GM 4104 Radiator fan & hub upgrade?

dtcerrato · October 03, 2017, 08:43:43 PM

Does anyone have any info on newer fan &/or hub set ups for the radiator fan on the GM 4104? The bus ran flawlessly back from the Evansville rally but I am concerned about the notorious mucho expensive hub (PTO coupling) after throwing a blade off the fan on the way there & was thinking on getting away from the "old school" heavy metal fan. I thought I might have seen somewhere that a newer version of hub (clutch) and plastic flex fan was available as replacement.

TomC · October 03, 2017, 11:03:39 PM

You're going to start experimenting with a system that has worked for over 60 years?

luvrbus · October 04, 2017, 04:18:33 AM

Dan,I use the belt drive system from a RTS or Flex transit bus to convert the 4104 and the 4106 it not that hard to do if you can find a RTS transit they are parting out.I buy my plastic fans from kit-masters if you need a plastic fan with more blades

B_K · October 04, 2017, 09:35:38 AM

Quote from: TomC on October 03, 2017, 11:03:39 PM
You're going to start experimenting with a system that has worked for over 60 years?

Tom the parts for these systems that have worked for over 60 yrs are getting worn out and and are made of "UNOBTAINIUM!"
Time to start finding a workable solution rather than parking the buses because of not being able to drive them!

BK

dtcerrato · January 14, 2018, 05:23:54 AM

Well, I finally got around to removing the fan shrouding to get a view of the fan hub fused rubber coupling (also called the PTO hub). I liked the results - included a before & after 1000 fast freeway miles. No evidence of movement so I can rest on the thought of loosing the radiator from fan impact (as I experience twice in earlier times). Just a follow up on a much forgotten component.

chessie4905 · January 14, 2018, 05:28:54 AM

You could convert it to the hydraulic fan setup like the 4905. Just find a GM old look city bus with the 6-71 and hydraulic fan setup. Less horsepower drag when not fully engaged.

dtcerrato · January 14, 2018, 07:03:10 AM

I would consider that if the paint marks were miss aligned but they haven't moved so I know the hub is intact & will leave well enough alone...

Nel · January 16, 2018, 05:37:15 AM

Dan, I have the same concern on mine but so far the fan feels pretty tight on the rubber hub, what I might consider doing is welding a grill out of round stock that will fit the cowling to protect the radiator just in case. I would make it removable for servicing though. Nelson