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LMTV Maintenance and employee proofing

FLBurner

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Florida
So for context, I am overseeing the maintenance and minor repairs of a 2002 LMTV w/ Cat 3126. It is used as a wildland fire truck by our county land management department but since it is on loan from the state surplus office, our county fleet department cannot work on it, so its up to me or I have to pay a contractor to work on it, which can be done but is a real administrative hassle. The guy that built this truck into a firetruck has since retired and didn't leave a lot of instructions for me.

I have another thread addressing specifically the air over hydro system and the kneeling cylinders but I wanted to post a range of questions pertaining to some other repair and maintenance projects for this group of experts insights.

I want to make sure I'm addressing the proper maintenance schedules and inspections. The truck does not get a lot of constant use but needs to be fire ready with as short as a days notice.

Obviously oil checks and changes, trans fluid checks, axles, hubs, etc. What kind of fluid change intervals would be appropriate for this truck? We don't put a lot of miles on it, so is there a good time interval that would work? Southwest Florida for geographic reference.

Grease fittings? How many are there and are there known lube intervals for them?

Any other maintenance or inspection points or intervals that I need to follow or have our staff perform?


As for repairs currently needed: With repairs, I can spend money where I need to, but I also don't have a blank check to go wild with the truck either.

- The CTIS system doesn't seem to work. I don't care if it works, but one of the tires constantly leaks, but the tire shop reports the tire is fine. I assume the leak is in the CTIS system somewhere so what would be the best way to address that. I've seen expensive delete kits but I've also seen 1/8" NPT to Schrader valves that could be threaded in somewhere potentially?

- There is a check engine light that comes and goes. Does this truck have OBDII or something else?

-The oil pressure gauge dances around with engine rpm. Do I potentially have actual oil pressure issues or is the sending unit a dummy switch? Or maybe just a bad sending unit?

- The upper bushing for the left rear sway bar has gone AWOL. This is a repair I'm perfectly comfortable with, but is it worth doing all 4 corners at once? Upper only? Upper and Lower?

-The ABS light is on, but I have a feeling that may be tied to the faulty CTIS Controller, other threads here mention unplugging the CTIS to see if it clears.

-A state mechanic giving us some one time assistance found that the fuel hand primer, water separator, and fuel heater in the sediment bowl were bad and in need of replacement. I think this is a job I can handle. Do I need the heated sediment bowl or can I just get by with the cheaper non heated bowl? (Florida)

-The mechanic also mentioned that the arm? device? elbow? thing aft of the fuel water separator, that the fuel filter mounts to, was bad. Apparently it was causing the fuel system to lose prime periodically. Is this a commercial CAT 3126 part or specific to LMTVs?
 

Guyfang

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Have you tried to read the TM's for this truck? Lots of your questions will be answered if you do. List the model number and NSN to the truck. Then we can get you pointed to the right books.
 

Mullaney

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So for context, I am overseeing the maintenance and minor repairs of a 2002 LMTV w/ Cat 3126. It is used as a wildland fire truck by our county land management department but since it is on loan from the state surplus office, our county fleet department cannot work on it, so its up to me or I have to pay a contractor to work on it, which can be done but is a real administrative hassle. The guy that built this truck into a firetruck has since retired and didn't leave a lot of instructions for me.

I have another thread addressing specifically the air over hydro system and the kneeling cylinders but I wanted to post a range of questions pertaining to some other repair and maintenance projects for this group of experts insights.

I want to make sure I'm addressing the proper maintenance schedules and inspections. The truck does not get a lot of constant use but needs to be fire ready with as short as a days notice.

Obviously oil checks and changes, trans fluid checks, axles, hubs, etc. What kind of fluid change intervals would be appropriate for this truck? We don't put a lot of miles on it, so is there a good time interval that would work? Southwest Florida for geographic reference.

Grease fittings? How many are there and are there known lube intervals for them?

Any other maintenance or inspection points or intervals that I need to follow or have our staff perform?


As for repairs currently needed: With repairs, I can spend money where I need to, but I also don't have a blank check to go wild with the truck either.

