Let's talk brakes

"AestheticsInMotion" (aestheticsinmotion) 08/05/2018 at 13:48 • Filed to: None

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I opened my hood today to see my brake level well below the *low* level. Yikes. 

I’ve got a slow leak somewhere, and if I had to guess I’d say something got tweaked while offroading last year. Six months ago my brake fluid was low so I topped it off, and now it’s low again. I know you’re not supposed to use brake fluid that’s already been opened but I’d imagine oldish fluid is much preferable to none.

So! I need to track down the source of the leak and fix it.

I need to get my parking brake adjusted. Wil wood says that their parking brake is pretty weak, but at this point mine does basically nothing.

Rotor resurfacing or replacement probably wouldn’t be a bad idea either. In the front I think I’ve lost more rotor surface than brake pad... Is that normal? Here, look at this. Front rotors compared to rears -

Rear rotors

Fronts. I’m almost completely through the slotted sections... Is this wear pattern normal? Should I adjust the brake bias a bit?

Eventually I’d like to find a pad that doesn’t squeal like a stuck pig, but that might also have to do with t he crusty rotors..? Idk. It’s been almost two years of daily driving and the pads still have a ton of life on them. Unfortunately without an odometer it’s hard to guestimate mileage, but that seems like a lot of life out of these pads.

I hate brakes. The first *big* job on the Miata was a wil wood brake kit on all 4 corners and it was miserable. Tons of broken parts, incorrect parts, bad or just straight incorrect directions.... And I had a 30 year veteran of muscle car/hot rod restos working with me! Eventually we handed it off to a brake shop, and even they had a nightmare of a time getting everything functioning correctly. Still, after that was all sorted out the brakes have been great!

If I had to do it again though, I wouldn’t buy Wilwoods and I certainly wouldn’t go through Flyin’ Miata. Their “ customer service” was laughable for someone who had numerous issues, and proof of defective and/or broken pieces of a kit they sold. Next time it will likely be a two piece rotor setup from stoptech...

BJ > AestheticsInMotion 08/05/2018 at 13:52

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Let’s NOT talk brakes - my new rear brakes are rubbing, so I have to go back to the shop on Monday morning and have them adjusted, I guess... what a pain in the ass! The noise they make is unbearable.

AestheticsInMotion > BJ 08/05/2018 at 14:00

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One of those things you really just want to work perfectly all the time so you don't have to think about it

sony1492 > AestheticsInMotion 08/05/2018 at 14:03

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Some brake pads are designed to wear the rotor out, some are designed to wear the pad. I wouldn’t say it’s weird that your rotor is wearing faster than the pad, it’s just the way the pad was designed.

You can’t resurface drilled and/or slotted rotors. If you replace them I would recommend not going with drilled rotors, they reduce the amount of heat the rotor can absorb, reduced swept area( friction surface) , when the rotor gets too hot they will be the first place to form cracks, and outgassing of brake pads is no longer a problem. Slots can be helpful in,”cleaning” or wiping away a glazed brake pad. Glazing being the surface getting too hot and creating a hard layer that does not create as much friction, alternatively you can take the pad out and sand away the glazed surface.

The way your front rotor is wearing may have to do with the depth that they cut the slot and not the angle of wear. If not it may be a bearing on the way out that angles oddly when the caliper clamps down.

Finding a less performance oriented pad will provide less squeal, performance pads will squeal until they are up to temperature.

TheRealBicycleBuck > AestheticsInMotion 08/05/2018 at 14:10

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I put Stoptech on all four corners of my WRX and the front of my wife’s Explorer. It was just rotors and pads, but everything worked out fine and we’ve been happy with them.

diplodicus forgot his password > AestheticsInMotion 08/05/2018 at 14:14

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You running a ceramic pad compound? Those always seemed to squeal on me. Semi metallic compounds seem like they squeal less ime. Using plastilube on the back of the pads where they meet the caliper helps as well.

Is your parking brake a drum in hat set up?

Make sure to check both your master and slave clutch cylinders for leaks, they use the same fluid reservoir as the brakes.

AestheticsInMotion > sony1492 08/05/2018 at 14:17

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Hmm. Didn’t know that. Always thought pads were supposed to be the “first to wear” item.

