MY NEW 7K M1028 & 2 Problems..

[decodeme2]

Hi Guys,
New guy here..I bought my 1987 M1028 at an auction about 6 months ago for $7,000 dollars, From the Navy. I would never have paid so much if it wasent exceptional. It only has 5000 Orginal miles and was kept in a hanger its whole life. I have the records/oil changes that add up, Looks like the day it was made. I plan on keeping it that way. Now the Problems.
Charging system sucks. I can charge the 2 new L series batteries up, and within a few days they are dead. So, i put the quick disconnet twist thingy on them and that helped. But after some running the front battery is almost dead. The rear battary reads 14 volts..running. The front reads 11.7 volts running also..I swapped 2 wires a yellow and orange i think on a block, over by the windshield washer bottle under a black cover . I was told at the Aberdeen Meet that it would help the batteries charge. Now I researched it and find out that there is a switch or something that checks the other battary every few seconds and charges that battary if it is low..I think i need to replace it if i knew what it was called. I have a volt meter guage that came on the truck and it always reads in the green. Guess its reading the rear battary..truck is still 24 volt. It has the orginal type large 100 amp altinators. Now I know why it has only 5K miles on it! The battaries were always dead. The belts are new and tight. Maybe 1 alt is not putting out...sounds like an old gird friend i once new,.There must be something, a short draining them. I would love to fix this problem, or find some who can fix it within 50 miles of me. After I fix this problem, I can try and get the glow plugs to auto work. I got the truck the navy, they bypassed the controler with a button. I replaced the board under the dash in the black plastic box, and nothing, same. But it starts great and runs perfect when you use the button. Wait for the light to go out and crank it.
The local garage told me no way./to leave...hehehehe....
Owell, any help will really help!..
Cevon..
Lothian Md.
Near Annapolis.

 

[mangus580]

Step one... have the drivers side alternator checked out. Your short is in your '12v' system. My guess is, even when its running you are losing voltage, that the alternator is shot. As far as the wires you switched, I am not so sure on that, did you do that trying to solve the problem?

Maybe you can snap a shot of the wires you switched?

A simple way of testing that alternator for the short, would be to unhook everything, and see if the batteries hold. If so, then you are probably looking for a major wire rubbed through somewhere, thats not fused.

Hope this helps

 

[decodeme2]

THANKS!, Will try that...!!Will get more pics..
Cevon...

 

[Armada]

Welcome decodeme2. Wow! That's a straight and clean, green machine! Glad you are keeping it original. Good luck, you'll get it working right.

 

[clinto]

Wow, that thing is clean. Congrats and good luck with your electrical problems. I have always hated electrical gremlins the most.....grr...........

 

[Ambulancechser]

I read your original post a little closer ,decodeme,and realise that you do ,in fact,have the m-1010 charging system in your 1028.This is a little unusual,as very few 1028's were ordered with the 28 volt dual alt system.
Any charging fixes for your truck will be the same as for an m-1010...the charging system is very different from other cucv's,and,sadly,never seemed to work perfectly,even when new!
If youv'e diagnosed the problem so far it means you have a decent multimeter.Don't lose it.You'll need it.
The pos post on the rear battery(the one that goes direct to the + 24-v bus on the firewall) should read 28-volts or so.if it dosn't (i think you mentioned 14)then something is wrong with the LOWER alternator.The one thats hardest to get at .Could be someone messed with the wiring at one time,or the regulator is pooched.
The pos post on the front battery(the one that jumps between pos and neg terminals) should read 14 or so.If it dosn't or can't maintain 14-v under load(ie:headlights on high,fan on high,and wipers on high)then something is likely wrong with the UPPER alternator or it's wiring.This is the alt that is controlled by that magic box on the drivers side fender.The Twinput Voltage Regulator senses voltage from the front pos terminal and,by useing a timer and a solid state switch,(read"not user servicable")varies voltage to the upper alts field wire,varying it's output .
The upper alt should cycle every minute or so.If it dosn't then something is wrong with the twinput regulator(the little black box behind the blue one) or all the attendant wiring.
I had something screwey with my upper alt,and it turns out that most problems with this system can be traced to the regulator/duvac combo.go to the tech manuals section on this forum and ferret out the info. I ended up removing the duvac setup and one alt,kept it 28-volt and used a battery equalizer( WWW.vanner.com )to get 12 volts.Works great but fairly pricy .good luck and keep us informed please!

