F3680 mower deck height adjustment

/ F3680 mower deck height adjustment #1  

jcummins

Veteran Member
Joined
Jan 14, 2007
Messages
1,640
Location
Creal Springs, IL
Tractor
Kubota M7040, F3680, Mule Pro Fxt
My first mowing with this F3680, I'd say the cut is excellent. Better than I hoped for. Perhaps it looks so good because it is shorter than I normally cut and that may be a more groomed look. But I want to raise the cutting deck height.

Over the years my understanding is that the front of the deck should be slightly lower than the rear. Supposedly that gives a better cut, with the deck slightly angled into the grass. The gauge wheels are set in the 3" position, the rear lift rods are set in the 2.75" position. The exact opposite of what I thought I knew. Now, I'm scratching my head, do I raise both equally or do I adjust it so the front is lower by 1/4". Given the cut quality, I'm now lost.
 
/ F3680 mower deck height adjustment
  • Thread Starter
#2  
I have a F3680 manual, but I do not have one on the mower deck. I've got good info on it though from the F3680 WSM manual you can download. I may have figured this out.

On the lift rods there are washers, 6 of them on my mower deck. Although I cannot find the source, I recall the washers are for fine tune of the deck height, left to right, etc. They've got 3 of the washers below the adjustment collar...and that adds to the rear deck height. And 3 washers measure 1/4". Not sure why the height adjustment was done in this way, but as long as I understand it, it's fine.
 
/ F3680 mower deck height adjustment #3  
It took me a little while to figure it out also. It's a good, robust system but not at all intuitive. There are probably a dozen deck height adjustment systems out there that are a lot easier to use. Once I got mine set to where I wanted it, I haven't messed with it since.
 
/ F3680 mower deck height adjustment
  • Thread Starter
#4  
Yes I agree. The ZD326 I had was the twist of a knob, however, I had to go through some troublesome adjustments to get the deck level. 5 years later, it needed that same adjustment again. The F3680 deck looks complicated, at first look, but actually it's fairly simple, once you understand the different settings. And as you said...robust. You can see it, compared to others. Once I set it, probably won't touch it again.
 
/ F3680 mower deck height adjustment #5  
Hi jcummins, I have a copy of the deck manual and you can download it from the Kubota support website:
http://www.kubota.com.au/media/2287/ops-rotary-mower-rck72r-60r-f36-rck54-f28-k5682-7111-8.pdf

You are probably aware of all or most of this by now but just though I would share my journey of discovery so far:
The recommendation is to make the deck level so what ever you set the front wheels to you do the same settings for the rear deck supports. I set mine at B-Y from memory which is the second most highest setting and that is because I am mowing my paddocks which are a bit rough in places with plenty of rock and debris which I want to keep the blades out of. My place is also quite hilly with areas 25 to 30 degrees so I hope the mower is up to it.
The washer shims at the rear supports are to fine tune that height and to get mine dead level I ended up with five on top and one left under and I assume that is due to the rubber block being a bit worn and compressed to some degree from new perhaps.

The thing to be aware of when making the adjustments is that the rear supports are numbered and lettered in the opposite direction to the front ones so where A is the top hole on the front pin and X the top hole in the collar, on the back ones, A is the bottom hole on the pin and X is the bottom hole on its collar. So using the same relative holes in the opposite direction should give you roughly level.

I have noticed too that when mowing that the two front wheels on the deck stay well planted on the ground when the deck control lever is in the fully forward position allowing the deck to properly float on the front jockey wheels but if the lever is in the neutral position one corner of the deck will lift seemingly not allowing the deck to float properly. I was initially mowing with it in the neutral position which was probably not the best idea.
 
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/ F3680 mower deck height adjustment
  • Thread Starter
#6  
Thanks for the manual link.

Keep us posted on your experience on slopes...I have the same issues.

So far the F does crabs a little, nothing even close to the ZD, .... just noticeable. I had 275lbs on the rear of the machine, not sure why the extra weight since many F's have no weights, and I've removed to see what difference it makes. Will mow again first of the week.