Yeah the drilled/slotted rotors were purely for looks haha. I’ll probably just go with blank rotors next time.

I probably should have gone with a different brake kit. There aren't a whole lot of pad options in this size, and if I ever end up boosting or swapping the engine, these brakes will need to be upgraded anyways

Highlander-Datsuns are Forever > AestheticsInMotion 08/05/2018 at 14:23

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That worn rotor, I’d put money on a stuck caliper. If you fixed it the car would feel like +20 hp.

gogmorgo - rowing gears in a Grand Cherokee > AestheticsInMotion 08/05/2018 at 14:24

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Fluid level in the reservoir will drop as pads and rotors wear. As the caliper pushes further out, more fluid stays in the piston. A sudden and severe drop will indicate a leak, but a gradual drop is normal as pads/rotor are consumed. I’d especially consider this possibility in your case, given rotor wear. You’ll probably want to check those to make sure they’re not below minimum thickness.

As to the wear itself, I imagine a set of particularly aggressive pads could do that to a rotor, but I can’t say for sure that’s what’s happening in your case. But generally yeah, fronts experience more wear than the rear, silly because the fronts are doing pay of the work.  In terms of setting up proportioning, the generally accepted way to do it is to find empty space and lock up the brakes. Get a camera on it so you can watch in slow-mo. You want the front and rear to lock at the same time. 

sony1492 > AestheticsInMotion 08/05/2018 at 14:26

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I just realized you were talking about the w ear front to back not specifically the front rotor. The blue color of your rear rotor shows that they are getting quite hot, if the bias was off too much they wouldn't be getting red hot.  I think the front wear has to do with the fact that the front brakes do 80% of the braking and your pads wear rotors instead of themselves

winterlegacy, here 'till the end > AestheticsInMotion 08/05/2018 at 15:25

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I have to tweak my brake bias at some point. My rears barely do everything while my fronts are taking 95% of the load, which I don’t think that’s supposed to be happening at all.

My bird IS the word > AestheticsInMotion 08/05/2018 at 15:40

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Take this as an opportunity to replace your soft lines if you haven't already. 

NKato > AestheticsInMotion 08/05/2018 at 15:55

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Ceramic brakes squeal more than semi metallic (at least, that’s what I think) . I use semi metallic, because they have better grab. Of course, my brakes have a long travel so sometimes I wonder if they went out on me. But the long travel lets me have a light touch on the brakes when I’m coming to a stop at the light.

Berang > AestheticsInMotion 08/05/2018 at 17:55

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The fluid levels in both circuits are below the minimum as well as below the divider in the reservoir. Which is certainly odd, and would indicate there are problems in both circuits of the brake system.

Check the minimum thickness of the rotors if you you know what it is, and check the pad wear too.

daender > AestheticsInMotion 08/05/2018 at 18:02

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Instead of going aftermarket, if you had to do it again , maybe just stick with factory calipers and some more aggressive pads with blank rotors?  I don’t see the need for heavier-duty brakes unless you’re pushing a lot of power with either an engine swap or forced induction.  Heck, I think my NB2 sport brakes are a bit overkill (and killing my ability to run cheap 14" wheels and tires for DD use).

AestheticsInMotion > daender 08/05/2018 at 21:52

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I did it for the weight savings. Dropping 5 pounds per corner of unsprung weight is pretty big... Honestly the braking performance is probably on par with NB sport brakes. Certainly wouldn’t be a good choice for medium-high hp builds. With the winter tires still on it's pretty easy to lock up the brakes and slide a bit. 100% nowhere near the limits of these brakes. 

Also just wanted something that looked good! Despite all the time spent offroading/rallying/drifing/autox-ing/etc.... I still plan on someday trying for some car shows. 

DC3 LS, Fuck Hyundai, now and forever > AestheticsInMotion 08/06/2018 at 00:08

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If your pads are about due for replacement, I’d knock them out and check the caliper seals while your at it. My guess is if you have a slow leak, it’s probably there.

Also may not be bad to replace your hoses. I know I replaced all four on my Civic when one failed, and replacing the still good ones made a huge difference in brake feel/response, you know what I mean.