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Discussion Starter · #1 ·
Can't hear it with my ear muffs on but I had them off for a little while yesterday to listen for issues while mowing and I realized the 60" 420 deck is getting louder. Sounds like the spindle bearings are almost worn out. Probably need to replace them. It spins freely though. No unusual noises turning it by hand. Just a howl when it's running. The left side spindle gets warm too. Haven't checked the other ones but it doesn't really matter. If I have to do one I'll do them all.

Always something..
 

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I wish I could pass along a fool proof way to make that job easier Army. I'd say pull the nuts off the pulleys in between mowings and start soaking the pulleys with the best penetrating oil you have. Put the nuts back on and mow. Repeat as many times as you have patience for until you are ready to change the bearings.

My spindles must have never been rebuilt previously because when I started working on them, I tried everything to get the pulleys off including lots of heat. Between rust and the half round shaft keys pivoting in the slots just enough to grab the pulley, none of the pulleys wanted to come off willingly. After the first pulley bent removing it, I was very careful with the next two, letting them soak for days, using heat, supporting the full pulley underneath while pressing but they would not budge either. I had to buy three new pulleys because they all deflected when I tried pressing them off.

Once I rebuilt it with all new JD bearings and grease seals, it ran quiet and I never had another problem with it. I used never seize so if the bearings ever so need replacing again, hopefully the pulleys will pop right off.

Good luck. I hope you can replace your spindle bearings easier than my experience.
 

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An option for pulleys if they are damaged on disassembly is to pick some up from vbeltsupply.com or surpluscenter. They sell solid cast steel pulleys that are much more amenable to being pulled. Still have to be careful but are a lot more robust. I reassemble with copper anti-seize to make the next disassembly easier. I put some solid pulleys on my Tilt-Dump and they're working out well. Picked up the new v-belts from them too. They're dirt cheap but getting a range of lengths allowed me to dial in nicely the right size for the application
 

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Discussion Starter · #4 ·
I realized yesterday that 400/420 deck spindles will interchange and I happen to have a set for a 400 that are good. However.. upon further review the gearbox actually seems to be the problem. I can spin the deck by hand no problem and it seems fine but it's really growly noisy at operating RPM. The particular sound it makes led to me to believe one or more spindles was bad.

I had to replace the roll pin and key for the drive pulley on the 420 deck shaft a few months ago and I'm wondering if the roll pin sheared off again. The only roll pins I have that fit are from the surplus store and they don't look very sturdy. I can wiggle the drive pulley up and down on the gearbox shaft enough to make me think that's the case. If it is, I'm gonna try using a 5/16 bolt instead of the roll pin. I have a 1/4 shear bolt on my blower and it has only broken once or twice in a dozen years so 5/16 should be strong enough ..but still breakable. The key should be doing most of the work anyway but the keyway on the pulley shaft is mangled somewhat on the 420 gearbox. Another option (if they're identical gearboxes) might be to swap the pulley shaft with one from a spare 400 deck gearbox I have.

I also have a brand new gearbox that will bolt right in but it turns the wrong way (story of my life) and I have another one on my spare deck (on my spare 400) I can try. I put new bearings and seals in that gearbox last year or thereabouts. And I also have another gearbox sitting on the shelf from the rotted out deck that came with the 400 I bought last fall. Not sure how good it is.

Or.. I might settle the question of whether 420 decks can be used on 400's and vice versa without any major mods and put my whole spare deck on it. We've debated the 400/420 deck swap more than once here at WFM but I don't recall anything conclusive about it.

The deck on my restored 400 is basically a 420 deck retro fitted for the 400's. Was in super nice shape on the bottom side when I bought it and still is. I oil it a couple times a year when it's out of service. It has a different width mule drive, belt routing, deck covers and lift arm design than a 420 deck but appears identical otherwise. Pretty sure the 420 decks turn faster too. I want to keep the nice deck on the nice 400 but using it on the 420 is still an option. Note the smaller wheels. One of the issues I've noticed with the 420 style decks is the wheels catch and dig in a lot so I put the small wheels on this one a few years ago. They work good. No issues at all.
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Bottoms up..
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One thing I thought of to mount my spare 400 deck is to reverse the 420's mule drive arms so they're wider. If they're still not wide enough or are too wide I think maybe I could use a rod long enough to connect the 400 mule drive to the deck instead of the J pins. Assuming the deck lift arms connect to the 420 ok I don't see any other issues. I've been wrong many many times before though.
266974
 

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Discussion Starter · #5 ·
I've done two sets of spindles over the years Mike. Don't recall any issues getting the pullies off. Maybe you were the Murphy's Law example on that issue. Usually it's me.

