Flail Mower Any Ford 918H owners?

[FF191]

Have a Ford 918H that I picked up at a good price. I have searched every document/ forum I could find for info on this specific mower. I did find a spec sheet that said it could be set to run in forward or reverse rotation but can not figure out how that would be done. Anyone with an owners manual or experience with a 918H that could educate me? I've found the owners manual online but I hate to drop $40-$50 just to find out if it can be reversed. Any info would be greatly appreciated.

 

[John0829]

I was going to scan the page from the manual for you but my scanner has decided it's toast but the long and short of changing direction of rotation is swapping the drive gear on the input shaft. Here it is word for word from the manual:

1. Remove the drain plug and drain the oil
2. Remove the bolts (6) securing the rear gearbox cover (1) and the side shaft support. Tap on the input shaft to loosen the cover. Disengage the side shaft.
3. Pry the rear cover and bearing off the input shaft (14).
4. Remover the input shaft from the gearbox.
5. Remover the gear (15), shim (11), and keys (13) from the shaft. Remove the spacer (12) and shims (11) from the other end of the shaft.
6. Install the gear with the keys and the shim to the end of the shaft that the spacer was removed from. Install the spacer and shims to the opposite end of the shaft.
7. Install the cover and the side shaft support setting the gear properly. Check the gearbox backlash with a dial indicator. The backlash must be from 0.008" - 0.0014". If the backlash is not to specification, re-arrange the shims. Replace the old gaskets.
8. Install the drain plug. Fill the gearbox with 3 pints of gear oil.

 

[FF191]

Thanks John. I had looked at the parts schematic and it almost looked like swapping the gear and spacer around might work but I hoped to hear for sure from someone who knew. I will go ahead and download the service manual, found it for $30 finally, and get it running the other direction. Thanks for taking the time to help me out.

 

[John0829]

Just to add when I got my 918H it was rotating clockwise or opposite the tire rotation and I figured it should cut better going clockwise or the same as tire rotation since in that direction it should pick up the growth laid down by the tires. Fact of the matter is, I could not really tell a bit of difference in quality of the cut after changing it. I never did not bother to change it back.

 

[FF191]

Thanks for the info. I'm actually running mine with a skid loader with a 3pt adapter and a high flow pto drive so I'm actually pushing it backwards. It's getting modified to run through sage brush in really rocky areas. I want it to cut on the upstroke and carry back over the top and to the ground instead of from the top and down towards the ground and out the back, which I'm staring directly at from the skid loader seat. I've ran it through the sage and it eats it up, but I don't like how it throws it towards my cab, even with 1/2" lexan shields.

 

[leonz]

Hello and good morning FF191,

I want to welcome you as the newest resident member of the "Flail Mower Nations" from the Western Slope of the Great State of Colorado.

How far are you from the Moffat Tunnel?.



Now about your flail mower; you wish/intend to set up clockwise rotation on the flail mower rotor to mow your brush with.

Is your high flow control valve capable of diverting oil flow in reverse???
If it can operate with the flow in reverse that is all you need to do.
If it is not it the detent can only be set in one direction like the old bobcats.

Before you worry and too much and end up fighting with it you need to ask
your equipment dealer if they offer a 2 position detent valve for the high flow
attachment loop so you can reverse the oil flow since you have a closed center
hydraulic system.


Leon

 

[FF191]

Leon, thanks for the reply. Its a bit of a jaunt to the Moffat tunnel, don't recall actually ever being there to be honest. That's in North Central part of Colorado, I'm a bit farther down in the Southwest corner.

With respect to my hydraulics. I can run my high flow hydraulics on my machine either way, there is no issue there, but in speaking with an engineer for the high flow PTO drive motor, was told that due to internal check valves in the motor, the drive is only able to spin in one direction. I know some lower flow drive motors are able to spin either way but not this high flow one. I'm in noway a hydraulic expert so I will take the engineers word on it. With the info received from John above, it should be a simple gear flip and won't cost me a dime. It will also keep my drive PTO direction consistent for other pto driven implements that I may use. Worst case scenario is that I have to make a new gasket.

 

[No1umfan]

I was going to scan the page from the manual for you but my scanner has decided it's toast but the long and short of changing direction of rotation is swapping the drive gear on the input shaft. Here it is word for word from the manual:

1. Remove the drain plug and drain the oil
2. Remove the bolts (6) securing the rear gearbox cover (1) and the side shaft support. Tap on the input shaft to loosen the cover. Disengage the side shaft.
3. Pry the rear cover and bearing off the input shaft (14).
4. Remover the input shaft from the gearbox.
5. Remover the gear (15), shim (11), and keys (13) from the shaft. Remove the spacer (12) and shims (11) from the other end of the shaft.
6. Install the gear with the keys and the shim to the end of the shaft that the spacer was removed from. Install the spacer and shims to the opposite end of the shaft.
7. Install the cover and the side shaft support setting the gear properly. Check the gearbox backlash with a dial indicator. The backlash must be from 0.008" - 0.0014". If the backlash is not to specification, re-arrange the shims. Replace the old gaskets.
8. Install the drain plug. Fill the gearbox with 3 pints of gear oil.

I’ve got one of these Mowers also. I have to replace the belts. Can’t figure out how to release the tension between the pulleys to let the belts slip on. Any help??

 

[the old grind]

Not a Ford flail but I bet typically, for me to change belts (2 B-size) I just to remove four bolts holding the lateral shaft's bearing mount at the top and push it down by hand to make slack. The holes are slotted for adjustment when I put bolts back in. If a bit stiff I'd loosen the bolts holding the gearbox but haven't had to do that yet.

btw, my mower specs 69 1/2" belts, rare and not at TSC .. but I can get 69"s and 70"s to work easily within the adjustment range. Costs ~1/2 as much and 3 stores within 10-20 min if I catch a few lights.

