I am having problems with my hydraulic fan motors
on my 1994 U280 With c8.3m Cummings . This started about 2400 miles ago when the shaft seal on the most forward motor dumped all hydraulic fluid going up a mountain in West Virginia.
Long story short, took fan motor to hydraulic shop in Sutton WVa. They were able to check bearings and bushings & gears and replace shaft seals.. Then pressure tested the unit. Returned to RV and installed and went on my way to VA. Spent most of summer there.
Left in August heading southwest. About 800 miles from after the repair, in the mountains of Tennessee, the same seals blew out again. Removed, repaired again and reinstalled.
Then, about 800 miles later inTexas, it did it again. Knowing the meaning of insanity, drove to Foretravel in Nacogdoches. Picked up a new motor and all adaptors to change to new motor. Job done and again headed southwest. Thought we were good to go😀.
Then about 800 miles later, the other fan motor blows shaft seals.
Currently staying in SKP Park in Deming, NM. Scratching my head. Have been looking
here and on the web for information on this hydraulic cooling system, such as operating pressure, flow, and components specs or a function diagram. All with little luck. Hoping the Foreforum brain pool can help!
The old motor is made by Haldex Barnes and has two numbers on tag: 11198 & 1820009. New motor is made in Italy. Any and all help will be appreciated!!!
Thanks in advance,
Gary
Sure sounds like PSI may be too high.
You need the info and then put a gauge on it.
I Agree still looking for that info
During all this did the filters for the hyd. system get changed?
Did the hyd. controller get checked?
Mike
No but has had 20 gal of fresh fluid go threw if and have no info, for controller to test it
Gary,
Even if the filters were changed recently (like just before this started) you sure need to check to make sure that one of your filters hasn't came apart. There is a chance that if the filter disintegrates due to age it can send filter trash through the system and clog up the controller orifice causing an overpressure problem.
Mike
I will swing by tomorrow and look you up. I assume you are at Dreamcatcher?
Good point will check asap
Thanks
Only oily Foretravel in the place
Checked filters this morning look good no metal or anything 😀
After removing fan motor today. I was tracing hydraulic lines and found the small line that connects between the two fan motors was caped off about three feet from the hydraulic reservoir. After further searching found small line coming off bottom of reservoir and was also capped off.
Does anyone know why this would be.
While tracing lines they follow this route. Starting at reservoir large line goes to pump. Pressure side of pump goes directly to top of fan motor. Coming off of bottom of that fan motor a line goes directly to top of other fan motor. From the bottom of that fan motor a line goes directly to the bottom of reservoir. I thought from reading on posts that a controller and some kind of relief valve were required. Am I missing something. :help:
Those lines sound like the motor drains. They are used to drain off hydraulic oil when there is an overpressure in the motors. If they are plugged off (or clogged as they were in my case) the overpressure can/will blow out the seals. Also did you notice a lot of heat coming off the hydraulic reservoir? My 92 didn't have a hydraulic cooler and after the pump/motor trade out my hydraulic fluid would go to 350º by the end of the day. That kind of heat will blow seals too. I ended up adding a hydraulic log splitter oil cooler to my system. Haven't had a problem since.
see ya
ken
Gary,
Agree it is confusing reading about all the different ways the hydraulic fans can be controlled. Several methods used by FOT over the years.
Your system sounds similar to ours. A very simple loop from pump to motor to motor back to pump. Our coach, to the best of my knowledge, does not have any kind of "variable speed controller". As soon as I start our engine, the fans are turning. If I raise the engine RPM, the fans turn faster. AFAIK, cooling fan speed is determined solely by engine RPM. Seems to work fine - we have never had any over-heating situation of any kind.
My fan motors are OEM. They seep slightly, but no oil dripping on the ground, so I just keep a close eye on them until leakage gets more serious.
I did rebuild my pump. Details here:
Vickers V10 Hydraulic Pump Rebuild (https://www.foreforums.com/index.php?topic=23846)
I didn't notice excessive heat at reservoir, but may not have noticed. Will watch for that in future.
That's what mine is just pump and motors, just does not sound right. Like having a electrical circuit with no fuse or circuit breaker.
I would check my drain line mine looks like they were caped off quite a while ago.
Thanks for confirming no other components in your system eather feal a little better.
There is a high speed fan solenoid on a '94 and you can default to run always on high speed. Did your seals seem to blow at a period when the fans should be running on high speed?
