Is it worth it to convert my drums to discs?

"Stupidru" (Schm1an)
01/18/2014 at 23:39 • Filed to: None

So my 03 Impreza Outback has drums in the back. The drums were pulsing due to build-up over 100k miles, so I swapped out the drums for new ones which solved the problem, but the road salt already ate through the black paint, so they're already rusty. I absolutely hate replacing shoes, and those will probably be due soon. I threw out a couple feelers on the forums and I can source rear knuckles, brackets, calipers, rotors, and pads for around $300-$400... if it were your money, would you upgrade? I plan on keeping this car for at least another 4-5 years and 80k-100k miles for whatever it's worth.

DISCUSSION (25)

RacecaR > Stupidru
01/18/2014 at 23:41

YES! I hate drum brakes, mostly because I just hate dealing with them.

signintokinjalol > Stupidru
01/18/2014 at 23:44

Only if the drums are destroyed, then you might as well.

But honestly, unless your going for max performance, there's no real point.

IDROVEAPICKUPTRUCK > Stupidru
01/18/2014 at 23:45

Eh, I don't think it's really worth it. Drums are actually sorta nice in snowy conditions and shit because the parts are all internal to the drum and are thus protected from the salt and stuff. And if you're not taking the car to the track you won't see any difference in performance. Drums can actually provide more braking force than disk brakes but they simply heat up faster, causing brake fade after sustained heavy braking. The amount of time it takes to swap out the drums for disks will probably end up being more time than you'll save working on them in the future, especially since you just serviced them.

Stupidru > RacecaR
01/18/2014 at 23:45

Tell me about it! I bought new shoes and a whole lotta Jesus springs, but I honestly just don't want to deal with replacing the internals plus taking a wire-wheel to the drums and re-spraying them black so the car doesn't look like trash. I'm betting I'll need to replace the shoes at least twice before the car is gone, and I honestly believe it's in the best interest of my sanity to just convert and be done with it

Stupidru > IDROVEAPICKUPTRUCK
01/18/2014 at 23:47

Well I swapped out the drums, so the shoes will need to be changed at some point. At that time I had no time to mess with shoes as I had to go to China and then get married as soon as I got back, and THEN it would be winter. I've had discs before and I've never had a problem with debris getting between the pads and rotors.

desertdog5051 > Stupidru
01/18/2014 at 23:48

Real men can change/refit drum brakes. The wussies can't

Stupidru > signintokinjalol
01/18/2014 at 23:49

Well I do autocross, but I'm almost positive I'll never generate the heat in the drums to make them fade

Stupidru > desertdog5051
01/18/2014 at 23:50

Oh I can. I have, and I hated it immensely

IDROVEAPICKUPTRUCK > Stupidru
01/18/2014 at 23:52

it's not about debris but more just that the braking surface itself is protected. If you ever leave you car sitting outside, especially in the snow and salt discs can start to rust pretty quickly. If you don't already have one get a drum brake spring tool, they make changing out shoes way fucking easier, way cheaper than swapping to discs. $5
http://www.northerntool.com/shop/tools/pro…

desertdog5051 > Stupidru
01/18/2014 at 23:54

Yeah me too. I have to do the rear drums on my old P/U. Showed them to a friend and he said something like "nobody can do that. It's way too complex". I told him, you do one side at a time so you can reference where everything goes.

IDROVEAPICKUPTRUCK > desertdog5051
01/18/2014 at 23:59

The first time I ever did drum brakes I didn't have the spring tool, so a friend of mine and I were just using needle nose pliers and vice grips, it sucked ass. A couple of weeks later we're helping his dad work on his old 1950s Ford Fairlane which had drums all around, and we're struggling. His dad was just like "Hey use this" and handed us the spring too. We felt pretty dumb for not knowing about it, makes a night and day difference in difficulty.

signintokinjalol > Stupidru
01/19/2014 at 00:01

Problem in drums is heat and brake dust, brake dust has no where to go so it builds up.

If you do autocross then you might as well do a disc conversion, also the extra feet you'll save might be handy.

Stupidru > desertdog5051
01/19/2014 at 00:01

I wish I had that kind of insight to at least take pictures before I dove in head first. I eventually had to call a friend and have him come over and help me with the drum brake on my LGT

IDROVEAPICKUPTRUCK > signintokinjalol
01/19/2014 at 00:03

I'm not sure I agree. Autocross doesn't result in brake fade since the courses are so short, and in a lot of cases drums actually provide more braking power since the shoes have more surface area to press against the drum. There is a reason why Semi-Trucks that have to stop tens of thousands of lbs use drum brakes.

signintokinjalol > IDROVEAPICKUPTRUCK
01/19/2014 at 00:05

Huh? More surface area doesn't mean better braking...

If it was so then if i ran 15 inch brakes on my FRS it would stop better then a ZR1 Vette, which it wouldn't.

