"Major Zippidy" M923 build

[juanprado]

dash fan

Uncle sam outlet had some nice nos metal dash fans with hi/off/low switch for $20 so I took the plunge.

I used a piece of universal angle bracket that Home depot sells with holes and spacers already cut out. Maybe 4 inches wide or so. I drilled 2 holes into the u shaped hard top mounting lip. Nothing in the way to hurt or interfere with the hard top or windshield frame. I ground the nuts flat on one side so they lay on the bottom of the inside of the lip and could not turn when fastened.

I grounded the 2 wire fan to the mounting bracket and ran the hot wire down the air wiper tubing and existing grommet in the dash.

Fan has nice airflow on high and also helps on rainy days to keep the windshield from fogging up.

 

[juanprado]

coolant filter

I was surprised that our trucks do not have coolant filters since they are standard with most civy trucks. Also not knowing if the coolant had the proper chemicals in the mix for diesels concerned me. Coolant filters not only filter the junk out but have the proper diesel anti freeze additive inside that is time released. I also found nastys in the bottom of the radiator and the coolant overflow tank when I flushed everything when my water pump was changed and wanted to get all the junk out.

I used a filter base off a detroit that came with a heavy duty L mounting bracket and the 2 shut off valves with the 5/8 hose bibs on ebay off a truck scrapper for cheap. Don't know what model as I did not get that info.

I do not have welding or fabrication skills or ability so I used a piece of heavy duty angle iron from Tractor supply bolted to the 3 existing holes on the bottom of the heater box frame. 2 already had bolts and the last one was empty. Just change to longer and I also used lock nuts. I did drill and add a small 1/4 bolt through the angle iron and the diagonal existing brace on the heater box. On the back closest to the firewall, I drilled a hole in the cab/hood alignment brace and used a shock bolt spacer inbetween the brace and angle iron as an extra security point. I drilled and bolted the filter L to the angle brace. It is rock solid and does not interfere with anything and the hood clearance is no issue. I wanted it all to look stock and clean.

One of the coolant filter shut off valves leaked and it was a simple fix to unscrew the handle, unscrew the nut at the top and replace a simple o ring that was old and squared from time. Standard o ring available anywhere.

My steel shut off valves on the engine were missing the handles and had bent stems. I replaced them with brass take offs from a m931 courtesy of CsmDavis earlier scappers. One of the valves was mostly rotted away at the hose bib and would have certainly been a point of failure in the future. Might want to check those non brass shut off valves and see if they are weak!

Installation was pretty straight forward. Add a closed nipple, T fitting, and a 5/8 hose bib. Napa sells the hose bibs in the balkamp line. Plumb everything. I did not have to add additional valves as the coolant base had the 2 extra new ones I needed.

I used double walled red heater hose as the silicone stuff was out of my price budget. New stainless clamps. I also changed the heater core hoses at the same time. I was surprised as to how much nastys were also in the heater core and flushed it for some time till she was nice and clean water.

Simple mod and peace of mind that the coolant will have the proper level of dca and the nastys will be filtered out.

 

[srodocker]

Any updates?

 

[MtnSnow]

Great thread!

 

[Carlo]

Juan never surprises me. He was one of my first contacts on SS. Never did he turn his back on me with my hundreds of questions..
Good man!

 

[juanprado]

Any updates?

No, I have not done anything worthy of posting. I thought I would do some work on my Christmas vacation but it was rainy here and cold. (not anywhere as frigid as the rest of the nation but my internal thermometer reads cold a lot higher than most of you I suspect)

I did have to change my alt and one battery due to some dummy leaving the power switch on Again Seems I did not learn my lesson the first two times since I got the truck 2 years ago...... and trying to start it with weak batteries.

I did change my heater core but I posted on its own thread as there was not any M939 heater core threads or info I could find and I thought others might use the info.

Should hopefully start to get more done in the new year like mounting my tow bar, 2 led truck lite spots, 2 rear facing auxiliary sealed beam spots, and some double halogen amber rotating warning lights I scored chap on epay. This is like owning a boat- endless money pit and you are never finished but I love it.

