BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Suspension | Brakes | Chassis
 
Evolve Automotive
Post Reply
 
Thread Tools Search this Thread
      11-06-2012, 11:25 AM   #1
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

Strange pad wear

Just done a little track day to finish up the season, and heard scratching on the way home. Checked the pads, and oh my - pads were done. The sheer amount of pad wear was very unusual - one relatively non-aggressive day (it was near freezing) gave me what I normally would get in 3-4 hard track days. But the bigger issue was that pads were word "diagonally" (see pics).

I am using Pagid RS29 in Alcon Superkit, and the pictures are of pads from rear 4 piston set. But all 8 pads are worn in the same way - the ear dramatically increases in the direction opposite to wheel rotation (so the edge that "meets" the disk rotation is worn MUCH more. For example, on rears the leading edge of the pad is done to the metal and the trailing edge has over 50% of the starting pad material.

So what went wrong and what should I do about it? I inspected the calipers and could not find anything wrong with them - everything is clean, moves easily, no corrosion or leaks.

In stock calipers I had very even pad wear for both stock and track pads.

I also inspected the street pads that came with the set and were used for just few months and saw a similar pattern on the fronts (rears have no visible wear yet). So it looks like the kit was doing that with other set of pads as well, and since it was new.
Attached Images
   
MaxL is offline   Canada
0
Reply With Quote
      11-06-2012, 11:44 AM   #2
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

Classic taper wear!I am suprised that the Alcons allow that much taper to happen.Max the DDT is quite hard on brakes compared to the GP track next door.I wore my rear RS 29's out on Sunday but they had about 15 days on them and there was very little taper wear compared to your pads.
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 01:14 PM   #3
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

Are you saying this is normal? Alcon advertises differential piston sizes and other measures to prevent taper wear, and what I am seeing seems pretty bad.

The pads for alcons are rather thin to start with, so on the rear I have almost 2/3 of the material left on one side and nothing on the other. If that's how it's supposed to be, it makes it a very expensive kit to run. I am hoping there is a way to improve that.
MaxL is offline   Canada
0
Reply With Quote
      11-06-2012, 01:46 PM   #4
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

Quote:
Originally Posted by MaxL View Post
Are you saying this is normal? Alcon advertises differential piston sizes and other measures to prevent taper wear, and what I am seeing seems pretty bad.

The pads for alcons are rather thin to start with, so on the rear I have almost 2/3 of the material left on one side and nothing on the other. If that's how it's supposed to be, it makes it a very expensive kit to run. I am hoping there is a way to improve that.
Not normal at all.Maybe the calipers need to be shimmed to eliminate this or the pads are binding in the caliper.Some investigation is in order for sure.Who did Shizzle buy the kit from?They would be the people to ask about this.My Stoptechs also have differential piston sizes and so far I have zero taper wear issues.It should not be any different with the Alcons.
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 02:01 PM   #5
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,916
iTrader: (7)

Definitely not normal. Wouldnt call it "Classic taper wear", more like extreme taper wear.

When was the last time you had the pads out? Guessing that is not just from one day.
Jaypod is offline   No_Country
0
Reply With Quote
      11-06-2012, 02:02 PM   #6
surlynkid
Captain
 
surlynkid's Avatar
 
Drives: 2013 E92 M3
Join Date: Apr 2012
Location: League City, TX

Posts: 848
iTrader: (1)

Garage List
sorry, but that is not normal. some slight taper perhaps, but not that. you have a problem.
surlynkid is offline  
0
Reply With Quote
      11-06-2012, 02:06 PM   #7
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

Just a thought here.When the brakes got transfered to your car did the calipers get switched from side to side?If so the pistons are oriented wrong which would cause the extreme taper wear for sure.
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 02:15 PM   #8
M3SQRD
Colonel
 
M3SQRD's Avatar
 
Drives: E92 M3s, R56 Cooper S
Join Date: Jun 2009
Location: EC

Posts: 2,421
iTrader: (2)

Quote:
Originally Posted by Gearhead999s View Post
Just a thought here.When the brakes got transfered to your car did the calipers get switched from side to side?If so the pistons are oriented wrong which would cause the extreme taper wear for sure.
+1 - is the bleed valve pointing up or down? This wouldn't be the 1st time a BBK was installed upside down on this forum - a ST Trophy kit was incorrectly installed and the installer blamed ST engineers

Also, agree with your previous statement, I wonder if the backing plate is binding on one set of pad guides?
M3SQRD is offline   United_States
0
Reply With Quote
      11-06-2012, 03:10 PM   #9
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

Quote:
Originally Posted by Jaypod View Post
Definitely not normal. Wouldnt call it "Classic taper wear", more like extreme taper wear.

.
When I had 5.0 Mustangs that was considered normal wear
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 03:15 PM   #10
Richard@M-World
 
Richard@M-World's Avatar
 
Drives: NASA TTA #92 M3
Join Date: May 2011
Location: TX/IL

Posts: 683
iTrader: (0)

Quote:
Originally Posted by Jaypod View Post
Definitely not normal. Wouldnt call it "Classic taper wear", more like extreme taper wear.
+1

Take a look at your calipers, is the larger piston above the smaller piston(s)?

I attached a picture of a front left caliper in the orientation it should be mounted.