Researching different tires...but not have much luck. Both local Kubota dealers have not been much help. But besides the muddy areas around the pond, kind of thinking holding the hillsides would be better with better tires.
 
/ F3680 mower deck height adjustment #7  
I also found the deck height adjustments to be more fiddly than it could be, but is pretty simple. As my machine had seen about 1500 hrs in council use I discovered early on that the shafts of the rear deck links had worn nearly all the way through but caught them in time and welded them solid losing just the bottom hole. Although I also run my deck at around 4" (10 cm), once I had it at a reasonable level I figure on just leaving it there.

As I am pushing the envelope on this (or any) machine on the steep 1/3 of our property I did add 3" (150 mm) wheel spacers to widen the main wheel track by 6" and also liquid-filled (water w/some antifreeze for anti-corrosion) those tires which added about 150 lb total and further helped the already good traction (new turf tires) and stability.

My machine was already equipped with the stock 110 lb rear counter weight but I figured I could use some more to take better advantage of the rear drive axle especially when I was partially lifting the mower deck to maximize main-wheel traction on the steeper hills (35+ deg), so I had another 115 lb (52 kg) weight fabricated out of steel and bolted it on top of the existing one. It helped noticeably. I had heard that the newer machines with the extra-wide wing-decks use about this much counterweight.

I was also looking to add a 2" trailer hitch receiver but figured to heavy-up the counterweight bracket before loading it any more..... however, if I decide to do a hitch-ball type, I may just sandwich a flat plate between my weights and let it go at that.

J Cummings - Your crabbing situation could be due to worn rear-axle bushings/bearing perhaps due to steering ram over-travel.....should check that possibility as JohnCar found.

Cheers, Rip
 
/ F3680 mower deck height adjustment #8  
Some great info there thanks Rip,

Interested to hear you are working on such steep slopes with it as 35 Degrees is getting up there. I couldn't find any other tyre choice through Kubota so rather than risk too much out of sync with the tyre diameters I will probably just fit a new set of turf tyres too when I can find a bit of spare cash. I do tend to slide down the slopes a bit when travelling across them but our climate is fairly dry and the grass can be a little slippery so there may be not much I can do about that.

Where did you source the wheel spacers? if you don't mind telling me as they sound like something I could use too and plenty of my block is 25 - 30 degrees plus. The mower feels fairly stable but an extra bit of track is very appealing.

For now I have fixed my steering ram over travel by turning up a nylon spacer and fitted externally on the ram as per the pic below. I was able to adjust the front tie rod end in enough to limit the right hand lock and then the spacer at 48mm long limits the left hand lock. I imagine that the kubot fix kit for this would be an internal spacer to do the same job but I didn't feel like pulling the ram apart so it seems so far so good with what I did. I machined in a bit of a recess so that debris is less likely to get jammed between the spacer and the push rod seal.

IMG_20150606_082216.jpg
 
/ F3680 mower deck height adjustment #9  
Hi John, I got the wheel spacers from Christian Hansen at thetrackscompany.com Phone +1-510 601-7550 in California. They were under US$300 including shipping two years ago......they fit perfectly and looked quite well made. There are a couple other outfits that make other styles but you seem to have a pretty well equipped shop so could fabricate something.

Your solution to the steering ram issue may well work long-term....I will have to see if I have the same issue.

The tyres on the machine when I looked at it were completely worn out (as were the mower blades) and I got the dealer to include new ones, but he was not going to go more than OEM....at least they were brand new.....more aggressive would be better traction, but at least I do not tear up the grass when I do spin a bit......but all we have is "mowed paddock" and not lawn.....works for us! The whole 4+ acres was quite overgrown (belly high to a horse) when we got it back in 2012 (renters, you know) so I put the F through a torture test for the first few months.....it did it (and on just a single V-belt, not the twin it should have had).

