Menu Close

Letter 3

Isuzu Trek Owners Infoletter #3

April Y2K


As a follow up to letter #2: Heeding the warning about not using tires beyond 7 years of age (one can tell the tire’s year of manufacture by the last number of the serial number), I installed six new 235/85-16 Goodyear G-159 all steel radials on the Trek last month, before driving it to Mexico.  The duals were inflated to 80 psi and the fronts to 60-65 psi, according to the manufacturer’s pressure/load tables. They replaced the OEM 215/85-16 load range E tires, all inflated to 80 psi.  We could tell no difference in handling characteristics (still have to ‘drive it’) but the ride was definitely smoother up front.

Last letter I gave you the load/pressure table for the 10 ply rated Yokohama tire, size 235/85-16 used in single (front) service. Here is the info for the Goodyear G-159 all steel belted radial (interesting to note the load/pressure for the single tire was the same as the Yokohamas, up to the load range E rating (the steel Goodyear tables go higher).

Weight, lbs.  Pressure, psi

Single    Dual

1700             35         40

1870             40         46

2030             45         51

2205             50         57

2335             55         63

2485             60         68

2623             65         74

2765             70         80 Max for load range E tire (dual)

2905             75         87

3042             80         93 Max for load range E tire (single)

Walk Around

You can check brake fluid level by looking through the driver’s side window, just behind the street side rear view mirror.

Check to be sure that the ‘hand-holes’ in the tire rims line up on each set of duals, especially after your tires have been worked on. Otherwise, the stems could be chafed, causing tire deflation and failure.

What Trek owners are saying

Tires and suspension

Jerry Rucks Gcrux (at)

I  wonder if someone has tried the Ellis wide tires and rims (ad in FMCA mag.).  They told me they had rims for the TREK and I think I have seen them on at least one Safari, but was not able to talk with the owner about his experience with them.

I added the Timbren rubber springs which stiffened the ride and stopped the side sway.  The rears needed some adjustment, but the fronts are fixed.  Fleet Maint. has and recommended them.  I also added Bilstein shocks which has improved the ride.  If you have any other info on ride improvements I would like to know what  other owners feel has helped.


Jim Kelley  jkelley (at)

lpg, as u probably know, has two disadvantages…

1. it will explode at room temperature and with minimum confinement

2. as a gas, it is heavier than air

That’s why the lpg detector is positioned near the floor and at the stove….but that means it will only detect lpg that pools inside the coach

More likely, an lpg leak and pooling will occur in the water heater, refrigerator, or furnace areas, or under the coach itself.  None of these areas are monitored by the detector.  Would i give you a problem without a solution???

It’s an lpg pressure gauge… cost $40… available from marine stores or by mail from West Marine…Installs in less than 3 minutes. Remove the regulator from the outlet pipe on the tank; install the gauge, which has the proper male and female fittings; reattach the regulator.  To test.. turn off gas at tank, note pressure, wait 5 minutes.  If pressure has dropped, you’ve got a leak

You will “automatically” test your system every time you fill the tank. That’s all there is to it…Camping world sells something called a gaslow… “supposedly” will tell u when the tank is low on fuel… this is nothing more than a pressure gauge without the graduated dial face. It will work as a leak detector, but it’s a bit harder to “read”.  Also, whenever Camping World is cheaper than a marine store, I’m always suspicious about quality; and I want a quality fitting here.

Techie notes

1. Never use Teflon tape on a gas line… itty bitty pieces can break off and foul your jets.. and we all know how serious that can be.

2. The regulator is reverse threaded to the tank. You can usually identify a reverse threaded nut by the vertical score inscribed on the center of each of the six sides of the nut

One last sales pitch…. boats can’t be insured without this device.. And boats usually have only one line, and one appliance.

Heater/Furnace   deremer (at)

Tired of your furnace running your batteries down while you listen to a noisy fan come on and off all night?  Need more storage space?  I installed a catalytic heater in my Trek. Love it! Considering taking out the furnace and turning that space into a storage cabinet.  If you haven’t seen the article, I have written all about it and included photos of the installation. If you are interested, e me requesting the article. Specify whether you want the photos included.

I will be unable to respond and send anything from May 10 – June 10. Dale.

