Towing Concerns
Q: I recently had to have our motorhome, built on a Chevy P-32 chassis, towed. The ignition switch had failed and resulted in no power in any of the circuits, including the parking brake system, which requires 1,200 psi fluid pressure to release the spring-applied brake. After the tow operator had hooked onto the front of the motorhome, he had to disconnect the driveline. He called his boss and asked him the best way to proceed and was told to jack up the right rear wheel and relieve the tension on the driveline. When he jacked up the wheel, it rotated about 8 inches, enough to have caused serious injury to anyone who had disconnected the driveline.
Howard Hoxie, F162490
Sterling, Colorado
A: Thank you for sharing your experience. We in turn shared this letter with a representative from Workhorse Custom Chassis who provided the following information.
“The parking brake system is applied by a Berg spring brake chamber. It is released by a hydraulic cylinder powered by an electric motor-driven hydraulic pump. The motor is controlled by a pressure switch that turns the motor on at 1,200 psi and off at 1,600 psi. Thus, it does take 1,200 psi fluid pressure to release the spring-applied brake. Pressure is maintained in the cylinder (to hold the brake released) with a normally open solenoid valve (valve is open with no electrical power). Loss of power, such as an ignition switch failure, will stop power to the solenoid, resulting in brake application. (The fail-safe feature is required in the standards for parking brakes.)
“A vehicle should be secured to prevent it from rolling and the loading removed from the prop shaft (jacking up one rear wheel) before removing the prop shaft to prevent injury and damage to the yoke.”
Suspect Starter
Q: I own a 2000 Damon Intruder motorhome built on a 1999 Ford F-53 chassis. Often it takes several attempts to get the starter to engage, but other times it works just fine. I know of another motorhome owner who has this same problem. I have removed and cleaned all the posts on the starter solenoid (located on the upper right-hand side of the chassis), and I’ve checked the grounds, the battery posts, and the ignition switch connections. Unfortunately, nothing that I’ve done has corrected the problem. I’m hoping that total failure will occur, and then maybe the problem will be corrected. However, I’ve been driving the motorhome for three years and it’s not gotten any better or worse. The problem seems to be related to this series of Ford F-53 chassis. Do you have any suggestions?
Clifton W. Nelson, F272739
Pace, Florida
A: When I first read your letter, it seemed that the problem would be related to a faulty solenoid. However, I decided to check with Ford as well. What the Ford representative said was that although the problem could be related to loose connections in the starter circuit, it is more likely being caused by a bad starter and not a faulty starter solenoid. With this information, my advice is to have the starter replaced. After the old starter is removed, make sure it is examined for damaged teeth on the engaging gear. If damage is visible, the flywheel or the starter ring may have to be replaced as well.
Tire Rotation
Q: You provided great reasoning as to why the right-rear inside tire of a dual-tire setup blows out more often than the other tires (“Tire Troubles,” page 20, March 2005). This helps explain a recent tire blowout that occurred with less than four years and only 32,000 miles on the tires, even though we weigh each corner and add 500 pounds for safety when we compute our tire pressures. Could you please tell me what the approximate mileage on the tires should be when they need to be rotated, as well as the rotation sequence (front to rear, right to left, etc.).
Sam Marks, F324483
Fernandina Beach, Florida
A: Start first by checking your motorhome’s owners manual for the manufacturer’s recommendations regarding tire rotation, and check with the tire manufacturer as well. Each of the tire manufacturers has slightly different recommendations when it comes to rotation.
Usually rotations are prompted by irregular wear patterns on the steering tires. A representative at Toyo commented that if you don’t see irregular wear, then there is no reason to pay for the dismounts and remounts involved in rotation. Michelin literature also indicates that maintaining correct air pressure and proper alignment may eliminate the need for tire rotation. If uneven wear is detected, the best course of action is to have the coach checked for misalignment, imbalance, or other mechanical problems before the rotation.
The Toyo representative I spoke with noted that for a coach with dual rear wheels, generally speaking the best thing to do is to rotate two tires off of the same rear wheel position to the front. They should have the same diameter and tread depth. If you rotate the spare into the mix, you then have tires with different tread depths and diameters on the same axle, so this is not recommended. Tire care information on the Michelin Web site does not specify any particular rotation pattern, but Michelin does recommend including the spare in the rotation process.
It is important to note that as the tires are being rotated, they should be inspected for any signs of fatigue, cracking, etc. It is especially important not to put marginal tires on a steering axle. Also, be sure the correct lug nut tightening sequence is followed and the proper lug nut torque is applied on each wheel.
Any Good Towables?
Q: Do you have an article about cars that are popular or good to tow behind a motorhome? We have a family of two adults, three kids under 10, and a beagle.
Edward Todd, F352356
Robbinsville, New Jersey
A: The January 2005 issue of Family Motor Coaching magazine contained an article about vehicles that can be towed four wheels down without significant modifications. The information was compiled from a survey of manufacturers and contains their recommendations in that regard. It pertains only to the 2005 model year. The January 2005, January 2004, January 2003, March 2002, and March 2001 articles are available to FMCA members and FMC magazine subscribers (login required) on FMCA’s Web site, www.fmca.com. Click on the “Motorhoming Guide” channel on the blue navigation bar and then click on “Towing” and then “Towing Four Wheels Down.” Links to the articles appear at the bottom of the page. We also published articles about the 2000 model year in the March 2000 issue and the 1999 model year in the March 1999 issue; however, these are not available on the Web site.
To obtain a photocopy of any of these articles, please feel free to send a self-addressed, stamped, business-size envelope along with your request to: Family Motor Coaching, 8291 Clough Pike, Cincinnati, OH 45244, Attn. Editorial Assistant.