How to Do an Axle Swap on an S10 Blazer

The S-10 Blazer had a pretty good run, with models built from the mid '80s until 2004, and there are a lot of different variants out there, from four-wheel drive to prerunners (two-wheel drive trucks with a four-wheel drive suspension and axle) and everything in between. If you have a problem with your rear axle, such as a broken pinion or axle shaft, sometimes swapping out the whole assembly with a used one is cheaper than repairing just the broken piece. It's not a fun job, but it can be done in just a few hours with some hand tools.

Things You'll Need

• Replacement axle assembly
• Wheel chocks
• Jack
• Jack stands
• Brake line wrenches
• Tire iron
• Open-end wrench set
• Brake fluid
• Assistant
• 1/2-inch ratchet and sockets

Instructions

1. Place the wheel chocks in front of the front wheels. Lift up the rear of the vehicle using the jack and place the frame and axle on jack stands. Make sure the vehicle is secure on the stands before you crawl underneath it. Then remove the rear wheels using the tire iron and place them to the side.

2. Disconnect the brake line that runs from the frame of the truck to the rear axle using the brake line wrenches.

3. Unbolt the u-bolts that secure the axle to the leaf springs using the 1/2-inch ratchet and sockets.

4. Unbolt the driveshaft from the axle using the open-end wrench set. There are two straps that hold the u-joint to the axle, and they're held on by bolts. undoing these will let you push the spindle into the transmission just a little bit and allow you to place the driveshaft on the ground.

5. Place the jack underneath the differential and jack it up to lift it off of the stands. Pull back on the jack, and once the axle is free of the jack stands, lower the jack. Pull the axle assembly back, using the jack as a set of casters. Set the assembly to the side, and set the new one on the jack. Then push the new assembly under the frame and set it on the jack stands, in the same manner you removed the old axle.

6. Secure the leaf springs to the axle using the u-bolts and the 1/2-inch ratchet and sockets. There is a hole on the axle that lines up with a bolt in the center of the leaf spring. Make sure the bolt goes in the middle of the hole on the axle, to be sure it's aligned correctly.

7. Bolt the driveshaft back to the axle using an open-end wrench and the straps that you removed in step 4. Reconnect the brake line to the brake lines on the axle using the brake line wrenches.

8. You're going to need to bleed the rear brakes. Pop the hood on the truck and add brake fluid to the master cylinder. Then have an assistant sit in the driver's seat with his foot on the brake, but not pressing down yet. Locate the bleeder screw on the rear of the brake drum. This is a screw with a pointed end and a little ball on the inside of a tip. Turn the screw counter-clockwise with the open end wrench and have your assistant press on the brake pedal. At first, air will come out of the bleeder. As each pump of the pedal slows, tighten the screw back up, then open it again when your assistant has pressure on the pedal. Repeat this until the brake fluid comes out clear and without bubbles. Repeat the process for the other wheel, and top off the master cylinder with brake fluid again.

9. Reinstall the wheels on the vehicle using the tire iron, then lift the vehicle off of the jack stands and place it on the ground.