squealing brakes ?

[nwparts]

Hi all-
so i just did the front brakes on my 68 bus.
I installed new shoes , new wheel cylinders, hardware, and had the drums turned.
The brakes are on and now they squeal ? The pedal is good and it stops well, but dang it is loud...will that stop? or is an adjustment thing?
any thoughts?
thanks guys

[SGKent]

chamfer the leading and trailing edges of the shoes a little with a rasp. Try not to make a lot of dust as it may screw up your lungs.

[nwparts]

ok will do , thanks-

[aeromech]

This usually doesn't happen with buses that I know of but is fairly common with modern cars because they sell semi-metalic pads that are noisy. In your case do what Steve said as well as scuff up the shoe material with sandpaper to remove any glazing that might be on there. Make sure to wipe the inside of the drum where the shoes contact with some kind of cleaner to remove any greasy fingerprints. I used to use MEK but now I use laquer thinner.
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[busdaddy]

Do these parts look familiar to you?

If not read this:
http://www.thesamba.com/vw/forum/viewtopic.php?t=308121
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[SGKent]

[busdaddy]

Oh.....yeah...drums......nevermind

Yep chamfer the ends of the shoes and maybe even go at the insides of the drums with some 50 or 80 grit to roughen them and help the shoes seat in.
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Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[nwparts]

ok well i sanded the edges down and scuffed the entire surface of the shoe, and even gave the adjusters another click...
seems to be the ticket, nice pedal and no noise

"go at the insides of the drums with some 50 or 80 grit to roughen them and help the shoes seat in." why? I already had the drums turned why would i take sandpaper to them?

[Desertbusman]

Since the good old proceedure of arcing shoes to drums is no longer performed we end up with new problems. The cost of cheapness. The arc of the shoes pretty much always doesn't match the radius of the drum. And possibly the center portion of the shoes, and not towards either end, is where contact with the drum usually is with new shoes. So the shoes and drums don't match on the full length of the contact surface until the friction material has worn down.

But when stopping, the same demand is concentrated in a small area instead of the whole surface and braking response is diminished. So you push harder to compensate and that smaller contact area ends up glazed.

Check the wear pattern and see if this is the case. I've used an orbital sander and course paper to shave down the high glazed portions on the shoes to remedy the problem. Squeals stopped and got much better braking.

Also different brands of shoes use different friction material. Some is metallic. Asbestos shoes had different problems.
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[busdaddy]