Cheers, Rip
 
/ F3680 mower deck height adjustment
  • Thread Starter
#10  
I also found the deck height adjustments to be more fiddly than it could be, but is pretty simple. As my machine had seen about 1500 hrs in council use I discovered early on that the shafts of the rear deck links had worn nearly all the way through but caught them in time and welded them solid losing just the bottom hole. Although I also run my deck at around 4" (10 cm), once I had it at a reasonable level I figure on just leaving it there.

As I am pushing the envelope on this (or any) machine on the steep 1/3 of our property I did add 3" (150 mm) wheel spacers to widen the main wheel track by 6" and also liquid-filled (water w/some antifreeze for anti-corrosion) those tires which added about 150 lb total and further helped the already good traction (new turf tires) and stability.

My machine was already equipped with the stock 110 lb rear counter weight but I figured I could use some more to take better advantage of the rear drive axle especially when I was partially lifting the mower deck to maximize main-wheel traction on the steeper hills (35+ deg), so I had another 115 lb (52 kg) weight fabricated out of steel and bolted it on top of the existing one. It helped noticeably. I had heard that the newer machines with the extra-wide wing-decks use about this much counterweight.

I was also looking to add a 2" trailer hitch receiver but figured to heavy-up the counterweight bracket before loading it any more..... however, if I decide to do a hitch-ball type, I may just sandwich a flat plate between my weights and let it go at that.

J Cummings - Your crabbing situation could be due to worn rear-axle bushings/bearing perhaps due to steering ram over-travel.....should check that possibility as JohnCar found.

Cheers, Rip

My experience with the weight on the back is different. Had 275lbs, took it all off, and I could not detect a difference. It makes since to have some weight back there....but my judgement is still out on this. I've got some steeper sidehilling I'll be testing it with...to darn wet right now.

Yep, going to check that steering ram.

Got to get the money first, but fairly certain I will be replacing the turf tires with Carisle AT101, and perhaps put rimgaurd in them too.
 
/ F3680 mower deck height adjustment #11  
Thanks for the info Rip, I will look into the spacers and also whether I can make them myself. Yes I have a decent workshop but no spare cash at the moment after buying the Kubota plus the few fixes and maintenance one has to do when buying second hand.
I have seen lug style tyres here locally on the main driving wheels of another second hand machine I was interested in but they looked significantly a bit bigger OD than the standards. I would be keen to consider some more aggressive tyres if I can find some that don't mess with the 4wd ratios. I will keep looking.

The other side of the coin is if it is sensible to try and make this machine go to places and angles it perhaps wasn't designed to do so further lowering it's safety margins. Lots to think about anyway.

My property we bought about 18 months back too had been rented out or the house at least was and the 68 acres had been neglected for at least the last 10 years so it's a big mess my wife and I are progressively trying to clean up. Being 60 yo this year, good machinery is important to help me with it.
 
/ F3680 mower deck height adjustment
  • Thread Starter
#12  
/ F3680 mower deck height adjustment #13  
JohnCar....sounds like you have a good place.....had though you were in West Australia, but the only Gympie I find is in Qld, north of Sunshine Coast.....that where you are??

You are absolutely right about good machinery....and while there are plenty of other good machines, one needs to carefully analyze what will be best for their particular situation and budget. Most things like this are expensive, especially in OZ, and thus our used municipal (council) machines fit the bill easier than brand new....mine is no thing of beauty, but mechanically has lived up to expectations.

Your F should be able to tame most of your block if set to max height (about 120 cm) and take it easy - small bites - and walk any areas first to find the odd fence wire, big rocks or old machinery bits before the blades do. Our place is only 4+ acres but had all of the above and vegetation was chest-high all over. Once finally tamed with multiple passes (and all with just a single V belt versus the twin it was supposed to have and now does), it is a piece of cake, although the steep parts are still just as steep! My wife has no desire for any seat time on the F as she is often afraid to even look at where I routinely go with it.....that's OK, as I will gladly stay out of her garden!

