Hot rear drum...part 2

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NU2theT
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Hot rear drum...part 2

Post by NU2theT » Tue Jun 15, 2021 6:30 pm

So I have some thoughts after some observations with my e-brake cam position as it relates to the lever position @ various positions.

The last picture is the cam when my lever is set @ 12 O'clock or neutral, looks to be level @ 9 & 3, brake lining relaxed approx 10 1/2"

The second picture is the cam position with lever set back as I would when stopped & parked, nose down @ 4 and heel up @ 10, brake lining extended approx 10 5/8" +

The first picture is lever forward as in high gear engagement, nose up @ 2 and heel down @ 8, brake lining is extending outward just a tick under 10 5/8" - this might be part of my problemo.

I think filing off some material on the brake cam upper right and lower left as pictured and some off the brake shoe ears in those locations where they ride will help relax the lining to a somewhat neutral lining position while in high gear (lever forward). Any input would be great.
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Scott_Conger
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Re: Hot rear drum...part 2

Post by Scott_Conger » Tue Jun 15, 2021 6:39 pm

It might seem intuitive that "neutral" means the brake cam is level, but that is not true. Your brake rods are adjusted a little too tight and the lining is likely dragging a little on the very ends of the material.

Do not alter the brake cam
Scott Conger

Tyranny under the guise of law is still Tyranny

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speedytinc
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Re: Hot rear drum...part 2

Post by speedytinc » Tue Jun 15, 2021 6:42 pm

DONT BE GRINDING.
When the cam is horizontal, the lever should be back about 10 o clock. If you could see it looking from the cam side. When activated ,lever moves forward to 2 o clock.
There are rights & lefts on those cams. Cams on wrong sides??


Allan
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Re: Hot rear drum...part 2

Post by Allan » Tue Jun 15, 2021 9:32 pm

When you are going down the road, the lever is right forward. This is when you need the brake shoes to be completely disengaged. So, the rods should be adjusted so the cam is level when the lever is forward. However, engaging neutral with the lever will slightly rotate the cam and likely make the brake shoes a closer fit.
Because there can be a little slop/wear in the components, the closer fit can be compensated for by adjusting any slop out of the system. With the lever forward, adjust the rods so that the slop gets the cam just engaged on the opposite cam face to where it usually activates the shoes. When the lever is pulled back into neutral, the cam will transition from that opposite face to the working face, with minimal action on the shoes. This gives the best chance of non dragging shoes going down the road, with least drag in neutral, and optimum cam action when needed.
The same steps can be used on the earlier brakes too.

Hope this is clear.
Allan from down under


Topic author
NU2theT
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Re: Hot rear drum...part 2

Post by NU2theT » Wed Jun 16, 2021 5:56 am

Thanks for all the input on this matter, the explanations help and can now adjust from my current setting. Get it road tested with better results.

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Mark Nunn
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Re: Hot rear drum...part 2

Post by Mark Nunn » Wed Jun 16, 2021 1:38 pm

I recall post by Allan Bennett where he suggested using the brake rod adjuster from Rocky Mountain brakes. It has a slot where the clevis pin goes that lets the lever move farther forward without counter rotating the brake cam. It's worth a look.


Jerry VanOoteghem
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Re: Hot rear drum...part 2

Post by Jerry VanOoteghem » Wed Jun 16, 2021 2:56 pm

Looking at your axle key. It appears in the photos, that end of the key, adjacent to the threads, is tapered. If that's true, then the key is installed upside down and backwards. The squared off end should be adjacent to the threads, and the tapered side should be facing "down", to allow clearance for the shallowing of the keyway, as it approaches the axle seal.

Like this...

Capture2.JPG

But maybe I'm just not seeing it right in your photos...

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