Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 10, 2025 ...

Re: Hydraulic motor is leaking... again

Reply #50 – April 16, 2019, 06:38:14 pm

Thanks "Dad!"  But no problem.  Got question answered before the motorcycle oil leak thread started.  I really appreciate all the input provided.

George

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Re: Hydraulic motor is leaking... again

Reply #51 – April 16, 2019, 09:39:28 pm

Part of the long term reliability on our coach was to change the dynamatic fan controller.

The oem is 180.  Starts in low at 165.  Full high speed at 180.

 Normal run down the road is 180.

Thermostat on the motor is not open fully until 195.

The rest of the industry uses a 184 low speed ramping up to 199.

Heats the oil used to run the power steering and the fans.

Nothing lasts as long.  Wanna bet it contributes to the steering box leaks?

Consumes 50-60 hp.  1 to 1 1/2 mpg.

Engine pulls better at low rpms after that change and the resonator install.

Pulls versus downshifting at 3/4 throttle under load.  Torque.

Low rolling resistance tires.  Blue tech air filter.  Solar so the alternator shuts down

Different ride than new to us

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Re: Hydraulic motor is leaking... again

Reply #52 – April 17, 2019, 11:56:26 am

Here is a pic of my "drip catcher" under the leaky fan motor after 200 miles of highway driving.  If you look carefully you can see a few oil stains, but not much.  So it definately seems to be a seep rather than a drip.  That is, assuming the pan catches the drips and given its placement, I think it does.  Even if the drips are displaced a bit inward by air moving from the fan toward the engine, the pan should still catch most of them. 

Update:  I added a pic of the "drip pan" after 400 miles of highway travel.  Same story...  not much. 

George

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Re: Hydraulic motor is leaking... again

Reply #53 – April 17, 2019, 12:04:55 pm

I would research and gather seals etc. and just leave it George maybe consider adding a quart of leak/seal conditioner.

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Re: Hydraulic motor is leaking... again

Reply #54 – April 17, 2019, 12:10:23 pm

I've done what John suggests with good success. The seal conditioner softens and lets the seal expand. I had a auto trans with a severe input shaft seal leak. So bad that I used two bottles. It stopped the leak at about 330,000 and still dry at 450K.

Might want to check with a shop first but think I might head this direction.

Pierce

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Re: Hydraulic motor is leaking... again

Reply #55 – May 04, 2019, 01:48:23 pm

Pan test probably invalid...  I got to thinking about the effect of the air movement from the fans on the drops of oil seeping out of the motor.  I set up a simple experiment with a household fan.  Even on high, I doubt the movement of air is anything like what the hydraulic motors create.  But the displacement of oil drops was still significant.  See the attached.  I now doubt that the pan to catch the drips would work because most the oil drips would be blown past the pan.  Plus you have the air movement from the movement of the coach when it is underway.  The area in the back of the leaky motor (toward the engine) is oily, but not excessively so. 

I should note that the hydraulic oil is very clean.  Bernd's boys changed it after getting water in the system (see above).  And I had the filters changed again last week to remove the last of the water.  I think the oil stain looks dirty on the cardboard because the drips have flowed over dirty areas of the frame holding the motor. 

This effect may explain what I am seeing.  When the coach is sitting (without the pan) I usually put a piece of cardboard under the leaking fan motor.  Attached is a photo of the oil spot from 24 hours.  The big question now is, does it leak more when I'm underway?  I'm still undecided as to what to do.  I did buy some of the Lucas hydraulic oil additive and will probably give it a try.

George

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Re: Hydraulic motor is leaking... again

Reply #56 – May 04, 2019, 02:09:14 pm

George,

FYI there are different stages of leaks.
1.Ooze
2.Seep
3.Drip
4.Trickle
5.Deluge

You have moved from #2 to #3 and that needs to be addressed. That is a lot of oil for just 24 hrs.  The oil additive can be effective on some leaks.  If it was an old seal the additive might help but I thought that this seal was new just a few months ago. I would be ready to install another seal if the additive don't help.  You sure don't want to progress to #4 or #5.