Carry a pair of small bolt (heavy duty wire) cutters if any chance at all of running into old fence wire....also be familiar with tilting the deck to vertical as that is one of the biggest advantages of an F-type over any other type of mower when in the field and having to untangle something from it.

There are Flail (drum) mower heads available for these front mower machines, and they raise what you can routinely tackle to another level or two.....they are expensive (especially in OZ - AU$8+K) new and difficult to find used, but if you find significant parts of your place too much for the rotary deck to handle, that is an option..... have your dealer be on the lookout for one or keep an eye on GumTree. They are all mostly made in Europe, so could import one directly. I considered one initially, but figured I would see how the rotary deck did and it was so beat-up I did not cringe when I was pushing it, but it did the job!. I guess you can always slash (bush-hog) the real nasty stuff first with your other tractor.

Cheers, Rip
 
/ F3680 mower deck height adjustment #14  
JCummins - Those AT-101 bar tires look nice, but not sure they would make enough difference over nearly-new turf.....would consider them if needed new tires anyway....could get a good deal if your dealer has some nearly-new take-offs or trade-ins though.

I considered a set of Terra-Grip ( Amazon.com: TerraGrips Tire Chains 24x12-12: Patio, Lawn & Garden ) for use as needed on my turf tires, but have not gone ahead with them.....still an inexpensive possibility that would likely do less damage to grass than steel chains, but at much less $$ than all new tires.

Cheers, Rip
 
/ F3680 mower deck height adjustment #15  
Same size as the turf tires on my F now.
Amazon.com: Carlisle AT101 Lawn & Garden Tire - 24X12-12: Automotive

Local Kubota dealer handles Grasshopper as well, and it is what come on those mowers.

And yes, it is amazing how neglected acreage will returns to an unusable purpose for anything except for deer hunting.

Thanks for the Tyre (tire) info jcummins. I will see if they are available over here. And yes there are the odd deer turning up in the hills on our block, it's so overgrown in places.
 
/ F3680 mower deck height adjustment #16  
JohnCar....sounds like you have a good place.....had though you were in West Australia, but the only Gympie I find is in Qld, north of Sunshine Coast.....that where you are??

You are absolutely right about good machinery....and while there are plenty of other good machines, one needs to carefully analyze what will be best for their particular situation and budget. Most things like this are expensive, especially in OZ, and thus our used municipal (council) machines fit the bill easier than brand new....mine is no thing of beauty, but mechanically has lived up to expectations.

Your F should be able to tame most of your block if set to max height (about 120 cm) and take it easy - small bites - and walk any areas first to find the odd fence wire, big rocks or old machinery bits before the blades do. Our place is only 4+ acres but had all of the above and vegetation was chest-high all over. Once finally tamed with multiple passes (and all with just a single V belt versus the twin it was supposed to have and now does), it is a piece of cake, although the steep parts are still just as steep! My wife has no desire for any seat time on the F as she is often afraid to even look at where I routinely go with it.....that's OK, as I will gladly stay out of her garden!

Carry a pair of small bolt (heavy duty wire) cutters if any chance at all of running into old fence wire....also be familiar with tilting the deck to vertical as that is one of the biggest advantages of an F-type over any other type of mower when in the field and having to untangle something from it.

There are Flail (drum) mower heads available for these front mower machines, and they raise what you can routinely tackle to another level or two.....they are expensive (especially in OZ - AU$8+K) new and difficult to find used, but if you find significant parts of your place too much for the rotary deck to handle, that is an option..... have your dealer be on the lookout for one or keep an eye on GumTree. They are all mostly made in Europe, so could import one directly. I considered one initially, but figured I would see how the rotary deck did and it was so beat-up I did not cringe when I was pushing it, but it did the job!. I guess you can always slash (bush-hog) the real nasty stuff first with your other tractor.

