Isuzu Trek Members Infoletter #48
October 2025
Welcome to Isuzu Trek Infoletter #48.
The I-Trek infoletter mailing list is managed in a Google Group: (https://groups.google.com/forum/#!forum/i-trekinfoletter). If you would like to be included in this exclusively Isuzu Trek group please request inclusion in our mailing list or e-mail the editor Bret Medbury for info at isuzutrek (at) gmail.com or islandduo (at) comcast.net. If you would like more detailed/higher resolution photos of any of the included ones please e-mail the original creator.
You should all be aware that a fantastic new resource for I-Trek owners has been added to the treasure trove of info on the Northwest Trek Fun Club website. Finally, with the help of John Herold NWTFC Webmaster, “we” (mostly he) has gotten the complete Isuzu NPR parts list posted. www.nwtfc.com/isuzu-infoletters/isuzu-trek-documents/ It contains every chassis part part number, right down to the screws and wire clips. My experience sez once you have a correct part number you can find the part. It is a large PDF file; I suggest you download it once then just keep it on your computer for ready access.
If you have any questions or would like more detailed photographs related to any of the below articles please contact the originator directly. E-mail addresses are provided for that purpose With an (at) replacing the ampersand @..
Improvement to Refrigerator Condensate Drain
Bruce
Hidden Access Panel Over Engine
Tom
One Piece Speedometer Cable
Bret
DIY – Delco RV620 Power Seat Adjuster Shoe Guides
Squeeto
1994 Sink Drain Upgrade
Bruce
Screen Door Latch
Bret
New Lithium Battery Bank location
Dave
Lithium Battery Upgrade “keep It Simple” Version
Bret
Add A little Insulating Help to Your Fridge
Bret
92 Trek Swing Arm TV Mount
Squeeto
Measurements For 92 Roof Truss
Squeeto
New “O” ring for leaky water separator
Squeeto
Exhaust Manifold Bolts/Studs
Greg
Hand Towel Ring Removal
Squeeto
+++++++++++++++++++++++++++++++++++++++++++++++
Improvement to Refrigerator Condensate Drain
Bruce Matlack matlackwindsurfing(at)gmail.com
When fridge drain over flows collection tray, it dry rots all below. when heater assy was withdrawn I found everything rotted. Solution: divert drain hose to outside-
Hidden Access Panel Over Engine
Tom tjgj(at) aol.com
Visited old stripped trek and made an interesting discovery. There is an access panel in front of the motor opening hatch.
It lies to the right of the shifter pedestal and forward of the hatch opening and would be under the Trek carpeting. If one were faced with changing an engine water pump or most any work on the front of the engine this access would make that work much easier.
One piece Speedometer Cable
Bret Medbury Islandduo(at) comcast.net
For those with an inoperative cruise control. or those that just want to simplify the speedometer cabling system here is a one piece cable long enough to go all the way in
one shot. Part number 1-83112-724-0 and manufacturer’s part number B-TS181293 claims to be for a Isuzu Rocky 175 Lorry 1984 – 1995 and is 380 cm long.
The original factory system was a multi piece (I think four piece) system that also incorporated the cruise control unit, (which has an almost 100% failure rate) Some of the Isuzu and Safari connections are difficult to match. The new cable will reach, but only if it is routed over the transmission to the driver’s side then through the firewall to the speedometer head.
DIY – Delco RV620 Power Seat Adjuster Shoe Guides
Squeeto squeeto(at) gmail.com
If you can still get the original-
P/N 22048993 (White – 4 needed)
P/N 22048994 (Black – 8 needed)
Maybe the same, from a Winnebago 2002 SUNCRUISER G-SERIES
081373-03-706 (White)
081373-03-707 (Black)
DIY-
The original seat guides are 4 white and 8 black.
The black guides are a little slimmer than the white.
The 4 extra black guides are used at the center of the rails.
This is probably for tolerance consideration so that the rail has less chance of binding.
My DIY guides are all the same, measured to match my existing rails.
I used a 12 x 3 x 3/4 inch block of UHMW (Ultra High Molecular Weight) polyethylene plastic.
Taking measurements from the white guides, I ripped strips with a table saw.
The existing black/white pair (for me) measured at 2.092″.
In order to get the guides to fit just slightly loose, I ripped the strips grooves a little deeper in steps.
For each step you need to cut off 2 little pieces to test fit.
12 guides and 4 extra.
Don’t forget to lube with lithium grease.
