Quote:
Originally Posted by Kilgore Trout I do not understand how you can use a beam torque wrench to measure rotational torque? |
The pinion nut is not itself torqued to a specification. Instead, it is tightened until there is a slight "pre-load" on the pinion bearings. The crush sleeve provides the tension to keep everything in place. The rotational resistance within the bearings offers a way to measure the pre-load.
The specification is 16-29 inch pounds for new bearings and 8-14 inch pounds for used bearings.
Basically place a socket on the pinion nut. In all likelihood the socket will be a half inch drive. Get two converters to step down to ¼” drive. Get a beam style torque wrench such as the following:
KD Tools 2955 1/4" Dr Fixed Beam-Type Torque Wrench 0 to 60 In/Lb KDT2955
Use the torque wrench to rotate the pinion in the normal direction of travel (clock wise) and watch the torque required to maintain rotation. Do not use the initial break away value. This is the pre-load.
Tighten the pinion nut until the pre-load is within specification. Be warned. When it is close, it does not take much turning to raise the pre-load. Do not back off of the pinion nut to reduce pre-load. The factory crush sleeve is a one use device. Get a new one. Even from Ford they are not expensive.
If the pre-load is too high, it will wear out the pinion bearings prematurely. If the pre-load is too low, the rear-end will make noise. It will also wear the contact surfaces of the ring/pinion gears as well as shot pen the bearing surfaces from the constant in/out every time the driveline goes from power to coast.
Therefore, if the pinion can be moved in and out by hand, there is NO pre-load. Note, the pre-load should be measured with the brakes removed.
I found it very difficult to measure pre-load while the axle was on the car (no service lift). At best, only 180 degrees of rotation is possible. This is where having the rear end off of the car helps. It is very easy to spin the pinion around several turns and get a good reading from the torque wrench.
I was also suprised to experience what 20 inch pounds feels like. With new bearings, the pinion feels harder to turn by hand than I would have expected. I would have gotten wrong without a torque wrench. I suspect, it will feel more normal after the bearings wear in a little.
If your intent is to re-use a crush sleeve (such as replacing only the pinion seal), the pinion pre-load needs to be measured before tear down. Reset the pre-load to the recorded value or GREATER (within the spec).
My first attempt to do this job did not go so well. I couldn't get a good reading working under the car. I don't believe I got the pre-load correct. A few months later, the rear-end started making noise. During a 2nd tear down, I could not find what was wrong. Ended up taking to a pro for rebuild. I am hoping to have better results on this attempt (different car).
I have not tried to rebuild the T-LOK clutches.