I'm thinking that maybe if you were running at high rpms and the fans did not speed up, the pressure built up.
After reviewing your pump Wright up I noticed that your pomp has 4 connections (mine has only 2) it also looks like it is in two parts. The top half has 3 connection and the bottom only 1.is it possible that the top half has a pressure relief in it.
Thanks
My system has no control only a pump and 2 fan motors nothing else except connecting hoses. Oh and a reservoir.
Thanks Ken do you know is that there only function. I have about 10000 miles on RV sens I purchased it. Wondering why it took so long to show up. These lines look like they have been plugged for years.
Thanks Gary
Are you positive you don't have this solenoid, drivers side? We have basically the same coach and it was Foretravel that told me about it.
Twig,
Does that solenoid show up on your electrical diagram? Which hydraulic hose does it control? I have never seen anything like that on our coach, and have spent quite a bit of time under there poking around.
Perhaps that was a change from '93 model to '94...
Twig
Just went to look to make sure and I see nothing like that on my rv.
When I was having a heating problem I called Foretravel help desk and was told that I have a solenoid that runs the fans on high. It is temp controlled and opens up to let the oil flow faster which in turn makes the fans go faster. Take the top off and the fans run on high full time. That's all I know. But the fact that the guy at Foretravel told me where it was and what it was, I assumed they were all the same. How do your fans run on high speed?
Like I said in my post above: when my engine runs at high speed, the fans run at "high" speed. When my engine is idling, the fans run at "low" speed. Exactly the same principle as any common direct-drive belt driven radiator fan. Also like I said above, it works. KISS at it's best!
My 95 U240 Cat 3116 has the solenoid(drivers side like twig) controlled by a water temp sending unit like for a temp gauge. If you want to default to high speed just remove/disconnect the ground wire. I have ran the ground wire up to my dash and I control the fan speed with a switch that connects the ground to the solenoid.
My problem after replacing both fan motors(2), main pump, star controller value by FOT, the fans still run about 600rpm slow and my Cat 3116 tends to run hot during the summer months when going up hill. Just a week ago on trip to Davis Mountain State Park from Lufkin,Tx , Going up hill 200-203 deg. and down hill 190 deg. at 60mph towing WOT. Not too bad for an old kitty cat!!
Twig
What engine is in your coach. I have Cummings c8.3 many that is the difference. All I can say is my hydraulic lines connect only to pump motors and reservoir.
Thanks Gary
If it was excessively hot you would have noticed. :)
I am far from an expert on hydraulic gear pumps and motors but I've only seen 3 lines out of a motor. Input, output and drain. Input and output are usually 5/8" lines. Drain lines are usually 1/4" to 3/8" lines. If I can find the time in the morning I'll pull out my old motor and pull it apart and take some pics for you. They are incredibly simple devices.
see ya
ken
Our 95 280 has the same setup as Twig,
Valve energized is low speed and defaults to high if valve fails.
Yes it is temp controlled and matches the hydraulic schematic.
Ken
No need to go to that trouble took pump to shop yesterday and they verified what you said. Small line is for case drain to protect seals.
Thanks Gary
Well I read your "no need" message after I had taken pics so here they are.
As I said they are very simple devices. The engineering to figure out the right size, flow, & pressure is the complicated part. I'm not sure why they are so expensive. It's just a hunk of aluminum with a couple of gears. IIRC this one was over $600 might have been $800. It's been 5 or 6 years ago that I dealt with it.
If the motor is engineered with a drain it must be clear and connected otherwise under high pressure it will put a LOT of stress on the shaft seal. Most likely resulting in a blow out. :(
This motor is probably not the one in your coach or a replacement for yours. And I mean anyone reading this. :)
see ya
ken
Good picture show. Good info I found it interesting and informative. I think others will also
Thanks Gary
Great photos and annotations! This should be in the media section. It makes understanding how the pump works simple.
Pierce
I have not abandoned this post, I am waiting for motor to be repaired. The repair shop revived seal kit yesterday and it was WRONG! Waiting for another to be shipped.
Gary
Well I picked up my fan motor this morning, and installed this afternoon. No leaks. The next 1000 MI. I will be very apprehensive.
Cross your fingers for me.
If I don't have any further problems this will end this post.
Thanks for all the help
Gary :))
1500 MI and doing good ;D