 

[mangus580]

Ambulance chaser, what are you talking about? ALL CUCV's came with dual alternators. the Duvac system just uesd a heavier set.

 

[Ambulancechser]

Mangus...Your correct,all cucv's came with dual alts,however the m-1010's and apparently a few 1028's,came equipped with dual 28-volt leece/neville alternators at 100 amps each.
The wiring for this particular charging system is different in many ways from a standard cucv,the alternators are in different locations and mounted in a different way,The wiring is not standard,and this Duvac/voltage regulator setup is involved,making a confusing mess of it all.It took me weeks to figure just how it worked,let alone fix it.(still a hack job,i'm not done yet).
Trust me magnus,i own one.Find an unmolested m-1010 and have a look fo yourself.Better yet,look down in the tech manuals section on this site,and look up the charging system for an m-1010.
One of these days i'm going to follow my own advice and get hold of a digital camera.That will make things much easier.

 

[mangus580]

now that I read through his post, I see how you were able to tell he had the 1010 system. Sorry for the 'correction'

Funny thing is, I was wondering what he was talking about

 

[Ambulancechser]

Mangus...no worries...i get the same thing a-lot.You should have seen the look some "experts" gave me when i was searching for a battery equalizer."You want a what?"
(insert involved explanation here)Their response? My response?
Finally found what i wanted at an RV place that sells coaches(the big million dollar kind)Turns out an equivalent to a duvac is used to split battery banks,so you can get 12-v out of 24 and still keep the bank properly charged Thanks to the guys at Woodys RV World in edmonton alberta,who took the time(2-hours!) to track down what i wanted online,then found a local distributor,Then made a phone call,and,one salseman to another,saved me 200 bucks!
Now i can keep the 24-v accesories

 

[Boatcarpenter]

Maybe this is how you guys needing 12v trailer brakes can get it.

http://www.smithae.com/surepower.html
http://www.thinkin3d.com/unimog/converter/pages/duvacdia.htm
second link courtesy of Google and Greg Maiser

 

[decodeme2]

Thanks guys,
Yes i have the large alts, top one and bottom one. guess the m-1010 setup..I was told its rare on a 1987..I would like to keep it orginal. I will have a crack at it again with my Volt meter. I think i have a bad altinator. Also maybe a bad blue box..the one that checks the voltage between the two, if i understand correctly. I will add a picture of my setup and the wiring on the terminal block on the drivers side by the windshield washer container. I will have to have my altinator rebuilt or buy an NOS one. Im sure they are expensive. I found a place that rebuilds them in my MVPA Supply magazine i get every so often. If i can lick this problem , I will take a look at my starting/glowplug/fuel guage problem..Its funny, the fuel guage only works when i press the bypass bottom to light the glow plugs!..I get a good reading only in the mornings when i press it until the light goes out.....I dont need to press it when its warm...Thanks for taking the time to help me...great web site!..
Cevon...

 

[Ambulancechser]

decodeme...the gadget that senses battery voltage is the little rectangular box that mounts just behind the blue box.The little black box is the Twinput regulator.it's all solid state.get a new one(good luck)or find an NOS piece that works.The blue box is the DUVAC.it's a high current capable DC to DC converter,taking 28-v in an giving you 14-v out.
this is not to be confused with a transformer.Totally different animal.
By your symptoms i'd try the bottom alt also.These leece/nevilles are still good numbers at prestolites website.Try cross referencing the numbers off your alts tag.
The good news is that these alternators are highly common on heavy trucks and busses,and have easily changable external regulators.The external regulator (# 95300 i think,at 28-volts) has a switch on them that allows a high,medium,and low setting,controlled by a small and very easily lost screw.This screw is located on the back of the regulator,and requires reg removal to change the setting.
The regulator won't work without this screw.It's less than 1/4 the size of your little finger nail.On the back of the reg' you'll see this tiny screw and three holes.I can't remember offhand which hole is the high setting,but "high" it has to be.
A rebuilt alt ,even this size,is not super expensive.you might be able to get away with just a regulator......good luck.