Return to Index
1994 Sink Drain Upgrade
Bruce Matlack matlackwindsurfing (at) gmail.com
This drain install was not easy, however after many hours and custom adaptation work to existing plastic under counter plumbing, it is finished.
Drain fixtures are for bathtubs. Plumbing pipe wrenches were necessary to unscrew Plastic from corroded metal drain fixtures.
Editor’s note: FYI we also replaced our sink drains in out 1993 this year. Original drains were pot metal and so corroded one literally disintegrated to chunks and dust. We found original style Stainless Steel replacements, however, as Bruce sez, installation was still a struggle. Here is an example similar to what we purchased APEX RV Stainless Steel Sink Drain with Removable Strainer, fits (2 1/2 inch) Sink Opening, Fits (1 1/2 inch) Pipe Diameter for RV, Camper, Trailer, Marine Vessel, Cabin, and Bar Sink. – Amazon.com be sure your drain diameter matches.
Ken Stein kastein(at)w1kas.net
Editor note: Ken did some extensive alternator troubleshooting. Below is some of the stuff he found. Way over my drain bamaged head, hope it helps you, The service manual Ken refers to is located here ISUZU TREK DOCUMENTS – Northwest Trek Fun Club along with a treasure trove of other good Isuzu stuff.
I had to learn this the hard way, so here is some knowledge I’ve collected:
– the factory Isuzu alternator B+ wire has been eliminated by Safari, and replaced with a wire direct from the alternator to the larger charge isolator under the hood. The small one is for the solar panel (if equipped)
– this wire can rub through on the Safari-installed aftermarket AC compressor lines. Luckily it did not start a fire in our case but there was zero insulation remaining. Luckily it rubbed through against a rubber AC line not a metal one or this would have ended differently.
– the Isuzu alternator control connector may not be crimped right from the factory. They failed to crimp the insulation grip teeth correctly on ours and after however many miles it broke off… Down inside the rubber seal on the connector where it was invisible till I poked it and it just slid back out.
– the reason the AC and blower motor cut out when the alternator stops charging right is that Isuzu used the L (lamp) output pin on the alternator, which normally grounds to illuminate the dash “generator” warning lamp*, to provide 12V to the coil of the charge relay when it’s working normally, turning on the power to fuses 19 and 20. (See volume 2 Isuzu NPR factory service manual page 8-12). These two fuses power “charge” and HVAC circuits. “Charge” from fuse 19 is a circuit direct to a pin (pin B29) on the gauge cluster that reverse feeds a bunch of diodes. The purpose of this is not immediately clear until you realize that the charge relay GROUNDS the circuit feeding fuses 19 and 20 when the alternator attempts to turn the warning lamp on. Which in turn forward biases the diodes in the gauge cluster, which still has its normal power supplied to pin B30, resulting in the charge, brake, fuel, and vacuum warning lamps all coming on at the same time, along with the vacuum buzzer. (See volume 2 page 8-80 to 8-81). Which is exactly the symptoms I had that led me on this goose chase (along with a failure to charge.)
Hopefully this helps someone understand the Isuzu charging system faster than I did. If people would like I can include the wiring diagrams I’m citing so you don’t need to have the full manual to figure out what’s wrong with your charging system.
* If you look at the wiring diagram for the charging system on page 8-34 you’ll see a diode internal to the alternator that should prevent this from working at all, but it clearly works, so my suspicion is that the manual is wrong here and this pin does not have a back diode in the regulator. This caused me a lot of head scratching.
Bret Medbury islandduo(at) comcast.net
All the Isuzus and some of the earlier GM chassis Treks used a bullet style latch for their screen door like the one in the photos. During Quartzsite Dave (I believe his wife is Cindy) came to me looking for a source. I did not have one then but I do now and now I cannot find Dave and Cindy. If anyone has contact info for them please pass this along or give them my e-mail, or? or? Dave and Cindy own a 1994 Isuzu with the film strips painted on the side.
The latch is made by JR products, part number 10785 and is available from e-trailer https://www.etrailer.com/RV-Door-Parts/JR-Products/37210785.html?
Return to Index
New Lithium Battery Bank location
Dave Martin calpersfatcat(at) yahoo.com
Greeting Trekkers;
Moved the battery bank from under sink to above water heater. Also added two more batteries for a total of six (6) 100ah batteries. Not easy. Not fun.
