In this episode, Weekend Mechanic Bruce Bonebrake services the front axles on a pickup truck. He explains and examines a failing CV-joint on one of the axles, and installs a new CV-boot kit to give the second axle a longer life. The problem: CV joints are critical in the operation of modern axles. If the boot surrounding the CV joint should become torn, road grime and debris can contaminate the joint and cause it to fail. Ignoring the problem could lead to further damage and become a safety issue. Our project pickup-truck has begun to show symptoms of a torn boot. A rupture in the boot is visible and axle grease is visible on the control-arm and surrounding parts underneath the vehicle. DIY Difficulty Rating for Repair: Although it does require some work beneath the vehicle, this job is not terribly complex. We gave it a difficulty rating of 2 on a 5-point intermediate-level scale. Depending on the nature of the problem, this job might be finished in a single day. Allow yourself a whole weekend, though, to allow for any possible complications. It took us about 10 hours to complete the project.
Important: Included below are the steps in this automotive procedure as shown in the episode. These steps are general guidelines that are applicable to most vehicles. With any particular vehicle, there may be procedures, specifications, settings, tolerances, components, etc. that are specific to that vehicle. There are also variations according to the type and brand of repair-kit you select. Always consult your vehicle's service manual when undertaking significant automotive repairs, and read and follow the manufacturer's directions and precautions that come with your kit or replacement parts. Safety Alert: Always wear eye protection, and follow proper safety precautions, when working beneath a vehicle. Safety Alert: As a standard safety precaution, always disconnect the vehicle's negative battery cable before you begin work on any electrical or mechanical components. In addition to standard auto-mechanic's tools, some of the specialty tools that will be needed for this project include an automatic center-punch and snap-ring pliers.
Examining the CV Joint
- In the term CV joint, "CV" stands for constant velocity. The joint serves to smoothly transfer power from the differential to the wheel at any angle. Our pickup has 40-wheel drive, and independent front suspension.
- The drive axle (figure A) is made up of three fundamental parts -- the inboard joint (that connects to the differential), the axle shaft and the outboard CV joint.
- As the suspension goes up and down, and as the vehicle turns, that axle has to flex (figure B).
- With the truck safely raised, and supported on jack-stands, an assistant holds the brake down as Bruce begins loosening and removing the nuts and bolts that hold the axle onto the differential (figure C).
- Holding down the brake during this procedure keeps the drive axle from moving as the bolts are being loosened. After the first bolt is loosened, the brake is released so that the axle can be turned to access the second bolt. The brake is then held down again. Repeat this process until the final bolt has been loosened (figure D). This will permit the axle to be removed from the vehicle.
- This process is repeated on the other side of the vehicle, before work begins on the outer wheel-side of the axle.
In the segment that follows, the old axles are removed.
RESOURCES :
The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books
Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896
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