BCM Community

Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: pabusnut on August 02, 2012, 05:47:47 PM

Title: Starter Problem (maybe) + Generator question
Post by: pabusnut on August 02, 2012, 05:47:47 PM
OK-- My 1973 4905(8V71, man trans)has been in the shop for rebuild of the power steering ram cylinder for about the last 3 weeks.  Expensive to say the least--$1100 to rebuild the cylinder with my parts!!!

Today they get it all back together and go to start it to get all the air out of the cylinder, and the bus won't start.  They report that it was throwing sparks down to the floor like a welder when they pushed the start button.  They tried using a jumper wire to the selenoid and bypass the switch, but it did nothing.  They also tried manually pushing in the selenoid with a broomstick, but again nothing.  (Note --the starter seemed to work flawlessly prior to taking it in to get the steering worked on.)

So they started to remove the starter, and then they called me.  I stopped by and looked, but can't diagnose much as they had the giant cable off that goes from the generator to the starter(which is missing much of the insulation near the ends and obviously needs replaced).  I told them to continue to get the thing off and bench test it--rebuild if necessary

Now for the part I completely don't understand.  The mechanic put his meter on the positive post at the generator(which now has nothing hooked to it), and was getting like 80 ohms resistance between it and the block, which I thought should be infinite.

Any thoughts(other than I got taken on the steering cylinder rebuild)??


Thanks!

Steve Toomey
pabusnut
Title: Re: Starter Problem (maybe) + Generator question
Post by: luvrbus on August 02, 2012, 05:54:54 PM
He probably broke the insulated stud on the alternator it is easy to do trust me lol not much wiggle room on that stud least bit of movement without holding a back up you have a problem  

FWIW a 4905 has a 24 volt D50 gear driven oil cooled alternator not a generator one of the few GM 24volts where did you go Sean 3 posts just vanished  lol
Title: Re: Starter Problem (maybe) + Generator question
Post by: pabusnut on August 02, 2012, 06:46:31 PM
I guess I assumed alternator.

Now that both these boards look alike I get confused too! ;D

steve
Title: Re: Starter Problem (maybe) + Generator question
Post by: luvrbus on August 02, 2012, 06:56:38 PM
LMAO I wondered what happen to you and Sean and here I am on the wrong board