I wish I could pass along a fool proof way to make that job easier Army.
 

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Army, here's my take on the roll pin. The key and the keyways do the real work. The roll pin's job is to keep the pulley from moving up and down on the shaft. I believe JD even suggests using a bolt and self locking nut instead of the roll or spring pin now.

If the pulley wobbles on the shaft, the bore of the pulley is worn out of round or the shaft has worn. What I found on my early 420 deck was a very worn bore, key and keyway in the pulley were badly worn. The pin hole was worn like an egg but the pin was just fine! The gear box shaft was remarkably right on size and straight. Definitely had to have a new pulley.
My deck has a Curtis gear box. Some use a Peerless IIRC. Looked on the Curtis website for a pulley but they didn't show one. Guessing JD actually made that part. I was still in shock from checking JD's price for one!

I found a cast pulley at McMaster-Carr that matched up well enough that I was willing to spend the $30 or so to see if it could work. It did not have the cross hole, and the hub side where the hole would go was shorter than the original. It did have a set screw that would lock down on the woodruff key though. That might actually be OK but I decided to add the cross hole and use a bolt and locknut. I may have had to face a small amount off the hub on the upper side to make the "V" match the original when installed. You don't have time to read about the Rube Goldberg way I got the cross hole in there with my limited home shop tools. A decent machine shop will have an indexer and extra length cutting tools to put that hole exactly where it has to be.

I've only used it for a season and a half but it is still tight and working fine. No noticeable wear on the belt from the "non-Deere" V angle.

tommyhawk
 

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Discussion Starter · #8 ·
Yah that makes sense Tommy. The tilting has to be an egged out bore like you said. I might have a pulley on the shelf that'll work. Haven't looked yet. Ideally I'd like to get the deck through the summer then work on it in the off season. Things rarely ever work out that way for me though. Used to be a machine shop near me that would do jobs like cutting a new keyway on the pulley shaft for cash on the side. Haven't run across an alternative yet.

Pretty sure all 4 of my 400 deck gearboxes are Curtis and the new backwards spinning gearbox I have is too. Don't know if the 420 gearbox is yet.

Me and Rube are old friends. We do everything together. :rolleyes:

It's off the 400 right now so if I can't readily fix the 420 gearbox/shaft issue Plan B is to try mounting the spare 400 deck on the 420 this morning, as much out of curiosity as the need to do it. Plan C is to use a spare 400 gearbox on the 420 deck. I haven't formulated a Plan D yet but E is to get my angle grinder out and teach that 420 gearbox a lesson :p.
 

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Discussion Starter · #9 ·
So as it turns out the 420 deck gearbox turns the opposite way to a 400 deck, however that was "good news good news ..chu chu chu!, as Sheriff Roscoe P. Coaltrain would say, because I had a brand new gearbox on the shelf that turns the same direction as the 420 gearbox. My original plan for that gearbox was to put it on a scruffy old 60 inch deck I have and flip the blades upside down for mulching leaves. At least I think that would work. My crazy theory is that the leaves get chopped up much better by backing up over them ..so spinning the deck in reverse should work too and I'd be able to drive frontwards instead of backing up. I can only turn my head a bit to the right and not much more to the left (car accident at age 19) so backing up with a mower is usually guesswork for me.

The 420 deck is pretty scruffy looking but it's in good shape. Just needs a good sandblasting and repaint, then oiled at least once a year. I usually flip them over, thoroughly clean the bottom side and oil the snot out of them in the fall when I'm done using them, and then hit them again in the spring before I put them back on. The shell has some pitting on the top and bottom but not real bad. Enough to annoy me though.
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New gearbox..
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The input stub shaft on the new gearbox is quite a bit longer than 400/420 gearboxes so I had to shorten the driveshaft about 1.5". There's still enough space for the shaft to slide back and forth as the deck is raised and lowered. The 420 driveshaft was already shorter than a 400 deck, which I didn't realize before. I also had to use a new drive pulley because the original one was egged out (exactly as tommyhawk predicted). The new one doesn't have the flat bottom in the V but going by the paint rubbed off the original pulley the belt never got that far in the groove anyway. The groove is wider too though. The new pulley works fine (so far) but I'm gonna try to find one with the same groove profile as the original. Will have to be a new one. No way to verify a used one is good for sure from eBay or wherever.
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Finished the assembly work and mowed some grass and the deck was much quieter. Pretty sure I can still hear a bit of growling from the left side spindle though. It feels warmer than it should too. If it gets any worse I'll swap it out and install one of the 400 deck spindles I have. Got 6 spares. The pullies on three of them are very thin though and as Mike U will attest to, they can be a bugger(!) to get off.

