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Just got a front set of stoptechs installed, and wow.. huge improvement over stock,. gave them a good run to bed in properly but may have overdone things a tad as I returned to the garage the front caliper region on drivers side simply burst into flames, after having somewhat of a sh!t attack I decided the best course of action was to jump back in and drive around at reasonably high speed (not using brakes much) to cool them down, and it worked,. the discs were literally glowing orange with heat beforehand and I haven't seen anything this side of a le_mans ceramic disk turn that colour, so im assuming this could have been remnants of oild that spontaneously combusted, but the cool thing was the stoptechs had displayed little evidence of fade even right up to the last high speed braking maneuver despite this heat.

Whilst I don't generally drive like that every day I think its probably a good idea to install those brake ventilation duct mods anyway, but the big question I have is that the pedal now seems abit soft & spongy with a lot of travel, even compared to stock.. I had the old fluid flushed out & replaced with dot4, and (I'm assuming) bled correctly front & rear.. but while being really effective, the pedal still travels down about half way before generating its max stopping power, so it doesn't really inspire confidence at high speed or while (attempting to) heel 'n toe.

I'm just wondering if this is normally attributed to big brake kit modifications due to increased piston size\fluid volume to callipers etc, or if there may still be some air trapped in the system, or indeed if maybe braided steel lines are needed at the rear to firm up the pedal at tad more,. any ideas? is it normal to have spongier than stock pedal feel with the stoptechs?
 

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i had the same pedal situation with my car...

A few thoughts...bleeding is rarely ever done 100% effective.

When the fire broke out, you might have boiled some of the fluid on that side, hence the fluid is toasted there.
 

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I agree, try re-bleeding the system. It can take a few times to get all of the air out of a 4 piston caliper.
That fire would have surprised the crap out of me too! :1:
Mike
 

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It'd be great if Dave Z can jump in on this discussion. But here's a summary of a talk he and I had a while back.

I always thought the M5 has great brakes, especially after the braking drills we had during the M5 DE. However, after I got the RUF, I felt that the brake pedal action of the M5 is too mushy, with excessive travel before the brake action commences. By contrast, the RUF brake action was firm, instant and confident-inspiring. I asked Dave if I switched brake components, including steel brake lines, could I get the M5 brake action to feel like the RUF, which I dearly love. His short reply is NO. He gave me a very thorough explanation on why some brakes are firm, and others not. Based on his input, I gave up the quest to firm up the M5 brakes.

Bottom line, we can upgrade the brake performance to the point that the M5 can tackle any track, brake-wise. But it is difficult to get that granite-solid pedal feel. :(

CP
 

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I would think if someone wanted to experiment with some different master cylinders, you may improve pedal feel. I believe the softer feel is from the increased piston area, so theoretically, a master cylinder with more pump volume should help feel. That said, my stoptechs feel pretty good. First inch or so of travel is soft (but you can feel them working, as opposed to soft from air or boiled brake fluid), then they firm up nicely. It did take maybe 4 bleedings over the corse of nearly a year for them to feel as good as they do now.
Mike
 

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You may find that the pedal firmness increases somewhat after a few days of driving. That was the case for me, even after a thorough bed-in process.
 

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They need to be re-bled, for sure. "Half-way down" is too far. I used ATE Typ 200 (ATE Super-blue without the "blue") and even then it took three bleeds to get all the air out after the initial install. The pedal firmed up a lot each time, even though the fluid hadn't been subjected to brutal heat.

By the way, if your rotors burst into flames, there might be a fluid leak - you should check that, too.

Also, make sure that the pads are free in the calipers - mine were tight enought to be sticky out of the box, but with a little trimming with a file, they freed up, and after that the brakes worked better and were firmer on the pedal as well.

Mine are "firm" at the top of travel, but not "hard".

