEAR
IN EITHER DIRECTION (SMALL RUBBER PAD PRESSED AGAINST RING GEAR TEETH WORKS WELL
FOR THIS). SPIN PINION/FLANGE BACK AND FORTH, 10 OR 20 TIMES, ENSURING 5 OR 6
RING GEAR TEETH MESH WITH PINION GEAR TEETH. RELEASE FORCE ON RING GEAR AND
ROTATE IT TO A POINT WHERE PREVIOUSLY MESHED TEETH (PATTERN IN GREASE) CAN BE
SEEN. PATTERN SHOULD LOOK LIKE CORRECT MESH PATTERN IN PICTURE AFTER PART 10.
25. REPEAT PROCEDURE, FORCING RING GEAR IN OPPOSITE DIRECTION. CHECK
PATTERN AGAIN. BOTH PATTERNS SHOULD BE IN CENTER OF TOOTH AND NOT RUNNING OFF
THE EDGE OF ANY TEETH. PATTERN CAN BE CHECKED AT VARIOUS LOCATIONS ON RING GEAR
TO ENSURE PATTERNS ARE THE SAME OVER ENTIRE RING GEAR. DOING THIS WILL ALSO
ENSURE RING GEAR IS SEATED CORRECTLY ON DIFFERENTIAL AND RUNOUT ON RING GEAR IS
ACCEPTABLE. IF RING GEAR/PINION GEARS WERE REUSED, SKIP PART 26.
26. IF PATTERN IS NOT CORRECT, IN BOTH DIRECTIONS, PINION
ASSEMBLY MUST BE REMOVED AND A DIFFERENT SHIM MUST BE INSTALLED. YOU SHOULD ONLY
ADD/SUBTRACT .002 INCHES OF SHIM AT THE MOST WHEN CHANGING THE SHIM(S) THICKNESS
THE FIRST TIME. THICKER SHIMS CAN BE ADDED THE SECOND TIME, DEPENDING UPON HOW
MUCH THE PATTERN CHANGES. IT TAKES SOME PRACTICE TO DETERMINE HOW MUCH SHIM TO
ADD/SUBTRACT. PINION ASSEMBLY MUST BE THEN RE-INSTALLED AND SIDE ADJUSTERS
SET UP AGAIN SO THAT BACKLASH IS ONCE AGAIN .008.
27. REPEAT STEPS 24-26 UNTIL PATTERN IS CORRECT. THIS IS
THE HARDEST PART OF REBUILDING A REAR END ASSEMBLY. IT MAY TAKE MANY TRYS OR
EVEN DAYS TO GET IT RIGHT. BE PATIENT IF IT IS YOUR FIRST TIME. SKIP TO
PART 28.
28. IF PATTERN IS NOT CORRECT, ADJUST SIDE ADJUSTERS AND
CONSEQUENTLY BACKLASH UNTIL PATTERN IS CORRECT. PINION SHIM THICKNESS SHOULD NOT
HAVE TO BE CHANGED, AS RING/PINION GEAR RELATIONSHIP HAS NOT BEEN CHANGED. IF
YOU CAN NOT GET PATTERN CORRECT, YOU WILL NEED TO REPEAT SECTIONS 24-26 UNTIL
PATTERN IS CORRECT.
29. AFTER PATTERN AND BACKLASH HAVE BEEN DETERMINED TO BE
CORRECT, YOU NEED TO ENSURE THAT SIDE ADJUSTERS ARE SNUGGED UP BY HAND
ONLY ON BOTH SIDES. SIDE ADJUSTERS NEED TO THEN BE ADJUSTED TIGHTER, TO
CREATE A PRELOAD ON DIFFERENTIAL BEARINGS. EACH SIDE ADJUSTER NEEDS TO BE MOVED
IN .004 TO .006 INCHES FOR NEW BEARINGS OR .003-.004 FOR USED BEARINGS. THERE
ARE HOLES LOCATED ON EACH SIDE ADJUSTER. ROTATING THE ADJUSTER TO MOVE FROM ONE
HOLE TO THE NEXT WILL GIVE YOU .005 INCHES OF PRELOAD FOR EACH HOLE TO HOLE
DISTANCE. YOU WILL HAVE TO EYE THIS AND MOVE THE ADJUSTERS ACCORDINGLY. IF YOU
HAVE ACCESS TO A CASE SPREADER, YOU CAN SPREAD THE MAIN CASE THE CORRECT AMOUNT,
AND THEN JUST SNUG UP THE ADJUSTERS BY HAND.
30. APPLY LOKTITE TO MAIN BEARING CAP BOLTS AND TIGHTEN TO
75-85 FT-LBS. INSTALL SIDE ADJUSTER RETAINERS, APPLY LOKTITE TO SMALL BOLTS AND
TIGHTEN.
31. ENSURE RING AND PINION MESH SMOOTHLY AROUND ENTIRE RING GEAR
SURFACE. REPLACE 3RD MEMBER IN AXLE HOUSING. I GAVE UP ON GASKETS, AS
THEY TENDED TO LEAK FOR ME. I USE ONLY GASKETMAKER BETWEEN THE HOUSING AND 3RD
MEMBER. INSTALL BRASS WASHERS. THEY MAY HAVE TO BE BENT BACK INTO SHAPE IF
THEY WERE DEFORMED UPON REMOVAL. TORQUE 3RD MEMBER NUTS IN A CRISS-CROSS
PATTERN TO 30-40 FT-LBS. INSTALL AXLES AND TORQUE 4 NUTS TO 50-75
FT-LBS. INSTALL BRAKE DRUMS, WHEELS AND ROAD TEST.
YA JUST REBUILT YA FIRST REAR!!! :-)
PS; IF IT BLOWS UP IN 20 MILES, JUST GET IT OVER WITH
AND GET A DANA 60. IT'S A MUCH BETTER REAR ANYWAY. HEEHEE.
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