hydraulic fan motor

[robertglines1]

I am in final decision phase on my fan drive for my 60 series in Prevost.I do not have original fan drive. when Monoco closed they had surplus hydraulic fan drives/switch.  I can get a new one for under 100$  or like Jim use the hub city 90 degree box. opinions.  Bob                       This was just covered in another post that I did not read carefully. Temporary Brain lapse. looks like cost would be same but control of fan easier with mechanical as I to have the air fan clutch from the transplant engine I can use.

[JohnEd]

I like the flex of hydraulic if I can modulate the fan speed to save power.  Otherwise I would go with Clifford's advice to KISS and go with the right angle mechanical linked affair.

This post beats your topic to death...I think. http://www.busconversions.com/bbs/index.php?topic=18844.0

John

[robertglines1]

sorry I should have read it more closely and not posted this question. Had a temporary brain lapse.   Bob

[kyle4501]

Hydraulic drives are like any other drive - if the components aren't properly matched to the system requirements, it won't work well. Sloppy execution yields sloppy results.
If one size fits all, then there wouldn't be so many to choose from! 
If system performance is your primary concern, then that should be your primary concern when selecting the components. If you need 5 gpm at 1500 psi, 3 gpm at 2500 psi isn't going to work - It won't matter how much cheaper it is! 

We do hydraulic drives here at work & have no more problems with them than any other drive.
We have customers who use hydraulics & a leak can cost them millions a day in lost production they can't make up since they are already running 24-7

Basically, here is what I'd do to design a hydraulic fan drive:
Start with the fan requirements to size the fan motor.
Then select the proportional valve to work with that motor. (to allow the fan to run only as needed)
Plan out the hose size, routing, & any other control features you'd like.
Based on total system flow rates & pressures, select required pump.
Only use SAE o-ring fittings & top quality hoses (the cheaper hoses are more prone to leaking around the crimped ends).

If you base your system on what you found somewhere, you aren't basing it on performance.
Nothing wrong with using what you have -IF- it also meets the fan system requirements.

If the pump is undersized, you won't be able to get the required flow rate at the required pressure.