M925A2 Fuel Sender Calibration, Adjustable Bracket

[74M35A2]

Replaced fuel level sender. New sender has plastic float, and is height adjustable via sliding bracketry and screws. It is working but not exactly accurate (ran out of fuel before reaching "E"). I once saw the adjustment procedure for this, and have not seen it since. If I remember correctly, it was just a simple measurement. TM just states how to replace sender, not calibrate it, unless I missed it. Unsure if the sender came with instruction of how to do so, because it has been a while now, but usually this is not the case. I'd like to calibrate it correctly, and not just "keep it above 1/4 tank". If somebody has or knows where this procedure is, it is greatly appreciated. Otherwise, it will be trial and error as best can be with a tape measure and gauge readings. The darn angle fill neck tank won't let you fill it all the way up anyway. I am prepared for lashings if somebody posts a TM link.

 

[dmetalmiki]

Fuel gauges and senders are a nightmare on military vehicles. And if one works correctly with full range indications, its a miracle. I get the level of the fuel to the Least pick up point, and then adjust to make sure the indication gauge reads empty. (plus 1 gallon.) Just my modus operandum. I hope yours works full range though, good luck.

 

[74M35A2]

You're zeroing in on my exact concern. Sender and gauge both "work". With the combination of the angle fill neck not allowing a full fill (forced expansion room), and the sender not yet being calibrated (height via sliding sender bracket), my full fuel is at 3/4 tank, and the truck has run out at both just less than 1/4 on level ground, and at 3/8 when going uphill. So, it is not much use right now. I'd like to at least get the E range working better, since that is what it is all about anyway. I also need to pull and check my dip tube to make sure it is not corroded off as others have found. I understand there is no dampening or baffles (I don't think), and that is fine. Really just want to calibrate "E" so it means something. Running out at 3/8 sucked, there were passengers in the truck, and luckily I thought quick and engaged the starter and held crank on to use the steering for two 90 degree turns to glide into a safe spot to crash land. Ever try to steer a rolling yet stalled 939? Not very easy, or even possible I think. At least did not seem so when I pulled with both hands down on the same side of the steering wheel.

 

[dmetalmiki]

Yes that sucks. So I would go with the "definitely empty" Plus 4 gallons. ( run-out reserve)and zero fuel on the gauge. At this point add fuel and see the first indication on the gauge indicates a true value. ( which is ok for you to interpret on journeys).