Rotary mower gearbox input seal. How often gear oil change?

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CobyRupert

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Have a Frontier 2084 7’ rotary mower. 6 years old. Gets used maybe 6-8 hours a year.
This year when i go to hook up, there’s an oil trail out of front input shaft. It’s never leaked oil before. Never saw any leaks prior to putting it away last year.
Do you think seal got a leak sitting over winter? It did sit in a place that gets sun (heating /cooling cycles).
How do I test that “breather bolt” / oil fill plug on top of gear box works?
Is changing input seal hard?

I don’t know yet how fast leak is.

Btw: How often do most of you change rotary mower gearbox oil?
 
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RedNeckRacin

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I just replaced the output shaft seal in my mx10 for the second time. The hardest part is getting thr stump jumper and blade holder back onto thr shaft. Your input seal should be alot easier if not for the simple fact you can work on top of the mower instead of under it. I think my breather got plugged last year and my gearbox drew some water because when I broke the castle nut loose a few ounces of water came pouring out. I am going to start taking my air compressor and blowing out the passages in the breathers before winter. I would have to check my manual for the mower again but the change intervals are not to often.
 
  
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CobyRupert

CobyRupert

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I’m not sure how to replace seal (part #7)
Do I take off cover plate around input shaft (green bolts) ?
Does this plate hold input bearing and seal in place?
Simply a matter of removing plate, seal falls off or out, pop new one in?
My projects are never that simple.
Do I have to drill and pull seal out?
IMG_4367.JPGIMG_4364.JPGIMG_4365.JPG
 
  
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CobyRupert

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My manual says “Storage: At end of your cutting season: 1. Drain and change the oil in the gearbox.”
I never have.
 
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Bigfoot62

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My manual says 鉄torage: At end of your cutting season: 1. Drain and change the oil in the gearbox.
I never have.

Me either.

But, look on the bright side: If the seal is leaking and you keep adding oil, that's basically changing it, right? :) Just kidding.

I would suggest, instead of changing the seal right now, top it off with 85W-140 and finish the season. Change it this winter, after you're done mowing.

To change the seal, it's pretty straightforward. Remove the 8 bolts that hold the front cover (faceplate) on. Remove the front cover. You may need to use a putty knife, sharp screwdriver, etc. to get it started. The input shaft will stay put, just slide the cover over it. The seal should come out of the back side of the cover. Remove the old seal. Install the new seal. It needs to be pressed in, or use a seal driver of the appropriate size. (a 3/4" drive socket, the same diameter as the seal, will do) AFTER you clean and de-burr the input shaft, re-install the front cover. If you don't remove any burrs or rust from the input shaft, you may damage the new seal. I like to use emery cloth to shine it up. I don't see a gasket or O-ring on the front cover. It will need to be sealed to the gearbox. If there's nothing there when you remove it, I would use Permatex #2. You could use RTV (silicone), but it has to be really clean, and then nothing else will ever seal that joint again. Re-install the driveline and guards. Fill the gearbox with oil.
 
  
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CobyRupert

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Me either.

But, look on the bright side: If the seal is leaking and you keep adding oil, that's basically changing it, right? :) Just kidding.

I would suggest, instead of changing the seal right now, top it off with 85W-140 and finish the season. Change it this winter, after you're done mowing.

To change the seal, it's pretty straightforward. Remove the 8 bolts that hold the front cover (faceplate) on. Remove the front cover. You may need to use a putty knife, sharp screwdriver, etc. to get it started. The input shaft will stay put, just slide the cover over it. The seal should come out of the back side of the cover. Remove the old seal. Install the new seal. It needs to be pressed in, or use a seal driver of the appropriate size. (a 3/4" drive socket, the same diameter as the seal, will do) AFTER you clean and de-burr the input shaft, re-install the front cover. If you don't remove any burrs or rust from the input shaft, you may damage the new seal. I like to use emery cloth to shine it up. I don't see a gasket or O-ring on the front cover. It will need to be sealed to the gearbox. If there's nothing there when you remove it, I would use Permatex #2. You could use RTV (silicone), but it has to be really clean, and then nothing else will ever seal that joint again. Re-install the driveline and guards. Fill the gearbox with oil.

Thanks for the advice Bigfoot.

That's exactly my plan. I added 85W-140 and ran it for a couple hours. Some leaked, but a little always looks like a lot and makes me nervous. I think the root of the problem is a bad breather vent in the fill plug.
When I loosened the plug the other day after the sun came out, and again after using it, I can hear pressure escape. This is what probably made the seal leak over winter. Don't know why breather plug would stop working, even after I tried blowing it out with air. Doesn't seem to leak as bad once pressure is relieved.
I ordered new breather plug and input seal.