Cheers, Rip

Yes Rip,
Gympie Queensland or nearby Glastonbury actually NW from the Sunshine Coast.
I have been pleasantly surprised as to the capability of the Kubota F mower. It seemed very hard to actually get any official info on what angles they can safely work. The one I bought was ex Qld govt dept of Communities. It only had 480 hours but not all that well serviced but cosmetically not in bad condition.
My Block is very hostile with lots of rock, old fences, logs, old mining equipment (gold mining) and no haven't found any nuggets yet, but always looking..
Did I mention rocks!! yes there are everything from pebbles to the size of a truck floaters and some that are attached to china I am sure.
There has been a lot of mining across my block over the last 100 years or so I guess with plenty of old mullock heaps from the mines and it is red soil scrub country.
So yeah things grow very well here which is good for the cattle etc but plenty of work keeping it under control.
The upside is that it is a very nice place to live and in my opinion well worth the effort. We love it here..

For the heavier work I have a 80 hp Tractor with multiple implements including a fairly robust 6' slasher and it is set up at about 9-10" blade height to try and miss a lot of the rock, but I still manage to find them. I have recently built a stick rake that fits onto the front end loader which finds most things before the slasher does. But I will never attempt to clear the whole block as some of it is just too steep and rugged, just the bits that are sensible to do so and within our capability.
So yeah areas that I have slashed and pushed with the tractor a few times and rock picked a few times are now being mowed by the Kubota and it is just starting to look nice and under control in those parts..

On the Kubota I removed the standard blades and from a second old set of worn out blades I made up a set of swing back blades. So not a real easy job cutting and drilling the old blades being tempered but managed it OK. So now I have the old blades cut down and just used as blade carriers and have fitted deutscher flat blades swinging on the ends. To me the advantage is that the deutscher blades are much cheaper, about $12 a pair, easy to sharpen and expendable if hitting something nasty. They also seem to cut cleaner with less load on the engine and transmission to the deck. They don't throw the clippings out as well though which has it's pros and cons, the upside is that the machine and me gets covered in less grass and a downside is that I will get a few clumps when mowing thick grass. I am mowing with it set at B-Y which I think is about 4 1/2" (110mm), seems to be going OK at that.
The flail mower idea would be interesting to try but unless I stumble across one at a bargain price it is not likely to happen. They are a bit pricey to buy and lots of bits to service over time. One of my neighbours just had his serviced and repaired with half of the cutters and bolts replaced and pretty sure he said about $1000 for a dealer shop to do it. Not sure how many blades are on the thing but it looks like a lot.
A pair of slasher blades seem pretty cheap by comparison.
Having one mounted on the front end loader however would be handy at times but would need a good hydraulic circuit to run it. I could do some serious damage with that.
 
/ F3680 mower deck height adjustment #17  
JohnCar, Glad I got you located in the greater world....not sure what gave me the idea early on that you were in WA. Since you have a full-size tractor, no need to even think of a flail head for the F, but there are many available for PTO and 3 PT. May be you can work something out with your neighbor for the first pass over many of your areas (after the rock-picking pre-run with your FEL) .... and save the slasher for the next pass......then the F to give it the finishing touches! Even flails do not like old fence wire though!

A flail really is the best for heavy growth with many obstacles as you describe on your block. I knew my place had been reasonable paddocks in the recent past although still a few surprises.....fence wire, football-sized volcanic rocks (like our house is built of), and the odd carcass or bone pile. Although I considered a flail early on, my 60" rotary deck is handling things just fine now, but a couple neighbors have areas that a flail would be ideal to bring things under control......if I had one I would help them out, but too much $$ just for that.....there are contractors that can be brought in for one-time needs.

Your swing-back blade ends will help, but keep your 3 spindles regularly greased. Many modern push mowers use a solid disk with 4 swing-away blade tips ( I think I have even seen them for slashers, but not sure) as that eliminates the severe shock that even your shortened inner blade could suffer from hitting the many solid objects you will encounter......just a thought, as you could still use the same tips you have made (plus a few more). The V-belt already helps in that regard for the outer blades, but not the center driven directly by the gearbox and PTO shaft.

