I have modded 5 m35a2's (in addition to other vehicles) for deep water fording over the years-- Four were for various agencies, the fifth is my own truck. Right out the gate, don't waste your time looking for a deep water fording kit-- they are expensive when found and don't offer much for what they are.
To set it up right, so as to be reliable and safe, you need to do the following:
- first off, make sure all seals are in excellent shape-- not only all axle seals , but shift boot, etc.
-remove all breathers and run 1/4 inch lines minimum to all axle vents, transfer, bell housing (actually bell housing line ideally should be larger since it feeds the bell housing and trans (via the input shaft).
-if you have the 60 amp alt, remove the voltage adjust plug and run a line to that port as well (that port is 1/8" npt and feeding air to it will assure that nothing can breach the alt). I learned this one over time after examining some alts that failed during flood rescues.
- I like to use a ball valve on the bottom of the bell housing (more convenient) but the plug will work just as well
-raise master cylinder vent, fuel tank vent, and airpack exhaust vent (do not rely on the one way vent valves as they fail at the most inopportune times)
-raise your air intake-- the original kit used a flex hose-- those are garbage. I had the intakes made from 4" steel exhaust pipe to bring the intake to the cab roof level.
- put a "T" on your slobber tube, route the horizontal outlet up along side the air intake, and put a ball valve under the "T" to allow direct to ground routing for normal operation.
- tie the lines from the axles together via any manifold design you like, route to a regulator (with gauge preferably) set to supply 3.5 psi
-tie lines from transfer, bell housing, and alt to second regulator set to 3psi (the reason the axles are higher is that they are lower and subject to higher static pressure when fording
-tie both regulators to an air valve of your choosing-- an airshift switch works nicely.
-find some way to seal your fuel tank cap effectively (the best is to have an m35a3 tank with the threaded cap that can be properly gasketed). The other options that I have seen used are a welded on collar around the filler that can accept a plug, or, plumbers putty tightly pressed around the cap right before fording (the caps seem to be a weak point when fording extensively)
-liberally grease (with dielectric grease) all exposed electrical points like battery terminals, battery cable to starter post, etc.
The above is just the beginning. On the trucks I modified, the operator procedure went as follows:
Driver would stop before fording, get out and shot valve on slobber tube to redirect to raised hose, shut bell housing valve, press a bead of plumbers putty around fuel cap (if applicable), get back in and slowly enter water, flipping the air switch on right as the front wheels would enter. Fording would then commence for whatever purpose (usually flood rescues as my clients are fire depts/rescue squads).
Immediately after fording:
-shut off air just as truck leaves water, then stop, get out and open slobber tube valve and bell housing valve; clear radiator of debris, do a quick walk around, then get back in and do a few sequential slow speed stops to ensure brake function.
Within a few days of fording:
-inspect all gearboxes, brake fluid, engine oil for water infiltration, inspect wheel bearings and repack where needed, inspect front knuckles, inspect steering gear box, open/drain/dry all compartments.
-take off turn sig and brake light covers and check for water intrusion
-remove plumbers putty from around gas cap (if applicable)
-check fuel for water infiltration
Some other notes and observations: pressurizing the axles and gearboxes serves to limit the possibility of water intrusion thereby saving the need to replace gear oil. Is it possible that water could still find its way in? Yes, but in that instance, the pressure helps to mitigate the amount of water that gets in during a fording exercise. Wheel bearings still need to be inspected and possibly repacked as well as the front knuckles as they technically would not see much in terms of pressurization if seals are correctly in place and doing their job.
The above mods and procedures have been used on many flood rescues going back as early as 2006 and none of the trucks reported any significant failures (also this setup has been modified for other vehicles to include some m35a3's a pair of 900 series 5 tons, and an m813 ). Be forewarned that it is very labor intensive and setting the truck up right can be costly. But, assuming everything is done right, it can be done reliably and safely.
Z
