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Letter 13

Isuzu Trek Owners Infoletter #13

 Firewall Bolts & Trek mirrors…

John W. Misiaszek ( <>) writes:I too had a firewall bolt crisis. Not only were all the bolts broken or missing, I had a 1/4 inch gap on the passenger side and a 3/8 inch gap on the drivers side. The dash really did a dance on rough roads, in all directions. I chose to fill in the gap with 2 inch aluminum bar stock with the proper gap thickness. I also used 6 inch wide stock, horizontally from the firewall flange to behind the side mirror brackets. I purchased new longer stainless steel tapping screws to mount the mirrors. The screws go through the body wall into the 6 inch aluminum filler. I believe this area of the wall is filled with solid chipboard and only 2 of the 4 mirror mounting screws actually hit the aluminum body frame. I used an adhesive to hold the aluminum fillers in place and then added replacement bolts where I could. Liberal caulking along the outside seam will hopefully keep out the moisture.Editor’s note: See infoletters #4, 6 and 7 for more about firewall bolts.

 Suburban Hot Water heater & leaking Pressure Relief Valve….

Our water heater is, I believe, the original installed by Safari and is now 10 years old. I cannot budge the anode rod and sooner or later the heater will have to be replaced. Due to money constraints, a new heater is on hold. So the best I could do is check it over and make sure it works properly. The high limit switch was open and it was replaced. The thermostat was ok. The pressure relief was corroded and leaked, and it was replaced. The pressure relief valve, high limit switch and the thermostat serve the same purpose and operate the same as on the typical residential domestic hot water heater, be it gas or electric. And so I began to think about all this ‘weeping’ talk I hear about RV hot water heaters. I suppose many things can make a pressure relief weep; age, corrosion due to poor water, high water temperature, etc. Most causes can be obviously spotted, but high water temperature can sneak by us all. The high limit switch and the thermostat on my Suburban heater are held in place against the heater tank by a flat steel spring clip. The water temperature is transferred to the two switches through the steel tank wall. Rust and paint can cause a heat transfer loss to the two switches. The thermostat on my heater opens at 130 degrees. High heat loss could cause the water to reach 140 or even 150 degrees before the thermostat is tripped. The pressure relief begins to open at 150 degrees. Guess what…….weeping. To minimize the heat transfer loss to the two switches, I did the following: Used emery cloth to sand the two areas where the switches come in contact with the heater tank. I removed all rust and paint. I bought a tube of silicone heat sink compound at Radio Shack and applied the paste to the sanded spots on the tank and to the mounting surface of the switches. I now have the maximum heat transfer possible. There should now be no weeping.Editor’s note: See also infoletters #4 and 8 on this subject.


When I bought our Trek, a year and a half ago, the tires looked ok and since I had a lot of work to do on the coach with no trips planned, I decided to forgo a close examination. This spring I finally got around to examining the tires. What a surprise! Even though they were about three years old with no checking, they were ‘D’ load range tires. The rear tires were borderline, weight-wise, but the front was definitely over the weight limit (And to think that I picked up the coach in Florida and drove all the way to Indiana with those tires). I immediately bought six new tires (‘E’ load range). I knew that the coach was underpowered and to gain a bit more mechanical advantage I chose the LT225/75R16 tire. The load capacity for this tire is the same as the stock LT215/85R16 tire and it is approximately 1 inch smaller in diameter. The LT225/75R16 tire turns in 711 revs per mile, as compared to 683 revs for the LT215/85R16, so I had to order and install a new driven gear for the speedometer cable (Isuzu part no. 94249064. Double check the part number. It could be a GMC part number. I bought it at a GMC truck dealer). The tires are working out fine, a bit harsher ride and more engine noise. She cruises nicely around 60-65 and can hang-in on the hills much better.

 Editor’s note: see also information and other opinions on tires in newsletters # 1, # 2 and # 3.

