Brush hog spindle nut

JML755

Well-known Member
I've been having a rough few weeks with tractors. My Ford 3600 is out of commission waiting for an upper steering column seal. My New Holland TC45 WAS down because I'm putting a front remote on it for a grapple bucket. But while waiting for the parts, I put the hydraulics back together as I needed to use it for brush hogging which I usually do with the 3600.

Went out yesterday afternoon and started to cut and it was making a lot of noise. Looked behind me and it wasn't cutting. Raised it up and the blades were spinning. :?: Stopped the PTO and the blades kept spinning while the PTO shaft was stopped. Uh oh. :shock:

This AM, I picked it up with the loader to work on it. The stump jumper was VERY wobbly and loose. I expected to have to heat the castle nut on the gearbox to get it off but it came off with just a wrench and some hard turning. Found that the female spline on the stump jumper plate was stripped. The output shaft of the gearbox looks ok. My suspicion is that the castle nut loosened (there was NO cotter pin present) allowing the stump jumper to drop off the tapered gearbox spline until it no longer "grabbed". There was about 1/4" of "good" spline left at the bottom stump jumper.

I looked around the net and a replacement stump jumper is about $100. I found a hub for $20 which I ordered. I'll have to cut off the old one and weld the new one in. Anyone done that before? Any "gotchas" or things to look for? It seems pretty straightforward.

I was also hoping to replace the castle nut as well but it looks to be a 7/8" x 13 TPI. No such animal that I can find. I checked the threads multiple times (both shaft and nut) with 2 different thread gages. It's definitely 13 TPI. I thought METRIC? But nothing is close. I couldn't get the old nut back on at first because the end of the shaft was buggered up. I used my angle grinder and cutoff blade to cut off the damaged last thread and was able to thread it back on by hand. Would sure like to replace the nut. [b:965178b42e]Can anyone shed some light on this?[/b:965178b42e]


In the meantime, the grass needed cutting BAD. I've got some paths where the grass and reeds are chest high. Good spots for ticks to hang out. :lol: So, I figured I'd put the stump jumper back on and hopefully engage that bottom 1/4" of good spline to at least me make a few passes in the worst spots. Just putting the nut back on didn't stop the wobble. I put a washer between it and the plate and was able to snug it up. (I'm thinking that maybe there was supposed to be a washer there in the first place and whoever had this thing before me left it off when doing some work on it.)

Well, it worked. I was able to cut for an hour or so and get the worst paths down to "walkable" height. I babied it, raised the mower when I got near any branches or logs. Hit a few hidden pieces that rattled around underneath the mower but everything held. I've got my fingers crossed that I get the new hub on time. Pretty amazing, bought it off Amazon this afternoon, free shipping from the supplier and scheduled to be here Saturday. I know what I'll be doing this weekend on Father's Day. :wink:
 

I looked around the net and a replacement stump jumper is about $100. I found a hub for $20 which I ordered. I'll have to cut off the old one and weld the new one in. Anyone done that before? Any "gotchas" or things to look for? It seems pretty straightforward.

Done it worked well...
 
How do you get the new hub concentric with the stump jumper plate, for balance? Is the new hub also the blade holder?

Garry
 
I did some repair work on the stump-jumper on ours last year, and when I got done I balanced it, seems to work fine. I put the half-moon gussets in the top, every time I would hit something it would bend up an hit the bottom of the deck, very poor design. This remind me, I should check the big nuts for tightness!
a270492.jpg
 
7/8"-14 is a standard UNF thread.

Are you SURE the pitch of yours is 13 rather than 24?
 

Google stumpjumper the new hub has a step that fits well in the old hole clamp it together and weld away. I went to a local implement dealer looking for a stump jumper he handed me a hub.

The owner is a hands on guy he keeps repair parts in stock :) He use to manufacturer/repair implements...
 
(quoted from post at 01:57:55 06/15/18) 7/8"-14 is a standard UNF thread.

Are you SURE the pitch of yours is 13 rather than 24?

