U-Joint

Remove and replace worn universal joints (U-joints) in the driveshaft of a 1972 Ford F-100 with 302ci V8, restoring smooth driveline operation and eliminating vibration or clunking.

Warnings

Tools required

Parts

• Driveshaft U-joint (Spicer 1310 series or equivalent) × 2 — Use OEM specification
• U-joint strap bolts and nuts × 8 — 3/8-16 x 1" grade 8

Preparation

1. Park vehicle on level ground and engage parking brake firmly
2. Chock front wheels on both sides
3. Raise rear of vehicle with floor jack at rear axle housing or frame rails
4. Support vehicle securely on jack stands placed under frame rails behind cab
5. Allow driveline components to cool if vehicle was recently driven
6. Inspect driveshaft for existing alignment marks or previous service markings

Procedure

1. 1

   Mark driveshaft phasing
   Using masking tape or paint pen, mark the relationship between the driveshaft tube and the rear axle yoke. Note that the slip yoke is integral to the driveshaft on this vehicle; the front and rear yokes are already phased in the same plane from the factory, so no separate front-yoke mark is needed. These marks ensure correct phasing during reassembly. The driveshaft must be installed in the exact same orientation to maintain factory balance.
2. 2

   Remove rear U-joint straps
   At the rear axle pinion yoke, remove the U-joint retaining hardware using a 9/16" socket. The 1972 F-100 typically uses either two U-bolts (4 nuts total) or two straps (4 bolts total) at the rear. Support the driveshaft with one hand while removing the final fasteners. Retain all hardware if reusable, though new grade 8 hardware is recommended. Support the driveshaft with one hand while removing the final fasteners. Retain all hardware if reusable, though new grade 8 hardware is recommended. Verified detail (Rear U-bolt nut size on this application is commonly not 9/16"; U-bolt nuts are frequently 1/2" or 7/16" hex. Socket size should be verified against the actual retainer type (U-bolts vs straps).): At the rear axle pinion yoke, remove the 4 U-bolt nuts (verify socket size — commonly 1/2" or 9/16") retaining the bearing caps. Verified detail (This waffles between two retainer types. The 1972 F-100 rear pinion yoke typically uses U-bolt-and-nut retainers (2 U-bolts, 4 nuts), not strap-and-bolt. The parts list specifying 8 strap bolts/nuts and this step's '4 strap bolts' should be verified against the actual U-bolt configuration.): The 1972 F-100 rear pinion yoke typically uses two U-bolts with four nuts retaining the bearing caps. Remove the 4 nuts using the correct socket size.
3. 3

   Separate rear U-joint from axle
   Carefully lower the rear of the driveshaft, separating the U-joint caps from the pinion yoke. If tight, use a pry bar gently between the yoke and strap. Keep the driveshaft supported to prevent it from dropping suddenly.
4. 4

   Slide driveshaft rearward and remove
   Slide the driveshaft rearward approximately 2-3 inches to disengage the front slip yoke from the transmission output shaft. Lower the rear of the driveshaft and pull it rearward and downward to clear the transmission. The slip yoke will come out with the driveshaft. Place shop rags in the transmission extension housing to catch fluid that may drip out when the slip yoke is removed.
5. 5

   Secure driveshaft for bench work
   Clamp the driveshaft tube in a bench vise with soft jaws, or securely on a workbench. Do not clamp on the slip yoke or U-joint bodies. Position the U-joint to be replaced at an accessible angle.
6. 6

   Remove U-joint snap rings
   Using needle nose pliers, remove the snap rings from all 4 bearing cap grooves in the yoke. If internal snap rings are used, they will be inside the yoke bore. If external, they will be visible on the outside face of the yoke. Clean the snap ring grooves with a wire brush if corroded. Note: 1972 Ford driveshaft U-joints on this application typically use external snap rings; verify your retainer type before removal.
7. 7

   Press out first bearing cap
   Position a C-clamp or U-joint press tool across the yoke so that one jaw contacts one bearing cap and the other jaw contacts the opposite yoke ear (not the opposite bearing cap). Tighten the clamp to press the bearing cap out the opposite side. The cap should protrude enough to grip with pliers or continue pressing until it can be removed. If using a hammer method, support one side of the yoke and strike the opposite yoke ear to drive the cap out.
8. 8

   Remove remaining bearing caps
   Grip the protruding bearing cap with pliers and pull it completely out. Rotate the driveshaft and press or drive out the opposite bearing cap. Once both caps are removed from one axis, the U-joint cross can be tilted and removed from the yoke. Repeat the process for the remaining two bearing caps if removing both U-joints. Inspect the yoke bores for wear, burrs, or damage.
9. 9