 

[decodeme2]

Hey Guys,
thanks for all your help and tips!
I will let you know how it turns out...
Cevon...

 

[M1028A1ShelterCarrier]

Hey Ambulancechaser,

I am installing a 100amp 24 12 equalizer. I plan on leaving my leece system if it will work together (I hope, what do you think). If not, did you just tear out the the DUVAC/volt reg and all wiring leaving just the lower alt in place hooked up straight to the 24v bus? I welcome your input on how I should do it. Thanks in advance.

 

[Ambulancechser]

equalizer

shelter...thats exactly what i did...took out the top alt,removed the duvac and twinput.I left the wiring in place for now,as i don't want to chop the harness to much yet.When i get back to it i'll meter it all out and decide what can be safely abandoned in place.
I'd also suggest making your'e wiring fairly heavy.since your running a large equalizer(i assume you have off-road lights and "stuff" to run)Perhaps you might consider a seperate 12-volt bus to wire to.I'm thinking the same .it's probably safer and less cluttered under hood.
The wiring i have now works very well and i have also installed resettable breakers instead of fuses.(this is so i can shut off the equalizer as most of them have a tiny parasitic draw that will drain batterys over time).Remember to have the 24 and 12 volt supply drawn directly from the battery terminals as this will help protect your'e expensive equalizer from surge loads(batterys take the surge,equalizer recharges)
Keep us posted!

 

[M1028A1ShelterCarrier]

Ambulancechser,

Where did you get the resetable breakers (need 125amp). I just ordered a Surepower 100amp equalizer severe duty (far more than I need, no extra lights etc) 3 wire 24v- 12v- and ground. I was going to hook it up directly to the second posts on my battery and then begin to unhook wires off of my Duvac/top alternator. Since the twinput has wires that go into the cab, I am nervous that something will go wrong. Also is your equalizer always working or is it wired into the ignition? Any Pics?

 

[wallew]

Ambulancechaser (and anyone else for that matter),
REGARDING YOUR 'need' to purchase a digital camera.

DO NOT BOTHER. Go out and purchase one of those disposable cameras with a flash.

Take the pictures you want to take. I always suggest taking two shots of ANYTHING that is important.

THEN, after taking all the pictures necessary, take the camera over to WAL MART and have it developed. WITH A CD ONLY. You should be able to have them develop it and produce just the CD for about six/seven dollars.

The reason the pictures I posted were a little fuzzy were because during resizing them I wasn't paying close attention to the detail.

 

[Ambulancechser]

wiring...

shelter...I was also nervous about all the left over wires.however i don't recall offhand seeing any wires from the twinput going into the cab.maybe your'e harness is a little less molested than mine was?
The only wiring i can recall is the charge meter wire that comes from the bottem alternator(white?)that runs into the harness on the passenger side,just behind the bottom alt.The wiring from the top alt should be running between the top alt,the 12-volt distribution block,the twinput,the duvac,and the 12-volt terminal on the front battery.pull the drawings from the manuals on this site and ferrit out the m-1010 charging system drawings(note that they seem to be "pre orange wire mod")
When i hooked up my equalizer i took out the duvac,twinput,and the top alt all at once.The charge meter in the cab still read in the green.I've driven the truck around a-lot since and no ill effects.(except for the detroit lockers bad habits on ice.does super easy dougnuts though... )
The breakers i found at a local heavy truck parts supply shop.the brand name is Pollack.be warned they might be fairly expensive,especially in the size you'll need.I doubt you'll find a MAXI fuse to suit your needs.As for pics,i intend to pick up a digital camera soon(time for this dino' to evolve) and i'll post when i can.

 

[M1028A1ShelterCarrier]

What would happen if I wired the top alternator just like the bottom and ran it also to the bus for more 24 volt power or do they have to be isolated. Now would having 2x100 amp alternators cause anything (like the batteries) to blow up/start a fire or would the alternator regulator be able to tell that no more current is needed.