Yup, I checked NUMEROUS times. 13 TPI gage fits perfectly. 12 TPI and 14 TPI are off, won't drop into the thread. Even used a scale to measure (old school, LOL) an inch and count the threads. If I get a chance, I'll post a picture. Metric would be 1.953 or close to 2.0 pitch. 24mm x 2.0 (fine) would be a likely candidate but a 2.0 thread gage doesn't fit as perfectly as a 13. It may be worth a try to get a nut, though, and try it.
 


thanks for encouraging words. :D After I cut off the old weld around the hub, does it slip out pretty easy or is it a press fit?
 

Don't remember having any problems I would hope its a stile press/snug fit nuttin a hammer should not take care of. I have done one its been awhile...
 
(quoted from post at 05:01:21 06/15/18)
(quoted from post at 01:57:55 06/15/18) 7/8"-14 is a standard UNF thread.

Are you SURE the pitch of yours is 13 rather than 24?

Yup, I checked NUMEROUS times. 13 TPI gage fits perfectly. 12 TPI and 14 TPI are off, won't drop into the thread. Even used a scale to measure (old school, LOL) an inch and count the threads. If I get a chance, I'll post a picture. Metric would be 1.953 or close to 2.0 pitch. 24mm x 2.0 (fine) would be a likely candidate but a 2.0 thread gage doesn't fit as perfectly as a 13. It may be worth a try to get a nut, though, and try it.
If you measured 7/8", you'd better look for a 22mm. 24 is closer to 15/16". There are 24.5mm in one inch.
 
(quoted from post at 21:48:28 06/17/18) JML, what brand of mower is it? I probably have the nut here.
Unfortunately, I don't know. I got it used and there are no tags on it anywhere to ID the mfr. I've looked all over it but there's nothing. Here's a pic of it:
18424.jpg


It's still in pretty good physical shape, no rust through anywhere. I've been able to reuse the nut for now but I've got bigger issues with it.

I received the hub on Saturday and spent Sunday trying to cut the old hub out. I cut off the weld on the bottom side and was pleased to see a hairline crack develop outlining the hub as I worked my way around it with an angle grinder. Easy peasy, I'll have this out in a minute, I thought.

18425.jpg

I then took a hammer and tried to beat it out. Nothing. I tried heating it, I tried cutting it from the other side (top) in case there was a weld there, although it didn't appear there was. Frustrated, I then took a sawzall and cut it in half from the inside bore and still it wouldn't come out, beating it with a cold chisel to try and pop the halves into the bore.
18427.jpg


Looking at the replacement, there's a step in it. This makes sense as the diameter of the crack is very close to the OD of the smaller (stepped) diameter on the new hub. I don't know if the old one has the bevel in it, however, as some I've see on the web do not have it.
18426.jpg


I suspect that the crack doesn't go all the way down to where the step in the hub is at. The only other thing to try is to get some cutoff wheels for my die grinder and measure down to where the step is and then cut from the inside all the way around. I'd like to try this on a small "pie shaped" section first to try and knock a piece out of it so I can see the profile. But then there's no guarantee I'd cut in exactly the right spot and get the hub to drop out of the bore.

I gave up around 6:00 PM in order to visit my FIL for Father's Day (he's 91).

Another thought I just had was to see if I can get it on my drill press and drill holes around the circumference.

Originally, I had told my wife that I'd try the $20 fix first before buying the stump jumper intact ( around $100). Right about now, It's looking like that would be $100 well spent. I've already spent an afternoon messing with it and at some point you've got to factor what your time is worth. I think I'm at that point now.

It's not like it's the middle of winter and I can play with it at my leisure. I've got grass to cut and projects that are pretty high priority. I've got to clear about 680' of easement by the end of the month so they can schedule the installation of the electric poles by Fall on my vacant property. Still got about a dozen trees to take down and brush to clear in about 200' of that 680'. (It's much cheaper for me to do the "line clearance" than the utility).

As you can see, I'm typing this in the middle of the night as it's been bugging me to the point I couldn't sleep. So I'll probably order the stump jumper in the morning and get on with life.
 
I think you're beating the middle of a trampoline with a hammer. I'd get a piece of pipe just large enough to fit over the hub, set the deck on the pipe and whack the hub with a sledge.
 