   Clean yoke bores
   Thoroughly clean all bearing cap bores in the yokes using a wire brush and shop rags. Remove any rust, old grease, or debris. Inspect for gouges or excessive wear. The bores must be smooth and clean for proper new U-joint installation.
10. 10

    Prepare new U-joints
    Remove new U-joints from packaging carefully to avoid dislodging needle bearings. If the U-joint has a grease fitting, ensure it is properly threaded. Some replacement U-joints come with one bearing cap loose or removed—reinsert it carefully, ensuring all needle bearings are in place around the bearing cap journal.
11. 11

    Install new U-joint cross into yoke
    Remove one bearing cap from the new U-joint cross (keep track of the needle bearings). Insert the U-joint cross into the yoke from one side. Align the cross journal with the yoke bore and carefully start one bearing cap by hand, ensuring it engages the cross journal squarely and the needle bearings do not fall out of position.
12. 12

    Press first bearing cap into place
    Using the C-clamp or press tool, carefully press the bearing cap into the yoke bore. Press until the cap is flush with the snap ring groove. Do not over-press, which can damage the cross or bearings. Check that the cross rotates freely as you press—binding indicates misaligned needles.
13. 13

    Install opposite bearing cap
    With the first cap partially installed, insert the opposite bearing cap onto the protruding cross journal from the other side of the yoke. Align carefully and press into place until flush with the snap ring groove. The cross should now be centered in the yoke with both caps at equal depth.
14. 14

    Install snap rings
    Install new snap rings (usually provided with replacement U-joints) into the grooves on both bearing caps. Ensure snap rings are fully seated in their grooves. Tug on each bearing cap to verify the snap ring is holding it securely.
15. 15

    Install second U-joint
    Repeat steps 11-14 for the second U-joint (either at the other end of the driveshaft or at the slip yoke end, depending on which U-joints are being replaced). Ensure the yoke alignment is correct for proper driveshaft phasing.
16. 16

    Lubricate U-joints
    If the new U-joints have grease fittings, use a grease gun to pump chassis grease into each fitting until grease appears at all four bearing cap seals. This ensures proper initial lubrication. Wipe away excess grease.
17. 17

    Reinstall driveshaft to transmission
    From under the vehicle, slide the front slip yoke into the transmission extension housing, aligning the splines. Push forward until fully seated. The slip yoke should slide in approximately 2-3 inches. Verify your phasing marks are still visible and correctly oriented.
18. 18

    Connect rear U-joint to axle yoke
    Raise the rear of the driveshaft and align the rear U-joint bearing caps with the holes in the pinion yoke. Ensure the phasing marks you made in Step 1 are aligned. The bearing caps should seat fully into the yoke.
19. 19

    Install rear U-joint straps and hardware
    Install the U-joint straps over the bearing caps and start all 4 bolts by hand. Ensure the straps are centered on the bearing caps. Tighten the strap bolts in a cross pattern to secure the U-joint evenly. Since no torque specification is available, tighten bolts firmly (typically 30-35 ft-lbs for 3/8" grade 8 hardware on this application). Verified detail (The Ford U-bolt nut torque for this era driveshaft is typically higher than 26.0 lb-ft (35.0 Nm) (commonly around 14-20 ft-lbs for U-bolt nuts on this rear joint, and strap bolts can differ). The stated range is a guess and should be verified against factory spec; presenting it as typical could under-torque the fasteners.): Since a verified factory torque specification should be consulted, tighten U-bolt nuts/strap bolts to the manufacturer's spec (commonly in the 14-20 ft-lbs range for this rear joint — verify before final assembly).
20. 20

    Verify driveshaft installation
    Rotate the driveshaft by hand through several complete revolutions. It should rotate smoothly with no binding, clicking, or rough spots. Check that all snap rings are secure and no bearing caps have shifted. Verify phasing marks are aligned.

Reassembly

1. Double-check that all U-joint strap bolts are tight and properly torqued
2. Verify driveshaft phasing marks are aligned as marked during disassembly
3. Check transmission fluid level and top off if necessary (Type F ATF)
4. Remove jack stands and lower vehicle to ground

Verification

• Start engine and place transmission in gear (with parking brake engaged), listen for abnormal noises from driveline
• Test drive vehicle at various speeds, confirming no vibration, clunking, or binding during acceleration or deceleration
• Check for any unusual vibration at highway speeds (55-65 mph)—vibration indicates phasing error or balance issue
• After 50-100 miles, re-inspect U-joint strap bolts for proper tightness
• If U-joints have grease fittings, add grease after first 500 miles and at regular service intervals

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