Stupidru > signintokinjalol
01/19/2014 at 00:05

I already replaced the drums because of brake dust build-up. It got so bad (wife never told me something was wrong) that I felt like my drums were oblong. I'm thinking that I want to upgrade because the drums lock up way too easily in any slippery condition, they look terrible, I hate replacing shoes, and there are far more options for autocross pads than there are shoes.

IDROVEAPICKUPTRUCK > signintokinjalol
01/19/2014 at 00:07

If you're not at the limit of the grip of your tires than more surface area can result in better braking. Normally the limiting factor is your tires.

"Due to the fact that a drum brake's friction contact area is at the circumference of the brake, a drum brake can provide more braking force than an equal diameter disc brake. The increased friction contact area of drum brake shoes on the drum allows drum brake shoes to last longer than disc brake pads used in a brake system of similar dimensions and braking force. Drum brakes retain heat and are more complex than disc brakes but are often the more economical and powerful brake type to use in rear brake applications due to the low heat generation of rear brakes, a drum brake's self-applying nature, larger friction surface contact area, and long life wear characteristics (%life used/kW of braking power)." http://en.wikipedia.org/wiki/Drum_brak…

signintokinjalol > IDROVEAPICKUPTRUCK
01/19/2014 at 00:11

Perhaps, but there are reasons why you don't see cars on track running drums.

Big Bubba Ray > Stupidru
01/19/2014 at 00:12

I'd say to do it if you really want. I can attest that drums are a pain to work on too. I've been working over my Baja Bug recently and just opened up the brakes and it sucks to service them. I've been slowly saving money to do a front disk brake conversion on my bug sometime in the future.

IDROVEAPICKUPTRUCK > signintokinjalol
01/19/2014 at 00:14

Yes, drum brakes are very susceptible to brake fade from overheating since their mechanism is internal and isn't directly exposed to airflow outside the car. But autocross laps normally last less than a minute, with significant time in between heats. Brake fade is not an issue in this case. If he were actually going to a track, they yes discs would be better but an appropriately designed drum brake is perfectly fine for a road car. They're a pain to work on, but they last longer than disc brakes and they're lighter too.

JGrabowMSt > IDROVEAPICKUPTRUCK
01/19/2014 at 00:17

My dad has both a spring tool, and what looks like a slotted screwdriver, which is a more primitive spring tool.

For some reason, the last time we did a full brake job on the car, my dad put the drums back together wrong, and it broke a spring (and made a hell of a lot of noise). I spent about an hour in a friends driveway fixing it right. He didn't like that I did it, but it took me far less time to do both sides than it too him to do one. He's not the kind of person to just tell me what to do and let me do it, he has to do it, and swear about it the whole way.

If it were my money, I actually would change them to disc. If you're doing your own brake jobs etc, then it will save you a lot of time later in swapping pads. Just know it's not a performance upgrade. If you spent 2 hours (lets say it takes 1 hour for each side to change) it would then take maybe 15-20 minutes to change the pads on a caliper, compared to a drum, which is definitely a 30-45 minute ordeal without the correct tools . It could theoretically make it worth keeping the car even longer (god willing nothing major happened) than the 4-5 you plan on (for example, new or rebuilt engine, etc). If you're thinking very long term, it would be worth it for time. If you're concerned about performance, get better tires for the $300-400.

IDROVEAPICKUPTRUCK > JGrabowMSt
01/19/2014 at 00:21

I think the amount of time you save in the future by only having to swap out pads will be totally overshadowed by the time you spend swapping the entire system over to discs, especially since shoes last longer than pads and the appropriate spring tool only costs $5. http://www.northerntool.com/shop/tools/pro…

JGrabowMSt > IDROVEAPICKUPTRUCK
01/19/2014 at 00:25

I'm not sure...with enough knowledge about it, and pre-assembling as much as possible, I think it could be a pretty easy swap. I mean, if there's another Impreza model that comes with rear disc, you could get full strut assemblies, and basically just pull off the strut and replace it with the whole new one (at 100k, might not be a bad idea if possible) connect the brake lines, and bolt it all together. This also assumes having all the right tools.

I'm definitely not adverse to modifying if it's going to save time later, especially if it helps out a DD. I'm curious if the pads really would get worn down to nothing faster on the rear, considering the front handles more than half the braking anyway. I had a pad separate from a shoe a few years back, and that ordeal was a nightmare. I'd definitely rather have discs on that account alone.

IDROVEAPICKUPTRUCK > JGrabowMSt
01/19/2014 at 00:27

I think if your brakes are working fine you shouldn't really fuck with them, they're the most important safety feature in a car.

JGrabowMSt > IDROVEAPICKUPTRUCK
01/19/2014 at 00:29

I can agree with that. I'd argue second most important however.

First and foremost, your attention is the most important safety feature in any car.