with Bill Johnston
KAM Selectable Electric LockerPart 1 - Installation
A few years back, when I first looked into the different lockers that were available for a Samurai, I came across a company that built one designed to be either cable or air actuated. I never got a chance to see one in person, but it sounded interesting. Well, that same company, KAM Differentials Ltd., has redesigned their locker and made it electric! There is no longer a requirement for an on board air system or a mechanical cable system - just a switch in the dash.
The first unit destined for the US (of the new design) was delivered to us to install and test. We will be reporting its performance on the kinds of trails not seen in the UK. Yes folks, it is destined to hit the rocks of Las Cruces and the surrounding areas to test its capabilities. But first we have to install it.
This month we go through the installation of the locker components into the differential and the modifications that must be done to the axle housing. The locker is installed in four steps. First we have to prepare the housing, the new axle shafts, the differential and then finish up with final assembly and testing.
The Axle Housing
Ok, first question: If we are adding a locker, why are we looking at the rear of an axle housing? The pieces that make it an electric locker have to go somewhere, and with the the housing built only to house the gears - it has to grow (and be easy to access).
*Important Note*Before starting, make sure the housing is 100% straight, as the locker will bind if the housing does not allow the axle shaft to enter the differential at a perfect 90 degree angle.
We start by removing the rear 'dish'. This is easily done with a cutoff wheel or a reciprocating saw. We used both. The cutoff wheel made the initial cuts and the 'sawz-all' did the rest. Be sure to cut just above the factory weld. This assures that you don't go too deep and that you have something to work with when making sure the finished cut is flat. This should leave a weld height of about 2mm. Using the new mounting ring as a flat surface to gauge off of, make sure that it fits flush and even. The larger diameter cuts should line up fit perfectly with the inner edge of the housing. Cleaning up the long side tube where the bracket will sit will give you a clean surface to mark for the cuts in the material that will have to be removed. This section will be strengthened by the new bracket, so no worries there. Again, using a cutoff wheel or reciprocating saw, cut out the section marked above. Clean up the sharp edges. When finished, again use the mounting ring to check to see that the openings match. The instructions (which were unusually clear and concise) gave us the option to apply the supplied Loctite 598 gasket material before OR after welding. We did it before we tacked the mounting ring in place. Taking it to a friends shop, we MIG welded the ring into place. Be sure not to do one continuous weld, as the heat can bend the housing and make it unusable. If you are new to welding, take it to a shop that can be trusted.
KAM is also working on a 'glue' that will allow you to attach the ring without welding. You would then need a grinder to remove the ring if the placement is off... This is the same material that they use to attach railway cars to their chassis, so it sounds pretty strong!
The finished weld should make a leak-proof seal all around the ring. This is very important if you want to retain oil and not make a puddle in the driveway... To the right you can see the finished housing, painted and ready.
The Axle Shafts
The KAM locker comes with a new set of axle shafts. These have been tested to be 40% stronger than stock axle shafts. You can also see the thicker, splined section in the short shaft that is a key part of the mechanism. Bearings, retainers and seals are also included in the kit. But one thing you will notice right away is that the bearings look a little different. While Suzuki stopped importing the Samurai style vehicle to the US, the rest of the world has seen improvements in the components. The new bearing incorporates the spacer into its design. In the photo on the left you can see the bearings (old style on the left with the spacer, new style on the right).
In the differential, we have to replace the end cap on the carrier with a new locking flange. So the first thing will be to remove the carrier from the differential. Here you can see the new flange next to the end that we are going to be working with. If you have new bearings you want to install, now is the time to do it. Removing the 8 stock bolts is all it takes to remove the cap. There may be thrust washers under the end cap, if so, make sure you put them back into the carrier. The flange is a direct replacement for the end cap. Torque the new socket head cap screws to factory specs and install the bearing. Loctite is also included to keep the screws from doing something stupid later on. The carrier is then installed back into the differential. You will need to set up the ring and pinion with the correct backlash, so don't just bolt it together and call it 'good'. You will be using a new (replacement) bearing adjuster. Look closely at the photo on the left and you will see that the inside diameter of the bearing adjuster ring has been clearanced to allow the sliding dog to fit into the carrier, over the new locking flange. When locked into place, this will lock the carrier to the splined short axle shaft to essentially turn the carrier into a spool. The fact that it is engaged only when you need it (turning it on) makes it a selectable locker. Final Assembly Next we put it all together. We used the same Loctite 598 gasket sealer to assure a leak-proof connection between the diff and the housing. You can see on the right where we have positioned the short axle shaft into the tube far enough to rest the sliding dog in place. What you don't see underneath is the actuator fork that slides over the dog before it is installed. You will see it again when we flip over the housing. Just make sure the sliding dog and axle shaft are out of the way before sliding the differential into place. The differential has to be seated and torqued down before continueing. When you turn over the housing, check to see that the differential fits into the ring like a key. Now, don't all those cutouts make sense? Once the position has been triple checked, wipe the excess sealant off the differential connection surface. After seating the axle shafts in place, you get to see how it all works. Here you can see the actuator fork and how it moves the sliding dog along the axle shaft and seats into the locking flange. We now start to assemble the solenoid bracket and the warning lamp micro switch. The solenoid assembly gets bolted in next. The wiring threads through the new diff cover and gets hooked up according to the instructions. Nothing hard there, just make sure the wires are tied down so they don't get chewed up in the ring gear. This is where we hooked up the electrical to a battery to test everything out. The locker is designed to engage in 0.8 of a second. The paper gasket is set into place under the cover and bolted down using the 16 stainless steel socket head cap screws provided. The new oil filler plug is now on the left.
KAM is also looking at releasing a Heavy Duty Alloy Diff Pan / Diff Guard and a Heavy Duty Rock Slider / Diff Guard. Come back next month to see us bolt it to a Samurai and hit the rocks!
Kam Differentials isn't just a name, they DO specialize in differentials. They are working on a Limited Slip Differential (LSD) for the Samurai. The new LSD will be fully compatible with the electric locker, so you can install either - or both! It is currently under development and should be released in 4-6 months. Manufacturer: