Guide: MS3 front brake conversion

[MR6]

In an effort to increase the safety of my family, I plan to convert the brakes of my van to Mazdaspeed 3 spec. The rears are already shared with the MS3 so all i did in the rear was slotted StopTech rotors clamped by Hawk HPS pads. The real work is on the fronts. The general opinion on the web is that this would be a simple bolt-on affair as the MZ5 shares so much of it's platform with the 3. Well it seams to be working out that way as yesterday i test fitted the MS3 caliper carriers with the MS3 spec StopTech rotors without issue.

As expected, I had to remove the MZ5 dust shield as it blocks installation of the larger rotor. I have the MS3 dust shields on order. While i've run big brake kits in the past without the shield, i really want the vehicle that my family travels in to be by the book as much as possible, ya know. I figure keeping the hot brake dust off of the CV boots was probably what the engineers had in mind.

So i stopped at test fitting the carriers since the calipers i bought off ebay are from a wreck. I want to rebuild the calipers with new seals, clean & strip them and finally repaint them pink for my lovely wife I'll detail as much of the rebuild & installation process as i can in this thread. For now, here are pics of the test fit.

Must start with a before picture:

MS3 carrier on Mz5 rotor. I just wanted to see what the difference in rotor size would look like

And the MS3 spec Stoptech rotor with MS3 carrier fits like a charm

 

[hibern8r]

Looking good! Keep us posted and definitely keep sending the pictures of your progress. What year MS3 carrier did you use and was the rotor for the same year? I have a 2010 Touring and assume you and I have the same stock setup.

 

[Rally Man]

I might do this after my current ones need replacing., which won't happen for some time.

 

[chad99]

In an effort to increase the safety of my family

Lol does your wife buy that as a valid reason?

My wife saw through those "increasing safety" excuses for upgrading my other car, I still did them, but she knew haha

 

[MR6]

Looking good! Keep us posted and definitely keep sending the pictures of your progress. What year MS3 carrier did you use and was the rotor for the same year? I have a 2010 Touring and assume you and I have the same stock setup.

I'll definitely keep the pics comin. Mine is an 09 Touring. I forget the exact yr but any 1st gen speed 3 caliper should do. Maybe even 2nd gen

Lol does your wife buy that as a valid reason?

My wife saw through those "increasing safety" excuses for upgrading my other car, I still did them, but she knew haha

Lmao! Well, i broke down the physics of how a larger rotor size increases leverage and shortens braking distances. The larger piston of the speed 3, yaada yaada. But imma cheater...i own a gen 2 speed3 and she drives it. She knows how much better it brakes. She's even avoided a deer in the speed that she admits she prob woulda hit in the 5. It was an easy sell

 

[Silentnoise713]

Looking good! MS3 brakes are a very nice and noticeable upgrade.
You really should consider SS lines too. While this won't decrease stopping distance, the benefits of a consistent peddle feel is worth it. Good excuse to flush out the old brake fluid anyway.

I am a proponent of the backing plate/dust shield. Good to keep dust where it should and for cooling. Unlike the track, you are more likely to hit a puddle while the rotors are nice and hot. How much are MS3 dust fields? I like the affordable clamp it flat route.

Would you be disappoint if the piston diameter were the same between the MS3 and Mz5? Benefit is not only that tho. Also, our rear brakes are actually slightly largely than the MS3 rear.

 

[MR6]

Looking good! MS3 brakes are a very nice and noticeable upgrade.
You really should consider SS lines too. While this won't decrease stopping distance, the benefits of a consistent peddle feel is worth it. Good excuse to flush out the old brake fluid anyway.

I am a proponent of the backing plate/dust shield. Good to keep dust where it should and for cooling. Unlike the track, you are more likely to hit a puddle while the rotors are nice and hot. How much are MS3 dust fields? I like the affordable clamp it flat route.

Would you be disappoint if the piston diameter were the same between the MS3 and Mz5? Benefit is not only that tho. Also, our rear brakes are actually slightly largely than the MS3 rear.

Thanks. I do have the Goodridge SS lines as well. A flush is definitely in order.

While clamping it flat will allow me to re-install the Mz5 shield, it will still leave about an inch of the rotor's edge exposed. The MS3 shields were a somewhat pricey, but I'd rather do it once & do it right, ya know. Cost is no object when it comes to my children although i admit i may be overreacting a bit.