Lithium Battery Upgrade “keep It Simple” Version
Bret Medbury islandduo(at) comcast.net
In our 1993, Isuzu based, Safari Trek the coach electrical needs had previously been powered by a pair of GC-2, 6 volt Golf Cart batteries. The current pair were eight years old and had been heavily used as 90% of our nights on the road are dry camping. From a preventative maintenance standpoint it was time to replace them anyway even though they passed all tests.
Lithium was a strong consideration here, but I was really hesitant to replace the current shore power charging unit, solar regulator, add a DC to DC charger to protect the alternator, as many others have done to be compatible with the new battery requirements. As luck would have it I just happened to be in a conversation with the wizard (no names here but the initials are Brad Teubner) who said, “no need to change all that. The stock charger will get your lithium to at least 90%, leave the alternator out of the game, and use your solar. His advice ticked many of those boxes.
I did a little research to learn that my existing, near 20 year old, Midnite Kid MPPT charge controller could be manually programmed to satisfy the lithium needs, so ticked that box. I did want engine alternator contribution though as we have no solar on the roof (just portable) and we spend nights in rest areas. I wanted modest recharge capability during next day’s driving. In addition the Isuzu is equipped with only a 75 amp alternator which I did not want to push too hard.
We purchased a 230 amp/hour LiTime Lithium Iron Phosphate (LiFePO4) battery on line paying only slightly more than a new pair of Golf Cart batteries would have cost. We did also purchase an 18 amp DC to DC charger, that is manually switched, to limit the load presented to the engine alternator and control charge voltage. No other alterations were made.
Cleaned up the electrical wiring a bit by creating homemade buss bars, one on the firewall and one in the under step battery compartment.
The new system offers twice the usable 12 volt power over the old system. While the pair of Golf Cart batteries were rated at a total of 210 amp hours, only 50%, or about 105 amp/hours, of that was usable on a regular basis, using more damages the batteries. With the lithium 90%, or about 207 amp/hours is usable without risk of battery damage. The new battery is also a bit smaller and about 50% of the weight of the previous batteries.
On a side note, Excepting only the Battery and DC to DC charger, I decided to attempt the complete upgrade using only “stuff” I already had. I succeeded.
Add A little Insulating Help to Your Fridge
Bret Medbury islandduo(at) comcast.net
A few weeks ago I decided to refinish the door panels on our fridge due to some wear and damage. The panels are home made using 1/8″ Birch plywood. The fridge door was designed to use thicker panels, probably 1/4″, so I had slid cardboard in behind the panels to make up the difference (one photo shows the cardboard still on the freezer door). I was surprised when I removed the wood for the re-finish to find it very cold on the back, fridge side, of the cardboard. This indicated to me that the layer of cardboard was doing a bit, maybe a surprising bit, of insulating on the fridge door.
With that knowledge I decided to go one better than the cardboard on re-assembly by using foil faced bubble stuff, I believe it is called Reflectix, in place of the cardboard. It would not only make up the difference in space, but be a better insulator than the cardboard.
Photos show the process. OBTW way back when, before the fridge was installed foam insulation board was added to both side walls intended to insulate them from outside temperatures, however they also resulted in a slip fit when the fridge went in therefore adding to fridge sidewall insulation.
Innovative sewer hose storage
Greg grrreaat(at) gmail.com
(otherwise known as Grrrreg)
Trekk-ly speaking, I was concerned your shelf idea for dump hose (documented in an earlier Infoletter) gutter housing might restrict airflow on my Onan. I already had the tube/ on a hinge mount for under the back bumper so I modified a 2×4 into a mounting strip “et voila”!
Hook/loop latch to lock it up and ‘Bob’s my Uncle’
Our Isuzu’s have that bottom lip at 60 degree and wanted to use stainless no-touch hardware if possible and came up with the combo of SS bonded washers with SS special finishing (fancy bent lip) washers. It conforms to the angle!
Thanks for putting me on this track!
Squeeto squeeto(at) gmail.com
I had a section of wall where the wood paneling bowed and separated from the frame and foam.
I just used an oscillating tool to cut out the bow and then re-glued it but this gave me the chance to see the blocking for a tv wall mount.
Here are the measurements for a 92 Isuzu 2830:
He says he will repaint later.
