...have a converted 4104 and need help with the battery hookup. Could someone explain and/or fax a diagram of the correct hookup for the series. Thanks, Mona.
us Nut Online forwarded your note to me. Your question is rather vague so let me talk about the subject a bit.The 4104 as delivered from the factory had the positive terminal of the battery connected to ground. While this is how GM did all their vehicles, including cars, in the early 1950's, it is unlike almost all other vehicles. This can be a real problem, as most electrical devices for RV's use the standard connection - that is, the negative terminal is connected to ground. I have a 1951 GMC PGA 3301. It, too, has a positive ground.
To make a viable conversion, I had to change it. I have seen articles in Family Motor Coaching that tells what is needed to change it. Obviously, the battery terminals must be changed. The generator also had to be changed to produce positive current. This required that a battery be connected with the negative terminal to ground and the line from the positive brushed quickly against the field terminal on the generator. There were also some diodes in the 4104. I think they had something to do with the gauges. The diodes looked like a red pile of square metal plates that have an air gap between them. This stack of 4 diodes had to be replaced.
I believe the 4104 is 12 volt. If that is the case, one terminal of the battery (or batteries) is connected to the frame. This is the ground. The other generally goes to the main terminal on the starter. Other uses for the 12 volt current are taken off of there.
If someone has changed your coach to negative ground, that is the way it should be for a conversion. If it is still positive ground, let me know and I will send you information on how to change the generator. You will have to ask a 4104 man about just what needs to be done for the diodes. My recollection is that the diodes are for isolation of two things from one another and that they are removed and replaced with diodes that conduct the other way. New ones don't look anything like the ones used in the 4104.
I suggest that you ask for help on the Bus Nut Online Bus Bulletin Board. There should be a lot of 4104 people there and they all had to make the change. They also might be able to help you get a copy of the diagram out of the manual if that is what you need. George.