 

[juanprado]

Juan never surprises me. He was one of my first contacts on SS. Never did he turn his back on me with my hundreds of questions..
Good man!

Thanks for the kind words and I also love your cool toys Wish you were just a little closer....

Happy and prosperous New Year to you and your family Carlo!

 

[wrenchturner6238]

Very nice thread and a lot of good information.

 

[juanprado]

self cancelling turn signal

Not my original idea as Suprman had posted it originally but I like to R&D (rip off & duplicate)

You will need a black turn signal switch off a hmmv nsn 6220-01-408-7785, part 19207-12447083 as it has the external cam on the top to reset it self when tripped.

Remove the original turn signal switch is easy: one cannon plug and a hose clamp

To prepare the black one, flip it over and there are 2 black plastic plugs. I removed those so I could remove the mounting blocks that slide in a rail as that mounting is not used on a 5 ton and I wanted the 2 slots for the using hose clamps.

Have truck wheels straight and steering wheel centered. There is a metal cup on the bottom of the steering wheel held by 3 screws. Remove the left 2 screws and replace with about 3/4-1 inch longer. They are common wood/ sheet metal screw threads. I actually had some from something else? but you should be able to match and pick up at any hardware store. I made a sleeve using a rubber vacuum line but that looks like it will not hold up well. Use maybe nylon air brake tubing or a cut up bic pen. Not sure it is needed but I wanted the cam to bite the bushing and not the screw directly.

I used 2 thin 5/16 stainless hose clamps range 1 15/16- 2 1/2. I could not find local nor NAPA so I ordered from McMaster carr 5388k34 which are made by breeze #3532. Regular hose clamp is too wide to fit the 2 slots and I did not want to cut housing. Make sure everything is snug as it has a lot of action because the cam hits the screw every time the wheel is turned.

I left a little gap inbetween lower cup and turn signal cam. It is easy to eyeball and can be readily adjusted by moving switch up or down.

Easy mod and real nice not to have to manually cancel turn signal switch on a turn!

 

[machinist75]

Juanprado, trying to pm you but your inbox is full.

 

[1 Patriot-of-many]

Nice job on everything! This thread gives me ideas.

 

[juanprado]

Adding a power steering cooler

I got a power steering cooler off an A2 from Matt (castlebravo) and installed it recently.

Pretty straight forward mod. I did it to keep the fluid cooler and add some capacity as heat is more my problem where I live than cold. think hot + 100% humidity

The cooler has 2 brackets with loom clamps that bolt to 2 of the radiator 3/8 tank bolts. Old bolts were long enough to reuse. It has 2 ports for standard 1/2 oil hydraulic hose with hose clamps. I got two pieces of hose 4ft and 3 ft of Weatherhead H10008 (H10108 will also work fine) from NAPA.

Disconnect your low side push on hose from the steering gear (too short to reuse) and run the shorter hose from the gear to the cooler. Run the longer hose from the other cooler port to the pump (other hose was not used either).

I reused the OE clamp to hold them together and a scouting leader had given me a ton of wiring loom leftover form a job. I enclosed all the hose in loom to give it an extra layer of protection and zip tied it together. There is plenty of room for it to hang down and not in the way of anything. The splash shield fits over it just fine and there is plenty of slack for movement but not close at all to anything to interfere.

The oil capacity increased by 37 ounces. I used plain ole power stg fluid as it has antifoam and antiwear additives specifically for power stg. It also mixes fine with transmission fluid. Mine appears to have been filled with dexron like my transmission.

A couple of turns and the pump burps all the air out and job finished.

 

[juanprado]

Just an update as it has been one year since I installed a coolant filter.

I had flushed out the system extensively 3 years ago when I changed the water pump and last year when I repaired the heater core. There had been a lot of nastys in the radiator, coolant tank, and heater.

Still found some sludge in the filter after cutting it up. It does confirm these trucks need a coolant filter and dca chemical in the coolant.

 

[goldneagle]

Just an update as it has been one year since I installed a coolant filter.