Cheers
JJ
 

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Ah ha! You are experiencing what a lot of us have noticed by putting on aftermarket braking systems. They DO NOT feel as good/firm as the stock brakes. This is inherent in the multi-piston design of the calipers. You can bleed the brakes all you want and they will never feel as firm as the stock brakes. Also, let me warn you. If you put on Axxis Deluxe pads, they are prone to uneven deposition of material on the rotors which will give you a horrible shuddering when braking from higher speeds. This is a tough problem that requires scrubbing the rotors with Hawk Blue pads and putting different pads. My advise to you is if you have the Deluxe, get rid of them and put on the Axxis Ultimate pads. They are dustier than the Deluxe pads but not as dusty as the stock pads. Follow the bed-in procedure that you can find on Dave Z.'s site. Good luck!

:cheers:
 

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Úbermensch said:
Just got a front set of stoptechs installed, and wow.. huge improvement over stock,. gave them a good run to bed in properly but may have overdone things a tad as I returned to the garage the front caliper region on drivers side simply burst into flames, after having somewhat of a sh!t attack I decided the best course of action was to jump back in and drive around at reasonably high speed (not using brakes much) to cool them down, and it worked,. the discs were literally glowing orange with heat beforehand and I haven't seen anything this side of a le_mans ceramic disk turn that colour, so im assuming this could have been remnants of oild that spontaneously combusted, but the cool thing was the stoptechs had displayed little evidence of fade even right up to the last high speed braking maneuver despite this heat.
An important part of the bedding process is to allow the rotors to cool down before coming to a complete stop. If you check out my bedding instructions, you will see that you need to cruise around for 5-10 minutes to let things cool: http://www.zeckhausen.com/bedding_in_brakes.htm You're really lucky not to have transferred a big chunk of pad material to the rotor, ending up with severe judder under braking.

I'm guessing you didn't clean out the bleed screws with a paper towel tip or brake cleaning spray before popping the rubber bleed screw caps back on. When they became super hot, the trapped brake fluid expanded, pushing the rubber caps off and dribbling some hot brake fluid onto the rotors. I'll bet that's what caught fire.

Whilst I don't generally drive like that every day I think its probably a good idea to install those brake ventilation duct mods anyway, but the big question I have is that the pedal now seems abit soft & spongy with a lot of travel, even compared to stock.. I had the old fluid flushed out & replaced with dot4, and (I'm assuming) bled correctly front & rear.. but while being really effective, the pedal still travels down about half way before generating its max stopping power, so it doesn't really inspire confidence at high speed or while (attempting to) heel 'n toe.
As others have said, you need to re-bleed those brakes. And it's a good idea to follow the best practices outlined here: http://www.zeckhausen.com/bleeding_brakes.htm in order to get every last bubble out of the system.
I'm just wondering if this is normally attributed to big brake kit modifications due to increased piston size\fluid volume to callipers etc, or if there may still be some air trapped in the system, or indeed if maybe braided steel lines are needed at the rear to firm up the pedal at tad more,. any ideas? is it normal to have spongier than stock pedal feel with the stoptechs?
No it's not. The StopTech brakes should be noticably firmer than the stock brakes. The caliper piston sizing is smaller overall than the stock. The Brembo brakes, on the other hand, do end up being softer than stock unless you pick an extremely agressive pad compound.

Mike O. - we should talk about your brakes. If they feel softer than stock, then something is still not right.
 

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Discussion Starter #10
I probably should have asked\read all this stuff beforehand then, but as you say, could'av been a lot worse.. will get them re-bled asap and report back to HQ with the findings.. to be honest I was a little disappointed (not with the actual stopping power or fade resistance) so this is terrific news as I didn't really know what to expect and having driven a mov'it\brembo equipped 5-series (993 turbo setup?) a while back it felt much the same.. Thanks for the info!
 

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DZeckhausen said:
An important part of the bedding process is to allow the rotors to cool down before coming to a complete stop. If you check out my bedding instructions, you will see that you need to cruise around for 5-10 minutes to let things cool: http://www.zeckhausen.com/bedding_in_brakes.htm You're really lucky not to have transferred a big chunk of pad material to the rotor, ending up with severe judder under braking.