One other thing I noticed right away is the blades spin slower now, going by the speed of the clippings coming out of the chute anyway. I had to run the Vanguard almost wide open to avoid a windrow. 23 HP is more than enough power to run a 60 inch deck about 3/4 throttle and still do a good job.

I didn't measure them but the correct 420 deck drive pulley is quite a bit smaller than what's on a 400 deck. A rough guess would be a couple inches. I assume that's where the increased deck speed comes from. I could go smaller and take up any belt slackage with an idler pulley but if I do that the belt might not have enough pulley circumference to grip. I'm no engineer so I can't calc the minimum diameter but there's a point where a smaller size pulley will cause the belt to slip instead of turning the deck. Kinda like the contact patch on a tire.

The drive pulley shaft keyway is very pooched. The roll pin was broken again too as I suspected. I put a wider key in it previously that was fairly tight but the keyway/key must still have been loose enough that some torque was transferred to the roll pin. No way it would stand up to that.
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Roll pin..
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With the newer pulley on the left spindle, it looks like someone already worked on that one or swapped out the whole spindle. Maybe the pulley will pop right off for you when you decide to change bearings.
 

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Discussion Starter · #11 ·
Good eye! I didn't see that.

With the newer pulley on the left spindle, it looks like someone already worked on that one or swapped out the whole spindle. Maybe the pulley will pop right off for you when you decide to change bearings.
 

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Discussion Starter · #13 ·
You're an outside the box thinker Jake. It's a valuable skill to have (y). I put a roll pin the new drive pulley. Gearbox is new too so the pin should be good.

You could put a second thinner role pin inside the first one, double up the strength.
 

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Discussion Starter · #14 ·
My 420 deck has been annoying me from day one. If I dropped it down to where it was mowing at a suitable height all 4 wheels firmly contacted the ground. The wheels were adjusted up as far as they would go but the deck weight was still riding on the wheels. I mow the grass at about 3" out back but the wheels were still supporting the deck. Enough to make it jerk and twist around a lot as the wheels followed the terrain, plus the wheels aren't intended to support a constant load like that, especially when turning. The problem was even worse in the areas I mow at about 2", like the front yard.

I'm stubborn so I kept trying to figure out why it was happening. No luck so I finally gave up and put the smaller front wheels on the back and a pair of non-JD wheels on the front that are half the height of the original wheels (pics to follow later today). Much better now. No problems with scalping or whatever. Between the gearbox fix and the wheel change it's like a different deck. Very smooth and much quieter too. I'm still baffled about why the ground contact happens with the correct support wheels though.

I also have to adjust the side to side deck height now because the right side is too low. Didn't realize that because the wheels were governing the height before.

This is the size difference between a 400 deck drive pulley and one from a 420 deck. About 2 inches. The new gearbox I put on the 420 deck must actually spin slower than a standard 400 deck gearbox because even with the smaller pulley on it it's not spinning any faster than my 400 decks do. Maybe not even as fast. I always have to rack me wee brain when thinking about pulley diameters and speed and which pulley should be what size so maybe I'm mixed up on this too. It's a curse. In any case there sure are a lot of variables with decks aren't there?
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I don't know anything about the 400 era deck but think my '83 420 deck is more like it than the later ones, but maybe not. JD parts is somewhat confusing on these decks. You probably already checked and compared the pulley diameters at the engine and the jack shaft to see if there are differences between the 400 and 420. I can't remember if the gearbox ratio is stamped on the tag on the box. They can be 1:1, 1 1/2:1, 1:1/2, or something else. Differences there can make the blade speed come out the same. On the GT's, JD didn't seem like to leave too many things interchangeable for very long, did they?

