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Webster Hydraulic Fan Motor
09-12-2013, 06:14
Post: #1
Webster Hydraulic Fan Motor
In the process of getting my 'bird back together and road ready, seems my fan was ailing. Loud "clicking" sound as the fan turned and would not get up to full RPM. Erring on the safe side, I decided to replace the fan motor. Why not? - already have a new hydraulic pump, new/rebuilt hydraulic solenoid, new oil and filters, soon to be cleaned Radiator...Should be delivered to my "home 20" in 2-3 days.

Brand new Webster Hydraulic Fan Motors are available and in stock:

Webster Pumps & Motors Division
Hydraulic and Pneumatic Sales, Inc.
11100 Park Charlotte Blvd
Charlotte, NC 28241

Tel. 704.588.3234

Contact Person: Clay Pettit

Part Number 237KB1ARX-24R


My experience with this firm was very consumer oriented - staff going out of their way to help. This is my second purchase; I bought a new Webster hydraulic Pump a couple of weeks ago.

Tommy Rountree, AKA RetDA
Still a Newbie
1994 WB
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09-21-2013, 06:44
Post: #2
RE: Webster Hydraulic Fan Motor
Morning, all:

I'm still disabled and beginning to think my hydraulic system is un-repairable. New fan motor, new hoses and fittings, new hydraulic pump, thoroughly cleaned radiator/coolers. Only thing I have not replaced is the old Danfoss hydraulic solenoid that switches the fan from automatic to manual. Apparently that part is extinct and cannot be found anywhere. I did have it modified to where it remains in the open position, theoretically to cause the fan to spin all the time as if the dash fan override switch is on all the time which I have done since I bought the bird 5 years ago.

Cranked up Thursday afternoon and the fan started up but never got over about 700 RPMs. (apparently something restricting pressure between the hydraulic pump and the fan but not in the direction of the power steering, because it came back up immediately).

Sad part is the brand new Webster hydraulic pump was apparently DOA (defective on arrival) and the pump shaft broke in two. Good news its under warranty and being sent back to Webster Pump Division in Charlotte for replacement.

Anyway, I'm beginning to wonder if that OEM Danfoss solenoid which is permanently modified to remain in the open position should be by-passed all together. That could result in a lot, maybe excessive pressure going to the fan motor. So, I got to thinking (bad for a techno-challenged person) why not install its place a gate valve to be able to control the hydraulic pressure going to the fan.

I'm beginning to think my beast is not going to get back on the road again.

Suggestions are very welcome.

Tommy Rountree, AKA RetDA
Still a Newbie
1994 WB
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09-21-2013, 11:11
Post: #3
RE: Webster Hydraulic Fan Motor
Tommy,

It's possible that you haven't yet rectified the root cause of your initial failure, the sheared splines on you 8V92 output gear. Your new pump may have failed for the same reason. Do you have an ultra close-up photo of the fractured shaft? Any gate valve that you install will need to be rated for 5000 psi.

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"I don't like being wrong, but I really hate being right"
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09-21-2013, 11:37
Post: #4
RE: Webster Hydraulic Fan Motor
(09-21-2013 11:11)davidbrady Wrote:  Tommy,

It's possible that you haven't yet rectified the root cause of your initial failure, the sheared splines on you 8V92 output gear. Your new pump may have failed for the same reason. Do you have an ultra close-up photo of the fractured shaft? Any gate valve that you install will need to be rated for 5000 psi.

Thanks David.

First thing John Boy Hughes did after removing the first and the second hydraulic pump was to check the splines in the DD output gear. He reports no damage and there was no damage to either of gears of the secondary assembly on the pump. I should have taken a pic of the damaged pump shaft, but John Boy took it back with him.

Do you think a gate valve would be an alternative to the extinct hydraulic solenoid? I have even thought about adding a pressure gauge aft of a gate valve. You probably know how lawyers think.....Sad

Tommy Rountree, AKA RetDA
Still a Newbie
1994 WB
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09-21-2013, 12:08 (This post was last modified: 09-21-2013 12:25 by davidbrady.)
Post: #5
RE: Webster Hydraulic Fan Motor
Tommy,

There should be a pressure relief valve somewhere, but I'm not completely familiar with the components on your system. Yes, a pressure gauge would be very beneficial. A valve could be an alternative to the extinct solenoid, but again I'm not familiar enough with your system to spec one other than to say that it would need to be a hydraulic valve and it would need to be rated for 5000 psi and that hydraulics can result in grave bodily injury! Be careful!

