reducing drum brake drag

[MadisonMPG]

Originally Posted by orange4boy

My experience is that eliminating the drag from my rear drums made a very noticeable difference in my coast down. It now coasts for ever............... No quantification though.

Brakes are made for one thing: friction. and they are very good at their job. Friction is an ecomodder's #1 enemy. Don't misunderestimate it.

I like friction between the tires and the road.

[bgd73]

misunderstanding your arms and engine strength is not going to nail down drag. One cannot spin it enough to realize they loosen as you move, and get warmer, the air cools. Thats like saying an engine without plugs in it has a problem..it still turns with some difficulty. it needs to run, warm, WOT, and ignore it.
manually adjusting is going to leave a cylinder popping, there is no such thing as a heavy duty wheel cylinder. I have popped one in tiny drums (subarus, vw rabbit sized) to the large 13-14 on gas trucks. humoring every little spring and auto adjust is imprtant to respect, it also helps bearings, the drum is a goofy thing to spin without the pads on the inside of it. Try spinning a tractor trailer drum sometime...claim it is drag on that one.

[Ryland]

I've never had a big problem with drum brakes dragging and have yet to see a disk brake that doesn't drag, my first motorcycle, a Honda CL160 had front drum brakes, did some short stops a few times with that bike and never had the front wheel lock up unless I wanted it too and never had a lack of braking power, I kind of wish my current motorcycle was a year older when they still did drum brakes as the disk on it is nothing but trouble.
my current car (1981 commuter vehicles, commuti-car) has drum brakes all around, the early model had disks in the front then they stopped and went to drums, smooth, trouble free, easy to work on.
at work both the car we use for going to bid jobs and the truck we have has the rear disks with drums for parking, worst idea ever, they do a poor job of stopping and we replace them every 15,000-20,000 miles, but they look cool and that is what sells.
If I had the money I would get a set of the first gen Insight rear drums, they are aluminum drums like the early CRX HF had, those CRX drums are sought after by people who race crx's for their light weight and their stopping power.

[orange4boy]

Originally Posted by orange4boy
My experience is that eliminating the drag from my rear drums made a very noticeable difference in my coast down. It now coasts for ever............... No quantification though...

Did you already write that up? Can you post a link for us here?

No write up. Sorry. You'll have to take my word for it. The butt o meter definitely noticed. I wish I could test every change I made but I gotta have a life too. Reducing brake drag, disc and drum made a big difference. I don't know whether other cars have the rear drum drag issue but it's worth it to check.

I've never had a big problem with drum brakes dragging and have yet to see a disk brake that doesn't drag

That's why I hadn't checked my rear drums until now and why I'm rebuilding my front calipers and lubing the sliders before winter. (and changing the brake fluid) The square O rings don't do much good if the pistons are rusted to the caliper.

[Frank Lee]

For the last 30 years I've had the same experiences as Ryland: drums haven't been draggy for me except regarding parking brake cable problems here in the Rust Belt, and that ain't the fault of the brakes. I've never had auto adjusters tighten things up til they drag- not that I can remember anyway.

Discs, though... the last two summers especially, I've been fixing draggy disc problems, as my and my friend's and family's stuff is all getting about to that age where this sort of thing comes up. I ranted here already re: Gold Wing caliper pistons sticking due to corrosion behind the seals locking everything up; the rest were cars that all suffered from rusty/frozen caliper sliders and some had sticky pistons too. We are talking, brakes dragging hard enough to warp rotors in the case of the Honda, hard enough to burn my fingertip on the Metro, and hard enough to waste fuel on 3 Fords.

I wish every car and truck I owned had brakes like my Corvair and Bel Air: 4 wheel drums. Clean wheels and freewheeling action discs can only dream of.

[Christ]

Originally Posted by Frank Lee

For the last 30 years I've had the same experiences as Ryland: drums haven't been draggy for me except regarding parking brake cable problems here in the Rust Belt, and that ain't the fault of the brakes. I've never had auto adjusters tighten things up til they drag- not that I can remember anyway.

Discs, though... the last two summers especially, I've been fixing draggy disc problems, as my and my friend's and family's stuff is all getting about to that age where this sort of thing comes up. I ranted here already re: Gold Wing caliper pistons sticking due to corrosion behind the seals locking everything up; the rest were cars that all suffered from rusty/frozen caliper sliders and some had sticky pistons too. We are talking, brakes dragging hard enough to warp rotors in the case of the Honda, hard enough to burn my fingertip on the Metro, and hard enough to waste fuel on 3 Fords.

I wish every car and truck I owned had brakes like my Corvair and Bel Air: 4 wheel drums. Clean wheels and freewheeling action discs can only dream of.

Of course, there must be a safety issue with that... there MUST BE.

[Frank Lee]

Rodent Track and the other car mags would raise holy helll over it so then everyone would pile on and bring their pitchforks and burning rags-on-sticks. So it's too much a risk I guess.

Didja know that ol '59 has BALL BEARINGS in the front hubs too?!? Give 'em a whirl when it's jacked up and they go forever.

[Christ]

Originally Posted by Frank Lee

Rodent Track and the other car mags would raise holy helll over it so then everyone would pile on and bring their pitchforks and burning rags-on-sticks. So it's too much a risk I guess.

Didja know that ol '59 has BALL BEARINGS in the front hubs too?!? Give 'em a whirl when it's jacked up and they go forever.

Obviously, I was joking up there^^^

The stopping distances are affected by heat build up more, but that could be solved with a lighter car, generally. 5,000# of steel and iron is hard to stop, regardless of brake configuration.

I think the largest arguments that I've heard against drums and for discs are Water and Heat Dissipation. Maybe dust build-up, but that shouldn't be an issue if you're checking your brakes like you should be.

[Nerys]

WOW I did not know all this about Drums and Discs. I have always wanted to go full disc because Drums are a PITA to me. For me it was cleaning. with my cherokee every time I went wheeling when I got home I had to REMOVE the rear wheels and REMOVE the drums to clean the MUD out of the drums or it would grind down my shoes in a month or two.

with the discs I just hosed them off through the holes in the wheels.

Drums are also a royal pita to change shoes on. not hard just annoying. I never knew about the dragging issues (though I can hear the tell tale snick snick of a dragging pad in my metro)

but in all my vehicles the problem when away when I replaced the calipers (they are pretty corroded on the metro)

VERY interesting info. I guess I will be keeping the drums on the metro rear wheels :-) mud's not a problem for my metro so...

[Andale]

I haven't got "1,000's of cars I've worked on" and would certainly never claim to "usually get 90,000 miles" from my pads, but on a realistic note my 2 opinions to this are:

1) It's a pointless concern. (AS FAR AS ECO GOES!) If your brakes are dragging enough to cause depreciation in your economy then parts need replacing. Case in point: I've actually had a drum I couldn't take off without cutting because my adjuster had not been replaced by previous owner and it had rusted into place. It didn't stop that wheel at all, but there was still a lip cut into it that caused problems.

2) The handbrake reasoning is sound but noone's mentioned that drum setups are cheaper for manufacturers, it was mentioned that they do bring in more return business tho.

I have found in the last few years that drum setups still prove to be easier to both diagnose and replace.

I wouldn't worry about it. The only way to improve the adjuster would be to custom build one with smaller teeth.