JD 420 Clutch Adjustment

edhughes

Member
I have 5-6 inches free pedal before clutch engages. Operators manual states to loosen clutch adjustment lock nut and turn adjusting bolt counter clockwise to reduce free pedal to around 1 inch. Had to use lock pliers to turn adjustment did so until it stopped. Still had too much free pedal. When I started tractor cltch housing was making mechanical noise and vibrating to pedal. Immediately shut off tractor and turned adjustment clockwise back to initial setting. Clutch engages fine but near top of pedal travel. Just got tractor and all else is very good. Is there a replacement clutch nut and adjustment screw that I can install externally or are there other issues that I may need to address. Sorry for the long winded explanation as I am just getting into owning classic JD?s.
 
I maybe confused in what you are saying. At the start of your post you say you have 5-6 inches of free play before the clutch engages. Are you saying the pedal comes up 5-6 inches before the clutch engages? The 1" free play should be measured at the clutch pedal, with it against the stop at the top of travel, down to where point where the throwout bearing contacts the fingers of the pressure plate. This is supposed to make sure the throwout bearing is not running on the pressure plate fingers when the clutch is engaged. Later in the post you say the clutch engages fine near the top of pedal travel. That sounds to me like the adjustment maybe close to right.
 
Jim
I know it was confusing. With the clutch pedal on the stop, there is 6 inches of free pedal before I feel any pressure. However with clutch
completely depressed and moving back toward the stop, it does not engage until almost when it gets to the stop. When I turned the adjusting
screw counter clockwise too far that is when I must have heard the throw out bearing rubbing against the pressure plate. I plan to leave it as is.
Is there a replacement adjusting screw, the one on the tractor is pretty mangled up. Thanks for your reply.
 
I don't know if you are familiar with the John Deere parts catalogs on line or not. If not, search JDParts Homepage. You will find the site where you can access the JD parts catalogs on line. Enter your model number to pull up the catalogs. Pick the right catalog, then you can find the drawing and part number for what you are looking for. (If you open the "previous parts catalog" it is easier to print from, in my opinion.) Once you have the part number you can go back to the homepage and do a part number search. That will usually tell you if it is still available or not. You don't have to sign in or register, but if you register with your local dealer you should be able to see if they have a part in stock and their price, if they participate in this program.

There are several clutch options in the 420 parts (Catalog # 505) for you to review. My gut feeling is you will find the linkage parts you are looking for will come up as NLA (no longer available). If that is the case you will be looking for used parts or having yours rebuilt. Having the right name and part number helps when looking for used parts.

If you don't have a service manual I would suggest getting one. It will help more than the operator's manual as you get deeper into things. I got a reproduced manual, for a 430 crawler (you may find the 420 and 430 wheel tractors and crawlers in the same manual as these were before JD split the green and yellow lines) I had, that had info for the earlier series added where needed as it seems John Deere did not always include info in a manual that was in a previous model's manual; they just referred to the previous manual. Some like them but I have not been impressed with the IT manuals, each to his own. Hope this helps, Good luck. Jim
 
To check your free play do the following. Get off of the tractor, and with your hand push the clutch pedal down as if you were disengaging the clutch. There should be roughly 1" of pedal movement with little to no resistance. You will feel the resistance once the throwout bearing is beginning to contact the pressure plate. Adjust the screw and nut accordingly to set to 1". I think you may be checking the free play incorrectly.
 
Measure for the 1" free play, down from the pedal stop, while you move the pedal by hand to the point where you feel it contacting the pressure plate fingers (resistance). Measurement is taken at the top of the pedal where your foot goes, in case the manual you are looking at doesn't show that. If you were pushing the pedal with your foot you might not have felt the contact.
 

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