Guide MS3 front brake conversion

Here is my clearance on the snow wheels:
IMG_20140306_162012960_zpsbknsqy1o.jpg
It looks like the design of these spoke may clear the added bulge. Not sure about ID clearance but I think these should fit ok but you wont know till you try.

This is on the stock first gen 17's:
IMG_20140306_161841856_zpsixe1dtvc.jpg
These look like it may interfere.
 
EFF! I'm almost certain the '12+ won't clear either, cuz they look like '08+ rims with inner curvature on the spokes... Picture coming later.

 
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So the brakes have developed a hum when braking at any speed over 30 mph. Braking power is still amazing. There is a slight vibrating sensation in the steering wheel & more so in the brake pedal. It feels like a woman's vibrator on my foot but faint. And it sounds like the groan a pickup on knobbies makes when slowing to a stop. I pulled the brakes apart again this weekend and found was that the slide pins were dry (never using anti-squeal again). So i cleaned and greased them with hi-temp lithium. I also found that when hitting the caliper in a very specific area with a rubber mallet, there was a clinking sound. I tracked it down to the pad "ears" hitting the carrier. Both calipers do it.

Also, the pads are wearing evenly and the rotor wear matches that of my speed3 exactly. My MS3 has the same EXACT hardware save for the goodridge SS lines and the speed does NOT hummmmmm. Could the lines really be causing this? My next move is to try the same rubber mallet test on the speed. Could aftermarket pad retainers causing a problem here?? Google has been no help. anything from stuck piston to slotted rotors at the cause. After rebuilding the calipers i'm fairly certain it's not the piston and if it were the rotors, my speed would be doing the same thing. Any ideas?
 
-Perhaps another bleeding (I assume you pressure bleed or use an aid, not relying on gravity bleed), followed immediately by another bleeding after a short warm-up drive (caution hot) to eliminate any possibility of air in the lines. I assume you bleed all corners (good practice), farthest from the MC first. I had to re-bleed the car to get it to feel right. There were still some bubbles in the lines for me. That, and breaking it in after a few hundred miles <- broken it in yet? I read ~500 miles but ~700 was my magic number when things finally settle to my liking.

-Did you clean the rusty hubs, making sure the surface area is even/level? Irregularities on the mounting surface (rust spots) may translate to a slightly out of round rotor. The rotor floats in-between the calipers, which is bolted to the knuckle so you may have an “ever, ever so” slightly wobbly disc against the pads. Cleaning the hub was the worst part of the job, right there next to getting the damn rusted rotor off.

-I used aftermarket Centric pad retainer and also Goodridge lines and no noise for me. It doesn’t make sense how the SS line (itself) can be a culprit. The hummmm sound you describe sounds like it is rotational and only happens when stopping at +30MPH. This would lead me to investigate the rotor/caliper/pads first sa they were things that were changed, then the wheel bearings and axle. BUT I only ran this setup for about 4K miles before selling car.

-I don’t use slotted rotors. Could this be a trait of the slots (totally guessing here)?
 
Slotted rotors can cause the slight chopping feel in the pedal (have a few cars with slotted rotors) but I have no idea about the humming sound.
 
-Perhaps another bleeding (I assume you pressure bleed or use an aid, not relying on gravity bleed), followed immediately by another bleeding after a short warm-up drive (caution hot) to eliminate any possibility of air in the lines. I assume you bleed all corners (good practice), farthest from the MC first. I had to re-bleed the car to get it to feel right. There were still some bubbles in the lines for me. That, and breaking it in after a few hundred miles <- broken it in yet? I read ~500 miles but ~700 was my magic number when things finally settle to my liking.

-Did you clean the rusty hubs, making sure the surface area is even/level? Irregularities on the mounting surface (rust spots) may translate to a slightly out of round rotor. The rotor floats in-between the calipers, which is bolted to the knuckle so you may have an “ever, ever so” slightly wobbly disc against the pads. Cleaning the hub was the worst part of the job, right there next to getting the damn rusted rotor off.

