Technical Inquiries: August 2003

Vibrating Vacationer Steadied

Thank you for the responses you forwarded to us regarding the shaking problem we experienced in our Holiday Rambler Vacationer (“Vibrating Vacationer,” March 2003, page 32). We took the motorhome to a Ford garage and a mechanic there was able to identify and fix the problem. Thankfully, the mechanic got the motorhome to shake during his trial run over rough roads. It turned out that the front steering stabilizer cylinder had lost its nitrogen and hydraulic fluid. The cylinder was replaced and the motorhome has driven fine ever since.

Thanks to everyone who responded with suggestions for solving our problem.

Ross Browning, F254032
Chariton, Iowa

Q: I have a 2000 Holiday Rambler Endeavor 36PBD built on a Ford Super Duty chassis that has a front axle rating of 7,000 pounds and a rear axle rating of 13,500 pounds, for a total GVWR of 20,500 pounds. With two slideouts, the load capacity of this coach is so low that I have to be very careful not to go over the GVWR. A later version of this Ford chassis is rated at 7,500 pounds for the front axle and 14,500 pounds for the rear axle, for a total GVWR of 22,000 pounds. The extra 500 pounds on the front axle is no big deal for me, but that extra 1,000 pounds on the rear axle would be a great benefit on this coach.

Exactly what has Ford done to gain this extra 1,500 pounds GVWR, and is it possible that a local Ford truck service center could install the parts on my coach to gain an extra 1,000 pounds of capacity on the rear axle at anything close to a reasonable price?

Bill Foster, F245358
Trinity, North Carolina

A: The real difference between the 20,500-pound GVWR chassis and the 22,000-pound GVWR chassis is in the rear, just as you’ve stated. According to a Ford representative, the rear axle housing on the 22,000-pound chassis is .010-inch thicker and 20 pounds heavier, and the rear springs are rated at 14,500 pounds.

To help alleviate your overloading problem, you could try transferring as much cargo as possible forward and traveling with as little fresh water as possible. Next, you could order heavier springs or add leafs to your existing springs to help transfer weight to the front axle. The added rear spring capacity also will improve vehicle handling by alleviating sway, which is quite often common to overloaded vehicles.

The bottom line, however, is that the rear axle housing is only designed to carry 13,500 pounds, no matter how large the rear spring capacity.
“” J.B.

Q: Much has been written about the steering qualities of the Chevrolet P-30 motorhome chassis. From my experience, I may have found the answer: lubrication, specifically, the lack of it.

When we purchased our motorhome, the passenger-side upper A-arm bushings were worn out. The dealer replaced them as part of the purchase agreement. I maintain my vehicles personally, so I took on the task of routine engine and chassis lubrication as well as brake and wheel bearing maintenance. The new bushings took grease extremely slowly. With an air-powered grease gun, it took five minutes of constant pressure before any old grease was visibly squeezed out. There are 27 grease points on the chassis and driveline, and I faithfully lubricate them with a high-quality lubricant each time I change the engine oil and filter (every 3,000 miles).

One year we were traveling at the time a chassis lube and oil change were required, and I could not do the work myself, so we stopped at a huge commercial truck and motorhome service center. After I carefully explained the number of grease points to the service writer and two other men who guided us into the service bay, a fourth person shortly appeared from the maintenance pit and stated that the work was completed and I could take the work order to the cashier. I asked him how many grease points he lubricated. Counting on his fingers, he said, “Seven.” No one had relayed the critical information to the person who actually did the work.

I had an epiphany. I suddenly knew why so many people had complained of worn steering and suspension parts on P-30 chassis, and why ours were worn out when we bought our motorhome. They are not being properly lubricated. Even if the service technician does find all of the grease points, I will wager that he gives each one only a quick pull of the trigger without carefully observing whether the joint has actually taken any grease. The service technicians are accustomed to solid-axle rigs with only a dozen or so grease points. They are unprepared for an independent-suspension rig with 12 Zerk fittings on the suspension, 10 on the steering, and five more on the driveline.

We have driven an additional 30,000 miles with no steering complaints. We have no aftermarket specialty steering remedies installed, and I continue to do all of my own service.

In my opinion, an independent suspension gives a far better ride than a solid front axle. In motorhomes, with the driver and passenger sitting directly over the steering axle, the difference is especially evident. But, as the saying goes, “The price of liberty is eternal vigilance.” Careful attention to lubrication will preserve the suspension system.

I have found one improvement that is worth making: Bilstein shock absorbers. Pre-Bilstein, we were buffeted by crosswinds and the bow waves of passing trucks, requiring constant attention to steering. Post-Bilstein, we almost can drive hands-off the steering wheel. The reason is the changing camber angle of the front suspension as wind gusts cause the body to roll and sway. The Bilstein shocks limit this motion to a remarkable degree.

William Bezdek, F265199
Mason, Michigan

A: Thank you for your comments. We’re sure other members will find them to be a great benefit.