Floor water damage repair

Also from John: An excellent way to solidify a chipboard floor with water damage is epoxy resin. Dry out the floor, vacuum up all the loose matter, use masking tape to seal the small holes, then build up the punky area with epoxy resin and glass cloth. The remains of the chipboard soaks up some of the resin and the glass cloth returns the strength to the floor. I already did that to my bathroom floor.

 Generator Advice

Some good advice from Dutch ( <>) about operating our gensets: My Onan Generator failed in Key West in March. After I got back home (to Washington state),I had it repaired at an Onan certified repair outfit. Cost was $2500.00 to repair(should have bought a new one).Generator had a total hours of 82. I usually only ran a test run before each trip.I ran into a lot of rain during the trip, and had not run the gen the first 4000 miles of the trip.

They said cause of failure was that I failed to run generator often enough, which causes slip rings in gen to corrode, which causes arcing, resulting in volt regulator failure. I had to replace stator, rotor, volt reg,, magneto, and also the propane carburetor.

The repair shop told me the slip rings needed cleaning and would be done in two days, then the job grew gradually ,over a three week period. When it got over a thousand dollars, I was going to cancel the repair but I already owed them $900 for labor.

I am now operating the generator monthly for about 15 minutes with air conditioner on to give it a load. If I knew the repair was going to cost that much I think I would have put more batteries in Gen space and ran without the Gen, as I very rarely use it.

Editor’s note: see other information about generator problems in Newsletters #7, 9 and 11.

 EMBed Comfort

Mike Northover (MNorth6869 <mailto:MNorth6869>at these tips for us: Hi Dale I have been over in France with my Trek and its been great so far. Some tips I found out: My wife was complaining about the magic bed mattress how she could feel the lumps underneath so I bought two sheets of ply 3ft x 4ft as the base was 4ft wide by 6ft long put them under the mattress and what a difference, great night sleep as the whole mattress is firm and a happy wife. Thanks for the letters great job.

Editor’s note: Mike is in the UK now. See other articles about EMB comfort in newsletter #8. ( Al’s Note: I used 1/8 ” masonite ?-the brown stuff)

Spare tire storage

Again from Mike: The spare wheel which I bought direct from Izuzu fits nice under the sofa bed. I put it in a black bin bag to keep it clean got the tip from another Trek owner.
Editors note: see also stories about spare tire storage in letters #10.


The Markham’s (susie_markham at got their microwave working and tell us:

we had problems with our microwave behaving erratically, occasionally agreeing to work but mostly refusing to do anything. In desperation we pried the touch-sensitive key-pad off and that cured it, even when we put the pad back on again. It has worked perfectly ever since.

 Towing the Trek

Also from the Markham’s: We have a question about towing. I want to check whether my 1991 Owners Manual is correct, given what we’ve read in some of your letters. Our book says that you may tow an automatic gear-box Isuzu with its prop shaft connected so long as you do no more than 30mph and 50 miles distance. Whereas for the manual transmission version you must disconnect the prop shaft. This seems to me the wrong way round. Have you any information on the subject?

According to the shop manual for the 1993 Isuzu Trek (Thanks to Al Readdy):


Isuzu Truck Service Manual (1993)

(Bold by Al)

The instructions for towing Front Wheels Off Ground only says disconnect propeller shaft with no note of Manual or Automatic transmission

Front End Towing

(All Wheels On The Ground)

Your vehicle may be towed on all wheels provided the steering is operable. Remember that power steering and brakes will not have power assist.

There must be a tow bar installed between the towing vehicle and the disabled vehicle.

To prepare a disabled vehicle for front end towing with all wheels on the ground, the following steps are necessary.

· Block the wheels of the disabled vehicle.