I'm guessing you didn't clean out the bleed screws with a paper towel tip or brake cleaning spray before popping the rubber bleed screw caps back on. When they became super hot, the trapped brake fluid expanded, pushing the rubber caps off and dribbling some hot brake fluid onto the rotors. I'll bet that's what caught fire.

As others have said, you need to re-bleed those brakes. And it's a good idea to follow the best practices outlined here: http://www.zeckhausen.com/bleeding_brakes.htm in order to get every last bubble out of the system.
No it's not. The StopTech brakes should be noticably firmer than the stock brakes. The caliper piston sizing is smaller overall than the stock. The Brembo brakes, on the other hand, do end up being softer than stock unless you pick an extremely agressive pad compound.

Mike O. - we should talk about your brakes. If they feel softer than stock, then something is still not right.
I have driven several M5s with stock brakes back to back with my M5 that has the front Stoptechs. The Stoptechs are firmer. I have had the Delux pads and did not like them and switched to the Ultimates. The Ultimates, even though they are "dustier", seem to grip a bit better and I have not had problems with deposits like I did with the Delux pads.
 

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I have the StopTech front BBK and Axxis Deluxe pads. I have not noticed deposits on my rotors, but maybe I'm just missing something. What would these deposits look like?

Thanks,
TexasM5
 

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What would these deposits look like?
You can't see them...you can feel them. When braking from say 80 or 90 and braking fairly hard, if you have deposition, the car will shudder violently.

:cheers:
 

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Discussion Starter #17
Just to let you know that I carried out the brake bleeding procedure as recommended by Dave Zeckhausen (it was on the stoptech instruction manual also - but bleeding is bleeding according to some mechanics who've done it their own way for years hmmm) and the pedal is now a lot firmer than before, there still that initial 1-inch or so of pedal travel before the it bites, but that bite is a lot stronger and firmer and pretty much sticks you to the road without too much effort, infact I got the fronts to lock up (on a track of course) at 100mph the other day before the abs kicked in on a DRY road, so they're a good deal stronger than oem even before you take into account their resistance to fade and heat dispersal.

Just not sure entirely sure about the weight distribution \ bias under braking though, particularly while swinging towards a corner as the rear tends to lift & swing that little bit wider than before, would a stronger pad in the (stock) rears help settle it abit ? Course I could alway have my braking done before entering the corner, but how are you meant to provoke the perfect slide with that attitude :7:
 

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Some observations on my StopTechs:
I have not found the pedal feel to be unusually soft or with excessive pedal travel. I have stainless lines all around and Hawk HT pads.
I had tracked with the Axxis Ultimates once as I did not have the Hawks yet and holy cow did they build up material and shudder! Had rotors scrubbed but it did not relieve all of the shuddering. The Hawks have scrubbed off most of it, especially after 2 days at Watkins Glen! Back to the Ultimates for street next week.
Temperatures off the rotors are much lower now with Hawks, Stoptechs, and ducting. Before going the brake kit route I had opened the ducts, installed cryo rotors, and Cool Willy pads. Helped a lot but now with the stoptechs I don't get any fade, good bite, and a whole brake marker deeper!
Might go Hawks on rear but still need more research. Car feels good with Ulitmates there.
 

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Hi Ubermensch,
Was hoping u would be at the track day in Mondello ,was looking forward to seeing the new brakes.
Maybe we can meet up
Ps:Did u see the option of the group buy for the Eibach system on the club website,prices seem competitive
Send a pm (Carbon Black)....regards
 

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Hi Ubermensch,
Was hoping u would be at the track day in Mondello ,was looking forward to seeing the new brakes.
Maybe we can meet up
Ps:Did u see the option of the group buy for the Eibach system on the club website,prices seem competitive
Send a pm (Carbon Black)....regards
 
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