how to replace upper and lower arctic cat aarms

What would it be worth to you, to stand in a boxing ring, eyes blindfolded, hands tied behind your back, to take a big-gun right hook smack from Mike Tyson or Evander Holifield? One hit, as hard as the heavyweight boxer can swing. Any takers?

This is what a front suspension faces every time you pile your sled off the trailer and barrel down the trail. Smack, smack, smack, smack.

Cory Foster, owner of TE MotorSports in Teton, Idaho, an Arctic Cat dealer, and service technician, Shawn Davenport, provide the information on swapping out upper and lower A-arms.

To complete this job, have a little patience and possibly a shop manual nearby. It may not hurt to have your telephone's speed dial feature programmed to your favorite Arctic Cat service technician- just in case.

Most A-arm replacements, according to Cory Foster, are from hitting a rock or a stump, very few, if any, are from normal wear or manufacturer defects. He says his dealership completes about eight A-arm replacements a season. Usually replacements are to the lower arm, but if the lower arm received a major tweaking, the upper went to the tweak house also; it too is replaced.

Half of all replacements, Foster says, require a new shock. Davenport adds that an A-arm, when receiving harsh impact energy, will generally twist rather than bend back.

By way of information, the top A-arms are the same for left and right, the lower arms are specific to right and left. This swap out is conducive for ZR, ZL and Mountain Cat sleds. Slight variations are present.

Suggested tools to use are wrenches that are a combination open-end and socket.

1. Elevate sled up a jackstand, Mar-Lift or roll sled over on its side.
Note: If rolling sled on its side, place some carpet on shop floor for hood and belly pan side to rest on.
2. Remove screws holding skid plate.
3. Remove skid plate.
Note: Removing the skid plate is necessary because only one access window exists to remove lower A-arm mounting nut and bolt.
4. Remove all screws off the tie rod boot and all self-tapping torx head screws forward the boot.
5. Remove boot.
6. Remove hood hinge bolt.
7. Remove applicable side bumper bolts/screws.
Note: This allows the repairman to pull the belly pan and bumper up and to the side. This is helpful by allowing the long upper A-arm mounting bolt to slide through and from the bulkhead and belly pan nose, and by the hood hinge and bumper mount. This also prevents removing the whole side panel.
8. Remove shock. Make note of spacer placement and where shock gas charging orifice is positioned, if sled is equipped with a high-pressure gas charged shock.
9. Remove bolts that secure tie rod to the spindle.
10. Remove the two bolts that tie the A-arm to the spindle.
Note 1: This allows the spindle and ski to be removed as one unit.
Note 2: Take note of axle bushings, spacers and washers, and how and where placed. If spacers and washers are not placed in original configurations when the A-arm is reinstalled and tightened, the bulkhead will pinch the A-arm thus hindering the A-arm's up and down movement.

Note 3: Keep track of washers and bushings and keep upper and lower A-arm spacers, bolts, nuts, washers and bushings in separate containers.
11. Remove top A-arm bolt from bulkhead (see also step 7).
12. Remove bottom A-arm bolt.
13. Remove A-arm.
Note: Notice the way the A-arm comes off the sled; this mental note will help in the future when installing the new A-arm.

14. Inspect brass bushings inserted in bulkhead - where A-arm bolts go through - for unusual wear or cracks.
Note: After removing the A-arms, inspect existing components for warping, elongation or cracks. If any of these appear, replace the bushing, bolt or washer.
15. Install in reverse order starting with the lower A-arm, upper A-arm, shock and spindle and ski unit.
Note 1: Do not lubricate bushings and bolts. Bushings are impregnated with petroleum and maintenance free; adding axle grease, for example, will serve as a magnet for dirt.

Note 2: Lower A-arms are positioned in a swept back and swept down view.
Note 3: When reinstalling skid plate, avoid over tightening screws, as this will break the screw heads.

After installing the A-arms, align the front end. To some this may not be necessary. I believe it is.

Before aligning the front end, the track needs proper alignment. Why? A straight edge is laid alongside the track, up to ski tip, and used a reference to measure ski widths and toe-in/toe-out. If the track is out of sync, so goes the front end.

Set track alignment by doing the following:

1. Ensure rear axle bolts are tight.
2. Tighten rear axle tension bolts, as the track starts to stretch, tighten each tension bolt turn for turn until proper tension poundage is achieved by using a spring scale, such as one to weigh fish, at a one-inch pull from the hyfax.
Note: For best results place the snowmobile rear end on a jackstand and hook the scale to a track clip at the track's center - equal distance from driver to the rear axle.

3. When proper tension is achieved, check alignment by starting the snowmobile and throttling the motor to spin the track several times.
4. Let track and motor come to stop without applying the brake.
5. Turn off the motor.
6. Approximately six-inches from the rear axle, measure the distance between the track clip and hyfax. Measure both sides. If one side has a narrower measurement, tighten the opposite side tension bolt. In other words, if the left side of the track has a narrow gap between clip and hyfax (more than the right side), tighten the right side axle tension bolt. The same is also true with a wide gap, loosen the opposite side axle tension bolt.
7. Retake the measurements.
8. When equal distances are claimed from a track clip to hyfax, lock down the tension bolts.

Now that the track is aligned, set proper ski width, by doing the following:

1. Slightly raise snowmobile.
2. Position handlebars in a straight-ahead position until the hole in the middle of the drag link is aligned with the half-moon shaped notch.
3. If the handlebar does not remain centered from this visual inspection, loosen steering tie rod jam nut.
4. Turn/adjust steering tie rod until the handlebar is centered and the drag link is properly aligned.
5. Tighten steering tie rod jam nut.
6. Place alongside the track's left side a long straight edge that will run the length from inside ski tip to the track end.
7. Measure distance from straight edge to front wear bar bolt (farthest from spindle front). Record measurement.
8. Measure distance from straight edge to rear wear bar bolt (farthest from spindle rear). Record measurement.
9. Move straight edge to right side and repeat steps 7 and 8. Record measurements.
Note: Measurements must be equal, the front measurements must not be less than the rear wear bar measurement (known as toe-in); if so, poor handling will occur. Front measurement is not to exceed rear measurement (toe-out) more than 5/32 of an inch.
10. Unlock appropriate right or left tie rod jam nut and adjust ski alignment by turning tie rod in or out.
11. Retake measurements as specified in steps 6 through 9.
12. Make further adjustments, if needed.
13. Tighten jam nuts.
14. Lower snowmobile.

These steps, replacing a trailing arm, adjusting tack tension and alignment, and aligning the front end is needed for clean riding. This is not high-tech engineering, but an afternoon of time burning and to heal the wounds of a Mike Tyson slug.

Many thanks to Cory Foster and Shawn Davenport at TE MotorSports for their help and allowing AmSnow to tear apart a Mountain Cat.

For more information contact TE MotorSports at 208/458-4835.