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"I don't like being wrong, but I really hate being right"
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09-21-2013, 12:09
Post: #6
RE: Webster Hydraulic Fan Motor
Tommy,
I'm not an 8v guy so here are some general suggestions when you have a situation such as yours with repeated attempts to fix an issue:
1) Inexperienced installers, don't know your shop but I presume you do and they are good to go but it was worth mentioning as it has been a root cause for others in the past and I am sure a retired lawyer such as you has already thought about this and vetted this one! Teehee :-)
2) I agree with David, root cause of initial failure not found yet. Have you posted this issue on the yahoo Detroit diesels forum yet to get some more feedback? Those guys over there have decades of OLD DD engine experience and have probably seen everything.
3) The new pump actually was defective, binding causing low pressure due to the binding shaft and the shaft broke. You are dealing with .001 & .0001 tolerances and we are after all only human and make mistakes on assembly occasionally .
4) I'm hoping a more experienced guy like Leroy will weigh in here but until he does here goes... A solenoid valve either turns something full on, full off, or can vary pressure incrementally depending on design. Not sure what your is but if parts are loose or broken in it, then theoretically it can restrict pressure enough to give you slow fan speed and back the pump up until the shaft breaks. Pics of the gears here would go a long way to see if that was root cause. Since you started the thread with a guess here trust your instincts, you still got it ole bean!!!!! :-)
Try and keep a positive attitude, yes birds are very challenging but very rewarding and the challenge part it the price we pay for our reward, good luck!
PS the yahoo diesels forum may be able to source the valve for you, you never know what one of those old guys has stashed in NOS!!!!!

Pete and Donna Chin
95 42' WLWB
On The Road Always! :-)
" We'll raise up our glasses against evil forces singing,
Whiskey for my men, and beer for my horses!"
-Toby Keith & Willie Nelson
- The bridge from Toby Keith's title album track "beer for my horses"
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09-21-2013, 16:06
Post: #7
RE: Webster Hydraulic Fan Motor
Tommy's shop is CoachCraft, so they should be very capable of repairing it. But sometimes things can elude even the best. Hopefully, this isn't the case.

John Mace
96 42 big bird
living in the wild hinterlands of the north
free to roam without the man getting me down
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09-21-2013, 22:03
Post: #8
RE: Webster Hydraulic Fan Motor
Tommy,

It'd be interesting to look closely at the failed 8v92 splines to see if you can determine whether that was a sudden fracture versus a slow wearing, fretting failure.

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"I don't like being wrong, but I really hate being right"
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09-22-2013, 00:23 (This post was last modified: 09-22-2013 00:56 by davidbrady.)
Post: #9
RE: Webster Hydraulic Fan Motor
Tommy,

There is a Webster Relief Valve in your hydraulic circuit. When neither the power steering nor the hydraulic fan is calling for pressure the relief valve redirects fluid back to the reservoir. I'd look closely at this valve. If it's failing to open pressures could build to excessive and damaging levels. Here's a schematic of your system. In the drawing item number 37 is the Webster Relief Valve:

─░mage

My theory is that the pump worked fine as long as you were moving the steering wheel, when you stopped the pressure built and the shaft failed. When you stopped, the pressure had no where to go most likely due to a faulty Webster relief valve.

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"I don't like being wrong, but I really hate being right"
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09-22-2013, 07:48 (This post was last modified: 09-22-2013 08:19 by RetDA.)
Post: #10
RE: Webster Hydraulic Fan Motor
(09-22-2013 00:23)davidbrady Wrote:  Tommy,

There is a Webster Relief Valve in your hydraulic circuit. When neither the power steering nor the hydraulic fan is calling for pressure the relief valve redirects fluid back to the reservoir. I'd look closely at this valve. If it's failing to open pressures could build to excessive and damaging levels. Here's a schematic of your system. In the drawing item number 37 is the Webster Relief Valve:

My theory is that the pump worked fine as long as you were moving the steering wheel, when you stopped the pressure built and the shaft failed. When you stopped, the pressure had no where to go most likely due to a faulty Webster relief valve.

David, thanks - all of this is is slowly increasing my "mental database". FYI my last conversation with Glenn Rogers and John Hughes, they said in all their years, they have never seen such a failure as his. Being the 'vanguard' of a new bluebird issue sucks. But perhaps what I have experienced may save somebody else a lot of grief.

David - Just thinking, as the opposite of a failure of the relief valve resulting in extreme and damaging pressure; another hypothesis: could a failed or failing relief valve, result ln allowing the power steering to continue to work, but a greatly reduced flow of fluid to the fan motor?

That was exactly the "symptom" for the first operational test following the installation of the new pump and the new hydraulic fan motor. Power steering was "1 finger lock to lock", but only 750 RPMs at the fan.

Disconnected eveything, hoses, fittings checked for restrictions, reinstalled, third operational test indicated no pressure at pump, fan motor and no power steering. We went back to the hydraulic pump and removed it discovering the pump shaft separation.

David, please forgive my convoluted thinking, but maybe we missed the boat on this one - since there appears to be only one relief valve in the system, perhaps we should have started there in the analysis of the problem.

Tommy Rountree, AKA RetDA
Still a Newbie
1994 WB
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