 

[John0829]

To loosen the belts first you loosen the 4 bolts holding the gearbox and back off the push bolt, then loosen the two bolts holding the pulley end and back off the push bolt on that end and then you can slide it back enough to get the slack you need to remove or replace the belts. To tighten just reverse the process trying to keep the pulleys straight with each other and not canted.

 

[No1umfan]

To loosen the belts first you loosen the 4 bolts holding the gearbox and back off the push bolt, then loosen the two bolts holding the pulley end and back off the push bolt on that end and then you can slide it back enough to get the slack you need to remove or replace the belts. To tighten just reverse the process trying to keep the pulleys straight with each other and not canted.

Could you post a picture of the 4 bolts holding the gear box? Also the push bolt on the pulley side is broken and I can’t turn the threaded piece that’s still there. Any suggestions?

 

[the old grind]

Time to apply the blue wrench? Looks like the OEM bolt froze and snapped off when trying to get it freed up. I've had 'em budge after cooling when they didn't seem to while still hot, roasted 'em good either way. Gear box bolts look to be accessed from the bottom. btw, nice pics, guys.

 

[John0829]

Penetrating oil and a small hammer will work on the bolt. Spray it and let it soak for awhile then start tapping it with the hammer while gently trying to turn it with vise grips or small pipe wrench. Keep soaking and tapping until it begins to move, it will take time so don't expect it to happen in the 5 minutes. Once it starts to move keep spraying and rocking it back and forth until you get it out.

I would use heat as a last resort.

The bolts for the gearbox are right under it.

 

[No1umfan]

Penetrating oil and a small hammer will work on the bolt. Spray it and let it soak for awhile then start tapping it with the hammer while gently trying to turn it with vise grips or small pipe wrench. Keep soaking and tapping until it begins to move, it will take time so don't expect it to happen in the 5 minutes. Once it starts to move keep spraying and rocking it back and forth until you get it out.

I would use heat as a last resort.

The bolts for the gearbox are right under it.

Thanks a million. You’ve been extremely helpful!! Just hope those gear box bolts aren’t frozen will let you know when I can get around to trying them. By the way why do you say use heat as a last resort?

 

[the old grind]

I mentioned heat, but only on the adjustment bolt/tab & not on the gearbox bolts. Sorry for any confusion. Kroil, Free All, Gibbs, Liquid Wrench NOT std WD-40 to loosen rust can be easier to use but 50/50 ATF & acetone still rules. All might need time to soak and reapplications can be every few hours.

tip: if you use 50/50 apply pure acetone every other time or so. (chip brush etc not poly) ATF will remain after the solvent evaporates out. The ratio once applied will favor ATF and lose its wicking ability to full depth, as in more acetone should suck into the oil vs be diluted/shared from more 50/50 mix. As I use up a small batch for a farm or machine job, say 2-4 oz (tall glass olive jar < 1/2 way, tiny drinking water bottle <1/2 way, etc) I just add a bit more acetone as I use it up.

btw: PO seems to have tried Vise-Grips on the broken adjuster bolt and failed. Bet it wasn't hot, can't tell if he knew not to loosen rusty chit 'dry'. I'd soak for a day or two if I had time (all bolts mentioned from all sides), maybe heat the adjuster if I didn't. Also, and from experience I wouldn't expect to have to loosen the gearbox bolts to change a belt set.

So say you let the bearing shield loose for now and see if you don't have easily and workably 1" - 1 1/2" of 'wiggle room' with mere hand pressure as I did. We need maybe 1/2-3/4" of it to get a belt off. And yeah, we do put 'em on one 'position' at a time and walk 'em over one groove to the next. (You knew that) Tell us when you get to the hard part.

 

[John0829]

As said soak it and tap it with a hammer the vibrations will help to get the oil to penetrate along the threads. I have removed many frozen bolts and pins by doing this. It is slow and can take days, I prefer to leave heat until the ultimate last thing when working around bearings and seals. I have seen to many people use a little heat, then a little bit more and a little bit more, then end up replacing seals that start leaking from being cooked.

 

[No1umfan]

So I’ve been soaking that bolt for a couple days. Really not making any progress. I did flatten it with a Dremel on both sides to try to turn it. But I just started twisting the bolt. Any reason not to just forget the lubricant and just try to drill it out. What’s the negative of that.

 

[John0829]

No negative at all, drill away, if you can get straight on and centered to it. Sometimes if you can find a left hand drill bit as you are drill they will come lose and back out. Finding left hand drill bits is the hard part.

 

[the old grind]

If you drill just saw off all but 2-3 threads and square it up with a file. Center-punch and use a #3-4 center drill or 1/8" stub drill to pilot the hole good & on center. Follow with a bit one size (1/16") smaller than the bolt/thread size. I have pic of one I did where the thread came out looking like 4-5 coils of a spring. It had been soaked in Kroil 2x/day for > a week & had to be drilled out anyway.

btw, when working under cars at Midas in the '70s I learned to just buff a broken exhaust stud flush to the manifold then drill & tap offset 1/8" or so leaving the old piece in a crescent shape as if part of the native metal. D&T was with airgun as I would use years later putting heli-coils in pan rails (not often) in a GM transmission plant. Again you don't really need to preserve the thread in the tab. If you're not comfortable with jam-nuts (double?) on both sides of it, opening the hole up and tapping for the next larger size bolt wouldn't take much. You want to be confident that the adjustment won't vibrate loose.

 

[dieselscout80]

If you drill it use a lefthand drill bit and it may loosen the stuck bolt.