How To Center Your Engine

Description

This page describes the procedure for engine centering. It is important that you do this if you ever remove your engine or replace an engine mount.

Symptoms

If you have broken an axle (axle twisted off or inner CV joint flew apart), then it is likely that the engine is not properly centered or the K-frame is misaligned. The inner CV joint is designed to slide in and out as the suspension moves up and down. The further down the control arm goes, the further "stretched" the CV joint gets. The inner joint is spring-loaded to keep a constant force on the outer CV joint. If the engine is not centered, the inner CV joint on one side will extend further out than the other side. If the engine is off center enough and the suspension on the side of the over-extended CV joint gets low enough, the tripod bearings inside the joint can jump out of the joint body. When this happens, you will either throw the axle, or the axle will suddenly seize.

Procedure

The procedure is fairly straight forward. Here it is:

With the vehicle on the ground, loosen the lug nuts on the two front wheels.
Jack the front of the vehicle up, place it on jack stands, and remove the front wheels.
You now need to remove the spindle nuts from the shaft. Remove the cotter pin, nut retainer, and spring. If you have an impact wrench, use it to remove the nuts and skip over the next step.
Put two lug nuts back on two studs that are next to each other. Use a long pry bar or a pipe to lock the hub in place by wedging the bar between the two lug nuts, or a lug nut and the inner part of the hub, and resting the other end on the ground. You want to do this so that the hub does not rotate counter-clockwise. Use a 32mm (1-1/4" works too) socket and a breaker bar to break the nut loose. This can take a lot of force, so be prepared.
Remove the hub centers or center caps (if you have them) from the wheels, bolt them back on, and drop the vehicle back down.
Use a socket wrench or a large screw driver to push on the axles through the wheels. If you apply enough force, the axle should spring in and back out. Measure the amount that you can push the axles in on each side. They should be about 5/8" on each side. If they are not equal, loosen the front and right-side engine mount bolts and pry the engine over with a long piece of wood and tighten the mounts. You want each side to be with 1/8" of each other
If you could not get the axles to move, jack the vehicle up part way. Make sure you are raising the vehicle evenly by measuring the distance from the frame to the floor on each side. Repeat the above step. The total amount of movement will increase, the further you raise the vehicle.
If your engine is now centered, tighten all engine mount bolts and raise the vehicle back up.
Remove the wheels and put the spindle nut, spring, retainer, and cotter pin back on. Be sure to torque the spindle nut to 180 ft/lbs (245 N*m).
Reattach the wheels, drop the vehicle, and tighten the lug nuts.

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Updated 10/31/2003.