· Disconnect the propshaft at the transmission or rear axle. Before disconnecting the propshaft yoke from the transmission or the drive pinion flange, apply the setting mark between the yoke and the flange. Secure the propshaft to the frame or crossmember. (Manual Transmission Models)

Move the selector into “N” position, vehicles can be towed at the speeds below 30 mph (48km/h) and up to the distance less than 50 miles (80km). (Automatic Transmission models)

 The Final Word on Towing Isuzu Treks

Comes from Peter Markham (petermarkham at who says:

We were recently at FMI in Portland and asked them about towing. The Service Manager, Larry Taylor, was adamant that the Owners Manual has it the wrong way round. You must NOT tow an automatic transmission Isuzu Trek without disconnecting the propshaft. He said he had on average 4 a year in with wrecked transmissions as a result if being towed.

Editor’ note: See also infoletter #8 on this topic.

 Cruise Control

In letter 11 you were asking for information on Cruise Control.There is a lot of stuff on, http:/…..scroll down to Acme Cruise Control instructions/troubleshooting guide. I found that mine was not working because the accelerator cable is broken,yet to be fixed.

 Air Cleaner

Peter also contributes:

The Problem
When we went to FMI to have a big service they told us that our turbo charger had been damaged by rust and paint flakes from the air cleaner and metal parts of the inlet tract being sucked into it. This had slightly distorted and abraded the blades, and could if left untreated have resulted in the turbo disintegrating and wrecking the engine. The cause of the rust and paint flakes was the position of the air intake so close to the wheel that it is in a continual shower in wet weather, causing it to become water-logged. Mine had standing water in the bottom of the air-cleaner. My air cleaner is a vertical cylinder with a short pipe coming out of it at 45 degrees with a rubber nipple. However the pipe is not at the bottom of the cylinder but a 1/2″ up, allowing a small amount of water to collect in the bottom. Larry Taylor said that the Isuzu trucks have the air cleaner horizontal rather than vertical thus leaving the rubber nipple at the very bottom, allowing any water that does get in to drain out easily.

The Solution:

The advice of an FMI technician was to refabricate the steel portions in
stainless steel and to manufacture a snorkel to move the airtake high up and
across to the centre of the coach. I decided that we couldn’t afford the
time and money to do the stainless work, but what I did do is throw away the
air-intake water separator thing as it wasn’t doing anything. I then
placed an E-Z Hose Connector in the rubber elbow from the air cleaner using
jubilee clips, and attached to it, also with a jubilee clip, a 5 ft
Ultimate Sewer Hose. I stretched this up vertically to the plywood dash and
then across to the centre of the coach. I attached it with cable ties that
have a hole which takes a screw.
The Outcome:

I’m hoping that as I’ve taken the wetness away no more rust will hit the
turbo. Now the Trek has more torque, I assume the snorkel is acting like a
high-torque ram. Hill-climbing is definitely improved.
Larry Taylor advised that I remove the rusty pipes and air cleaner and have
them bead-blasted and repainted, as a cheaper solution than stainless steel,
which I would have done if we’d had the time. He also said it would be
pointless to replace the turbo without installing the snorkel.

 Editor’s Note: My ’94 has a snorkel fitted, coming out of the front of the air cleaner housing, near the top, extending up. This was apparently in place when delivered new. My air cleaner/filter is never wet, even when operating for many days in rainstorms. The filter is easy to check, though, and Peter makes a good case for why we should check it often, especially after operating in wet conditions.

Also, see infoletters #7 and 9 on the above topic.

Speedometer Cable break, Transfer switches

From Mark Foster:

Dale, something you probably already know, but if the connection from the speedo breaks (eg the gear at the transmission housing), the econo light will flash on the dash, indicating a transmission problem. Finally, you might pass on that Camping World is about the most commonly available source for reasonably priced transfer switches. On my 1992 trek rear bedroom model the switch failed…where was it??? It was found buried behind the 110 volt panel, located in an inaccessable spot between the rear centre access hatch and the right rear tail light, what a b-tch! I relocated it to the centre access hatch for future easier access. Thanks for the great info source. Mark Foster <>

Editor’s note: See also infoletters #6, 9 and 10 for more on these topics.