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Discussion Starter · #16 ·
Yah good point. That's definitely the case Tommy. The two models look very similar but the 420's and the decks for them are completely different than the 400's. I actually can't think of anything off the top of my head that's exactly the same. One example is the hoods will swap back and forth but the headlight lens is not the same design and the hinges have the same bolt pattern where they attach to the hood but are otherwise different. Another example is the hydro control lever. On the surface they look alike on both models but they're not. As far as I can tell nothing will interchange except maybe the orange ball on the end. Wouldn't surprise me if the hole in it is a different diameter. Never checked the steering wheel/hub. They look like they might be swapable but I haven't verified that yet. In some cases it's like they made modifications for no reason at all. Engineers love to change things.

Same thing with the decks. The later 400 version looks just like a 420 deck but most of the parts are completely different. The spindles supposedly interchange but I haven't actually tried that yet.

I should take the time to document a thorough comparison of the two tractors and attachments to use as a sticky. Maybe next winter. I really appreciate the guys who take the time to do that and also the mods who verify the info is reasonably accurate before flagging it as a sticky.

JD didn't seem like to leave too many things interchangeable for very long, did they?
tommyhawk
 
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Discussion Starter · #17 ·
This is what I have for wheels on the 420 deck now. Much better! The deck isn't jerking and crabbing along the ground anymore. The smaller wheels did the trick but something is not right with the deck support setup or I wouldn't need them. The newer 400 deck I have that's very similar to a 420 deck has the same issue on the front. Back wheels are fine but the original front wheels dig in all the time when backing up or turning sharply and are contacting the ground way too much at a proper mowing height. That's where I got the small front wheels for the 420 deck. Took them off the 400 deck. Don't recall where I actually got them to start with but I gotta replace them on the 400 now. Hopefully I have something on hand I can use.
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Just a note about those pullies. You're likely aware some (actually many) pullies are made to run both A & B Belts. (1/2" and 5/8ths) It would appear the pullies in your photo may be that type. At least one of them. If you're a believer in the often mentioned theory that Deere belts are different and special, well who knows? But it looks like those two pullies are different widths. The one on the left being a 5/8" belt pully, the right a 1/2". If you run a 1/2" belt on a 5/8" pully it will run deeper in the groove and effectively change the ratio and speed somewhat. And change the belt length along with it.

As for the two pullies in the photo with the tape measure, if those were in the same position on the machine, it would make a dramatic difference in speed. Very close to half speed or twice as fast as the circumference is nearly double. Depending if it is the driving or driven pully.

Calculating ratio's is not that hard. Takes a bit of time to get the hang of it but it's not rocket science. Deere made it really complicated with their goofy PTO arraignments on the 400 series. So many possible variables. Engine pully size, reduction in the front gear case, reductions in the rear case, Pully sizes on the output shafts, pully sizes on the mower deck and the possible reduction in the mower gear case. No wonder you and everybody else is confused.
 

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Army, the top portion of the front wheel spindle assembly on your mowing deck looks different than the set up that was on my 420. I just sent you a private message with a couple pictures of mine. Mine worked very well and was adjustable to accommodate normal size wheels. It's possible they had various designs over the years and possibly yours could be easily modified to improve its function.
 

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Discussion Starter · #20 ·
Wow, I hope I never see hubs like those again. That’s nasty. Looks almost like someone used channel lock pliers or a pipe wrench to keep them from spinning when tightening and loosening a blade??? But getting a wrench back there behind a blade to hold the spindle would be difficult at best. Did they grip the spindle when trying to remove a pulley nut? I can’t imagine what would tear them up like that.
If the pulleys are that thin, it makes a person wonder how many thousand hours use they have. That’s a lot of wear for sure but a real testament to how well Deere built things to last.
Yah they're pretty bad aren't they. And that was after I cleaned them up quite a bit. The hub end was thick with crusty rusty crap from the deck shell rot. The shell and the blades were junk. They went to the big smelter in the sky. I kept the wheels, the mule drive, the gearbox and the driveshaft. I doubt I ever will but the belt is still usable so I stashed it with the rest of my JD 400 stuff too. It also had a pretty decent deck cover. I don't usually put the covers on my decks but it's too good enough to toss out. I have a wide variety of stuff that fits in that category. Like my father before me.
 
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