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 C2 Front Brake Screech
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1983ChevroletWayne
Senior Member

Canada
165 Posts

Posted - 04/16/2013 :  09:02:26 AM  Show Profile  Reply with Quote
Hey guys,

Just wondering if anyone out there might have a fix or an idea about the squeel of C2 front brakes.

We have a few "around the town" buses with screeching front brakes. They seem to be glazing up pretty bad, and the only slight cure seems to be taking them out at highway speed, and apply the brakes hard a few times to get rid of the glazing. Although it seems to only work for a few days or a week.

Someone had mentioned using a different ceramic shoe from NAPA that seemed to be reducing this, and lasting a bit longer.

The driver's of these buses are complaining about the ear piercing screech.

Just wondering about your thoughts or suggestions.

FYI: We use air brakes.

Edited by - 1983ChevroletWayne on 04/17/2013 4:14:00 PM

Fastback
Top Member

972 Posts

Posted - 04/16/2013 :  09:28:52 AM  Show Profile  Reply with Quote
When one of my buses has brake shoes that squeel severly, I become suspicious that the driver rides the brakes going down hills rather than downshifting the transmission.

Why yes, the ORIGinal CHARGER is a Fastback
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bluebirdvision
Top Member

USA
994 Posts

Posted - 04/16/2013 :  7:02:33 PM  Show Profile  Click to see bluebirdvision's MSN Messenger address  Reply with Quote
I had a mechanic tell me that I was doing damage to the transmission downshifting it. I wanted to ask him where the hell he went to school?

Shane Kirley
New York Bus Sales Delivery Driver. (I know its not much, but its a start)


Facebook Page: Blue Bird Corporation Fans
https://www.facebook.com/home.php?sk=group_212311114614&ap=1


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BJ Henderson
Advanced Member

USA
225 Posts

Posted - 04/17/2013 :  04:22:03 AM  Show Profile  Send BJ Henderson an AOL message  Reply with Quote
Ceramic pads have been good for us on our support vehicles. Haven't used them on any buses as of yet. I would think that one set of them could be used on a problem bus for a test. Make sure the driver is not aware of your testing to make it a true blind test.

CMTT,CMAT,CMBT
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Thomasbus24
Administrator

USA
3320 Posts

Posted - 04/17/2013 :  05:32:25 AM  Show Profile  Reply with Quote
Talk to a good, knowledgeable brake guy before you buy. Some schools have been testing them in my area and have learned that some ceramic shoes are far too aggressive for a school bus (see throwing kids into the seat ahead of them).

Next time I see my brake guy, I'll ask what he is selling that seems to work.
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bwest
Administrator

United States
2296 Posts

Posted - 04/17/2013 :  07:05:23 AM  Show Profile  Reply with Quote
I didn't catch if you had air or juice. You did mention "pad" so I am assuming juice. I have juice brakes on everything except one and they all used to squeak on me. I started putting ceramic brake lube on the back of the outboard pad and piston cushions on the piston side (piston cushions on all pistons on a 4 pistons caliper). This has gotten ride of my brake squeak problem except when I get a rock in one. This happens when a rock gets in the channel that the tab runs in and then when the pad wears down to the diameter of the rock it squeaks until I get it out of there. This wasn't a problem until our rural road commissioners started using river rock instead of limestone rock. The limestone rock will just break up into dust when it gets squeezed between the two metal surfaces.

Bryan
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1983ChevroletWayne
Senior Member

Canada
165 Posts

Posted - 04/17/2013 :  4:12:43 PM  Show Profile  Reply with Quote
Bryan,

Sorry I said "pad" but I meant to say shoes. We use Air here. Sorry about that, but thanks for your tips!

Formerly "83ChevroletWayne"



Pic courtesy of: "schoolbusdriver.org"
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bwest
Administrator

United States
2296 Posts

Posted - 04/18/2013 :  05:44:40 AM  Show Profile  Reply with Quote
No problem. I know some of you guys just love air brakes but hyd works great for me. I don't like the way air applies, too sudden for me. Good luck

Bryan
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partsman_ba
Administrator

United States
285 Posts

Posted - 04/18/2013 :  06:42:42 AM  Show Profile  Reply with Quote
I was the one testing ceramic brake shoes, both to combat squeaking and excessive drum wear from both OE and Abex linings in 6Q-4715 front applications. Only seen them at the one source, NAPA. Using the 20K material as it tests lowest on drum wear. Part # is 084U90-6N (084 is their size code, U90 is the 20K material, and -6N indicates a wheel kit rather than one shoe).
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IBTMech
Top Member

USA
973 Posts

Posted - 04/18/2013 :  07:22:23 AM  Show Profile  Visit IBTMech's Homepage  Reply with Quote
We used to score the brake drums with a hacksaw blade which helped somewhat. Combination linings have helped too (GG and FF on the same shoe).
I think if anyone finds a sure cure there are a few brake manufacturers who like to talk to you.

If it doesn't fit, FORCE it.
If it breaks, well, it needed replacing anyway.
Pullin' wrenches for 45 years.
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Thomasbus24
Administrator

USA
3320 Posts

Posted - 04/18/2013 :  10:22:16 AM  Show Profile  Reply with Quote
My Napa brake guy agrees, 20K. Some schools tried 23K and it was ugly.
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Thomasbuilt_547
Active Member

23 Posts

Posted - 04/30/2013 :  10:11:44 AM  Show Profile  Reply with Quote
I would recommend removing the hubs, take some 80 grit sand paper, and take the glazing right off. Can't say it'll be a permanent fix but it'll cut the noise down

All I need is my Thomas
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