Generator test adaptor? generator testing?

[6x6XL]

So I believe that I am having an issue with either my generator, generator harness, or regulator. the gauge is constantly on left side of the yellow section and will occasionally be in the yellow section. I just replaced the batteries (3 weeks ago) with 2 deep cycle/ rv batteries. they were at about 12.8 volts per when I put them in and now sit at about 11.8v and 11.6v with the truck running at idle. ive had enough vehicles with the alternator go bad to recognize some signs such as dimming lights and weak voltage.

I looked through the tech manual and it references a test adaptor that goes in the generator harness and test procedures. Does anyone know what is inside that test adaptor? can one be made or does anyone know where to purchase one? I found some on ebay but they aren't for me truck specifically.
what would be a better way to test without adaptor?

when I get the time im going to start replacing all the battery cables and terminals.

What does it take to do a 60 amp conversion? I have seen wiring harness replacements for this a couple times for other trucks.

Thanks you.

 

[nattieleather]

The test sets are not truck specific as they would work on any M series truck with a gas motor and generator and voltage regulator. Basically the kit provided a new cable to go between the gen and the regulator with spots to hook a VOM to get a look at what the system was producing. It also gave a set up to hook up to the distributor and spark plug to be able to properly time your motor. If own any M series vehicle that isn't a diesel with an alternator then the kit is a must. Pick one up off of ebay and you'll be good to go. Here is what one looks like

Again it's a must have for an older with the waterproof system.

To convert to the 60 amp alternator you need the kit the army came out with in the late 70s and early 80s to do just that. You can find them if you look around. The good think is they were made for the M35s so it will work in the M211/135 with out to much problems.

 

[6x6XL]

Also, does the park brake, obviously not the hand brake on the floor, but the switch on the dash, use voltage while its on and just sitting there?

 

[hendersond]

I believe it does.

 

[6x6XL]

yeah I agree I think it was pulling off the batteries while it was sitting in the driveway. the label for is faded but I it states its for temporary parking brake only

 

[nattieleather]

That temp switch activates a solenoid that puts air to the air pack and thus applies the brakes of the truck. That's why it's a temp brake and not a long term like the regular e-brake is. And yes it does draw power when it's applied.

 

[butch atkins]

And yes the switch causes SIS (Self Inflicted Stupidity) I know someone who took his M211 to get a stuck truck out of a field!alcohol related and not his own field.said M 211 driver got out of truck and engaged temporary parking brake hooked up to stuck truck and promptly dug the wheels on M211 in because with brakes engaged it spun the wheels with least brake pressure ,while dragging the wheels that were locked up.Both vehicles were able to make an exit through the hole in the fence. I can only wonder what the farmer thought when he saw the 200+ yd 8 ft wide 2 ft deep mud track through his field.oh and I promptly disconnected the temporary parking brake switch ASAP to avoid making the same mistake twice!

 

[cmpman]

That temp switch activates a solenoid that puts air to the air pack and thus applies the brakes of the truck. That's why it's a temp brake and not a long term like the regular e-brake is. And yes it does draw power when it's applied.

Not on any M135 I have ever seen. The switch activates a solenoid that traps applied hydraulic brake pressure into the brake system. To use it, you can energize the solonoid either before or during applying brake pressure. To release it, you turn the switch off and the pressure will return to zero. It is not for long term parking of over an hour. We had a warning on this system that even the loss of a couple of drops of brake fluid while the emergency park brake was applied caused the emergency park brake to lose effectiveness. In Canadian service most of them were disconnected, and this trend continued to the later M35 Canadian. The temporary park brake was especially good during winching operations as it saved you having to hold the brake pedal down.

Regarding the generator test sets, we rarely used them (actually read never) in service. It was quicker to change the regulator and if that didn't work, we changed the generator. Regulators did fail occasionally, and we rarely changed a generator. There is a timing light adapter and a tach/dwell adapter in those kits that is very useful, and they are worth the price of the kit alone.

Conversion to the 60 Amp alternator is an easy one, and very effective for charging. You remove the old generator and regulator, install the new 60 Amp alternator in the place of the 25 amp generator, and there are only two wires to hook up....3 if you include a ground cable. A large wire of about 8 gauge is run from the battery to the battery terminal on the alternator, and an ignition switch controlled power wire is hooked the the small wire coming off the alternator. You should also run a ground wire from the case of the alternator to the frame of the vehicle. I have found the 60 amp alternators to be slightly less reliable than the old 25 amp generator systems, but well worth the trouble as the charging is far superior. The alternator was a drop in to the same mounts as the old generator, and the pulley from the generator fits onto the alternator. One caution though is that the ignition controlled wire to the alternator must be of proper field voltage. If you tap into a source of power that is of reduced voltage, then the alternator will overcharge in an attempt to bring the field voltage up. I discovered this when I installed one of these alternators on a British FV432 APC and inadvertently tapped into a power source that had a resistor in line.

