John Deere 420c steering clutch adjustment

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E.Huffman
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John Deere 420c steering clutch adjustment

Post by E.Huffman » Fri Feb 05, 2021 7:41 am

So I am back working on my 420c again and the right steering clutch/brake is not engaging the clutch soon enough. We adjusted the throw out bearing and brake bands according to the procedure in my service manual, How ever in order to get the track to stop it requires a good yank all the way back on the lever. What is the chances of the pressure plate not adjusted right?

dtoots1
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Re: John Deere 420c steering clutch adjustment

Post by dtoots1 » Fri Feb 05, 2021 10:11 am

i would try adjusting again doing each step by the book , have found that it may require several adjustments to get the proper feel on these little girls. they seem to be just a bit funky at times....mine actually went back too far and got to the clicking and went back to adjusting procedure again and got it back properly..did something wrong the first time or 2...

i am assuming you put new clutches in or some teardown work...did you use the gauge on the clutch if you had disassembled it?

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E.Huffman
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Re: John Deere 420c steering clutch adjustment

Post by E.Huffman » Fri Feb 05, 2021 10:18 am

I have never had the clutches apart However it looks like a brand new pressure plate, I am wondering if some one put a new one in with out adjusting it. We have tried multiple times but have not gotten it to click. It feels like the brake is doing all the work.

dtoots1
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Re: John Deere 420c steering clutch adjustment

Post by dtoots1 » Fri Feb 05, 2021 12:28 pm

am not getting clear picture of what you are trying to say....it sure sounds like an adjustment issue period....the clutch actually releases just a bit before brakes are applied, when adjusted properly...you literally have to release the locking bolt on the throwout bearing to get proper adjustment and then tighten it back up to lock in place for the adjustment. the bearing throws out or releases the clutches so that track is locked by the brakes. it seems you are telling me that the..brakes are being applied while the clutch...has not been released....if you are jerking hard on the lever and clutch is releasing..then either the bearing is not adjusted far enough out...or..you may have collapsed the clutch fingers....mine on my jd440 did just that with my 280lb farmer friend doing just that...they are 60 years old and don't take that too kindly!!!

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E.Huffman
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Re: John Deere 420c steering clutch adjustment

Post by E.Huffman » Fri Feb 05, 2021 12:59 pm

Ok I did adjust the bolt on the throw out. However when I took it for a spin, the bolt adjustment is clear out adjusted as far as possible. But even though the adjustment is as far as it can go it still is acting like the clutch needs to be adjusted more. (thus making the brake do it all and stalling the engine when turning on that side) Which makes me think there is a possibility it could be adjustment on the pressure plate. I just don't want to pull the final drive if I don't have to. I hope it is clearer than mud to understand :roll:

dtoots1
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Re: John Deere 420c steering clutch adjustment

Post by dtoots1 » Fri Feb 05, 2021 1:55 pm

ok...mine is exactly like that...i did new clutch, pressure plate and all new fibres and steels....yet my throwout bearing..locking nut rides right at the edge of the groove with a washer under the head of the bolt to be as far out as possible so that clutch releases...

i am not sure just where in that groove it will be when clutches get worn down more...i have to assume that bearing would ride deeper into the groove as clutches wear...

sounds like you may well have new clutches in there too...so get throwout bearing as far out as you can...mine actually rides in the drop off edge of the bearing.

if you cannot get bearing to that point..i would say you need to tear it down to see if fingers are collapsed....tho i would invest in a small camera borescope to see if you can actually see the clutch fingers...they certainly are cheap enough and can hook up to cell phones or laptops etc...

edit...and if you do tear it down....i am thinking it well may be that clutch fingers do need adjusting...to a higher height..which would indeed make throwout reach it ...and maybe ride in the groove....i do have the gauge for mine ..from Lavoy..so believe would do yours as well

that pressure plate release movement is very small...mite be 1/16 inch !!!! so on the edge may get you here..

see you down to Dayton way!

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E.Huffman
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Re: John Deere 420c steering clutch adjustment

Post by E.Huffman » Fri Feb 05, 2021 5:47 pm

Ok Great! I am getting some clutch at this point So I will try to adjust my brake again

dtoots1
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Re: John Deere 420c steering clutch adjustment

Post by dtoots1 » Sat Feb 06, 2021 7:14 am

Report back results if you will

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E.Huffman
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Re: John Deere 420c steering clutch adjustment

Post by E.Huffman » Sat Feb 06, 2021 7:32 am

So I couldnt really see any thing with a long camera, but i adjusted the brake band. So right now the adjustment is all the way out and it is clutching but now I have way too much travel in my lever, which I tried adjusting via brake band but goes back to the same problem of braking before clutching. I think i might try to use it for a bit as it is and maybe see if the clutch disc maybe wear a little. Currently to get it to clutch brake with out stalling i have to pull the lever almost back to the seat. If you have any ideas on how to adjust the lever with out adjusting the brake i would appreciate it!

