John Deere 4120 Questions

[Willie71]

Fist of all thanks to all that helped me out with questions on the 4X00, 4X10 and 4X20 series tractors. Final decision went to a used 4120. Feel good about the tractor - has 450 hours and still 10 months on the bumper to Bumper warranty and the additional year on the powertrain. I plan on having a 400x loader with Heavy duty bucket and pallet forks for it next week. The tractor is a power reverser with top and tilt on the back. Although i have not had a chance to "use" the tractor yet i do have several questions. Keep in mind all my experience has been from larger John Deere row crop tractors from the 70's and 80's (2440 & 2630 still running strong with daily use on the farm)

1) there is no resistance when engaging the clutch pedal on the 4120- not complaining just not used to it - is this normal?

2) The brakes have about 1/2 to 3/4 ' inch of travel before fully engaging and you have to stand on them pretty hard to stop/keep the tractor stopped. There seems to be no gradual it is all or nothing. Again i am used to the hydraulic brakes of the larger tractors not the mechanical brakes of the 4120.

3) when i cut the tractor off it will roll even though the power reverser is engaged and there is a range and gear selected (as if the tractor was in neutral )- is this normal - unless you lock the parking brake it will roll. Again i am used to putting a standard transmission in gear and the tractor won't move without turning the engine.

I am sure i will have more questions as I use the tractor - thanks for the advice on the purchase and help with the above questions

 

[MT. Sparky]

the clutch is normal,the brakes can be adjusted under the tractor. i had to adjust mine. I never noticed the tractor rolling, i guess I just pull the brake when I stop it.

 

[jcmseven]

Willie, for what it's worth I think you made a good decision. I have been using a few different tractors from my local dealer, some of which have the PRT. Each one has very little clutch pedal resistance, so I think that normal. The brakes on the PRT machines get generally a lot more use than doe those on an ehydro machine, so at that hour count, they probably need to be adjusted. I would ask the dealer to do that for me as part of your purchase. They do tend to loosen over time but are not worn out (this takes quite a lot of hours I am told). Just make sure they are adjusted equally, for one machine I have used recently would lurch to one side under braking--not good with a full bucket--even with the pedals latched together.

John M

 

[shot_gun]

Willie the tractor will roll because the engine is not running to drive the hydraulic pump to supply the hydraulic clutches with oil to lock up the transmission. So you will get a not quite but close too freewheeling effect. Hope that explains it. Ther is no mechanical connection so to speak between input and output.

 

[Willie71]

Thanks for the answers! Look forward to having a chance to enjoy using the tractor and learning its features and capabilities.

W.

 

[hog611]

I have a JD 4120 and love it!!! my clutch is very close to the top and seems to stumble a little, is this normal??

 

[RoyJackson]

I have a JD 4120 and love it!!! my clutch is very close to the top and seems to stumble a little, is this normal??

I think you mean the clutch engagement is near the top of the pedal travel. Your operator manual should have a section on how to adjust freeplay. My clutch engages about halfway from the pedal stop (fully depressed) and that's where I like it.
You do want to get in the habit of fully depressing the pedal and, of course, never riding the clutch.

 

[beenthere]

I have a JD 4120 and love it!!! my clutch is very close to the top and seems to stumble a little, is this normal??

hog611
:welcome:

How long have you had the JD 4120?

 

[hog611]

It has 300 hrs total on it. I bought it about 1 1/2 years ago new.

 

[hog611]

I cant find anything in my 4120 manual about adjusting the clutch.

 

[RoyJackson]

I cant find anything in my 4120 manual about adjusting the clutch.

Yeah...noticed that later when I looked at the operator's manual. That kind of sucks.


Well, head to your local Deere dealer and either ask for the instructions (out of the service manual) or spend the 30-60 buck and buy the manual on CD-ROM.

 

[Riverrat]

Any thoughts on the e hydro version. Compared to the power reverser.

 

[sunnyside360]

I cant find anything in my 4120 manual about adjusting the clutch.

Some other tractor manufacturers who make hydraulic type clutches also do not specify how to adjust the clutch. Can't imagine why not. But, their service manual does state how to adjust the clutch. The JD shop guys may tell you how to do it.

 

[sunnyside360]

..............
2) The brakes have about 1/2 to 3/4 ' inch of travel before fully engaging and you have to stand on them pretty hard to stop/keep the tractor stopped. There seems to be no gradual it is all or nothing. Again i am used to the hydraulic brakes of the larger tractors not the mechanical brakes of the 4120.

My 4320 brakes require a fair amount of push to work so maybe it's normal. Also, it is possible the previous owner ran your 4120 with the brakes in the locked position like my son-in-law does occasionally --- not good for the brakes.

 

[sw14976]

When does the "tier IV" emissions kick in for the 4120, as opposed to the interim tier IV? I am a little concerned with the new technology with tier IV (i.e. clogging particulate filters and such). I noticed that John Deere is putting Yanmars in the new 4 series tractors coming out this spring. Any comments?

 

[Tx Jim]

Some other tractor manufacturers who make hydraulic type clutches also do not specify how to adjust the clutch. Can't imagine why not. But, their service manual does state how to adjust the clutch. The JD shop guys may tell you how to do it.

Most true hyd clutches are controlled by a "hyd valve" so there's no clutch pedal adjustment(free travel) that can be performed. Without the aid of a tech manual I think clutch pedal rod attaches to parts key #52 on a PRT trans which controls clutch valve(parts key #35)

 

[arlen4720]

When does the "tier IV" emissions kick in for the 4120, as opposed to the interim tier IV? I am a little concerned with the new technology with tier IV (i.e. clogging particulate filters and such). I noticed that John Deere is putting Yanmars in the new 4 series tractors coming out this spring. Any comments?

I think tier 4 has kicked in. As you said the new 4 series is coming out now. Tier 4 is the reason they have Yanmar engines in them. JD is focusing on 75HP and up, and getting smaller engines from Yanmar. They are puting Yanmars in their skidloaders too. I'm sure that they are great engines, but I hate to see the JD powertech engines go.

 

[sunnyside360]

....... I hate to see the JD powertech engines go.

Ditto on that. But, the Yanmar engine in my 2007 3720 has been trouble free . The JD Powertech engine in my 4320 has been excellent also. Darn tier 4 .........

 

[sw14976]

I'm leaning towards the 4120 to get the JD engine. I grew up using a 4020, and really loved to hear that big inline six growl.
All of the specs except HP are the same for this series. Does JD just use more boost, and different injectors?

 

[arlen4720]

I'm leaning towards the 4120 to get the JD engine. I grew up using a 4020, and really loved to hear that big inline six growl.
All of the specs except HP are the same for this series. Does JD just use more boost, and different injectors?

Yes, more boost, and the 4520 and 4720 have a totally different injection system than the 4120 and 4320. Both types use unitary injection pumps. So there is a separate pump/injector for each cylinder. The pumps are driven from extra lobes on the camshaft. The 4520 and 4720 have an electronically controlled engine so the injection system is simpler mechanically, and leads to the eThrottle feature which is not available on the 4120 or 4320.
Take a look at the parts breakdown from JD parts, you can see the reduced component count.
The Powetech engine has been a fantastic engine for JD.