I had flushed out the system extensively 3 years ago when I changed the water pump and last year when I repaired the heater core. There had been a lot of nastys in the radiator, coolant tank, and heater.

Still found some sludge in the filter after cutting it up. It does confirm these trucks need a coolant filter and dca chemical in the coolant.

I do the coolant bypass mod to all my MVs. Now I feel the cost is worth it.

 

[wsucougarx]

How did I miss this thread? Glad I found it. Got some great ideas!

 

[grendel]

Thank you very much for this thread. I'll be doing some of the mods.

 

[juanprado]

New socks and shoes

Thanks to help with Zev and his tire guy we are sporting some new footwear.

Goodyear MV/T 395-85-20 all around. 4 tires brand new with zero miles and 2 like new. I wanted the good years because of the speed rating.

The front wheels are New Camian steel wheel assemblies that I got 3 from GL Ft. Polk. They are beveled on both sides so they can be mounted anywhere unlike some other camian wheels. They look exactly like fmtv wheels but are stamped BAE and camian assy. NDT believes they are the same except that they have run flats. Unknown what type? We did not disassemble but used them as is with removing the ctis hoses, valves, and brackets and inserting a standard valve core. The valve is not threaded externally at the top so no cap option. I wanted the security of the run flats on the front and what is a few more lbs since I had already also added a winch. Other one will become the spare.

Rears are standard new 5 ton combat wheels with the 3/4 studs I picked up in OKC.

Thanks to an excellent post by peashooter with the exact specs, I felt very comfortable mixing the types of rims as they are literally almost the same with just a slight diff. fmtv to 5 ton combat wheels. Felt like tracking and steering performance was the same on the interstate on the way home.

Valve stems are NOS valves picked up at GA Rally that are 2 piece spuds and large bore valves. Unsure of what they fit but worked great. The M939's dual direction valves are real pricey and I don't see rotating the tires anytime soon.

Seems to ride better with the new shoes and weight from the winch. Picked up 4-5 Miles. Top speed 63/64 with the NHC 250. With the 11:00's my top speed was 59/60.

I think I will change the shocks next to Gas charged Monroe's and ditch the old school hydraulic shocks to see if that also gives me a smoother ride.

Only hitch is one of the like new tires had a puncture hole, last one of course and had to come off to get patched. I am 100% Hispanic but have some Murphy mixed in.

 

[turnkey]

Great build...Lots of good info on the mods also...Nice to readed up on..

 

[goldneagle]

I am glad we were able to get you set up with the new shoes on your truck. It was a bit "soggy" maneuvering those heavy tires and rims around. (we had heavy rains all week including this morning.) But the results were good. Thee truck looks more manly with those wide Super-singles on it. They match the "shoes" on my M923 truck. My road service guy Vince does great work with these heavy tires and rims. He has been assembling and mounting my truck tires for years now.

 

[juanprado]

Winch counter weight trays for storage

Just wanted to share an idea that I did when installing a winch on my truck. I also installed the M936A2 front counter weight trays as I thought they would make some cool storage. Only the A2 have them because the 8.3 motor is lighter than the nhc 250. The trays already have 2 bolt holes for the weights.
I used 2 long bolts with washers/lock nuts to go through multiple links of the big wrecker BII chain. I also have a smaller chain that I used to have slung under my bumper clipped in. Everything is rock solid and no chance for it to go astray. Easy to unbolt in minutes. I did not want to clutter up the tool boxes and figured I did not use these often and a good place to store them and likely closer to where they would be needed. I sprayed the chains with black rusty metal rattle can so they would not rust as quickly.

On the other side, I got a dual ammo box tray for hmmvw gun truck beds I believe off ebay. I cut off the smaller .50 cal tray and used a large tall 1500 round 7.62 mm box that fits the tray perfectly and the hold down straps. The straps have a cam lock action and are snug. The tray is bolted down with 6 1/4 bolts and lock nuts. It is solid and does not interfere with the winch or hood. I use it to store axle clamps, tow bar feet, Armour feet, extra pins, and a civy tow strap. All the goodies for towing right at the source.