Belts for the 50D

[DominicM]

I am assuming the generator is a 50D.  During the drive from Big Spring to Nashville, I burned up a set of belt.  I am in contact with the PO and he assured me that there was nothing wrong with the system I must not have allowed the air to completely build to apply pressure on the tensioner.   So with me now self doubting I did spin the bully and all seemed fine. I did use the belts that were provided that happened to be a pain to install. 

On the way back from Baltimore to Nashville I burned up another set. This time the bully will not turn either.  I have taken it off to get the unit replaced.  Does anyone know the correct size of belt that I should be running so I can ensure that I am putting the correct belts on?

[eagle19952]

toss the air cylinder and install a turn buckle or other adjuster...

[DominicM]

toss the air cylinder and install a turn buckle or other adjuster...

Why remove the air cylinder? Mine appears to apply pressure, it does not retract after the air pressure is 100 lbs and valve is shut off, as the instructions indicate but I just figured I was doing something wrong.  I attached an airline to the air cylinders power in side and it retraced the unit so that I could try to spine the pulley. The cylinder operated properly. 

With the Cylinder retracted all the way the belts are still too small to fit on the pulleys. I assume the PO installed belts that were too small. Once I get the new generator installed I will take a retracted measurement  and purchase 4 belts that will fit

[muldoonman]

Don't know, on my 1991 XL pulled Carrier ac compressor and neither one (air cylinders) would retrac enough to get belts off. Had to pull both cylinders and brackets on mine to remove belts. Hadn't started to go back together but figure it will be a pita.

[luvrbus]

Those belts on the MCI do fit snug you probably have the right belts,to much slack they will throw the belts before the tension cylinder air ups,just remove the 2 bracket bolts on the cylinder then they go on easy     

[bevans6]

You said the "bully" will not turn now.  If you mean the four belt pulley on the alternator, then if it is seized you have a problem.  It has to turn easily and smoothly with no belts on it.  The four belts are supposed to be a matched set, but I think most people don't bother.

[Dave5Cs]

This might help. On my 6V71 on an MCI MC5C, don't know if same size. Take yours with you and see if they are the same or a little bigger than yours.

Alternator  Belts NAPA, NBH 25-7410   or   #Dayco  5133601   4-8485

[luvrbus]

Here in the US matched belts are a thing of the past Jim the belt guy that worked for Gates said that stopped years ago because the manufacturing on belts had changed and they were all the same

[bigred]

Good site to remember      vbeltguys.com Great service great inventory and the only place I can get that wide belt for my Prevy .It is not even available from prevost any longer.

[buswarrior]

The alternator has to be lined up, it can be hard to "eye ball" the pully being in line and square in there, too many angles back there.

A straight edge to be close, pay strict attention to square and parallel, straight edge long enough that it touches both pullies, front and back edge.

Misalignment throws belts, then you start blaming everything else without cause.

The air tensioners are lovely, when working correctly. Pressure, seals, apply and release.

And are a great source of air losswhen they are not...

Happy coaching!
Buswarrior

[eagle19952]

Here in the US matched belts are a thing of the past Jim the belt guy that worked for Gates said that stopped years ago because the manufacturing on belts had changed and they were all the same

but they aren't.
belts have cut numbers.
yes i'm that pain in the @$# at the parts house.

[luvrbus]

I don't know take it up with Jim Shepherd he was a engineer at Gates for over 20 years I just presumed he knew what he was talking about and I have no reasons to doubt him 

[dvrasor]

 I heard they don't sell matched sets any more either.
I used to by them  for a dirt track late model years
ago. Guy I buy from said same as Cliff.

Dave Rasor

[eagle19952]

I don't know take it up with Jim Shepherd he was a engineer at Gates for over 20 years I just presumed he knew what he was talking about and I have no reasons to doubt him 

HE DOES..I just do it my way
Even if I have to buy 12 and return 10

[chessie4905]

Here:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://ww2.gates.com/IF/facts/documents/Gf000194.pdf&ved=2ahUKEwjXs5nE_ODbAhVxrlkKHbGKBBQQFjADegQIARAB&usg=AOvVaw1YqK46A9jqTK7CDzSQNJxw