2 I have another question ( it might be better to post new thread) But my main clutch has brand new pressure plate and disc and i have the right amount of free travel in the pedal however when I tried to get a full bucket load of gravel in 1st gear and the engine rpms are dropping, my clutch is slipping.... Thats not the nature of new clutch discs is it? Maybe my pressure plate needs adjusted?
I dont put a lot of stock in the things the guy did to this crawler before I got it. He put the clutch disc and pressure plate in, He also put a block on the engine that had a hole in the cylinder wal :x Just saying!! :shock:

dtoots1
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Re: John Deere 420c steering clutch adjustment

Post by dtoots1 » Sat Feb 06, 2021 8:04 am

not sure what happening on the main clutch...someone else may well have answer to that.

if i recall correctly...my lever measuring from the dash...is about 5 or 6 inchs to the lever..when i adjust the brake band...i usually put a flat screwdriver in the contact point to hold lever in position while doing adjustment...i think the critical point is..that the brake is applied just as the clutch is being released..so it could be greater than 6 inchs to reach that point...just so long as timing works for that release.

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Re: John Deere 420c steering clutch adjustment

Post by Lavoy » Sat Feb 06, 2021 10:16 am

Brake adjustment has nothing to do with clutch adjustment. You need more clutch, not less brake band. Move the throwout bearing out to where it should be, then adjust the brake. Lever should not come back more than 4 inches or so maybe. If adjustments don't fix the problem, then you need to pull the final and see what is wrong someplace.
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Jim B
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Re: John Deere 420c steering clutch adjustment

Post by Jim B » Sat Feb 06, 2021 11:58 am

To your question about setting the pressure plate on the main (engine) clutch. Yes you could have an issue there if it was not set. At the time a disc and pressure plate are installed the finger height is supposed to be set with the JD7 gauge. JD7 is the same gauge used for the steering clutches but there are two different measuring locations for the engine and steering clutches.

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E.Huffman
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Re: John Deere 420c steering clutch adjustment

Post by E.Huffman » Sat Feb 06, 2021 1:47 pm

Honestly I don't know if he adjusted I am just assuming since he got brain injured 2 years before i bought it. I guess My question is., would that be symptoms of a pressure plate that was not adjusted?

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Re: John Deere 420c steering clutch adjustment

Post by Jim B » Sun Feb 07, 2021 11:04 am

Lavoy, someone will correct me if I'm wrong on this. I see the adjustment of the pressure plate fingers as setting them at the proper starting height to get the maximum clutch life and adjustment as the clutch wears. As the disc wears the fingers get higher. This explains why you have to adjust pedal free play over time and use. If the fingers start out too high you may run out of adjustment before the disc is worn out.

You say the engine rpms drop, your main clutch is slipping. If the rpms are dropping it is holding some. What gear are you using? Do you get the smell of a slipping clutch? Is there a chance the clutch disc has been contaminated with oil, grease or such? If the flywheel or pressure plate have rust on them, that could contaminate a disc. If the flywheel disc surface was turned and the rim where the pressure plate bolts wasn't brought to the correct height as well, the pressure plate will have less clamping force. Did you have the clutch off off the flywheel when you swapped engines. I take it you don't have the JD7 gauge and didn't check the fingers at that time. You have a wet clutch reverser. Those will slip if not adjusted tight enough. They are in oil so it is not likely you will smell those. Steering clutches can slip in a hard pull if they are contaminated or if discs and pressure plates are worn. If you back it against something immovable, in the same gear as you are using forward, does it slip the same way? If it doesn't I would suspect the forward reverser clutch. Do both tracks spin? If just one or neither steering clutches may be the issue.

Does the brake pedal move when you push the clutch? There have been cases where the shafts going into the case seize together(brake cross shaft runs inside the clutch shaft) and affect the clutch action.

Just some thoughts and questions that might turn up another clue.
Jim

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Lavoy
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Re: John Deere 420c steering clutch adjustment

Post by Lavoy » Sun Feb 07, 2021 12:35 pm

My feeling is that the clutch in general is not adjusted correctly. Pressure plate adjustment is a possibility, but unlikely. Go through the entire clutch adjustment procedure in the service manual to a tee and see how it acts.
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