If I get over my head, I hear filling gear box with "corn head grease" is an option to replace leaking oil.

What do you mean by "nothing else will ever seal that joint" again if I use silicone?
 
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LouNY

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On many gear boxes if the seals leak just a bit we will give them 20-30 pumps of grease to mix in with the gear lube.
Quite often the breathers will get plugged up and some spray brake clean and or a soak in a bit of gasoline then an airhose blow and they will be good to go again.
 
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the old grind

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If you've changed enough seals and aren't confused by the #7 in second pic pointing to the gap behind it vs the seal itself, you oughta see you shouldn't have to remove any bolts to replace the seal.

First pic shows "ready R&R the seal." I haven't slept in a Holiday Inn lately, but I replaced a lot of input & output seals (hundreds) working leak-test/repair in a GM transmission plant in the early '80s. Scoring or porosity in a seal bore can be fixed using any old-school rawhide glue or Permatex #1.

Study your pics well before you take apart stuff you didn't need to. The importance of a 'fix' should never make 'getting it right' more difficult by 'technical intimidation'. This one should take 15 min at most. Starting a seal into bore may be the tricky part if you don't have a 'driver' to hold it on-center or 'the touch' for it. Buff the shaft with steel wool as best you can reach where the seal's lip seats. 'You got this.' ;)
 
  
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CobyRupert

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If you've changed enough seals and aren't confused by the #7 in second pic pointing to the gap behind it vs the seal itself, you oughta see you shouldn't have to remove any bolts to replace the seal.

First pic shows "ready R&R the seal." I haven't slept in a Holiday Inn lately, but I replaced a lot of input & output seals (hundreds) working leak-test/repair in a GM transmission plant in the early '80s. Scoring or porosity in a seal bore can be fixed using any old-school rawhide glue or Permatex #1.

Study your pics well before you take apart stuff you didn't need to. The importance of a 'fix' should never make 'getting it right' more difficult by 'technical intimidation'. This one should take 15 min at most. Starting a seal into bore may be the tricky part if you don't have a 'driver' to hold it on-center or 'the touch' for it. Buff the shaft with steel wool as best you can reach where the seal's lip seats. 'You got this.' ;)

I'm sorry for my ignorance, but what do you mean?

I still have to take off the cover plate (green bolts) to replace seal? That is, do you agree with Bigfoot's assessment that cover comes off then seal comes out backside of cover?

(Note: the 4 silver bolts shown in picture previously held a pto guard/housing in place).

I don't understand the diagram showing "phillips screw heads" (?) where the bearings are, but I don't think this doesn't matter in regards to the seal. Right?

What do you mean by "ready R&R the seal"?
and
"Scoring or porosity in a seal bore can be fixed using any old-school rawhide glue or Permatex #1."? - I still need to replace seal right?
 
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LouNY

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Many seals will drive in from outside a gear box,
looking closely at your picture it looks like that one may.
If it does, I have collapsed them and peeled them out,
many people have success running a couple of screws into the seal then prying them out.
Once out one of the hard parts is sliding the new seal over the shaft without damaging it,
then keeping it square in the bore as you tap it in.
 

the old grind

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Seal comes out the front .. or we haven't seen the right diagram. Removing the 8-bolt cover would be necessary to replace the bearing. (on the bench) Only the shaft being 'slightly' in the way and the job being <knee-high should add difficulty. The shaft will center a new seal for installation but will do nothing to hold it square to bore or make it easier to press into it w/o bending it.

I shouldn't make pounding one in with just a hammer out of confidence sound like an easy 1st time DIY. Might you find a piece of PVC pipe or fitting whose dia ~matches the seal and is a big longer than the shaft protrudes? The longer it is the less likely the seal will tilt as you tap it in place with a BFRH. (big friendly rubber hammer, ~2lb) Get an extra hand or bush the pipe if you can to hold the driver and seal concentric for that first blow.

I guess LouNY types faster than me, or woke up earlier. :p
 

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Regarding the Phillips head screws, those are cross sections of the ball bearings not screws.
 