-I used aftermarket Centric pad retainer and also Goodridge lines and no noise for me. It doesn’t make sense how the SS line (itself) can be a culprit. The hummmm sound you describe sounds like it is rotational and only happens when stopping at +30MPH. This would lead me to investigate the rotor/caliper/pads first sa they were things that were changed, then the wheel bearings and axle. BUT I only ran this setup for about 4K miles before selling car.

-I don’t use slotted rotors. Could this be a trait of the slots (totally guessing here)?

- I used a Motive power bleeder to do a full flush. Ran an entire 32 oz bottle through. And yes bled every corner repeatedly - at least 5 times each.

- Used a rust dissolver and a wire brush on each corner. Habit..

- The slotted rotors wouldn't be the cause unless they're warped. I wish i could get the speed in the air at the same time and swap the rotors. The perks of having two vehicles on the same platform also requires a two car garage :(

So, i MAY have had a eureka moment last night. I got her up again to poke around the brakes and found an off-white greasy substance on the passenger side. The source was the tie rod. It's blown. It doesn't click when hit with the mallet though. The boot appears to be intact but the grease is gone. Now, i may be crazy buuuut bear with me here...in theory, a failing tie rod would give a lil under braking, throwing off my toe. The hum i hear could be tire groan as it angles inward (or outward) under the force of braking. It's no coincidence that i swear i feel and hear it more from the passenger side. Ordering the outer tie rods tonight. Gotta start somewhere...

Will this ever end?! I'm having VW flashbacks lol thx for the feedback!
 
Ah. Toe change under stress would do it. :) It's not easy to tell in forum speak if the pulsing feeling you have in your pedal is the same as the slight pulsing I get from my slotted rotors... and it's more of a sound at initial bite more than anything else for me. Yay for the vagueness of the written word!
 
i'm not 100% on this yet since the rain tonight has really prevented me from testing this safely, but i don't think it hums if i brake while turning...which would further prove my tie rod theory.

phunky, it's definitely not slotted rotor effects. i know what that feels like since my MS3 exhibits that sensation and what the van is doing is straight up pickup truck on knobbies groan that resonates the whole floor pan, pedal, etc...
 
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I would think the slotted rotor is the cause of the noise but the fact that it wasn't present right away says its not. Assuming its not the tie rod, I would think that its possible that there are deposits on the rotor from the pads or some sort of contamination. I would try swapping rotors left to right and see what happens. If nothing changes, I would see if there is a way to recondition the surface of the rotor and pads and see if its that.
 
i'm not 100% on this yet since the rain tonight has really prevented me from testing this safely, but i don't think it hums if i brake while turning...which would further prove my tie rod theory.

phunky, it's definitely not slotted rotor effects. i know what that feels like since my MS3 exhibits that sensation and what the van is doing is straight up pickup truck on knobbies groan that resonates the whole floor pan, pedal, etc...

Yeah, hard to translate sounds/sensations through the highly descriptive internet...
 
I'm beyond frustrated at this point. I changed the tie rod ends yesterday. All i accomplished was MUCH smoother steering and a blown alignment. The rattley sound is still there. AND so is the braking hum. BUT, while i can't definitively say that it improved....it's different. Not as loud or intense but still there. So i would say i'm on the right path.

After i put the wheels back on i grabbed them with one hand at 3 o' clock and the other at 9. i wiggled them back and forth and CLEARLY heard a rattle clunky sound coming from in the steering rack. Each wheel moved slightly (1/4") in conjunction with the sound. Is my rack shot? If i can move the wheels while they're up in the air, does it stand to reason that the toe is randomly changing under braking on BOTH sides? I noticed in the shop manual yesterday that there is a troubleshooting section dedicated to the steering linkage and rack. That's my next move.

Then it's off to a shop to confirm my findings. I'm done throwing money at guessing parts. I'll let them figure it out, play broke and leave, then buy the parts and do it myself.

I wonder if the speed would fail the same test............
 