- The CTIS system doesn't seem to work. I don't care if it works, but one of the tires constantly leaks, but the tire shop reports the tire is fine. I assume the leak is in the CTIS system somewhere so what would be the best way to address that. I've seen expensive delete kits but I've also seen 1/8" NPT to Schrader valves that could be threaded in somewhere potentially?

- There is a check engine light that comes and goes. Does this truck have OBDII or something else?

-The oil pressure gauge dances around with engine rpm. Do I potentially have actual oil pressure issues or is the sending unit a dummy switch? Or maybe just a bad sending unit?

- The upper bushing for the left rear sway bar has gone AWOL. This is a repair I'm perfectly comfortable with, but is it worth doing all 4 corners at once? Upper only? Upper and Lower?

-The ABS light is on, but I have a feeling that may be tied to the faulty CTIS Controller, other threads here mention unplugging the CTIS to see if it clears.

-A state mechanic giving us some one time assistance found that the fuel hand primer, water separator, and fuel heater in the sediment bowl were bad and in need of replacement. I think this is a job I can handle. Do I need the heated sediment bowl or can I just get by with the cheaper non heated bowl? (Florida)

-The mechanic also mentioned that the arm? device? elbow? thing aft of the fuel water separator, that the fuel filter mounts to, was bad. Apparently it was causing the fuel system to lose prime periodically. Is this a commercial CAT 3126 part or specific to LMTVs?
.
It might be a good thing for you to have the TM's (Technical Manuals) for your LMTV. There are tech manuals that specify Lubrication Order (-LO) as well as maintenance books.

 

GeneralDisorder

Well-known member
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Location
Portland, OR
So for context, I am overseeing the maintenance and minor repairs of a 2002 LMTV w/ Cat 3126. It is used as a wildland fire truck by our county land management department but since it is on loan from the state surplus office, our county fleet department cannot work on it, so its up to me or I have to pay a contractor to work on it, which can be done but is a real administrative hassle. The guy that built this truck into a firetruck has since retired and didn't leave a lot of instructions for me.

I have another thread addressing specifically the air over hydro system and the kneeling cylinders but I wanted to post a range of questions pertaining to some other repair and maintenance projects for this group of experts insights.

I want to make sure I'm addressing the proper maintenance schedules and inspections. The truck does not get a lot of constant use but needs to be fire ready with as short as a days notice.

Obviously oil checks and changes, trans fluid checks, axles, hubs, etc. What kind of fluid change intervals would be appropriate for this truck? We don't put a lot of miles on it, so is there a good time interval that would work? Southwest Florida for geographic reference.

Grease fittings? How many are there and are there known lube intervals for them?

Any other maintenance or inspection points or intervals that I need to follow or have our staff perform?
Best to read the -10 manual and follow all it's guidance. There are a LOT of grease fittings. You will want to also read the -23P manual for all the annual and bi-annual services. Treat the air system with EXTRA attention and service the dryer regularly. The compressor's like to eat exhaust valve springs if the system is neglected.

As for repairs currently needed: With repairs, I can spend money where I need to, but I also don't have a blank check to go wild with the truck either.

- The CTIS system doesn't seem to work. I don't care if it works, but one of the tires constantly leaks, but the tire shop reports the tire is fine. I assume the leak is in the CTIS system somewhere so what would be the best way to address that. I've seen expensive delete kits but I've also seen 1/8" NPT to Schrader valves that could be threaded in somewhere potentially?
You can simply remove the wheel valve assemblies and put the shrader core from the valve assembly into the wheel valve stem. It will work like a normal tire at that point but the valve stem is a little weird and some inflator fittings don't work on it.

- There is a check engine light that comes and goes. Does this truck have OBDII or something else?
J1939 heavy duty truck interface. You will need a scan tool or dedicated laptop to speak to it and IMO this is absolute must-have if you plan to service the truck yourself.

-The oil pressure gauge dances around with engine rpm. Do I potentially have actual oil pressure issues or is the sending unit a dummy switch? Or maybe just a bad sending unit?
Concerning. Because these trucks had poorly designed oil pumps that CAT redesigned several times. Take a reading with a mechanical shop gauge but having seen what these oil pumps do I would just change it out.

