GMC Fluid Drive Fan LEAKS!

[Mrbill4108]

Hey guys need some help/info on a GMC Fluid Drive fan /torus housing setup that leaks.

I have a 4108 with the Fluid drive fan that leaks oil at the oil seal behind the fan.  I know some of you have this setup and have posted repairing the leak.   I was wondering did you ever really fix the leak and if you did how long did it last.   I have replaced the seal many times with not much luck.  Sometimes I can get up to 5k miles before I see its starting to leak oil, other times I only get a few hundred miles before it starts to leak. 

I have replaced the seal with a new bushing just about each time, after the first seal failed quite fast, (less then 100 miles) I polished the bushing when I replaced the seal.  I have been polishing the new bushings ever since then as the kit comes with a bushing with a ruff looking finish. 

I use emery cloth to polish the bushing and I mic it afterwards, most I've taken off is 2 thousands.  I don't think that is to bad as with the ruff surface the seals don't last at all.  Been there, tried that twice, when someone told me I was causing the problem that way.   

Anyway, I am wondering if maybe I'm just not getting good seals or if there is something I'm missing.   I get the seal kits from Mohawk and the seals are made in Taiwan.  So no telling how good the quality really is I guess.  I just ordered a National seal to try next.

I have not bugged Luke yet but I most likely will later, just wanted to see what I could find out here first.

Thanks for your inputs,
Mrbill4108

[gmbusguy1]

MrBrill, I have not done many of these drive rebuilds but the ones I have done have not leaked. the problem may be a imbalance of the fan or a worn shaft.
I do know that the seal is installed backwards from the way one would think to put it into the housing. the seal actually deflects the oil and does not really seal the shaft. if you look in your service manual it has a section on rebuilding this drive READ it Carefully and follow the instructions paying attention to the seal orientation and I think you will have success and no more leaks. if the bearings are worn or the shaft is bent it will leak. you can always change the drive out and use a direct drive fan instead. I do have a couple of the oil drives that need to be rebuilt if you need parts let me know.btw I think the Taiwan parts are just fine as delivered and you should not be polishing them.

I would not hesitate to call Luke at US Coach for help with this

hope this helps

Chris   

[Mrbill4108]

Chris,
Do you have that rebuild info in a PDF that you can email me?   
My manual does not cover the fluid drive.
I got a 4106 parts manual for the parts breakdown but not the repair of the fluid drive.

Thanks,

Bill

[gmbusguy1]

Hi Bill, I will find it in the morning and get it to you

Chris