Working on the little gray truck, Tuffy II

                                                                Rear Axle Clock

The main purpose for clocking the rear axle is to gain a little ground clearance, and get the u-joint away from the rocks.

I also hope to reduce a driveline vibration.

  After the Marlin 4" Spring swap, I noticed a severe vibration at highway speed. I presumed it was because of the increased angle at the u-joint, created by the extra lift gained with the springs. This shot of the u-joint, at the transfer-case output flange, shows the angle of the driveshaft.

  This shot shows the angle of the driveshaft, at the u-joint connected to the pinion flange. I hope clocking the rear, will eliminate the vibration by decreasing the angle that the driveshaft has to operate at.

       I wanted to just pull the axle, cut the old perches off, and weld on the new ones, but I didn't want to take the chance of melting the axle seals. So...first step in the process...drain the lube.

While that was draining, I pulled the bolts holding the driveshaft on. I'm pulling the axle completely out of the truck and stripping it bare, so everything has to come off.

   The brake lines are disconnected. I hung a coffee can to catch the steady drip of brake fluid.

  The shocks will have to come off.

  This job is made a lot easier, because I don't have rear drum brakes on Tuffy II. One of the earlier modifications was building the '86-'95 rear axle. Part of that build included a rear disc brake conversion from TSM.

Just unbolt and pull the calipers. Then the rotors slip right off.

  The adapter bracket unbolts from the axle flange.

From the  drivers' side, the caliper has been removed and the rotor is being taken off.

Here you can see the adapter still bolted on to the axle. The bolts holding it on also hold the rear axle bearing housing to the end of the axle tube.

After removing the bolts, the adapter comes off...

  and, from the passenger side now, the axle assembly slide out.

Here is a good shot of the rear axle seal. I want to preserve these, I don't have  replacements, so I'm not going to pull it. I hope my welding doesn't hurt it. I don't think it will.

OK, I've got the u-bolts holding the axle to the springs removed .

Here's the pile of parts. Imagine if I had drum brakes?

      It will be easier handling the axle with the differential  removed, but the blue silicone RV sealant is holding the assembly together.

Here it is.

With the axle out, I can work on separating the diff housing from the axle housing.

     I hammered a putty knife in between the two pieces and carefully separated them.

Now I can start to remove the old spring perches. The shock mounting brackets will also have to be relocated .

Here are the new spring perches. I bought them a while ago, form Marlin Crawler. I will use one of the offset holes to move the axle forward. Notice the new perch is longer for more support of the spring pack.

     I don't have a torch, so I tackled the job with my trusty Harbor Freight nose saw and grinder.

This is a long and noisy process.

Sawzall and grinder.

    A little while later, a nice clean job.

Time to put these to good use.

The best way to tell where they should weld on; mock it up. I want to make sure I center the axle and clock it as close to 'just right' as I can. The jack stands are keeping the springs from drooping. I have taller ones supporting the truck at the frame. The floorjack is holding the axle in place.

  With a CV joint at the output flange of the transfer-case, I want to point the pinion directly at it under load.  I'm applying the science of estimated guesswork to determine the correct positioning.

When I'm happy with it, it's time to weld it. Looks like my seal is going to hold up to the heat o.k.

Because I'm moving the axle forward, I need to do a little modification to the u-bolt plate.

With the axle moved forward, the spring pin falls in the rear offset hole of the newly welded on spring perch. Modifying the hole in the plate, allows the u-bolts and plate to sit square over the axle tube.

I wanted to shorten my wheelbase to be within W.E. Rock specs. They allow up to 3" from stock. Mine was at 115.5 inches, while the stock wheelbase for this truck was 112.2".

I was outside the specs by less than 1/4 inch. Now I should be within specs. I haven't measured yet, but I think the offset holes in the new perches are about 1 inch apart, so I should be at 114.5 now.

  It's not pretty, but this stuff will seal the diff housing to the mounting surface and keep the lube in the axle.     No leaks.

The V6 rear diff housing is bolted back in.

The driveshaft is back on. You can tell the angle is better already.

The rear axle is in and caliper bracket is bolted on. The brake rotor is in place and the u-bolts are set in place.

Before I get to far, I want to weld the shock tabs back on in their new position. Using the handle of the wire brush as a spacer, the gas pressure shocks hold the brackets right where I want them.

After tacking, I pulled the shocks back out, ( I didn't want to melt the bushings), and finished the welding.  Here you can see the brake line going back in too.

The brake line needs to be re-fit, because the tabs holding the ends had to be re-mounted. The old perches had them welded to them, so after I cut them off, the little tabs needed a new mounting place.

Here they are, welded to the back of the new spring perches.

Shocks are bolted back in place. These are gas pressure shocks, folks. They are a bear to position. They want to be fully extended.

The brake lines are run, the wheels are back on and the u-bolts are tightened.

I may have over-clocked it a bit, but after the test run, the springs settled and it looks great. Oh yeah, and the vibration is gone!

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