LouNY

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I'm finishing my 3rd cup of coffee and contemplating getting my butt in gear and doing something, maybe even productive or not. :dance1:
 
  
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CobyRupert

CobyRupert

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Many seals will drive in from outside a gear box,
looking closely at your picture it looks like that one may.
If it does, I have collapsed them and peeled them out,
many people have success running a couple of screws into the seal then prying them out.
Once out one of the hard parts is sliding the new seal over the shaft without damaging it,
then keeping it square in the bore as you tap it in.

Yeah, I'm afraid to start drilling to run a couple screws for prying and then hitting the bearing......especially if the procedure might be to take off the cover plate and remove seal from the backside of cover plate.
I just don't know.
 
  
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CobyRupert

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Here’s the follow up to this in case anybody else was as ignorant as me...yes I know it’s 10 months later!
Like I tell my wife when she asks me if I’m going to fix the vacuum cleaner: “I said I would and I will! No reason to keep asking month after month!” (Old joke, I know)
Anyways....
-Removed seal from outside with just a couple small screwdrivers.
-Had to be more careful to not bend screwdrivers.
- Rightly or wrongly, I used some plumbers grit tape to buff around input shaft. It felt smooth before and after (i.e. no burrs)
- Luckily I noticed that there’s a metal “spring” ring that’s part of the old and new seals. The old one was left behind on the input shaft when I took the old seal out. I thought maybe it belonged there until I saw the new seal has one “built in” a groove.
- Put some oil on the seal and used a rubber mallet and some PVC pipe to knock it into place. “Looks” seated. Proof will be when I refill.

IMG_8565.JPGIMG_8567.JPG
 
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LouNY

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Looks good, if you were doing that this afternoon, hope you were in the shade and had the breeze getting to you.
It's been down right miserable for me working outside the last few days, going from winter to mid summer is rough.
 
  
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Yes, I left it in the shade where it gets parked to work on it instead of bringing to the sunny driveway in front of the garage. Much, cooler and nicer there, but 3 times doing the 4 minute round trip walk to the garage for “one more thing” balanced it out. Today is ideal out in sun and cool breeze.

I still think there’s something going on with the vent cap fill plug. Soon as I put a screwdriver along seal, the oil ran out, something makes me think there may of been some pressure. I put a brand new cap on it last year when seal first leaked. Maybe I’ll replace plug with something that vents more “obviously”.
Suggestions?
Thinking a threaded pipe with a 90 degree sweep and a plug with a weep hole?
 

LouNY

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Several places have breather vents, one from Surplus Center has a dip stick which could be cut of;
1/2" NPT Breather Cap With 3.75" Dipstick | Reservoir Accessories | Hydraulic Reservoirs & Oil Coolers | Hydraulics | www.surpluscenter.com
Also you can get the stone/wire mesh vents which go into cylinders when used in single acting systems.
I had to replace the one on my generator gearbox it was allowing moisture to get in and contaminate the gear lube.
That was a metric thread and I finally found and umbrella type for it, seems to be working.
 

flyerdan

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Pulling the cover looks like it might have taken the bearing and shaft with it as well, as those four inner bolts are there for a reason, probably a bearing retainer.
To pull a seal like that, use an awl or other sharp punch to make small holes for a sheet metal screw (or three), then you can pull on them like pulling a nail. I use a scotchbrite disc to burnish where the seal runs, if you haven't removed all the burrs it will chew up the finishing disc and let you know it's there. Pack the area between the seal lips with grease and be sure to drive it on squarely, which you've done, and it should be fine.
For venting, you might see if you can get a sintered bronze fitting, they use them or single acting air cylinders to allow air flow and keep contaminants out. They shouldn't get rained on, so if it can be positioned such or fab up a small shield for it it should be good.
 

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I usually drain the oil and add corn head grease to a gearbox when it starts leaking. Typically the grease and oil aren't supposed to be mixed. If you guys think working on a gearbox in NY is hot, try it in Florida!!
David from jax
 

LouNY

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We were in the upper 80's with high humidity in the same month that we got snow storms :confused3::thumbdown:
 

sandman2234

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We were in the upper 80's with high humidity in the same month that we got snow storms :confused3::thumbdown:

High 80's with what kind of a storm? Is that anything like a Cat 3 hurricane?We have those both in the same month!
David from jax
 

weazilbarb

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I had leaky gearbox problem too. After all the regular oil leaked out I added in a bottle of STP stop lead and then grease gunned in JD Corn Head grease until just above full line. Corn Head grease solidifies quickly after melting due to gear reaction and therefore doesn't leak. I haven't had any leakage since (and didn't have to mess with replacing gaskets). Make sure you use Corn Head grease. Others won't work.
 
 
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