Electro Majic Bed

Al Readdy  readdy (at)

When I replaced the motor in my EMB the old motor had a decal with duty cycles on it.  I don’t remember hearing of this and think it is important for all TREK EMB owners to know (even though some will not know what it means ).

Duty cycles are:

                        45 seconds on; 1 minute off.  and

                        1.5 minutes on, 15 minutes off.

Does not seem like  lot of  “ON”  time but when you consider that the motor is inside a metal tube and has no ventilation to speak of it makes sense.  So the message is don’t run your bed up and down a lot at one time.

From Dale: here’s more on the EMB, which is showing more failures among Isuzu Trek owners as the bed, and its components, get older. I have heard of three EMB failures since the last letter. Most seem to be motor failures…..perhaps because we are abusing them? Some ideas:

-See duty cycle times above

-Don’t try to run the bed up to the limit switch shutoff if there is more bedding on the bed than when the limit switches were last adjusted.

-Don’t operate the bed, up or down, with any weight at all on the bed.

-Don’t operate the bed if the voltage is low (the bed motor is 110v)

-If you have an EMB motor failure, here is Important EMB Information. It is found at the end of the newsletter. It is a description of one Trek owner’s method to release the EMB motor to raise/lower the bed after a motor failure and how to replace the motor. If you are a do-it-yourselfer, this might really help.  If the work is being done away from the factory, it still might help.

Also from Al:

Well, the s*** hit the fan. My bed is stuck 2/3rds of the way down.  Safari says–based on my trouble shooting that it is a 90% chance the motor is shot and they will not have them in stock for 2 wks. So we are sleeping a little

higher now!  I’m sure the kids will be happy when we finally get to leave.

Below is the SOMFY web site.  The new motor is LT 540R2–which I found.  I did not find the old motor number..  One of the pages has a view of motor but it did not look exactly like my new one.  Somewhere it stated there was a brake so I guess I was wrong about the planetary gears providing this function.

Jim said he repaired his motor.  Need to have him report on success over time.  Sounds like he took the bottom out of his bed!!!!!!!  When I have more time will email SOMFY to see if they have my failed part.

Exhaust leak (also from Al Readdy)

My oldest son fixed my exhaust leak and also found that the 2 bolts (forward) on the exhaust manifold had fallen out!!  How this could happen I do not know since exhaust fasteners are so hard to remove–as a rule. [So check your nuts/bolts!!!]  After replacing them all was well.

Cruise Control

Dale: There has been quite a bit of e-conversation about cruise control problems. Some problems have been complex, needing a technician and the Acme factory input to resolve. Several have been more-or-less expected maintenance oriented. The Acme cruise control operates with cables to provide throttle movement and throttle position feedback, etc. adjustment of which adds to maintenance problems.

Mine is working normally (drops 4-5 mph from set speed before it settles in) except I can’t get it to set or maintain speeds over 55 mph indicated (on the speedometer) which is really about 50 mph as speedometer reads 5 mph high (as checked with GPS and with milemarkers and wristwatch).  Any ideas why it is doing that? Anyone?

Dutch sums it up well:

William Dutcher  dutch98221 (at)

I finally got to road test the trek cruise control.  Works fine, except it is always 4-5 MPH lower than speed when setting, I can live with that

 I think the reason it didn’t work was oxidized contacts (aluminum) where wires connect to module causing poor connection.

Sewer hose

Dale:  Storage of sewer hose on our Treks is less than satisfactory. Dutch did a nice installation by cutting a hole in the street-side wrap around of the rear bumper and installing a piece of PVC pipe in which to store the hose.  I have also seen an installation of a PVC pipe in the generator compartment in which to store hose that looked quite satisfactory.

From Dutch dutch98221 (at)

The socket for storing the sewer hose is unsatisfactory, too short and such small diameter that the fitting has to be taken off one end in order for it to fit in the storage provided. Am going to cut a hole in bumper and install a piece of 6″ pvc pipe so I can  have a 10 ft sewer hose and leave fittings on that hose)my sewer hose in now only about 4 foot when stretched out)If you are interested, can send a snapshot when it is completed.