Q: Our motorhome is a 1983 35-foot Beaver with a 454 Chevrolet engine. The odometer now registers more than 100,000 miles of almost trouble-free travel. A short time ago, while I was returning from a club outing, the engine began to stall each time I got down to 10 mph, but it would perform flawlessly at highway speeds. Of course, I lost my power steering or power brakes when the motorhome quit running. There also was considerable engine backfiring, but the engine temperature did not go up. I had the carburetor overhauled and thought that would correct the problem, but it did not. During the next trip out, I had similar results with less backfiring (great performance on the highway, but it would stall when I had to slow down to 10 mph or less).

The problem seems to be heat-related, since initial stops and starts appear to be no problem, but after traveling 50 miles down the road, I encounter the same problem!

Vaughn F. Davis Jr., F133269
Palo Alto, California

A: Here are a few things you should investigate as possible causes of this type of problem.

1. Have the fuel pump pressure and fuel volume tested before replacing the fuel pump.

2. Check for a vacuum leak, and also look for soft, mushy vacuum tubing. Check out the PCV system, intake manifold gaskets, etc. A vacuum leak could cause a lean fuel mixture, resulting in low-speed stalls.

3. Have your mechanic check and verify the condition of the spark plugs and ignition cables; then check that the distributor’s mechanical advance weights are free. Remove the distributor cap and see whether the rotor can be moved 15 to 18 degrees against its springs and then snap back into place when released. Take the rotor off and check the wear between the weights and the pivot pins.

4. With the engine up to operating temperature (the engine should have a steady idle, 600 to 750 rpm), remove the air cleaner (top lid only) and with a good flashlight look straight down into the primary venturis and see whether there is gasoline dripping from the high-speed tubes.
“” R.H.

Q: I own a 1992 Winnebago 31-foot type A motorhome on a Ford F-53 chassis with a 460 electronic-fuel-injected V-8 engine, and it has approximately 50,000 miles on it. When the outside temperature is 92 degrees Fahrenheit or higher, the engine seems to suffer vapor lock and quit. My routine after this happens has been to open the engine cover and put three wooden clothespins on the incoming fuel lines and three on the return lines. (I soak the clothespins in cold water before clipping them on the lines.) I then wait about two minutes and start the engine. As long as the cover is off, the engine runs fine “” no more cold clothespins are needed and it doesn’t experience vapor lock. However, the problem returns when the cover is put back in place.

A Ford RV customer service representative told me that the fuel in the return line heats up and the in-tank fuel pump can’t do its job. They said there is no fix. Ford customer service also told me that the fuel pressure when leaving the fuel pump is 100 psi, but it then goes through a regulator, which drops it to 35 to 45 psi for the electronic fuel injection system. I have been under my rig for two days, and I can’t find a regulator or Schrader valve (to reduce fuel pressure) anywhere.

I have four friends with the same problem. One of them installed a new fuel pump, to no avail. I have installed insulating tape on both lines, but I don’t know whether the problem is solved “” the weather hasn’t been warm enough to check. I hope I can correct this problem before summer.

By the way, I travel with a friend who owns a type C on a Ford chassis, and it doesn’t have this problem. Winnebago told me that since it involves the engine, it is a Ford problem, not a coach problem.

Buck Masser, F83804
Vancouver, Washington

A: According to a representative from Ford, the solution to your problem can be found in Technical Service Bulletin 97-23-9, which directs the owner or service technician to install a revised fuel pump and sender assembly. The revised pump and sender has a four-pin wiring connector and requires a jumper harness to adapt it to the original three-pin wiring harness.
“” J.B.

Q: I’m looking for a towed vehicle that has some camping potential. Can the Volkswagen EuroVan Camper be towed four wheels down? Are there any other vehicles with sleeping potential that can be towed four wheels down? We have a 37-foot Beaver motorhome with a Caterpillar engine that provides plenty of horsepower, and we tow a 2002 Dodge Durango now.

Ron Rice, F190680
Wheaton, Illinois

A: Each time we have requested information from Volkswagen for the annual FMC towing survey, the company has indicated that none of its vehicles are approved for flat towing. However, I have a few suggestions if you have the power to pull them. As with any towed vehicle, be sure not to exceed the motorhome’s gross combination weight rating. Sportsmobile makes a four-wheel-drive type B motorhome with a transfer case that can be shifted to neutral and towed (www.sportsmobile.com). Since you are towing a Durango, you probably know that there are many sport utility vehicles (equipped with the proper transfer case) that can be towed. These vehicles can be outfitted with an innerspring or inflatable mattress for comfortable sleeping. You also might choose any mid-size or full-size pickup with either a manual transmission (or the correct transfer case) that is equipped with a truck cap covering the bed. Several automakers offer aftermarket bed tents that are designed to fit snugly into the pickup.
“” J.B.