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MR6, I've never used Hawk pads before, but someone I know has and had similar issues after the pads bedded in. He was able to determine which side the noise/vibration was coming from, swapped pads side to side and confirm that it moved with the pads. He sanded the faces of the pads and rebedded and hasn't had the problem since. The noise may change during steering because there is some flex/movement to the brake components/rotor during turning.
In regards to the steering rack movement, the wheels should not not be able to be moved much at all (barely perceptable) without the steering wheel moving. Even if the steering is locked (key out of ignition), there will be some minor movement allowed in the steering gear, but that movement should have corresponding movement of the steering wheel. IE; stand at the driver side wheel with the front lifted off the ground. move wheel/tire assy with your hands at the 3 and 9 o'clock position while watching steering wheel. The amount of play in the steering gear should be almost imperceptible. Clunk while moving steering gear back/forth in this manner is normal and doesn't indicate a problem. (figured this out while chasing down sway bar bushing clunk). I hope this is somewhat helpful as I know you're frustrated with this problem.
This is what I use to lube caliper slide pins https://www.fcsdchemicalsandlubricants.com/main/product.asp?product=Silicone+Brake+Caliper+Grease+and+Dielectric+Compound&category=Greases
Due to the open nature of the slide pins regular greasing is necessary.
 
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I'm still looking to drop the van off at a shop and have them diagnose it but that bit about the rack is good to know. I'll take it with a grain of salt if they recommend an expensive rack replacement. I also plan to run through the shop manual's steering troubleshooting steps for good measure. It's might also be the control arm bushings or ball joint...or maybe it's Katy Perry....who the hell knows! I'll post when i know....the naked bonfire is still on the table
(gah)

This holiday weekend netted me a couple of days off. I'll sand the pads on both sides and re-bed. I hope it works. It'd be great to put at least ONE of my issues to bed. Thanks!
 
Just a note. My backing plates are different than what it seems everyone else has. These are the factory backing plates that came on my 2010 Mazda5. I didn't have to bend or tweak them at all to fit the MS3 rotors. It looked like the PN for the 2010 plates and the earlier models are the same. Maybe some sort of factory screw up and I have different backers.

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That is some funky stuff!?!? You are the original owner since new, correct?

While freebies are nice, I do not like how these leave a lot of exposed metal in the back (hot rotor meets cold puddle). I would much prefer to mod the slightly smaller OE backing plate as it mostly covers the MS3 rotor. The small trim that needs to be done is mainly for clearance.

I’ve been checking Porsche rotors in passing. They use some HEAVY duty backing plates. I mean, they appear to be super ridiculously THICK and completely cover the rotors. The Mazda in comparison is as thin as tin foil (above do seem thicker) and can easily bend with your hands. Get what ya pay for.
 
Rod, that's a lot of exposed rotor you got there! I much prefer the factory approach of completely covering it, as most mfr do. There is probably a good reason. From your pic, one reason i can guess would be protecting your ball joint boot from the rotor's heat.

And so i haven't tried sanding the pads yet. Kitchen remodel has had me tied up. But the delay has revealed new info. My speed starting doing it but only mild, and only at the very end of hard braking. My new theory is that the speed is less pronounced because the bad rubber lines don't apply the pressure needed to trigger the groan, but hard braking over the course of 3 seconds or more (like approaching a sexy off ramp) triggers it. Where as the van's SS lines inherently apply more pressure by design and would naturally cause this groan more regularly. Hawks and slotted pads just do this????? I don't know. But both cars are wearing normally and stop strong so..i may still sand the pads for s**** n giggles but i'm no longer too concerned about it.
 
revisiting the backing plate issue: did everyone get new ms3 ones? or just cut/bend the stock mz5 ones? i finally got the parts in on this mod. waiting for rebuild centric calipers took FOREVER.
 
revisiting the backing plate issue: did everyone get new ms3 ones? or just cut/bend the stock mz5 ones? i finally got the parts in on this mod. waiting for rebuild centric calipers took FOREVER.
MR6 got MS3 replacements (be warned, they be expensive -each) and I went the bend AND cut (two different section, can technically just bend both parts but it’d be sloppy IMO) route. Rod, as you can see above had a little bit of good fortune on his side. What do you want to know?
 
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