Issue link: http://read.dmtmag.com/i/34501
VIBRATION DIAGNOSIS VIBRATION COMPLAINT When a motorhome owner comes in with a vibration complaint, contact the appropriate chassis manufacturer to establish an incident report and get possible motor- home warranty handling instructions. The following procedure should take care of most complaints. 1. Driver interview — this should include the following: – has this vehicle been worked on by the chassis manufacturer or MICHELIN dealer for this complaint? – type of complaint – driving and road conditions when the vibration occurs - mph/rpm acceleration/deceleration – when in the life of the vehicle did it begin? – where does the vibration seem to be coming from? Front or rear? – recent maintenance or modifications to the vehicle 2. Vehicle test drive - ride in the vehicle and have the owner demonstrate the complaint to you to verify that there is in fact a problem. Include the following observations: – speed at onset of vibration and the speed range – does the vibration phase in and out, or is it constant? – sensitivity to road surface? Smooth roads? Rough roads? Both? – effects of acceleration/deceleration/constant speed – is vibration felt through the seat? Floor? Steering wheel? Other? – is this a ride quality or a drive train vibration complaint? 3. Complaint history – check all motorhome warranty records, etc., to determine past history of the same or similar complaints on this vehicle – have there been any changes or modifications to the chassis since manufacturing? – has any prior effort been made to diagnose or correct the complaint? By whom? 2. Measure and record the radial runout on the vehicle of each assembly with tire runout gauge. Mark the highest point of the assembly. Rotate each assembly until the high spot is at the 12:00 position (without allowing the assembly to turn). Loosen all lug nuts and re-torque in the proper sequence. Re-measure and record the radial runout of the assembly. If either front assembly still exceeds 0.040", measure the rear assemblies and put the two assemblies with the least runout on the steer axle. 3. Repeat the vehicle test drive. If the vibration still exists, contact the appropriate chassis manufacturer. VIBRATION DIAGNOSIS If the vibration seems to be driveline related and from the wheel ends, then perform the following: Tire/wheel assembly inspection 1. Jack up the front of the vehicle and spin each assembly, observing the wear conditions of each tire and concentricity of the tire on wheel mounting. If the variation in the distance between the line-up (“gg”) ring and the wheel flange exceeds 1⁄ 16", have the assembly broken down, relubed, and remounted (see diagram). GG-Ring Wheel Section Five: MICHELIN RV Tires 81 ®