Mike

Edit: I just went back and reread your first post on this, so those seals are what I would call new.

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Re: Hydraulic motor is leaking... again

Reply #57 – May 04, 2019, 02:50:06 pm

I think there must be 1 more

OH SHI*

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Re: Hydraulic motor is leaking... again

Reply #58 – May 07, 2019, 10:31:54 pm

Another installment in "What the #@%% is going on with my fan motor?"...  As I mentioned in my last post on this topic, the pan to catch drops of oil from the leaky/seepy motor probably didn't catch much due to air movement from the fan and the motion of the coach when underway.  I needed another way to asses how much oil was being lost by the motor. 

So I took to monitoring drips using a large piece of cardboard under the leaky/seepy motor.  I took the coach out for a spin at highway speed for about 35 miles once a day for three days.  Then I checked under the coach visually to see if there was any obvious oil from the fan motor sprayed around it.  After the inspection, I put a piece of cardboard under it for 18-24 hours to check for leaks.  The first day I had a few drops, not much.  The second and third nothing.  Not a single drop.  And I could see no evidence of leakage when I checked the area around the motor.  Although I must admit that I have little skill in this area of expertise.

As I mentioned in my previous post,  I did have the hydraulic filters changed again last week when I had some work done at Cummins.  Maybe getting the last bit of water out of the system helped.  Water can affect the viscosity of oil.  Probably wishful thinking!

So I'm not going to pull the motors at this time.  We're headed north to Anacortes on Sunday and I will continue to monitor the leaky/seepy motor.  Wish us luck.

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Re: Hydraulic motor is leaking... again

Reply #59 – May 08, 2019, 06:23:36 am

George,

Is it possible that this oil was setting on the angle iron framing for the fan motors and didn't get cleaned up after they were installed? You might want to check this area for evidence of oil.

Mike

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Re: Hydraulic motor is leaking... again

Reply #60 – May 08, 2019, 08:29:42 am

George, did you add the Lucas hydraulic additive?  So far I know of three "miracle in a bottle" products (other than  pharmaceutical which is another story.)  Lucas hydraulic additive, Trans X auto transmission additive and Deoxit D5.

Lucas hydraulic conditioner completely stopped a steering rack leak in a VW Westphalia Wasserboxer.  From a quart a day to zero. Still leak free a year later. My experience. 

Trans X (which used to cost ten dollars a can but came with an instant money back guarantee if it didn't work) watched my brother add it to a pickup with a totally non responsive auto tranny, which then began to shift normally and did so for months afterward.

Deoxit D5.  Resurrected many electronic devices, microswitches etc.  Cleaned up corrosion in my hearing aids after some unintentional total immersion saltwater therapy.

Added heavy dose of Lucas to seeping hydraulic steering and fan motor system six years ago.  Stopped the seep but is now slowly recurring.

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Re: Hydraulic motor is leaking... again

Reply #61 – May 08, 2019, 09:58:37 am

Our '02 had the same pump with the same issue. We were about to meet some grandkids at an airport and spend some weeks on the road with them, and I did not want to be stranded while we waited for a rather rare pump to arrive from FOT, so we purchased one to carry with us as insurance. ($$$$$) FOT advised us to just monitor the issue and keep adding oil as needed.

We did that for more than 18 months.  After doing his own research on the issue, the new owner of our coach is doing the same thing, I believe.

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Re: Hydraulic motor is leaking... again

Reply #62 – May 08, 2019, 10:32:19 am

Good point about oil on the frame, but I had Cummins steam clean that area after they worked on it.  I guess this is SOP for that shop since I didn't ask them to clean the engine.  I wanted to start with a clean "slate" so to speak after they did the hydraulic filter change.    Regarding the Lucus hydraulic additive, I did add a quart to the system (~4%) for good measure after I did my cardboard drip tests.  It probably needs more, but I will have it along if need be.  The stuff is really thick!

George

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