I envy your shop as I had a pretty good one in Colorado (now sold) where we lived 20+ years, but have a very minimally equipped one in Tassie, but there are several good fabrication shops in the area, but fairly $$$ and best if you can tell them exactly what you want and not for tinkering.

Good Luck Cheers, Rip
 
/ F3680 mower deck height adjustment #18  
Thanks for the info Rip, I will look into the spacers and also whether I can make them myself. Yes I have a decent workshop but no spare cash at the moment after buying the Kubota plus the few fixes and maintenance one has to do when buying second hand.
I have seen lug style tyres here locally on the main driving wheels of another second hand machine I was interested in but they looked significantly a bit bigger OD than the standards. I would be keen to consider some more aggressive tyres if I can find some that don't mess with the 4wd ratios. I will keep looking.

The other side of the coin is if it is sensible to try and make this machine go to places and angles it perhaps wasn't designed to do so further lowering it's safety margins. Lots to think about anyway.

My property we bought about 18 months back too had been rented out or the house at least was and the 68 acres had been neglected for at least the last 10 years so it's a big mess my wife and I are progressively trying to clean up. Being 60 yo this year, good machinery is important to help me with it.
Did you proceed with wheel spaces for the front 12x12 rims or were they not necessary in the end ? Cheers, Neil
 
/ F3680 mower deck height adjustment #19  
OrangeRidge, I did install 3" spacers on the main 12X12 wheels and they provide significant additional safety margin on the steepest parts of our place, although I was able to do a few runs under ideal conditions before I got them. I already had brand new turf tyres all around, and liquid filled (to top of rim) them as well....did not do the rear steer tyres, but later added an additional rear 48kg counterweight.

I am also in my 60s and was never a thrill-seeker, so puckering-up is not the high point of my day! I can and do the steepest parts up & down although I can go cross-hill sometimes. As you may have discovered, the brakes only work on the main drive wheels and are not much good for slowing down, but mainly for parking. I thus depend on modulating the hydrostatic even giving it some opposite direction to stay under control (with 4WD and Diff locked as well) and so keeping under power is the KEY TO LIFE! For this reason, I have also disabled the seat switch (some newer machines may not be so easy) so that even when my butt gets light on the seat (do wear the belt) the engine will not suddenly cut out and send me on a full speed run down the hill.....at least I have a good level run-out for a bit before thru the fence and into the Bass Strait! While I wish I had the dual steering brake option for other reasons, probably would not make much difference in this situation.

Back to your original question, while these F-Series machines are very stable as they are, and I could safely do 80+ % of my paddocks without the spacers, they do add a comfort factor for no other negative (but a few $$) and I would not tackle the really steep section (35 to 40 Degree) without them. Just fluid-filling the tyres will lower the CG, add a bit of traction, and cost nothing though.

I am still on the lookout for a good used F-3680 with the rear-discharge 72 in deck for a reasonable $$ already in Tassie, but they are often snapped up from ex-council usage. I will be off to the states for a bit visiting family and such, but most of my rye grass does not grow much in this season. Good luck with your machine!!

Hope you did not cop it too bad with Cyclone Debbie and all the flooding! Cheers, Rip
 
/ F3680 mower deck height adjustment #20  
Did you proceed with wheel spaces for the front 12x12 rims or were they not necessary in the end ? Cheers, Neil

Hi Neil,
No I didn't end up fitting spacers although there are times I wish I had. I have pushed the limits with my F3680 often having one of the drive wheels off the ground and have gone into an uncontrolled downhill sideways slide a couple times. A bit frightening when that happens.
I have learnt it is probably a very good idea to engage the diff lock any time on steep slopes and to try and always work up and down the slope with very minimal turning. I was however pleased though that when out of control on the machine just slid sideways down the slope and didn't flip over. The turf tyres were possibly a blessing when that happened so as to slip and not bite in.
The spacers would definitely give that little extra insurance though and they are still on my radar.
 

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