Brake band dragging on a 450()

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Cle Elum John
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Brake band dragging on a 450()

Post by Cle Elum John » Sat Jun 27, 2020 8:32 am

I put new brakes and clutches on a 450 straight about a year ago. Brakes were set intentionally loose when reassembled. After about 20-30hrs the brakes got quite a bit looser so I went through the manual's process for adjusting. To the ABSOLUTE letter. The clutch was still dead-on but the brakes were about 6-7 detents loose. I reset it exactly as the manual said three detents, 1 and a quarter turns. One of the brakes dragged badly the other side just a little. One side started to smoke a little after 100 yards. Backed off another detent (half turn), it's much better but still heats up a little. Has anyone else had fairly new brakes drag like that on readjustment? I'm thinking of resetting it another detent looser. Would two detents (one turn) looser than factory spec be unheard of while the bands are still seating? Am I missing something? Something obvious? Do those brakes all drag a little and heat up after readjustment?

Thanks for any help.
John
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LeonardL
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Re: Brake band dragging on a 450()

Post by LeonardL » Sun Jun 28, 2020 7:33 am

I'm usually one of those old mechanics who likes everything to be spot on. As in right with the book. However there are those rare occasions where I go by feel rather than what the book says. As long as your clutch releases first before the brake engages is what's important. It sounds to me like either a linkage is hanging or out of spec in some way. This causes your adjustments to be off. I would adjust the brake until it isn't dragging. As I said it is always clutch first and then the brake. Do what makes your machine work properly. As long as everything engages and functions without causing other issues then you'll be fine.
40 years working on JD 350s and other equipment.

Cle Elum John
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Re: Brake band dragging on a 450()

Post by Cle Elum John » Sun Jun 28, 2020 9:28 pm

I am pretty darn sure none of the linkage is sticking and that the return springs are in place. I just rebuilt the clutch and brakes last fall. Only have about 30 hours on it since. Everything I could see looked right.

I went through the whole process again this morning. Exactly like the manual says. I payed particular attention to the brake band adjustment detents and getting the adjuster exactly on the crown of the lobe between the detents for setting the cam screw. The clutch free travel is right on. Backed off on the adjuster 3 detents. Put it back together and ran it about 1/2 mile using very little brake. Measured the band temperature with a non-contact thermometer it still heated up to about 220degF on one side 180 on the other. Not hot enough to smoke. I backed off the brake off both sides to the next detent, ran the same 1/2mile. It came back about 30degF cooler on each side. The extra travel on the sticks is noticeable. I am thinking that there are high spots on the brake bands that may take some time to wear to circular. The brake drum was turned during the rebuild so those are smooth and round.

I am I overthinking this whole thing? Has anyone had similar experience? At this point I may just button up every thing, run it and have a look after another 30 or 40 hours. Any opinions?

Thanks
John
Reporting from the Peoples Republic of Washington State.

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LeonardL
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Re: Brake band dragging on a 450()

Post by LeonardL » Tue Jun 30, 2020 8:10 am

I have ran into some of these aftermarket brake bands being out of round and over thickness on the lining. I worked on a 350 one time and we used aftermarket bands on it. The company that had made the bands had made the thickness of the lining about two hundred thousandths too thick. Plus, the metal bands were egg shaped. They wouldn't let the brake drum pass through them no matter how we backed things off. So I ended up digging an old brake shoe grinder out of the shed and re-configured it to allow me to remove some of the lining and get the linings back to Deere specs. Then I took a brake drum and hammered the bands back rounder so they would engage the drum correctly. Now when I buy these bands the first thing I do is check to see if they are round and within specs before I install them. Whether this is part of your issue or not doesn't really matter. You have them installed and appear to be working all be it incorrectly. I'm just saying what I have found and what I do now.

If it was me on your machine I would run it as you said and let it wear in. Then try readjusting after you put some hours on it. It sounds like the bands you installed have thickness issues or as you said high spots. As long as your clutch releases before the brake engages you are good to go. I would run it. You're not going to hurt it by doing so.
40 years working on JD 350s and other equipment.

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Lavoy
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Re: Brake band dragging on a 450()

Post by Lavoy » Wed Jul 01, 2020 7:14 am

On 40 or more year old machines, the book specs do not always work out due to accumulated wear and other issues. As Leonard says, I adjust to function, not necessarily what the book says on those occasions.
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Cle Elum John
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Location: Cle Elum, Wa

Re: Brake band dragging on a 450()

Post by Cle Elum John » Sun Jul 05, 2020 10:41 pm

Closed it up with the brake band detent backed off another notch. The extra travel at sticks before the brake engages is more than I like. Aside from that the function is fine. I will run it for a while and then try to re-adjust it.
Reporting from the Peoples Republic of Washington State.

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