- The upper bushing for the left rear sway bar has gone AWOL. This is a repair I'm perfectly comfortable with, but is it worth doing all 4 corners at once? Upper only? Upper and Lower?
No anti-roll bar on the front. Just do them all.

-The ABS light is on, but I have a feeling that may be tied to the faulty CTIS Controller, other threads here mention unplugging the CTIS to see if it clears.
It is not related to the CTIS in any way. You need the scan tool / laptop again......

-A state mechanic giving us some one time assistance found that the fuel hand primer, water separator, and fuel heater in the sediment bowl were bad and in need of replacement. I think this is a job I can handle. Do I need the heated sediment bowl or can I just get by with the cheaper non heated bowl? (Florida)
The heater is to melt any frozen water in the bowl so it can be pumped out with the hand primer - this is in the -10 manual as one of the PMCS check points (weekly or monthly I think). That said you probably don't need it in Florida.

-The mechanic also mentioned that the arm? device? elbow? thing aft of the fuel water separator, that the fuel filter mounts to, was bad. Apparently it was causing the fuel system to lose prime periodically. Is this a commercial CAT 3126 part or specific to LMTVs?
The fuel/water separator with primer is not a CAT part. Baldwin makes the filters. Also these trucks ALWAYS have bad fuel lines. There are three primary fuel lines - supply, return, and for the HEUI pump. Remove them and have new ones made by a hose shop. They will be disintegrated from age and could be sucking air.
 

FLBurner

New member
9
8
3
Location
Florida
Have you tried to read the TM's for this truck? Lots of your questions will be answered if you do. List the model number and NSN to the truck. Then we can get you pointed to the right books.

Ive looked at them a bit. I have a copy of the big manual as well. Ill have to do some hunting for the model and NSN. Im not currently on site with the truck
 

FLBurner

New member
9
8
3
Location
Florida
Best to read the -10 manual and follow all it's guidance. There are a LOT of grease fittings. You will want to also read the -23P manual for all the annual and bi-annual services. Treat the air system with EXTRA attention and service the dryer regularly. The compressor's like to eat exhaust valve springs if the system is neglected.



You can simply remove the wheel valve assemblies and put the shrader core from the valve assembly into the wheel valve stem. It will work like a normal tire at that point but the valve stem is a little weird and some inflator fittings don't work on it.



J1939 heavy duty truck interface. You will need a scan tool or dedicated laptop to speak to it and IMO this is absolute must-have if you plan to service the truck yourself.



Concerning. Because these trucks had poorly designed oil pumps that CAT redesigned several times. Take a reading with a mechanical shop gauge but having seen what these oil pumps do I would just change it out.



No anti-roll bar on the front. Just do them all.



It is not related to the CTIS in any way. You need the scan tool / laptop again......



The heater is to melt any frozen water in the bowl so it can be pumped out with the hand primer - this is in the -10 manual as one of the PMCS check points (weekly or monthly I think). That said you probably don't need it in Florida.



The fuel/water separator with primer is not a CAT part. Baldwin makes the filters. Also these trucks ALWAYS have bad fuel lines. There are three primary fuel lines - supply, return, and for the HEUI pump. Remove them and have new ones made by a hose shop. They will be disintegrated from age and could be sucking air.

This is all great info, thank you.


I knew the CTIS wasnt tied to the ABS at all but I had read on this forum that people had noticed a link between a bad CTIS controller and triggering a false ABS light. Ill see if one of the fleet guys would be willing to at least scan it or loan me a scanner.

As for the fuel hand primer, I have located a source for replacement primer assemblies and separators but im actually referring to the assembly directly rear of that unit on the block that holds the much skinnier spin on fuel filter.

I will probably do the fuel lines as you have suggested.
 

GeneralDisorder

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Portland, OR
As for the fuel hand primer, I have located a source for replacement primer assemblies and separators but im actually referring to the assembly directly rear of that unit on the block that holds the much skinnier spin on fuel filter.
That is the factory CAT fuel filter. All those parts will be available at any CAT dealer - just bring them the engine serial number off the rocker cover.
 
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