Why do wet drum brakes pull ??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Scott70Chevy · 07-20-2002, 06:18 PM

I still have 4-wheel drums, no power. When they get wet and I apply the brakes, truck pulls hard to one side (sometimes locking a wheel). Let up and apply again, and it may pull the other way. Seems to be random which way it will pull. I'm sure this is not normal for a properly functioning system, so what specifically should I look for to fix it?

bbs1965 · 07-20-2002, 06:56 PM

whichever drum and shoe is wet say the right side it will pull left.
whichever side has more friction is the winner so the dryer side wins everytime. There is just about nothing to correct this. When your driving a drum brake vehicle in rain apply the brakes every so often to keep the shoes and drum hot and dry other wise might find out you got no brakes at the wrong time.

Longhorn Man · 07-20-2002, 08:38 PM

Just like when your sliding down the driveway (on foot) when it is icey out. (not that a Texan would know what real ice is..

) If your foot hits a non iced spot, it'll have more friction, and you'll fall and bust your @ss. (you'll also twist and fall in the direction of the added friction)
Much like your brakes, a smooth wet surface is much like ice. your drums are smooth, so it's like rubbing a semi-metalic surface on ice, and the other is dry, so it creates the stopping power you need, hence, it will pull to the dry side.
Nothing is wrong with your brakes. This is how drums work. This is one reason why they don't put them on the front of vehicles any more.
This is also one reason why they alwasy say not to drive on flooded roads.
Discs will do this too, just not nearly as bad, nor as long.

bbs1965 · 07-20-2002, 09:16 PM

Hey i'm a Ohio boy from Loveland Ohio to be exact
but i've been in Texas since 1983. I guess i'm a yankee thats been southern fried. You can keep that snow and ice but i'll overnight you some 100 degree days in even trade for those high 70's summer days anytime. And with all that salt on them roads the old car population is terrible up there. I was in Cincy a few months ago and was bummed out at the lack of early iron. Its getting like that here too but you still see good early iron running around on a daily basis. I went the wrong way home ended up real close to corbin Kentucky where my parents are originally from and thought I would see some old iron but didn't. talking bout drum brakes man i would hate to have been driving in them Kentucky hills on a rainy day in the early 50's. They must of had some serious wrecks back then. I like Texas but Kentucky is the cream of the crop. They have some of the coolest down to earth woman in the world, I love that accent. any ways back to them drums. I have heard of companies that make aftermarket high performance shoes but why when you can upgrade to discs so cheaply and stop a million times better. Disc brake pads actually drag a little on the rotors and run alot hotter thats why the are better in rain. Drums are used primarely by drag racers who don't want resistance when rolling, These cars never see rain or some idiot in an import coming to a dead stop at a green light. I would upgrade to discs as soon as possible you'll love em. My old tow truck was a drum truck I got a new one now and its discs the difference is day and night.

Longhorn Man · 07-20-2002, 10:01 PM

I spent a few years down there in the lone star state...I know what you mean about the lack of early iron up here...depressing.
There are new carbonfiber brake pads and shoes out there, they are 10 times better, and last 10 times as long, ond only ar 5 times the price.
The carbon fiber shoes in a drum brake truck are awsome. The fade from a panic stop is all but eliminated, it's in the adhesive they atach the material to the shoe base, and in the way they compse the braking surface...real high speed sh!t there.
68 suburban (screen name)...he has them on his, he swears by them. I have met a few others that have done it too.
A real advantage to drums, besides the reduced weight, and the reduced rolling resistance, is the added braking surface area. They add more brakeing torque than a disk ever can, and they use the line pressure much more effectivly too. These are the reasons that those 35 ton tracter trailers still use drums to this day.

Scott70Chevy · 07-20-2002, 10:27 PM

Thanks for the info. I grew up with a '67 SWB. Just didn't remember it pulling when it was wet as bad as my '70 does.

Disc brakes are one of the things I want to add when I get extra time, extra money, extra room to work on it, extra....Well, you know how it is!

bbs1965 · 07-20-2002, 10:30 PM

go to paul martins and get a clip from a 73 chevy truck
I have the spindles and rotors and calipers for $75 off of a 1972
already pulled.
In waxahachie.

Denny · 07-20-2002, 11:34 PM

Do they make the carbon fiber breaks for the 69 c10? Hows that Caddy engine doing? Have not been online for a couple weeks nad have been reading posts for the last 8 hours LOL. Got to love this site.

Longhorn Man · 07-20-2002, 11:54 PM

Yep, they have them for your 69...they aren't cheap...be warned, but they are well worth the $$.
http://www.praisedynobrake.com/
The caddy engine has been sitting do to lack of time, but I just got the Pontiac motor ready to jerk out, gonna rent the lift in the morning...

07-20-2002, 06:18 PM	#1
Scott70Chevy Registered User Join Date: Jan 2001 Location: Waxahachie, TX, USA Posts: 114	Why do wet drum brakes pull ??? I still have 4-wheel drums, no power. When they get wet and I apply the brakes, truck pulls hard to one side (sometimes locking a wheel). Let up and apply again, and it may pull the other way. Seems to be random which way it will pull. I'm sure this is not normal for a properly functioning system, so what specifically should I look for to fix it? __________________ Scott70Chevy '70 CST: LWB, Fleetside, black ext., black/gray int., 350-4bbl, 3-speed, 12 bolt 3.07, deep dish rallye wheels, NO RUST!