 

[6x6XL]

Thanks for all advise. The guy I got my truck from had disconnected the switch originally and hooked it back before I got it. He told me of a truck he had in which the switch failed inside (the switch) and locked up the brakes going down the road so he has never trusted them. I only used it as my driveway has a very slight angle to it and I didn't want 13k pounds of truck moving anywhere on its own.

as far as the 60 amp alternator/regualtor...where would I get my hands on one? ive looked all over and I cant find the test adaptor or the 60 amp conversion stuff. I know parts are becoming harder and harder to find so I don't expect an over-abundance, but dang. until I can find the 60 amp stuff, ill order a new regulator from alpha heaven since he seems to have a good amount of parts, install that and see if itll charge the batteries.

I installed 2 new deep cycles at 13.6 v per, took the truck on a couple drives to work and a friends house, lights where dimming, starter was weaker, etc. I then tested them at 11.6v per with the truck running and 11.8v per with it off. the batteries have been on a trickle charger since. but I don't think the truck is charging the batteries while its running.

thanks

 

[NDT]

The M35 conversion harness is really not needed. Just make up a 8 gauge cable going from the 1/4" power stud on the alternator to the + battery terminal on the passenger side. Then splice in a 14 ga wire at the ignitor connector and run it over to the excite pigtail on the alternator.

The electric brake lock helps a lot to use when bleeding brakes by yourself. Pump up the pedal, engage the lock, then bleed the air pack/wheel cylinder, pump up again, bleed . . .

 

[6x6XL]

so is the alternator I need from a m35? im sorry for asking many questions on something that may be common knowledge, but this is my first military vehicle of any kind and first 24v system, so im trying to soak up as much information as I can.

 

[NDT]

so is the alternator I need from a m35? im sorry for asking many questions on something that may be common knowledge, but this is my first military vehicle of any kind and first 24v system, so im trying to soak up as much information as I can.

The 60 amp alternator was used in almost every US tactical vehicle from 1966 to present. Several manufacturers made them, and they are interchangeable.

 

[cmpman]

Off the top of my head, look on that un-named auction site for 2920-00-909-2483. That was the basic NSN for them, although there were some variations. As NDT mentions, they were commonly found on the later SMPs including M151A2s (and possibly A1s?) , very late M38A1s (late 60s to early 70s here in Canada) the M800 series diesel 5 tons, and even the M939 series of trucks used them. I had a quick look on the auction site and they will run form a little under $200 up to around almost $900. You may well find one on the classified section of this site for a more reasonable price.

 

[6x6XL]

great info! thanks fellows. im next summer ill be going through the motor and getting some heavy work done to the truck and this along with a separate 12v system are on the order to get worked out.

 

[hendersond]

I have a 25amp that comes with the purchase of a cab??? I believe we are pealing out of here on Thursday the 23rd at noon.
Looks like 623 miles and 9 hours and 23 minutes from our house. Maybe we will find a motel and stay there and go to Macus's in Custer in the morning.

 

[m1010plowboy]

G749 Low voltage

Just to keep things simple my M207 had some important info drawn and scratched into the hood before I got it. Not saying your batteries are hooked up wrong, but if someone in the future hooks them up incorrectly they'll have similar symptoms to you, ......and only 12 volt. We have turned over a motor with 12 volt so it happens.

If everything is hooked up correct it should look like this fancy schematic. Can you see it, felt pen just above the horns, very technical.



To be sure the kids put the batteries in correct and matched the schematic, they also scratched into the hood, a P for positive and a N for negative.



My M135 had a 24v to 12v convertor hooked up when I got it and it ran a stereo and 2-way radio. It is handy to have 12v for phone chargers. Good luck getting her a little more reliable!

 

[nattieleather]

Not on any M135 I have ever seen. The switch activates a solenoid that traps applied hydraulic brake pressure into the brake system. To use it, you can energize the solonoid either before or during applying brake pressure. To release it, you turn the switch off and the pressure will return to zero. It is not for long term parking of over an hour. We had a warning on this system that even the loss of a couple of drops of brake fluid while the emergency park brake was applied caused the emergency park brake to lose effectiveness.

Okay so I was close...heck it's been um let's see 18 years since I've owned or worked on a M211 so the memory is a bit fuzzy.

 

[6x6XL]

m1010plowboy, that is technical lol. the batteries are hooked up correct as far as I can tell from the manuals and various other info. drivers side ground to chassis ground then cable from positive to the negative on the passenger side battery then from the positive on passenger down to the starter and other fun stuff, looks like 3 cables coming off the passenger side battery and heading down.

Ill also be changing out the battery cables and ends here soon.

night before last (after the batteries had been on the trickle charger all weekend) the needle on the gauge was bouncing from the right side of the yellow to about half way into the green. now ive been told that of the needle is hanging out too much into the green that its bad. im really thinking its the regulator. hendersond is bringing me a different one next weekend (thanks again by the way) ill put it in and see what happens.

next summer I hope to install a Delco alternator and separate battery for a complete separate 12v system for lights and other toys for the truck when I put the crew cab on.

Thanks again everyone. ill post up a couple pictures of my routing and keep posting on this thread as I work things out.

 

[6x6XL]

drivers side batterypassenger sidepassenger side again