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jdemaris
04-19-2004 14:01:48
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Re: jd350 steering brake grabs in reply to MrBill, 04-19-2004 11:22:44
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This is, as asked for, a "quick" rundown on adjustment. This is assuming the adjustments
are not rusted fast and the clutches are not swelled or stuck. It's difficult to describe this
without photos to follow, but I'll try. Keep in mind, you want to achieve a situation
where, when the steering lever is pulled back, first there is some free-play (before contact
with the clutch throw-out bearing), then clutch disengagement . . . then just as the clutch
is fully disengaged, the brake starts to grab. You DO NOT want the brake taking hold
while the clutch is still engaged. That being said, pull the little top cover off the clutch
housing you wish to adjust (four bolts). Then, find the initial-adjuster on your brake band
- probably takes a 3/4" inch wrench, look for a nut on a threaded stud attached to one end
of the brake band. It ought to have flats on it so it wants to rest in one of two possible
positions, 180 degrees apart. Turn the nut clockwise until snug (not wrench-tight, just
snug). Then back off one turn. Now, notice how the linkage inside the housing operates
when you pull back a steering lever. There’s a little threaded rod with a small ball joint at
each end. One end is spring loaded and can be popped off for adjustment. When you pull
back on a steering lever, that threaded rod actuates a flag-shaft that in turn, pushes on the
steering clutch throw-out bearing. The action of the said threaded rod also, at a certain
adjustable point, begins to engage the brake. The point of brake engagement is
determined by a bolt locked by a jam nut; 3/8" bolt I believe. So, to put things in proper
sequence, loosen the brake-actuating bolt and back off for now. Then, set the free play in
the steering clutch by popping the threaded rod off and shortening in (by turning in a ball
joint end on the threads). If you get an inch of free-play at the start of travel in the
steering lever, that's fine. Keep in mind there's probably slop in the lever an linkage too;
you must have actual free play in the clutch. You can look down with a flashlight and see
the throw-out bearing and clutch fingers if you're not sure. Note: If you cannot get
free-play because the clutch pressure plate fingers are too high, the clutches are probably
swelled and rusty. It is possible to re-adjust the pressure plate fingers from the outside,
but it's difficult. Assuming you've got the free play, and you’ve done the initial
adjustment on the brake band, now you want to pull back the lever until the clutch
disengages. At that point, adjust the brake actuating bolt so it just makes contact when
the clutch is disengaged. This is easier to determine by running the machine. When I
worked for John Deere, I'd put the crawler on a steep hill facing up. Put it in forward and
start climbing the hill, and then pull the levers back until the crawler rolled backwards. If
it won't roll backwards, then the brakes are grabbing too soon. You should have a narrow
spot in the lever travel where the clutches are disengaged but the brakes are not quite
grabbing yet - that's why the crawler should roll backwards.
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