Kubota Grand L 60 series seat bottoms out

troverman

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2019 L4060 HSTC; 2020 Kubota Z421KW-54 zero turn mower
Jun 9, 2015
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Looking for a solution - my 1 month old L4060 HSTC has the standard (non air) seat, and when I sit in it, the seat bottoms out. I'm 6'5" 265lbs.

It's annoying from a variety of standpoints, but mostly from the fact that I'm not sitting up high enough to have adequate leg room. I can operate the machine this way, but it isn't comfortable for long stints.

My previous Kubota MX4800 and L2501 had no issues with their seats supporting me.

Anyone found a solution aside from springing for the $1000 air seat?

Thanks in advance
 
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NWAZL3560

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L3560, LA805 loader, BH77 backhoe, rock bucket, box blade, pallet forks
Jun 11, 2018
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Mesquite, NV
Did you adjust the seat tension with the knob in front of the seat?
 

troverman

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Jun 9, 2015
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Did you adjust the seat tension with the knob in front of the seat?
It's all the way to max. Even my 225lb co-worker sitting in it causes it to sink to the bottom or right near the bottom. However, a couple of guys under 200lbs can sit in it without issue.

I've read there may be a difference between the seat suspension on open station vs cab L60 series machines?
 

Bmyers

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May 27, 2019
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I hope you find a solution. If I have one compliant about my L3560, it is the seat. I can bottom the seat out with it at max. Thankfully, I'm shorter than you, so I can sit low comfortably, but would like to have a little cushion when I hit bumps.
 

troverman

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Jun 9, 2015
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I'm going to remove the seat over Thanksgiving and see what can be done.
 

SDT

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multiple and various
Apr 15, 2018
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SE, IN
Looking for a solution - my 1 month old L4060 HSTC has the standard (non air) seat, and when I sit in it, the seat bottoms out. I'm 6'5" 265lbs.

It's annoying from a variety of standpoints, but mostly from the fact that I'm not sitting up high enough to have adequate leg room. I can operate the machine this way, but it isn't comfortable for long stints.

My previous Kubota MX4800 and L2501 had no issues with their seats supporting me.

Anyone found a solution aside from springing for the $1000 air seat?

Thanks in advance
The seat on my L6060 does not bottom out but I'm under 200 Lbs., and it's cranked up most of the way. I remember thinking that it probably would with a heavier operator even if cranked up fully.

SDT
 

mikester

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M59 TLB
Oct 21, 2017
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www.divergentstuff.ca
Sorry for the bad news but a $1,000 air suspension seat with 4 inches of travel is the solution. OEM Kubota seats are dreadful. My M59 has about 1/2 inch of travel and bottoms out regularly- I think it was designed to use your spine as the suspension system. Then they sloped the slippery seat forward so you bottom out, crunch your spine, then slide off the front.
 
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troverman

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2019 L4060 HSTC; 2020 Kubota Z421KW-54 zero turn mower
Jun 9, 2015
941
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NH
Sorry for the bad news but a $1,000 air suspension seat with 4 inches of travel is the solution. OEM Kubota seats are dreadful. My M59 has about 1/2 inch of travel and bottoms out regularly- I think it was designed to use your spine as the suspension system. Then they sloped the slippery seat forward so you bottom out, crunch your spine, then slide off the front.
I'm fairly confident I can create a solution using the existing seat.

Aside from the weak springing, this stock seat is actually very nice. It easily has 4" of travel or more, swivels 15 degrees either way, has a reclining backrest, armrests, and a high back. It doesn't tip you forward either.
 

D2Cat

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I replaced the seat on my L4240 a few months back, but I had no complaints about the seat...the seat pan just rusted out. When I went to Kubota to buy a replacement the cost was a bit over $1100.

I put the seat I found on sale for $49 dollars on it, and it's a tad better then the original Kubota seat because the arm rest are adjustable and covered so no seat pan is required that can catch rain. If the replacement seat cost $1100, wonder why Kubotathey doesn't put a Grammer on them in the beginning?
 

troverman

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2019 L4060 HSTC; 2020 Kubota Z421KW-54 zero turn mower
Jun 9, 2015
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NH
By way of a small update, I still haven't had time to remove the seat and examine the suspension. However, I did find a custom spring builder that seems confident he can recreate the springs with a stiffer spring rate.

I'll post updates as I get further into this.
 

notforhire

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Kubota L47
Dec 5, 2019
29
2
3
Meadows of Dan VA.
By way of a small update, I still haven't had time to remove the seat and examine the suspension. However, I did find a custom spring builder that seems confident he can recreate the springs with a stiffer spring rate.

I'll post updates as I get further into this.
I needed more leg room on my L47, so i raised the seat and set it back by using 1 1/2 inch square tubing. I also changed the "leveling blocks" on the back side of the seat base so that the seat doesn't slope forward as much.
I've heard of people raising the seat three inches using a similar method.

I don't know if these changes would help with your spring issue, but I'm 6 ft 2 in, about 220# and don't even come close to bottoming out. Sitting up higher may transfer some of the weight from the seat to your legs.
 

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troverman

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2019 L4060 HSTC; 2020 Kubota Z421KW-54 zero turn mower
Jun 9, 2015
941
47
28
NH
I needed more leg room on my L47, so i raised the seat and set it back by using 1 1/2 inch square tubing. I also changed the "leveling blocks" on the back side of the seat base so that the seat doesn't slope forward as much.
I've heard of people raising the seat three inches using a similar method.

