replace idler wheels

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Bogies or idler wheels are little parts that do important work. A slide-rail idler wheel rides on top of the track to help ease the friction between the track and hyfax, particularly at high pressure points along the rail. The rear-most idler wheels, or rear axle wheels provide the main turning point for the track and also provide track tension and alignment. The upper idlers guide the track up over the rear skid frame mount and also provide a guide route for the track to meet the drivers. All these little functions come together for the larger purpose of allowing the track to rotate easily.

A sled can go thousands of miles - depending on your riding style and conditions - before its idler wheels start showing signs of wear. Poor storage conditions also can shorten bearing and wheel life, and when the bearing seizes - the wheel stops spinning - track damage begins.

If the bearing fails and comes apart, the wheel will spin and bounce on the shaft and cause damage to skidframe components. If this happens on a rear axle wheel or upper idler, the track can become misaligned, the track clips will then tear up the hyfax or get stripped off and suspension components damage the track.

If a rail idler wheel fails, the track will ride only on the hyfax and cause shaft damage and possible skidframe damage. The track can become misaligned and lead to more problems, the least being excessive hyfax wear. Furthermore, a seized bearing steals horsepower.

Maintenance
Checking and maintaining the idlers is fairly simple. First, release the track tension and spin the wheel while listening and feeling for any growling, or just move the wheel from side to side checking for slop in the bearing. You often can replace the bearing in most idlers instead of buying an entire wheel/bearing assembly.

To remove idler wheels, place the snowmobile on a sled lift, rear end on a jack stand or roll the sled on its side. If you put the sled on its side, make sure the oil, fuel and radiator caps are tight. Then, most slide rail idlers can easily be unbolted, removed and replaced.

If replacing a rear axle idler wheel, loosen the rear axle bolts and the alignment bolts. Placing a mark on the slide rail at the alignment bolt's head or measuring its position will speed reassembly. Next, remove the rear axle bolts and the idler wheel. If an inner wheel needs replacing the axle needs to be removed.

If replacing an upper idler, release the track tension as above. Then remove rear skid mount bolts and swing the suspension out from the tunnel. The idler can then be slid from the shaft. Finally, reinstall idlers and skid frame components and tighten track to original settings and check alignment per the owner's manual.

If a wheel starts to seize while you're in the hills or on the trail, swapping idler wheels around is a good get-you-home measure. However, the upper idler bearings are smaller than the axle idlers or slide rail idlers for some manufacturers. You can swap the outer axle idler for a center. If snow is good it's no problem to run without a few slide rail idler wheels.

Hyfax replacement
With the advent of bigger-lugged tracks and the growing necessity to ride in substandard conditions, the hyfax on today's sleds risk damage from melting.

Hyfax, made of UHMW plastic (the same compound used for composite skis), heats with the friction of the track clips. If you spend miles on tightly packed or icy trails, consider buying ice scratchers for your sled. These skidframe mounted metal pieces dig into the hard packed snow and ice and spray the hyfax with much needed water. Ice scratchers are made of sprung steel, and are coiled like a spring to press into the snow. Once used mostly for mountain applications, they are catching on in the Midwest now.

Before you fire up your sled for an outing, inspect the hyfax, especially where it meets the track near the front of the skid at its attack angle. If the hyfax wears through, the track clips will wear on the rail assembly, and then you're headed to the nearest repair shop. Instead, take an hour to replace a set of hyfax.

First, measure the track window's width and the hyfax width. If the window is wider than the hyfax, you can easily slide the hyfax back through the window at the rear axle. If the hyfax is wider than the window, you will have to remove part of the rear suspension.

Idler wheel bearing replacement
1. Remove designated idler wheel from rear suspension skidframe.
2. With a snap ring puller, remove the bearing's snap ring.
3. If using a bearing puller, remove bearing.
4. If no bearing puller is available, place the idler wheel on top of an opened vise (opened wide enough to expose bearing and race).
5. Using a socket or round bar, drive the bearing out by the inner bearing race.
6. With the bearing removed, inspect C-clip groove for improper wear or damage.
7. Clean the idler wheel with a cleaning solvent.
8. Set the new bearing on top of the idler wheel and tap into place using a bearing driver, socket or pipe that is the same size as the outer race. Driving the bearing on the inner will damage the bearing's roller surfaces.
9. Reinstall C-clip on bearing. Ensure C-clip is secured in its groove.
10. Return idler wheel to skidframe and secure.
Note: Bearings are not proprietary and can be picked up at almost any bearing shop if a dealer isn't available.

Hyfax: Track window
1. Lay the snowmobile on its side.
2. Loosen the track tensioning bolts and lock nut at the rear of the skid.
3. Remove the hyfax mounting screw at the slide rail's front.
4. With a strong effort, pull the old hyfax out through the track window. You may need a hyfax removal tool or pliers to grip the old hyfax to slide it out. More ingenious actions may be needed if the old hyfax is hung up on a burr on the rail, or if it's cemented to the rail with dirt and grime. One way to get a stubborn hyfax off the rail is to drive a screwdriver into the side of the hyfax at a 45-degree angle, just deep enough so as not to hit the rails. Then, pound the hyfax toward the rear axle.
5. With the old hyfax removed, align and slide the new hyfax onto the slide rail.
6. Tighten the front hyfax mounting screw.
7. Check track alignment and make necessary alignment and tension adjustments.
8. Tighten the tension bolts and lock nut.

Hyfax: Partial suspension removal
1. Lay the snowmobile on its side.
2. Loosen the track tensioning bolts and lock nut.
3. Remove the rear suspension rear mounting bolt.
4. Remove the hyfax mounting screw located at the front of the slide rail.
5. Swing the skidframe out of the tunnel.
6. Pull up on the skidframe's rear, out from the track, just enough to expose the hyfax.
7. Pull the old hyfax off the slide and replace it with the new hyfax.
8. Slide the suspension back through the track.
9. Replace the hyfax mounting bolt.
10. Replace the rear suspension rear mounting bolts to the skidframe and tunnel.
11. Align the track and adjust the tension.
12. Tighten the track tensioning bolts and lock nut.