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Brake puzzle
https://slantsix.org/forum/viewtopic.php?t=17674
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Author:  RossKinder [ Sun May 21, 2006 2:59 pm ]
Post subject:  Brake puzzle

When braking at slow speeds (just before it comes to a stop) I get a clunk, clunk, clunk from the front right wheel. It seems timed with each revolution of the wheel. I can find nothing wrong. I've packed the bearings and checked their tightness. I see nothing broken. I feel nothing unusual in the pedal, no pulsing. Everything seems snug and in place and getting the job done. What am I hearing? TIA

Author:  slantvaliant [ Sun May 21, 2006 6:47 pm ]
Post subject: 

What car, year, disks or drums, stock?

FWIW I have had interesting very low-speed noises come from the hubcap.

Author:  DusterIdiot [ Sun May 21, 2006 6:56 pm ]
Post subject:  What kind of clunk?

Is the clunk metallic or ???

If it's a dull "lub, lub" then you might have a belt separated in your tire.

???

-D.Idiot

Author:  64'4$peed [ Sun May 21, 2006 7:01 pm ]
Post subject: 

ya know slantvaliant I was gonna tell him about hubcap noise, but I figured He'd have pulled em off checking for wheel bearings and brakes. thus finding whatever was loose in the hubcaps

Author:  SlantSixDan [ Sun May 21, 2006 7:44 pm ]
Post subject: 

If you've got drum brakes, there are a few causes for brake knock. If the drum was machined too fast, there'll be a spiral groove in the braking surface of the drum. When you apply the brakes, the shoes will ride the groove to the limit of the hold-down springs, then snap back to the backing plate with an audible "Knock!" each time. A brake knock like this can also be the result of a cracked brake drum (or disc, for that matter) or loose debris within the drum assembly.

Author:  RossKinder [ Sun May 21, 2006 9:47 pm ]
Post subject: 

Quote:
What car, year, disks or drums, stock?

FWIW I have had interesting very low-speed noises come from the hubcap.
Sorry about that. I was distracted.

65 valiant, drums, stock.

Author:  RossKinder [ Sun May 21, 2006 9:55 pm ]
Post subject:  Re: What kind of clunk?

Quote:
Is the clunk metallic or ???

If it's a dull "lub, lub" then you might have a belt separated in your tire.

???

-D.Idiot
Not to be smart, but more ??? than "lub, lub." I've had belt separation that sounded less sharp than this. Having said that I can't exacatly say it sounds metallic either. More of a clunk than a thump.

I just thought of something. An old concrete highway with good sized tar ridges at the joints. Almost like driving on one of those, but only one wheel and, of course, slower than highway speeds.

Author:  RossKinder [ Sun May 21, 2006 10:08 pm ]
Post subject: 

Quote:
If you've got drum brakes, there are a few causes for brake knock. If the drum was machined too fast, there'll be a spiral groove in the braking surface of the drum. When you apply the brakes, the shoes will ride the groove to the limit of the hold-down springs, then snap back to the backing plate with an audible "Knock!" each time.
You know that strikes me as a possibility, judging fromt he sound.
Quote:
A brake knock like this can also be the result of a cracked brake drum.
Hm, anybody know a good substitute for developer?

You know this sounds almost as if I had loose lugs and the wheel was thunking around wallowing out the holes. Except that would be more than one clunk per rev. Thanks

Author:  RossKinder [ Sun May 21, 2006 10:10 pm ]
Post subject: 

Quote:
ya know slantvaliant I was gonna tell him about hubcap noise, but I figured He'd have pulled em off checking for wheel bearings and brakes. thus finding whatever was loose in the hubcaps
Come to think about it I haven't tried running with no hub cap on that wheel. Thanks.

Author:  slantvaliant [ Mon May 22, 2006 6:34 am ]
Post subject: 

Quote:
thus finding whatever was loose in the hubcaps
In my case, there was nothing loose in the hubcaps - it was the hubcap itself ('64 full wheel cover, one piece of stainless steel), combined with some rim flex. Everything looked fine. I tweaked the teeth, and it stopped. I'm still concerned about the rim flex, but I'm working on changing the bolt pattern and going to rallye rims anyway.

My sister had a really bad low-speed rattle in her Lumina. I happened to be outside when she pulled up one day. We pulled the caps off her AR aluminum wheels to find that two of the lugs had broken off. The sound was the lug/nut combos bouncing around inside. :shock: When it got up to 15MPH or so, the centrifugal force was enough to keep them from moving.

Author:  RossKinder [ Tue Jun 13, 2006 4:45 pm ]
Post subject:  Did I find it?

I think I have found the reason for the noise I described, what do you think? I removed the wheel and drum and could find nothing wrong around the brakes. Smidgen of moistness. Even wear on the shoes. Adjuster working. I decided to put the wheel back on.

But as I looked at the drum it became quite obvious that the turn was off center. Admittedly low, it showed just about 1/8" on one side and about 3/16" on the other side. Any warpage at all would either fix it or make it somewhat worse. (I haven't checked for run-out yet.) Do you think I have my culprit?

Thanks

Author:  AndyZ [ Tue Jun 13, 2006 7:35 pm ]
Post subject: 

That doesn't sound right. I bet it gets worse after they heat up a while.

Author:  Joshie225 [ Tue Jun 13, 2006 7:47 pm ]
Post subject:  Re: Did I find it?

Quote:
I think I have found the reason for the noise I described, what do you think? I removed the wheel and drum and could find nothing wrong around the brakes. Smidgen of moistness. Even wear on the shoes. Adjuster working. I decided to put the wheel back on.

But as I looked at the drum it became quite obvious that the turn was off center. Admittedly low, it showed just about 1/8" on one side and about 3/16" on the other side. Any warpage at all would either fix it or make it somewhat worse. (I haven't checked for run-out yet.) Do you think I have my culprit?

Thanks
What do you mean the turn was off center? What the heck is the turn? Can someone catch me up on my hillbilly?

Author:  RossKinder [ Tue Jun 13, 2006 9:42 pm ]
Post subject:  Re: Did I find it?

Quote:
Quote:
I think I have found the reason for the noise I described, what do you think? I removed the wheel and drum and could find nothing wrong around the brakes. Smidgen of moistness. Even wear on the shoes. Adjuster working. I decided to put the wheel back on.

But as I looked at the drum it became quite obvious that the turn was off center. Admittedly low, it showed just about 1/8" on one side and about 3/16" on the other side. Any warpage at all would either fix it or make it somewhat worse. (I haven't checked for run-out yet.) Do you think I have my culprit?

Thanks
What do you mean the turn was off center? What the heck is the turn? Can someone catch me up on my hillbilly?
Did you never take a drum in and have it turned? It's like turning it on a lathe, only the machine looks as much like a coffee grinder as a lathe. :)

Thanks

Author:  Joshie225 [ Wed Jun 14, 2006 12:12 am ]
Post subject: 

The drum was machined/turned off center! I get it! That's hard to do on a brake lathe. I don't know how else someone would try to turn a drum, but I'm sure someone will volunteer a novel method.

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