Author Topic: Positive Ground on the new (to me) 4103? About to move the bus!!!  (Read 2026 times)

Offline Rick59-4104

  • Sr. Member
  • ****
  • Posts: 310
  Started the process of readying to move the 4103 I posted earlier about, I am thinking the bus was originally positive ground, no batteries in it the cables are not color coded or marked. If I put new batteries in it assuming it is still positive ground any danger of smoking anything if it has been changed over to neg. ground?  I am thinking there is really no way to tell?

 I removed the front wheels today, that was fun :)  Rear wheels still have air, lots of tread but will have to be replaced eventually due to age but should work to move the bus. I plan on replacing the split rim 20's on it with 22.5 rims and some rolling tires for now. Have a couple of options for getting the bus the 20 miles home. My Brother has a 16 ton 24' dovetail equipment trailer that the bus will just fit on with its 21' wheelbase. I will have to hang several feet off the front and the rear of the trailer but it should work. It should measure just under 13' 6" in height on the trailer, Here in Arkansas I can hang about as much off the rear of the trailer as I need to as long as I have lights on the bus if more than 4 feet is hanging over the rear of the trailer..  He has a 10 wheel dump truck to pull the trailer with. Or I may spend a couple of days on site changing fluids, filters, brake lines, flushing the old fuel out and try to start it there.

The more I am around (and under) this old girl the more I like her, The bus body, panels and underneath the bus is in really good condition.


Any advise on my battery question appreciated!
NW Arkansas
1959 GM 4104  No. 4115
1972 Grumman Kurbmaster Stepvan Conversion
1957 Airstream 13 panel Overlander

Offline DMoedave

  • Sr. Member
  • ****
  • Posts: 347
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #1 on: February 22, 2011, 08:23:41 PM »
rick, if it still has the generator instead of a altenator, it could still be positive but not a 4 sure. When we did our change over some of the guages had to be replaced with the senders. the was some wierd stuff here and there but it wasent as bad as the dreading doing it. when we did we switched to altenator.  If you dont you will have to spark the fields, check the archives on the other board ( probably this one too) glad you got the 03, really nice coaches
we love our buses!!! NE Pa or LI NY, or somewhere in between!

Offline Rick59-4104

  • Sr. Member
  • ****
  • Posts: 310
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #2 on: February 23, 2011, 01:48:42 AM »
 I will check and see if the gauges look original, if they do I will cable the batteries up with positive ground.  My 04 is positive ground and has not been enough of an issue with me to change it over as of yet.

Rick
NW Arkansas
1959 GM 4104  No. 4115
1972 Grumman Kurbmaster Stepvan Conversion
1957 Airstream 13 panel Overlander

Offline desi arnaz

  • Hero Member
  • *****
  • Posts: 560
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #3 on: February 23, 2011, 03:38:31 AM »
before connecting, connect with sean  he will know.....
thomas f  Bethlehem n.h

Offline Busn-Gramps

  • Newbie
  • *
  • Posts: 23
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #4 on: February 23, 2011, 03:56:35 AM »
Hi Rick,you can check by hooking up the cables and turning on the lights or something that will draw power,check amp gauge if it shows charging it is backwards,if it shows discharge it is right.If you do not start the bus this will not damage anything if it is wrong.
Paul
1984 MC9  8v71 HT 740

Offline eddiepotts

  • Sr. Member
  • ****
  • Posts: 446
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #5 on: February 23, 2011, 04:52:52 AM »
I know this sounds too easy but you battery terminals are differant sizes. pay attention when hooking them up. You will know if it fits right. You would have to tap the pos. side down if not on the right one.

artvonne

  • Guest
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #6 on: February 23, 2011, 05:16:59 AM »
  Started the process of readying to move the 4103 I posted earlier about.

  4103? Where did this come from? You turning into a Busnut?

  There isnt a lot youll mess up if your wrong. Lights and gauges wont care though your amp gauge will read reversed, motors wont care, but the voltage regulator will fry. I been wracking my brain trying to think this through and slowly realise I dont know how to tell. But IIRC, the battery cables should have different sized holes at the battery connection. Just make sure to mark it all VERY well when you figure it out, or switch it over to the 21st century so you never have to ponder this again.

artvonne

  • Guest
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #7 on: February 23, 2011, 05:31:42 AM »
If you do not start the bus this will not damage anything if it is wrong.

  Are you sure? Are you Positive? I blew the regulator on my old Ford tractor but cant recall if I turned the key or not.

  I thought the regulator Bat terminal went to the chassis on pos ground, but looking at the wiring diagram it shows it goes to the battery. Sean???

  There must be some simple test to determine how they are polarised rather than trusting the battery cable terminal hole size.

Offline Len Silva

  • Hero Member
  • *****
  • Posts: 4086
  • Angle Parked in a Parallel Universe
    • Leonard Studio
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #8 on: February 23, 2011, 07:15:32 AM »
I don't know for sure on the 4103, but on the 4104, the carbon pile regulator was isolated from ground.  Once you re-connect the battery (in either direction) and flash the field, the charging system should be OK.

The electric gauges, oil pressure and temperature will have to be replaced and the selenium rectifier that controls the alarm buzzer will have to be rewired, or replaced with diodes.

Just reversing the battery will not cause any catastrophic problems AS THE BUS WAS ORIGINALLY WIRED, it's just that some gauges and/or the charging system may not work correctly.  We cannot account for what may have been done to it since then.

Hand Made Gifts

Ignorance is only bliss to the ignorant.

Offline gus

  • Hero Member
  • *****
  • Posts: 3632
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #9 on: February 23, 2011, 03:25:56 PM »
I've reversed grounds on a few oldies and all I ever did was flash the generator field, reverse the coil primary leads and reverse the leads on the ammeter. If you have a volt meter they will also have to be reversed.

Of course you don't have a coil to reverse but on a gasser that makes for a stronger spark.

I never had to change any gages since most of them use some kind of resistance in the sender, the sender could care less what the polarity is.
PD4107-152
PD4104-1274
Ash Flat, AR

Offline buswarrior

  • Hero Member
  • *****
  • Posts: 4619
  • '75 MC8 8V71 HT740
Re: Positive Ground on the new (to me) 4103? About to move the bus!!!
« Reply #10 on: February 23, 2011, 06:14:41 PM »
Where is Dallas?

He's got a 4103...

Try over at BNO, if he doesn't respond here.

happy coaching!
buswarrior
Frozen North, Greater Toronto Area