drivetrain

CV Boot - Inner

for 2021 Ford F-150 3.5L V6 EcoBoost · 4WD

Difficulty

Advanced

Time

1.8 h

Tools

Steps

This procedure covers the replacement of the inner CV boot on a 2021-2024 Ford F-150 with 3.5L EcoBoost RWD, requiring removal of the driveshaft from the differential and separation of the CV joint to access and replace the inner boot.

Warnings

⚠RWD F-150 uses a traditional driveshaft, not independent rear axles with CV joints like AWD models. Verify your vehicle configuration before proceeding.

⚠️Never work under a vehicle supported only by a jack. Always use jack stands rated for the vehicle weight.

⚠Mark all component orientations before disassembly to ensure proper phasing during reassembly and prevent driveline vibration.

ℹ️This procedure assumes a two-piece driveshaft with center support bearing. Single-piece driveshafts may have different removal requirements.

Tools required

Floor jack and jack standsEssential

Torque wrench (0-300 Nm range)Essential

Socket set including 13mm, 15mm, 18mm, 21mm, 36mmEssential

CV boot clamp pliers or boot clamp toolEssential

Pry bar or large flathead screwdriverEssential

Paint marker or chalk

Drain pan (if differential service required)

Wire brush

Brake cleaner

CV joint grease (included with boot kit)Essential

Snap ring pliersEssential

Rubber mallet

Parts

Inner CV boot kit with clamps and grease × 1 — Use OEM specification
Differential cover gasket (if seal is damaged) × 1 — Use OEM specification

Fluids

Motorcraft 75W-140 Synthetic Gear Oil — 2 qt

Preparation

Park vehicle on level surface and engage parking brake
Chock front wheels securely
Raise rear of vehicle and support on jack stands at frame rails
Remove rear wheels to provide working clearance if needed
Inspect driveshaft configuration and identify inner CV joint location (typically at transfer case end on AWD, or center carrier bearing joint)

Procedure

1
Mark driveshaft alignment
Use paint marker to mark the relationship between the driveshaft yoke and the differential pinion flange, and between all driveshaft sections. This ensures proper phasing during reinstallation to prevent vibration.
2
Support driveshaft
Place a jack or support under the center section of the driveshaft to prevent it from dropping when fasteners are removed. Support the weight but do not apply upward pressure.
3
Remove rear driveshaft mounting bolts
Remove the four bolts connecting the rear driveshaft flange to the differential pinion flange. Use a pry bar to hold the driveshaft from rotating while loosening bolts. Keep bolts organized for reinstallation.
⚠Driveshaft will become loose once all bolts are removed. Ensure support is in place.
Torque spec
Driveshaft Bolts85 Nm (63 lb-ft)
4
Remove center support bearing bolts
Locate the center support bearing mounted to the vehicle crossmember or frame. Remove the mounting bolts while supporting the driveshaft. Note the orientation of any shims or spacers present.
Torque spec
Mounting Bolts31 Nm (23 lb-ft)
5
Remove driveshaft from transmission or transfer case
Slide the front section of the driveshaft rearward to disengage the slip yoke from the transmission or transfer case output shaft. Lower the entire driveshaft assembly carefully and place on clean work surface. Have a drain pan ready as some fluid may drip from the output shaft.
⚠Mark the slip yoke position before removal to maintain proper installation depth.
6
Inspect and identify inner CV joint
With driveshaft removed, locate the inner CV joint (typically where the slip yoke connects to the center section or at a double cardan joint). Clean the area thoroughly with brake cleaner to remove dirt and old grease.
7
Remove old boot clamps
Using boot clamp pliers or cutting carefully with side cutters, remove both clamps securing the inner CV boot (one at the joint end, one at the shaft end). Discard old clamps.
8
Slide boot away and clean joint
Slide the old boot down the shaft away from the CV joint. Wipe away old grease from the joint and inspect for wear, pitting, or damage. Clean the joint housing and balls thoroughly with brake cleaner and allow to dry.
9
Remove CV joint retaining mechanism
Locate the snap ring, circlip, or retaining mechanism holding the CV joint onto the shaft. Use snap ring pliers to remove it. Some joints may require the joint to be separated at a specific angle or position. Note the orientation of all components.
⚠CV joint components are precisely matched. Do not mix balls or components between joints.
10
Remove old boot and inspect shaft
Slide the old boot completely off the shaft. Inspect the shaft surface for grooves, rust, or damage where the boot seals. Clean the shaft thoroughly and lightly sand any minor surface rust with fine sandpaper.
11
Install new boot and clamps
Slide the new boot onto the shaft with the small end first. Position the small clamp on the boot but do not tighten yet. Ensure the boot is properly oriented according to kit instructions.
12
Reinstall CV joint
Pack the CV joint housing with the grease provided in the boot kit (typically 50% of supplied grease goes in the housing). Reinstall the CV joint onto the shaft, ensuring it seats fully. Install the retaining snap ring or circlip securely.
13
Pack boot and secure clamps
Add the remaining grease from the kit into the boot. Position the boot over the CV joint housing ensuring it seats properly in the grooves at both ends. Remove any air pockets by burping the boot. Install and tighten both boot clamps using the appropriate tool, starting with the small end first.
ℹ️Boot must not be twisted and should have slight expansion room to flex during operation.
14
Reinstall driveshaft assembly
Raise the driveshaft assembly into position. Insert the slip yoke into the transmission or transfer case output shaft, aligning to the depth mark made during removal. Install the center support bearing to the crossmember using mounting bolts and any original shims.
Torque spec
Mounting Bolts31 Nm (23 lb-ft)
15
Connect driveshaft to differential
Align the marks made during disassembly between the driveshaft flange and differential pinion flange. Install all four bolts and torque in a cross pattern to specification.
Torque spec
Driveshaft Bolts85 Nm (63 lb-ft)
16
Final inspection and wheel installation
Check that all fasteners are torqued properly and no tools or parts are left under the vehicle. Reinstall rear wheels if removed and torque lug nuts in a star pattern. Top off transmission or transfer case fluid if significant loss occurred.
Torque spec
Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

Ensure all alignment marks are properly matched to prevent driveline vibration
Verify center support bearing is mounted with original orientation and any shims are in place
Check that CV boot is not twisted and is properly seated in both grooves
Confirm all boot clamps are tight and secure with no gaps

Verification

Lower vehicle and start engine with transmission in neutral or park
Listen for any unusual noises from the driveline area
Test drive vehicle at various speeds (20-40 mph, then highway speeds) to verify no vibration is present
Inspect CV boot for leaks or movement after test drive
Re-check all driveshaft bolt torque after 50-100 miles of driving