Measurements For 92 Roof Truss
Squeeto squeeto(at) gmail.com
I had to replace some roof trusses and this is how they measured:
New “O” ring for leaky water separator
Squeeto squeeto(at) gmail.com
For a leaky water sedimenter (separator), I measured the o’rings on the end drain to be:
I didn’t have a socket big enough to fit the end piece but a plumbing tool seemed to work:
I could have used a pipe wrench but this was cleaner.
I hope that this helps your next newsletter.
Better “Elusive” Fuel Screen modification
Squeeto squeeto(at) gmail.com
Editor Note; The Elusive fuel screen is located within the lift pump inlet (documented in earlier Infoletters) and has been an “elusive” problem for many. Squeeto has suggested an additional pre-filter/screen before the existing water separator. Additional suggestions are included here as well. I found this screen that I believe will be appropriate Amazon.com: iFJF 130306380 Pre-Fuel Filter Assembly Replacement for Perkins 403D-07 403D-11 404D-22 1103A-33 1103A-33T 1103C-33 1103C-33T Engine Aluminum Filter Screen Replaces 0000000038 FINFF30614 : Automotive
What if you ditch that pump filter and just add something like this before the fuel/water sedimenter (separator):
Pros:
easier access
easier to inspect
easier to clean out
no need to replace pump’s bonded sealing washer
possibly will allow you to also ditch the tank screen
Another I-Trekker, no names mentioned here, but his initials are Big Al took this idea and did this;
I posted this last summer sometime after dealing with copious rust coming out of the fuel tank. There was a large quantity, and flushing the tank was not particularly helpful.
I Put this filter in the line leaving the tank and put it near the fuel fill, so I could keep an eye on it. I’ve already had to clean it out!
Greg G W <grrreaat(at) gmail.com>
After being on my ‘to do’ list for many years and several Quartzite Rally Tech Talk’s I dove into replacing the remaining 4 bolts with studs on the Exhaust Manifold.
1st- Locate actual Grade 8 equivalent hardened studs, nuts and washers. This was harder than I thought but eventually went through a fastener supplier direct.
2nd- One bolt was just completely GONE already…so take these Tech chats seriously.
The next 2 bolts came out so easy…”like putting butter on popcorn” but when I moved the wrench to the last bolt and only looked at hard it SNAPPED!
UGH!
Getting access to drill and tap this side of the motor would require a LOT of painful disassembly, the very reason Isuzu owners should do this procedure as ‘Preventative Maintenance’ in the first place!
After much cursing and tearful phone calls to several on Trek Tracks Forum…I thought I would be clever and tack weld a slightly larger NUT to the top of the bolt accessing it from the top of the motor.
Pic #2 shows 5 trys all from the top of the motor (SIDE of the bolt) or trying to reach in from the wheel well, Drivers side (TOP of the bolt) and with different welding wires/tips but no MIG configuration would get a good enough melt to stick. All the while taking very careful precautions to protect the rest of the motor components and not to weld the very broken bolt in place.
Finally- I notched out one face of a good sturdy nut with my grinder to expose the joint and reach in from the ‘top’ of the motor to weld the ‘side’ of the bolt and YAHTZEE!
Socket wrench easily fit over it and bolt came out SOOO Easy.<Pic#3>
Seems so simple now in hindsight.
Editor Note: To prevent future broken fasteners always replace with studs Vs bolts and be sure to replace any lost or broken washers with hardened washers. One member found adequate washers at Tractor Supply. As Greg sez this upgrade should be done before bolts break.
Squeeto squeeto(at) gmail.com
These are on my ’92 Isuzu; I believe that they are stock.
They are not the usual set screw or release notch type.
You remove them by gently tapping on the bottom.
Remember the I-Trek Infoletter is created using content submitted by you people, the owners and users of these fantastic machines. In my opinion there is no better way to help the owners and users than to share between all of us. PLEASE feel free to submit anything that you believe might be helpful to other I-Trekkers to me at islandduo(at) comcast.net at any time and I will include it in the next infoletter.
FYI the Trek Gathering in Quartzsite Az. 2026 will be better than ever as it has been decided to extend the “official” dates of the gathering. It will be from January 15 thru 20 2026. There will new activities and more time to learn about your Trek and socialize as well. Remember these are the “official” dates as many will arrive early and many will stay late, some by weeks. Any questions feel free to e-mail me.
I apologize for the lateness of this issue, initially I was short material for it, even after begging, so I resorted to snitching good stuff from Trek Tracks. In the end I have a superfluity! Probably the longest I-Trek Infoletter to date. If you enjoy it please contribute to the next one.
Bret