JD350B Steering clutch and brake band adjustment/replacement

[johnmoose]

Hi everyone, I am new to the site and so far I find the information here very helpful. I bought a 1972 JD350b crawler loader recently and I was hoping for some input on some things. I am really enjoying the 350b crawler so far!

Please help me with a couple of questions that I have?

1- Steering clutch and brake adjustment:

I opened up the two covers for the adjustments and successfully adjusted the steering clutch on each side and the both brake bands... however I was concerned with the brake set screw setting on the left side. In order to set that side to the spec. (so it touches the crank arm and then back two turns) the screw went in almost all the way... The right side screw did not need to go in nearly as far...
Do you think this indicates that the brake band on the left side is significantly more worn than the right? To replace the band, the final drive and track do have to come off, right?

2- Hazards in disassembling dry clutch discs and brake bands: Is anyone aware of the asbestos use in brake and clutch wear surfaces pre-1980? Just wondering if anyone has done this job on the forum and what your experience with it was...?

John

[original possum]

Did you "tighten (the) brake band adjusting screw clockwise until snug, ending with screw on the flat portion of the lock and not in the detent position." before adjusting the brake set screw? (P. 140-5-3 of service manual). That should shorten the distance the screw goes in.

[johnmoose]

Yes I did tighten the brake band screw ending up on the flat portion and not in the detente before adjusting the set screw. I even did this a second time to see if it would make a difference in the set screw setting but it did not. The adjustment worked well but my only observation was about the set screw distance on the left when compared to the one on the right... I thought that it seemed that the left band must be considerably more worn than the right one. Do you think that this is true?

[jtrichard]

Sounds like your brake band is on its last leg

[original possum]

If it snugged up on the drum (and not on the threads) then the setting should be the same on both sides. Either you ran out of thread or the linkage is worn. You do not have to take off the battery box and fender to remove the clutch. Break the track, remove the sprocket, and screw in 20" or so 1/2" bolts (where the two bolts with 3/4" socket size heads come out. Support these with bolts in the sprocket cover holes that have and "L" shape welded to the bolt. Adjust so you can slide the final out like on rails, then reach inside, push the shaft into the center case, and roll the final out supported by blocks set level. Heavy, but a whole lot less work. You can even change out a pressure plate while it is still on the "rails". Go back the same way and it will guide the shaft so you don't damage seals or throwout tube. A clutch job this way should take four hours or less. I'm old. Takes me five.

[Lavoy]

On my 350, one of the levers or whatever you want to call it was bent. My guess is from stuck clutches at one time, and instead of fixing correctly, they just kept jumping on the brake pedal trying to break the clutches loose with the levers back to get more brake force. It had pulled hard enough that it bent the lever up on top enough that the set screw had to be set differently.
Lavoy

[johnmoose]

Thanks for the tip on changing out a clutch Original Possum. It sounds like it would make doing the job a lot more efficient to do. And 4 or 5 hours is pretty damn good!

Lavoy, I think you may be right about one of the levers being bent. It sure does sound very similar to the problem that you had with your 350. Thanks!

Does anyone know how long one should expect the clutches to last before needing service. I know that there are some variables but what has everyone's experience been?

Do you recommend tying back the steering levers when storing the crawler over winter? I do store my crawler indoors...

[sullyt28]

The brake band on my crawler actually fatigued to the point the brake band broke apart. Didn't realize this until I took the machine apart.

Hats off if you could replace this in 5 hours. Took me considerably longer but in they end it wasn't to bad.

[Tigerhaze]

Do you recommend tying back the steering levers when storing the crawler over winter? I do store my crawler indoors...

You can find my thread discussing this in detail- it helped at first but I think keeping them disengaged (sprung) damaged them.