[Richard]

During our last tour of the country, we developed a small leak in the hydraulic fan motor. I didn't want to tear into it while on the road, so 5000 miles later, we have a nasty grimey engine bay. 

Tom was here to help me get the motor out, and it was quite a learning curve that may help someone else in the future. 

First of all, it wasn't the hydraulic fan motor that was leaking. There is a device bolted to the hyd motor, that is supplied with hyd fluid via a small hose coming off the hyd motor, and a small return line going to the hyd reservoir. There were no identifying marks or lableing on the device that brought up anything in google that looked like the device.

The device is called an Overhung Load Adaptor. It is made by a company called ZeroMax. https://www.zero-max.com/b-overhung-load-adaptors#1  Mine was model L600130. The purpose of the adaptor is to keep any sideways load off of the hyd pump motor. It's a pretty simple device with two tapered roller bearings mated back to back to handle both axial and radial loading. The spline from the hyd motor slips into one end and the other end is the tapered hub for the fan. 

My model was a Zeromax 600 series overhung load adaptor with a high pressure seal on the output shaft. Here is an invoice with the part numbers for the overhung adaptor seals.

OrdAck1630136.pdf Size: 186.01 KB  Downloads: 72

The pump is a Vickers MFE 15. I replaced the front seal on it just for grins. Here is the invoice for that seal.

NEWELL.pdf Size: 130.55 KB  Downloads: 73

Here are a few tips that Tom and I learned along the way.

We confirmed the leak at the OHLA seal, by taking the motor out but leaving the hoses attached. Then we cranked the engine, and unplugged the speed control solenoid to make it run on high. A white paper towell really shows up red ATF. 

The OHLA has to be taken apart to get out the front seal. Remove the rear seal by standard neanderthal method. There is a huge circlip that holds the bearing assembly in. It takes a serious pair of circlip pliers to compress it enough to remove. The circlip has a bevel on it. When reinstalling, place the bevel facing outward or to the rear. The bevel preloads the bearings. When the bearing assembly is out, the front seal is punched out the front. Carefully press in the new one.

The front seal on the Vickers hyd pump is easily removable without disassembling the motor. I drilled two 1/8 holes in the face of it, screwed in two small sheet metal screws, and pulled it right out. 

You are going to drain almost all the ATF out of the hyd system when you take the hoses off the motor. Be prepared for the flood. It would probably help to empty the reservoir first, but the hoses are still going to spew ATF.

[DanB]

Good information but Wow...a seal costs 50 bucks? Seems really expensive. Any idea why?

[Richard]

Dan,

I winced too. I also spent just enough time looking at seals on line to see that the possibilities are endless. Most high pressure seals I found were 25 to 50 bucks. Given the labor invested, I wasn't willing to put in a seal that I specified, and risk a leak. It was a good three hours each way to R&R the hyd motor.

[superbirds]

Awesome Job !!
Wow you really get after it -- excellent rendering of the work.
I hope it hangs in there -if the seals were that expensive I'd hate to see the cost of the whole unit.

[encantotom]

today a buddy of mine and i took the hydraulic motor and OLA out of the 99 coach i recently purchased.  it was leaking somewhere, lost about 1-2 quarts in the 400 mile drive home.  i always need a small helper to get in tight places.  glen is a canadian farmer/mechanic and a great neighbor who jumps in and helps me when i need it.  and he is small....ha

i assumed it would be leaking at the same seal on the OLA that richards was.  but...it was not.  we took it off the mounting bracket and cleaned it all up with brake cleaner and ran the engine for 10 minutes or so.  no leak at first but after it warmed up it was leaking steadily out of the OLA hydraulic fitting.  

we did things a little differently than we did when i was at richards.  today we took the hose off the OLA and took out the entire fitting.  you cant get a wrench on it and you can see where they tapped it on with a punch.  we did the same thing to take it off.  low and behold, there was no o ring on it like it should have had.  we plugged the hole with a rag, put a bucket  under it and put my kiddie plastic play pool i used to catch fluids when working on things under it.  

off to napa we went and for 13 bucks we had an entirely new fitting.  put it on and then took the big steel motor bracket loose, took the fan out and i pressure washed it, and we cleaned the engine compartment and underneath as it had been leaking for some time.  

we are letting it dry and will put it back together on monday, but we are sure that is where the leak was.  

i will update on monday after finishing it

tom

[encantotom]

today we put it all back together.  tested it once we had all the atf put back in.  i used a bucked and kept the old fluid, only leaked out about 4 quarts and i filtered it and put it back in.  

no leaks and all is good.  

tom

[pairodice]

Thanks to all - it looks like this will be in my near future!

[pairodice]

I just removed the big bracket holding the OLA in the coach - it took about an hour by myself (4) 1/2” bolts through the bottom of the coach. Removing the two 3/4”/19mm bolts from the OLA was a pain for the rear-facing bolt - two 3/4” wrenches and a ball-peen hammer and it eventually came loose...
My leak looks to be coming from the bearing/seal area nearest the fan but will test it once I get it all out.

[pairodice]

Any advice on how to remove the FAN from the OHA/Motor? I removed the bolt from the inside of the fan holding it to the shaft and can see the ‘key’ in the shaft holding the fan. I put a bunch of PB Blaster on it last night. I will try this afternoon to remove it again using maybe a 2x2 piece of wood (pine) and beating it with a hammer/mallet. I will move the fan around like installing a tire on a car (move around from opposite lugs)... hopefully it will give up without destroying anything...

[Richard]

Easy does it. I have used two large screwdrivers as pry bars. One each on opposite sides of the shaft. I also have heard a "pickle fork" normally used to deinstall front end joints will work.

I don't recommend beating on it with anything. One the hub is aluminum and you could deform it or fracture it. Two, you could slip and take out a fan blade. Three, you could damage the bearings in the OHLA.

The fan is a simple press fit onto a taper fit.

I don't understand if you can see the keyway why it doesn't pop right off. The keyway is buried in the taper on mine.

Make sure you are trying to separate the hub at the taper, and not trying to remove the taper from the OHLA shaft.