Why do I always see people saying drum brakes are simpler than discs?

Just an FYI: Disc brakes can be complicated, too!

My 1987 Ford Van uses a spring clip to hold part of the caliper in place. They can be a real pain to remove. And the rotor is integral to the front hub = change the rotor, change the front wheel bearings.

Heh, heh…I’ve got hubs like that on my F150 too, which is why I run a soft pad, trading more pad replacements for (hopefully) FEWER rotor replacements.


@shadowfax See, I would approach that same thing from the opposite side: it’s a moot point if “plain old discs” are simpler than drums, if DOT regs won’t let you have plain old discs. (On the rear.)

change the rotor, change the front wheel bearings

At least it forces you to install new, greased wheel bearings. Bearings that have gotten so cheap that it is dumb not to change 'em instead of clean and re-grease. I remember years ago, a full set of tapered rollers was $40 in 1980. They still ARE $40 in 2016 dollars.

But yeah, there are complicated calipers, too. Especially the rear integral parking brake models with a ball-screw inside. Whadda PITA!

Maybe I’m misunderstanding the design: on my Ford, the brake disc is also the “race” of the adjustable bearing. Replacing the disc means repacking and readjusting preload on the bearing–a PITA, but only out the cost of some grease.


Are you saying there are designs that require you (hydraulically) press in a new sealed bearing unit every time you swap discs? That’s fouled up!

That’s a good point @CapriRacer . Were I in the market for a new car I’d definitely avoid purchasing a model using the integral rotor/hub design. Driveway diy’ers don’t need that aggravation.

@ Oldtimer ,I think they are fine but overpriced.Rock Auto has good parts ,but with shipping and core charges ,its not worth the hassle IMO.

Meanjoe, on those designs that have pressed-in bearings the disc comes off by unbolting it from the hub. The disc is replaceable without fooling with the bearings at all.

Simpler may mean “one and done”. There usually isn’t any shaking brake effect with drums. You can just replace the shoes and adjust them and go on with life. Warped rotors can’t happen without rotors.

I find the hardest part of disc brakes is getting the old disc's off the hub.

I like it when the discs have the screw holes like drums do. Insert a couple of bolts, turn 'em evenly, and the disc pops right off.

I’m embarrassed to admit that I was not aware of those holes on my first disc brake job, which is why I sat there with a mallet for half an hour beating away at the disc before it finally came off. :wink:

@pleasedodgevan2

Warped drums . . . if they’re on the rear . . . can cause the entire vehicle to shake

You can feel it in the seat of your pants

The severity depends on how warped they are, the size of the vehicle and the size of the drums

On a good sized truck or van, the effect can be quite severe and unnerving

Drums can fracture, too.
Both drums and discs convert the inertial energy to heat. Lots of heat. Whenever heat is generated in metal parts followed by widely varying environmental exposures, metal begins to expose its weaknesses. There’s no way around it, discs and drums can both warp.

Each way has its inherent strengths and weaknesses. And they both work well, all things considered.

When we only had drum brakes, there was a lot of work involved, you had to check for them not being worn more than .060 over. Chrysler used to mark theirs good for .090 over but NY State would not allow a drum to be turned more than.060. You also had to check for bell mouth or taper, and if you wanted a good job, buy shoes with oversized lining and have them arc ground to the drum. Then clean and repack the wheel bearings and finally adjust the shoes. also almost half the makes on the road required a wheel puller to get the rear wheels off.

I often wonder what happened to all those wheel pullers, every corner gas station had one , they all did repairs, there were no standards for mechanics, you just learned by doing with someone more experienced available, Now every collector of those cars needs to buy a wheel puller.

Early on I found out it was a lot easier to break em than to fix em so I took up truck driving.

I may be misinformed . . . but I seem to remember hearing that arcing the lining is illegal, nowadays

Meaning it’s illegal for a shop to do this and collect payment for it

I’m not sure if it’s illegal for you to arc them in your garage for your personal vehicle

I can’t imagine why it would be illegal, It’s just grinding the surface of the pads slightly to match the arc of the drum, but the comment interests me.
Anybody?

Maybe because some shoes still have asbestos

I've worked on both. I won't say a rear drum is easier to work on than a rear disc without the mini-drum

Have you ever replaced the rear mini-drum brakes inside the rear disc brakes? Now that’s a pain in the butt. Luckily they don’t need changing much since they are only used for parking. However if you forget to relieve them when you drive a few times…you could wear them down enough that they need replacing.

Interesting thought, Texases, but I cannot imagine that asbestos would be allowed in shoes either.

Some thoughts occurred to me, concerning the possible illegality of arcing brake shoe lining . . .

Asbestos has been proven to be harmful to lungs, if inhaled, and that’s probably ONE of the reasons why it was initially prohibited

Arcing brake shoes does technically REMOVE some lining, so I can see how that could be considered “tampering” or “altering” of the brake system

I did a little research and Washington state banned asbestos brake pads and shoes effective in 2014. It seems that is the only actual ban in the US. The OSHA regulations I found deal with personal protective equipment and exposure limits. Individual shops may not allow grinding but it does not appear to be illegal in 49 states. I was also under the impression asbestos was completely banned.