40c/420c steering brake

rogberndt · Post by **rogberndt** » Thu Oct 20, 2016 2:35 pm

Hello, I inherited a 40/420 crawler, I believe it is mostly a 40c with a 420 five roller under carriage and transmission. I have no steering on the left side. I peeked inside the clutch housing and could see that the brake band had slipped toward the inside off the drum. After unable to pry it back on I removed the final drive and replaced the brake band. Everything seemed to fit nicely on reassembly. When it came time to adjust the steering clutch and brake band with proper arm throw I could not tighten the band enough, the threads going through the adjusting nut came up against the arm and bottomed out so you couldn't tighten it any more. The right hand side has pressure plate issues to be addressed but there is very few threads above the adjusting nut on the brake band. Any thoughts, ideas or similar experience? Thanks, Roger.

Post by **Lavoy** » Thu Oct 20, 2016 2:56 pm

Okay, maybe I am a little confused. You say the RH pressure plate has issues, but there is little thread above the brake band adjusting nut? Two different adjustments, the brake band adjusting nut has nothing to do with the pressure plate.
You replaced the brake band on the LH side with a new one, or a used one? Is it worn out? Possibly the brake drum has been machined in the past? That is about the only way you can run out of adjustment on a brake band.
Lavoy

rogberndt · Post by **rogberndt** » Thu Oct 20, 2016 3:36 pm

Yes, I realize the two adjustments. I just wanted to compare what the right hand side looked like, I wanted to fix the left hand side first before opening up the right hand one. The band was a reconditioned at 10566 t same as original. The original wasn't that bad but did have groves cut in from rubbing on the drum a skewed, didn't want to chance it happening again. The tractor ran fine a few years ago until a renter of the property took it upon themselves to use it. I can't figure how the band slipped off in the first place.

rogberndt · Post by **rogberndt** » Thu Oct 20, 2016 3:48 pm

The right hand steering clutch works however it's way out of adjustment. There's a rather loud click sound when you pull the steering lever, and there are posts about that. There's also some oil present so probably looking at clutch rebuild and a new seal.

Paul Buhler · Post by **Paul Buhler** » Thu Oct 20, 2016 6:33 pm

My guess would be that two or more quill springs are broken which lets the quill skew causing the clicking.As you probably know, a common shaft controls the throw out bearing and the brake band. Being deep in the darkness I don't think you can see all the springs. The only way I got to understand the clutch/brake interplay was to take apart my final and go through it with the manual in hand.
When reassembling the final, it's easy to misalign the brake band, so care is needed to get it on the bottom dowl, or it won't align or adjust properly. When everything is apart, I found that it was well worth the time to disassemble all the adjusting screws and fixtures so that the clutches and brake adjusted easily when putting things back together. In particular I spent time freeing up the shaft with the ball sockets that activates the quill; it needs to be adjusted carefully. I hope some of this is helpful, and best wishes. It's no fun having an ill machine.
Here's a link to when I did my finals. I got a lot of help from others.
http://www.jdcrawlers.com/messageboard/ ... inal+drive

rogberndt · Post by **rogberndt** » Thu Oct 20, 2016 10:17 pm

Thanks Paul, can't start on it for a couple of weeks, I like your pictures so I'll post some when I can. I was wondering how to get the final to clear the track frame just like your picture showed. I will study your post and hopefully figure it out. Thanks for your input, Roger.

Post by **Lavoy** » Fri Oct 21, 2016 9:34 am

Usually the clicking is because the throwout bearing is travelling too far because the brake is not tight enough.
On the LH side, that is still confusing, if the band was relined correctly, should be no way to run out of adjustment on the T bolt.
Virtually impossible for a band to slip off, only way that can really happen is when installing the final drive the band gets pushed in. There is a raised part of the steering clutch housing that prevents the brake band from slipping in.
Lavoy

rogberndt · Post by **rogberndt** » Fri Oct 21, 2016 12:40 pm

I agree Lavoy, I'm thinking something got bent, I did have to straighten parts of the lever the t bolt goes in. When I tightened the adjusting nut the t bolt came up and contacted the lever preventing anymore adjusting, that's when I looked at the right hand side to see how many threads were above the adjusting nut which was not very much. The track frame prevented me from completely removing the final, so next time I will completely remove it and take a closer look at everything inside. It was a little tricky on the install, but I made sure the band was in proper position, it fit so well I thought I had it. And yes, I see no way that band could slip in off the drum. Thanks for all the input and advise, Roger.

original possum · Post by **original possum** » Fri Oct 21, 2016 4:26 pm

Push the drive shaft out of the clutch and into the "differential" while the final is suspended. Then it will clear.

Post by **Lavoy** » Sat Oct 22, 2016 9:02 am

Drive shaft is held into the clutch hub by snap rings, can't push it in. Easiest way is to just rotate the final drive about 90 degrees and then pull it out. Look in your service manual, it shows a bent rod that the factory recommends to do this.
I did just have another thought. I have seen brake lever "crushed" so to speak. There is a running change in the 420's where the lever is greatly beefed up. Usually you see it where someone has been reefing on the steering lever trying to unstick a frozen clutch and it bends the heck out of the brake lever. This could influence the amount of brake band bolt sticking out, but shouldn't be a lot of difference.
Lavoy

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