I don't know if these changes would help with your spring issue, but I'm 6 ft 2 in, about 220# and don't even come close to bottoming out. Sitting up higher may transfer some of the weight from the seat to your legs.
Thanks notforhire. The seat on your L4701 is very different than on my 60-series. I've owned a number of open station tractors and never had any problem with the springing not being stiff enough. I had an L2501 and an MX4800, both were fine. The Grand L 60 series uses a totally different suspension with long travel...like probably 6" or more designed to mimic the function of an air ride seat. (In fact, Kubota offers an air ride seat for $1000).

However, I appreciate your ideas. I plan to take the seat apart and see if there is anything I can do to solve the problem. I'd like to retain the plush travel of the seat, just have it stiff enough to support my weight. I'd also like to get out of it as cheaply as possible.
 

SidecarFlip

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M9000HDCC3, M9000HD, Kubota GS850 Sidekick
Oct 28, 2018
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What you need to do is take apart the suspension and shorten the adjustment rod an inch or so and reassemble. That will increase the spring tension. You also might want to add spacers to the underside of the rails to increase the height, exactly what I did on the OS M9 I bought last spring but I also bought a new suspension from Rural Kine when I ordered the replacement seat that D2Cat refer's to.

The replacement seat is a Grammer knock off and it's very comfortable and has a nice water resistant Cordura covering.

I think the replacement suspension from Rural King set me back an additional $150 bucks plus the cost of the seat for a 200 buck upgrade. You can get a self contained full air suspension seat base from Tractor seats.com but it will set you back about a grand. Your existing seat will bolt to any replacement suspension, seats and bases are all ISO compliant, which means the bolt patterns all match up no matter what you get.

My Cab M9 has a Grammer from the factory and I added a National Seating air ride base that I bought from a truck salvage yard. I added a small 12 volt compressor to inflate the air bag in the seat suspension fro Harbor Freight. Think my total outlay was about 150 bucks plus some install time and the National Seat base (unlike the Grammer air ride seat bases), has grease fittings.

The seat pan mount is also ISO bolt pattern so any base will mount right up

It's all 'plug and play' with seats and bases, just takes time to remove and replace them, especially in a cab model where access is limited and if you go the air ride base route, there is a power wire behind the seat on the right side that you can use to power the compressor.

The compressor I bought at HF is the 12 volt one for tire inflation and I added a cut off pressure switch so the compressor pumps up about 75psi and shuts off which is quick because the air bladder under the seat don't take much air to inflate and the compressor tucks under the seat suspension out of the way, out of sight.

Couple ways to go but I'd start with shortening the actuator rod that tensions the springs first, that is the least expensive and easiest solution.

...Conversely, you could go on a diet.....:)
 

troverman

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2019 L4060 HSTC; 2020 Kubota Z421KW-54 zero turn mower
Jun 9, 2015
941
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NH
Thanks Flip for the suggestions.

As far as the diet, it seems these seats are bottoming out if you're much over 200lbs at all, and at 6'6" with a large frame I'm never going to be less than 240, so something will have to be done regardless.
 

SidecarFlip

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M9000HDCC3, M9000HD, Kubota GS850 Sidekick
Oct 28, 2018
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Thanks Flip for the suggestions.

As far as the diet, it seems these seats are bottoming out if you're much over 200lbs at all, and at 6'6" with a large frame I'm never going to be less than 240, so something will have to be done regardless.
Said that in jest. I'm pushing 200 myself and I think the suspensions were designed for Japanese people of smaller stature....

The spring ride seats all have a center threaded adjuster rod that can be shortened but you'll have to take apart the base. Just be careful as even in the least tension position, the springs are still under tension so when releasing the threaded rod you need to be careful not to get a 'Purple Herbie' when the springs let go.

Good lock and be careful.
 

troverman

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2019 L4060 HSTC; 2020 Kubota Z421KW-54 zero turn mower
Jun 9, 2015
941
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NH
Thanks, that was my thought...designed for Japanese people. Then again, I never had trouble with my open station seats.

I asked the dealer right away, and they basically said they could retrofit the factory air spring with compressor for about a grand. I guess I was annoyed after spending $45k on this tractor that it needed another grand to accommodate me.
 

Mistermike

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L4060
Nov 22, 2019
7
0
1
Walpole, New Hampshire, USA
As luck would have it, I had a Kubota tech at the house today to repair a squeaky seat in a new L4060/cab. During the service visit he said the seats are good up to 225 pounds. I happen to be 250. I bottom out once in awhile but not continuously. I guess there are not to many heavy Japanese.
 

SidecarFlip

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M9000HDCC3, M9000HD, Kubota GS850 Sidekick
Oct 28, 2018
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As luck would have it, I had a Kubota tech at the house today to repair a squeaky seat in a new L4060/cab. During the service visit he said the seats are good up to 225 pounds. I happen to be 250. I bottom out once in awhile but not continuously. I guess there are not to many heavy Japanese.
Time for you to shorten the threaded adjustment rod as well. All the adjustment rod does is pre-load the seat spring. Shorten the rod and it increases the pre-load and gives the seat more 'tension on the suspension'....:)