No disappointment here. Idk if it was you or phunky's thread i ran into while researching this conversion but i know the piston sizes are the same. Largely irrelevant in this case as the much larger rotor provides a significant upgrade in braking leverage and the larger speed 3 pad will also go a long way to increasing clamping force and area. Bet you know that already though

 

[hibern8r]

I'd rather do it once & do it right, ya know. Cost is no object when it comes to my children

Yep and absolutley!!!

 

[MR6]

Tomorrow I'll be done stripping the previous owners ricey red paint job. This guy actually sprayed them with the calipers on the car. It was so inconsistent and sloppy. There was paint on the piston seals. The brake pads were even red! I bet the rotor was red too lol. I'm hoping get to painting them tomorrow, let them cure and rebuild on Friday. I REALLY hope this pink isn't like some 80's hot pink s***! I think i would just spray them black if it is and sell the kit to one of you guys

Coming along nicely. The MS3 caliper feel enormous in hand.

 

[MarkVII88]

MR6, do you know whether the OEM 16" rims would fit over the new MS3 front brakes? I'd love to do this mod but I run my snow tires on the stock rims and need to have them on the car half the year. Thanks.

 

[MR6]

highly doubt it. Another member here had to use spacers to clear the stock 17's. That MIGHT work for you but the only way to find out is unfortunately the hard way...unless we can figure out a way for me to make a template for you...hmmmm. Anywho, that's why i went ahead and just bought a used set of gen2 MS3 18s.

 

[MarkVII88]

MR6, thanks for your thoughts. I figured this wouldn't work. I run 225/45/17 on aftermarket rims for the summer and I'm sure these would fit, but I'm not willing to go buy another set of 17" rims and new snow tires for winter.

highly doubt it. Another member here had to use spacers to clear the stock 17's. That MIGHT work for you but the only way to find out is unfortunately the hard way...unless we can figure out a way for me to make a template for you...hmmmm. Anywho, that's why i went ahead and just bought a used set of gen2 MS3 18s.

 

[MR6]

Quick update. Calipers are cleaned and ready for paint. This recent storm has dropped temps in my garage too low for paint. I would bring it inside but I'm hoping to surprise my wife. If the temp doesnt rise soon though, I'll have to forget the whole surprise idea and just do it in the bathroom or something

 

[Silentnoise713]

highly doubt it. Another member here had to use spacers to clear the stock 17's. That MIGHT work for you but the only way to find out is unfortunately the hard way...unless we can figure out a way for me to make a template for you...hmmmm. Anywho, that's why i went ahead and just bought a used set of gen2 MS3 18s.

The spacers are needed only bc stock '08-10 rims have a very high offset AND the spoke design is too flat. It sits too flush an the spokes scrape on the caliper body. Diameter wise it clears the calipers with no problem. MS3 guys confirm they can mount stock 16" but I'm not sure what rim they are using. Also, I tied to put 15" BBS on and it was juuust a tad too small.


Are you using G2 paint by chance? If so, would like to hear some feedback. Look forward to seeing your finished product!

 

[MR6]

Yup. G2 from tire rack. Temps are picking up by Monday. Hopefully i can get to it then.

 

[TonyC]

bookmarked. the m5's brakes are pretty atrocious. it looks like even the previous gen's MS3 front set-up should be a bolt-on for '12 w/ 17s? I'm all-in.

 

[phunky.buddha]

Try it- if not, fab a bracket and sell it.

 

[MR6]

bookmarked. the m5's brakes are pretty atrocious. it looks like even the previous gen's MS3 front set-up should be a bolt-on for '12 w/ 17s? I'm all-in.

I'm curious to see if they would as well. After I'm all done with the 5, i have to do the front brakes on my gen2 MS3. I'll take a "precision" tape measure to the bracket. AANNNDDD, I'll trace the gen1 bracket onto a piece of paper and then lay the gen2 bracket over the trace.

 

[TonyC]

having a hardtime finding junkyard gen2 MS3 front brake carriers. dang, how did you even come across yours, just ebay?

 

[sac02]

... the m5's brakes are pretty atrocious. ...

I'm curious, what is your complaint with the mz5's brakes? I find them to have good power and feel/modulation, and I'm fairly critical about these things. A direct comparison to MS3 braking performance is not apples-to-apples - the MS3 is lighter and lower and the physics of the two vehicles says the MS3 has an inherent braking advantage.

The only potential downside I see is that they aren't large (physically - thermal mass) and thus may have issues with overheating and fade with extended hard driving/lapping. I'm planning a fairly large power increase and don't expect to do any work to the brakes other than adding some cooling ducting from the fog light holes and more aggressive pads. If I was doing HPDE's with the car I would have a different opinion though, I think.