Stowage for sewer hookup hose: I used a piece of 6 inch heavy wall PVC pipe. I had enough left over(I bought 5 ft) to increase size of existing storage, by cutting off the end back end of storage door assembly and gluing on a piece about 1 ft long, this allows storage of fittings and gloves. The 6 inch dia. pipe can be routed out a small amount to allow pipe to be slid over the back side of door assembly.

For the hose storage, I cut hole in fiberglass bumper and mounted pipe with home made clamps. (did not have to drill any holes, used existing holes)


Dale: Here is a bit of info all of us need to know:

Hugh McCusker writes:     mcquic (at)

Hi Dale:  Have just finished repairs on the Heart inverter 1200 Unit:  Unit was damaged by moisture that had corroded the bottom circuit board.  This destroyed all 10 power FETS mounted on that board. Cleaned the board and replaced all the power fets.  Have been running tests on it all day.

More importantly the damage was created by the center elongated stop light that was installed just above the rear compartment door.  I don’t know if all 94 Treks had this item installed.   Anyway, the gasket around this stop light disintrigrated and allowed water to get inside and drip down on top of the inverter.

I removed the stop light and applied some marine silicone sealant then reinstalled.

Dale:  I checked mine. There are definitely water marks on the outside of my inverter and its coming from that center brake light.  My inverter is mounted horizontally and it doesn’t appear that the water is getting inside but I didn’t open up the inverter.  I definitely need to fix that leak or be sure the water is routed away from the inverter!  Better rush right out and check yours! Thanks, Hugh!


Dale: They sure are nice, as any camper will tell you after setting up lots of camps where leveling had to be done manually!   I found the ‘bong’ on mine was going off more and more often when rocking through a ditch or driveway or hitting a bump.  So I got out the book and read it.  What was happening was the unit’s fluid level was getting low, so rocking caused the fluid to depart the side where the sensor was located, causing the ‘bong’ which warns of low fluid level.  The reservoir is located behind the left front wheel (thanks, Al, for showing me–nothing like having an ol’ Trekker walk around your Trek with you and show you all about it!  And all I had to do was have Trish feed him!  Anyway, I found I had to fashion a funnel of just the right dimensions out of a larger plastic funnel, and follow the directions in the book. The ‘bong’ stopping tells when the fluid level is high enough.  Don’t put in the wrong kind of hydraulic fluid!

EMB Emergency (Motor Failure) Raising Procedure

from Jim Gibbens  jibber (at)

First, remove fuse from bed and turn off circuit breaker.

The key to manually raising or lowering the EMB is to release it from the disabled motor. Rather than removing the driver side window and dealing with the drive sprockets and disconnecting chain drive etc.,  I chose to work from the other end and disconnect the anchor bracket from the motor.

The EMB motor bracket is secured to the cross member approximately 47″ from the drivers side (head) of the bed frame.  To access the bracket it is necessary to remove the luan (plywood) floor of the bed box from the drivers side corner toward the co-pilot’s side approximately 56 inches in and about 16 inches wide (toward the front of the coach).  It will be necessary to have this much area open in order to grip the motor tube with a pipe wrench and rotate the top of the tube toward the back of the coach.  This rotation will take weight and thus the tension off of the

bracket and allow the two cap screws to be removed from the bracket (from the co-pilot side of the cross beam). Be sure to have a pipe wrench still engaged with the motor tube to support the bed until your helper can put a prop under the bed. (A support is necessary and should be placed under the cross beam and centered in the middle of the bed width).With the cap screws removed the end of the motor tube can be raised high enough to remove the cotter key and the bracket from the 5/16″ square motor shaft. Next it is necessary to disconnect the wiring from the motor. This is done by blocking the inboard end of the motor tube up slightly higher than the top of the cross member in  the bed frame and removing two small Torx head screws from the yellow terminal box cover and pull the cover straight out. This gives you access to the terminal screws, (be sure to diagram the wires as to color and to which

terminal.)  Next remove the clamp holding the cable and loosen four screws at the wire terminals. Lay the wire against the near side of the bed box.

By blocking the motor tube up to level from the bottom of the bed box, and using two pipe wrenches alternately to rotate the motor tube (clockwise from the drivers side) , I was able to very slowly and laboriously raise the bed so it would have been possible to drive the coach.

Note:  Before driving the coach, the EMB should be supported by a scaffold built under the bed by a competent constructor!!