07-20-2002, 10:27 PM	#6
Scott70Chevy Registered User Join Date: Jan 2001 Location: Waxahachie, TX, USA Posts: 114	Thanks for the info. I grew up with a '67 SWB. Just didn't remember it pulling when it was wet as bad as my '70 does. Disc brakes are one of the things I want to add when I get extra time, extra money, extra room to work on it, extra....Well, you know how it is! __________________ Scott70Chevy '70 CST: LWB, Fleetside, black ext., black/gray int., 350-4bbl, 3-speed, 12 bolt 3.07, deep dish rallye wheels, NO RUST!

07-20-2002, 11:34 PM	#8
Denny Registered User Join Date: Jul 2002 Location: Cedar Hill, MO Posts: 426	Do they make the carbon fiber breaks for the 69 c10? Hows that Caddy engine doing? Have not been online for a couple weeks nad have been reading posts for the last 8 hours LOL. Got to love this site. __________________ 1969 Chevy C10. Dakota Digital Gauges, 383 Votex Engine, MSD 8361 Distributor, MSD 6A Unit, Demon Carb, Phoenix Transmission 4L80E trans, 3:73 Posi Rear End Early Classics 6 Lug Disc Brakes and Spindles All Stainless Lines

07-20-2002, 06:56 PM	#2
bbs1965 Open Sundays 10 till 10 Join Date: Nov 2000 Location: Waxahachie,Texas 75165 Posts: 1,009	whichever drum and shoe is wet say the right side it will pull left. whichever side has more friction is the winner so the dryer side wins everytime. There is just about nothing to correct this. When your driving a drum brake vehicle in rain apply the brakes every so often to keep the shoes and drum hot and dry other wise might find out you got no brakes at the wrong time.

07-20-2002, 08:38 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Just like when your sliding down the driveway (on foot) when it is icey out. (not that a Texan would know what real ice is.. ) If your foot hits a non iced spot, it'll have more friction, and you'll fall and bust your @ss. (you'll also twist and fall in the direction of the added friction) Much like your brakes, a smooth wet surface is much like ice. your drums are smooth, so it's like rubbing a semi-metalic surface on ice, and the other is dry, so it creates the stopping power you need, hence, it will pull to the dry side. Nothing is wrong with your brakes. This is how drums work. This is one reason why they don't put them on the front of vehicles any more. This is also one reason why they alwasy say not to drive on flooded roads. Discs will do this too, just not nearly as bad, nor as long.

07-20-2002, 09:16 PM	#4
bbs1965 Open Sundays 10 till 10 Join Date: Nov 2000 Location: Waxahachie,Texas 75165 Posts: 1,009	Hey i'm a Ohio boy from Loveland Ohio to be exact but i've been in Texas since 1983. I guess i'm a yankee thats been southern fried. You can keep that snow and ice but i'll overnight you some 100 degree days in even trade for those high 70's summer days anytime. And with all that salt on them roads the old car population is terrible up there. I was in Cincy a few months ago and was bummed out at the lack of early iron. Its getting like that here too but you still see good early iron running around on a daily basis. I went the wrong way home ended up real close to corbin Kentucky where my parents are originally from and thought I would see some old iron but didn't. talking bout drum brakes man i would hate to have been driving in them Kentucky hills on a rainy day in the early 50's. They must of had some serious wrecks back then. I like Texas but Kentucky is the cream of the crop. They have some of the coolest down to earth woman in the world, I love that accent. any ways back to them drums. I have heard of companies that make aftermarket high performance shoes but why when you can upgrade to discs so cheaply and stop a million times better. Disc brake pads actually drag a little on the rotors and run alot hotter thats why the are better in rain. Drums are used primarely by drag racers who don't want resistance when rolling, These cars never see rain or some idiot in an import coming to a dead stop at a green light. I would upgrade to discs as soon as possible you'll love em. My old tow truck was a drum truck I got a new one now and its discs the difference is day and night.

07-20-2002, 10:01 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I spent a few years down there in the lone star state...I know what you mean about the lack of early iron up here...depressing. There are new carbonfiber brake pads and shoes out there, they are 10 times better, and last 10 times as long, ond only ar 5 times the price. The carbon fiber shoes in a drum brake truck are awsome. The fade from a panic stop is all but eliminated, it's in the adhesive they atach the material to the shoe base, and in the way they compse the braking surface...real high speed sh!t there. 68 suburban (screen name)...he has them on his, he swears by them. I have met a few others that have done it too. A real advantage to drums, besides the reduced weight, and the reduced rolling resistance, is the added braking surface area. They add more brakeing torque than a disk ever can, and they use the line pressure much more effectivly too. These are the reasons that those 35 ton tracter trailers still use drums to this day.

07-20-2002, 10:30 PM	#7
bbs1965 Open Sundays 10 till 10 Join Date: Nov 2000 Location: Waxahachie,Texas 75165 Posts: 1,009	go to paul martins and get a clip from a 73 chevy truck I have the spindles and rotors and calipers for $75 off of a 1972 already pulled. In waxahachie.

07-20-2002, 11:54 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Yep, they have them for your 69...they aren't cheap...be warned, but they are well worth the $$. http://www.praisedynobrake.com/ The caddy engine has been sitting do to lack of time, but I just got the Pontiac motor ready to jerk out, gonna rent the lift in the morning...



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