Warm Brake Drums

Issues with shocks/springs, tires, stopping, etc.
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jrcotner
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Warm Brake Drums

Post by jrcotner » Wed Mar 08, 2017 1:19 pm

I recently bled and adjusted the brakes on my Pinz. I just got back from a drive around some mountain fire roads, and when I checked the brakes at back home discovered that the front brake drums were pretty warm, but the rears were just slightly warm. Granted, it is a long downhill back home, but is any warmth unacceptable? When I adjusted the brakes I snugged them up just to the point I could hear some drag and then backed off one click.
Thanks,
John Cotner
1946 Willys CJ-2a
Elizabethton, TN

undysworld
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Re: Warm Brake Drums

Post by undysworld » Wed Mar 08, 2017 1:24 pm

John,
A few thoughts offhand:
You did adjust both shoes on each side? (I assume you know the fronts have 2, unlike the rears with 1.)
You secured the drums when you made the adjustments?
You adjusted them in opposite directions? (One side is reverse thread, the opposite side is normal thread.)
Is it 1 or 2 clicks back on the fronts? I can't remember?

Sorry, just reread it. If you went downhill far, you should expect heat. How much constitutes 'too much heat' is hard to quantify. I'd think you'd see smoke and smell the brakes if you'd overheated things. As long as the wheel spins "freely" when the brakes are off, you're probably okay. A cheap pyrometer allows you to measure things like this easily too.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
I hope to die in my ski boots... ...just not today. Me

jrcotner
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Re: Warm Brake Drums

Post by jrcotner » Wed Mar 08, 2017 3:21 pm

You did adjust both shoes on each side? Yes
You secured the drums when you made the adjustments? Not sure what you mean.
You adjusted them in opposite directions? (One side is reverse thread, the opposite side is normal thread.) Yes.
Is it 1 or 2 clicks back on the fronts? I can't remember? I can't either. I just loosened each adjuster one click from the point of hearing drag. If one didn't remedy the drag, I loosened another click.
Thanks,
John Cotner
1946 Willys CJ-2a
Elizabethton, TN

jrcotner
United States of America
Posts: 153
Joined: Fri Aug 21, 2009 2:17 pm
Location: Elizabethton,TN

Re: Warm Brake Drums

Post by jrcotner » Wed Mar 08, 2017 3:22 pm

I can't quantify "warm", but imagine putting your hand on the hood of a car on a summer day. About that warm.
Thanks,
John Cotner
1946 Willys CJ-2a
Elizabethton, TN

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Jimm391730
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Re: Warm Brake Drums

Post by Jimm391730 » Wed Mar 08, 2017 4:34 pm

You secured the drums when you made the adjustments? Not sure what you mean.
The drum needs to have at least two lugs holding it on tight when you adjust the shoes.
imagine putting your hand on the hood of a car on a summer day. About that warm.
That's not bad; the drums will get that hot just stopping from 40mph one time! They can probably be expected to get to several hundred degrees (more in a problem situation) without damage to the drum and shoes. However, that much heat can boil the brake fluid and create vapor in the lines and wheel cylinders; when this happens the pedal will go to the floor with no braking at all!!! This is why trucks need to downshift to take advantage of engine braking during a long downhill run.
Jim M.
712W and 710M

undysworld
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Re: Warm Brake Drums

Post by undysworld » Wed Mar 08, 2017 4:41 pm

John,
When you adjust the shoes, you should first bolt the drum back in place without the wheel. This secures the drum, so you adjust the shoes accurately. Three nuts will do.
The procedure is to tighten the adjuster until the wheel locks, then back it off a certain number of clicks. The exact numbers are given in the manuals. Sorry, I don't recall them.
I wouldn't worry about that heat at all. If you can touch it, it's not that hot.

...like Jimm said...
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
I hope to die in my ski boots... ...just not today. Me

jrcotner
United States of America
Posts: 153
Joined: Fri Aug 21, 2009 2:17 pm
Location: Elizabethton,TN

Re: Warm Brake Drums

Post by jrcotner » Wed Mar 08, 2017 8:17 pm

Thanks for the info. I did hold the drum on with lug nuts, albeit only two. The brakes had no fade whatsoever the whole trip, and haven't worked this well in years. I'm sensitive about brake drum heat since I had the drums turned a few years ago and the machine shop said they became somewhat egg shaped due to excessive heat.
Thanks,
John Cotner
1946 Willys CJ-2a
Elizabethton, TN

pinzinator
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Re: Warm Brake Drums

Post by pinzinator » Wed Mar 08, 2017 8:31 pm

If they brakes didn't pull to either side and the rears didn't lock up, I would say you have them adjusted about right. At least from my armchair!

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