(quoted from post at 09:13:42 06/18/18) I think you're beating the middle of a trampoline with a hammer. I'd get a piece of pipe just large enough to fit over the hub, set the deck on the pipe and whack the hub with a sledge.
Kevin, you may be right. I did support the plate CLOSE to the hub on some 2x8's but you may be right that there's enough "give" in that plate to absorb the blows. I'll scrounge around my "pile of steel" to see if I can find something that will work. I started to order the stump jumper today and noticed a slight oil puddle from the shaft so I'm going to change the seal while I've got it apart. I want to verify the size first. With my luck, the typical output shaft seal won't fit. I know the shaft size but I'd rather have the old seal in my hand when I order it.
 
Well, the hits just keep on coming. :(

I posted earlier that I was going to order a complete stump jumper but figured I'd change the output shaft oil seal as well since it was leaking. It wasn't too bad of a leak but since I already had the mower apart I thought that the leak wouldn't fix itself over time and only get worse.

Well, I wish I had left it alone. It was a pain to get the old seal out and now I can't find a replacement. It's a metal case seal 3.125"ODx1.5"IDx .5" width. I've searched all over and the closest I could come to that size was a National 210914 which costs close to $100! Yikes! At that price, I'd be better off just buying a new gearbox.

Can any of you guys who know about seals help? Thanks.
 
Not your size, but I just bought a seal for my Servis hog (3.375X2X0.5) for $15 at a local bearing supply company. You need to shop elsewhere....$100??????????????!!!!
 
(quoted from post at 15:24:31 06/19/18) Not your size, but I just bought a seal for my Servis hog (3.375X2X0.5) for $15 at a local bearing supply company. You need to shop elsewhere....$100??????????????!!!!
Yeah, that sounds more like the price I figured. Guess I'm so used to just going to a website, typing in the size and having a bunch of inexpensive choices in seconds. I'm going to call some places tomorrow.
 
(quoted from post at 17:39:08 06/17/18)
(quoted from post at 05:01:21 06/15/18)
(quoted from post at 01:57:55 06/15/18) 7/8"-14 is a standard UNF thread.

Are you SURE the pitch of yours is 13 rather than 24?

Yup, I checked NUMEROUS times. 13 TPI gage fits perfectly. 12 TPI and 14 TPI are off, won't drop into the thread. Even used a scale to measure (old school, LOL) an inch and count the threads. If I get a chance, I'll post a picture. Metric would be 1.953 or close to 2.0 pitch. 24mm x 2.0 (fine) would be a likely candidate but a 2.0 thread gage doesn't fit as perfectly as a 13. It may be worth a try to get a nut, though, and try it.
If you measured 7/8", you'd better look for a 22mm. 24 is closer to 15/16". There are 24.5mm in one inch.



25.4mm in 1 inch - 24.5mm is .9645 - 1mm = .03937
.03937 x 25.4=.999998
 
Well, I got an oil seal (National) for the brush hog at a O'Reilly Auto Parts for $15. Ordered a new stump jumper and spent a little more time trying to beat the old hub out while waiting for it to arrive. No go.

Got the stump jumper, flipped the hog on end and put the oil seal in. Turns out the hub I bought was perfect for driving the seal in. I measured the seal and it was the same thickness as the old one but it just wouldn't go in far enough to allow the washer to be installed above the split retaining ring. I cleaned the bore pretty well before installation, so I don't know what's going on. I ended up just putting the ring on and calling it good. The only problem is that the lower lip of the seal is curled down and showing in a spot about .25" long. Didn't notice this before driving it on. I had greased the seal and spring pretty well beforehand. I tried to push it up but didn't want to tear it, so I just left it and crossed my fingers. Since it's a double lip seal, I'm hoping it'll hold. Plus this is not a "pressure" situation as it's just holding the gear oil back from gravity.



Got everything back together (even bought new blade bolts) and went to cuttin'.

19039.jpg


Spent about 4 hrs on it, got back and checked for oil on the top of the pan: NONE, checked gearbox level: OK. So at least the seal is holding. Time will tell and I'll just monitor every time I use it. Chances are the pinched lip might just shorten it's life or...... it won't matter at all. In any case, it's a $15 problem, not something I'm going to lose any sleep over.

Also, I've heard about guys jacking up the mower and working on it from underneath. I can't imagine working with those heavy parts in that position.
 

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