Name:  4.jpg
Views: 178
Size:  178.5 KB
__________________
Authorized AiM Dealer - Solo/Solo DL | SmartyCam HD | www.m-world.us

Last edited by Richard@M-World; 11-06-2012 at 03:25 PM.
Richard@M-World is offline   United_States
0
Reply With Quote
      11-06-2012, 03:28 PM   #11
klammer
Brigadier General
 
Drives: 11 spc gry m3 e90, 07 X5
Join Date: Jan 2010
Location: chicago

Posts: 3,221
iTrader: (0)

Very not normal. I have the Alcon kit and have run through a few sets of pads and have not seen anything close to this kind of wear. Strange things are afoot at the circle K :
__________________
mods: akra evo, dinan 3.45 diff, ess akra tune, dinan stg.3, Alcon bbk, HRE P40
klammer is offline  
0
Reply With Quote
      11-06-2012, 03:33 PM   #12
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

All bleed valves are facing up and "pretty" side is facing outward, so nothing is flipped. I wish it was that easy, though... Pads are moving freely in the caliper - I could not see any evidence of binding against the guide pins. I'll contact the vendor to see if it's a known issue. Also, the pads that came with the kit and were installed very briefly by the original owner on another car seem to have some taper wear too, just much less of it (little wear in general, though)
MaxL is offline   Canada
0
Reply With Quote
      11-06-2012, 04:12 PM   #13
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

I would still check for the proper orientation of the pistons as per Richards picture.Maybe the calipers were installed wrong on the 1st instalation with the bleeders reversed!
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 06:23 PM   #14
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

Just checked - all pistons are exactly the same size. I'm pretty sure I've read that Alcon uses differential sizing, but I could not find evidence of that. Anyway, I do not think anything is reversed because the lettering on the calipers is just like in their brochure and everyone's photos - not reversed.
MaxL is offline   Canada
0
Reply With Quote
      11-06-2012, 06:32 PM   #15
Richard@M-World
 
Richard@M-World's Avatar
 
Drives: NASA TTA #92 M3
Join Date: May 2011
Location: TX/IL

Posts: 683
iTrader: (0)

Quote:
Originally Posted by MaxL View Post
Just checked - all pistons are exactly the same size. I'm pretty sure I've read that Alcon uses differential sizing, but I could not find evidence of that. Anyway, I do not think anything is reversed because the lettering on the calipers is just like in their brochure and everyone's photos - not reversed.
If the pistons are non-staggered, that would be the cause of taper wear. All the bbk's I've seen for the M3 offer staggered piston sizes. Perhaps there is a special reason for Alcon's design?
__________________
Authorized AiM Dealer - Solo/Solo DL | SmartyCam HD | www.m-world.us
Richard@M-World is offline   United_States
0
Reply With Quote
      11-06-2012, 06:45 PM   #16
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

Quote:
Originally Posted by Richard@M-World View Post
If the pistons are non-staggered, that would be the cause of taper wear. All the bbk's I've seen for the M3 offer staggered piston sizes. Perhaps there is a special reason for Alcon's design?
Perhaps - according to schematics on their site, they have staggered pistons in cheaper sets but not in this one. Beats me why they decided to do so. As soon as I confirm who the original vendor was, I'll try to investigate with them or manufacturer.
MaxL is offline   Canada
0
Reply With Quote
      11-06-2012, 06:48 PM   #17
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

Quote:
Originally Posted by Richard@M-World View Post
If the pistons are non-staggered, that would be the cause of taper wear. All the bbk's I've seen for the M3 offer staggered piston sizes. Perhaps there is a special reason for Alcon's design?
According to Alcon's web site they manage taper wear by piston placement.No mention of staggered piston sizes.Very unusual to what I have seen in other BBK's or full race setups.
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 06:54 PM   #18
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,685
iTrader: (0)

Quote:
Originally Posted by Gearhead999s View Post
According to Alcon's web site they manage taper wear by piston placement.No mention of staggered piston sizes.Very unusual to what I have seen in other BBK's or full race setups.
Now on another Alcon site I find this
[quote]Monobloc 4 / 6 piston design for high stiffness (firm pedal) & low weight
Piston bore sizes are staggered to ensure even pad wear
Pin-mounted pads provide low threshold pressure and low noise
/QUOTE]

http://www.alcon.co.uk/brake-kits.html

Maybe your calipers are not the proper ones or they were manufactured improperly?
Gearhead999s is offline  
0
Reply With Quote
      11-06-2012, 07:37 PM   #19
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

[quote=Gearhead999s;12953007]Now on another Alcon site I find this
Quote:
Monobloc 4 / 6 piston design for high stiffness (firm pedal) & low weight
Piston bore sizes are staggered to ensure even pad wear
Pin-mounted pads provide low threshold pressure and low noise
/QUOTE]

http://www.alcon.co.uk/brake-kits.html

Maybe your calipers are not the proper ones or they were manufactured improperly?
This parts list clearly mentions that pistons are all the same size - says 6 x 34.9 at the front and 4 x 31.8 at the back: http://www.alconusa.com/client_images/files/92_1222.pdf

Part list for other kits do show stagger. So I guess it was meant that way.
MaxL is offline   Canada
0
Reply With Quote
      11-06-2012, 08:21 PM   #20
sawzall
Major
 
sawzall's Avatar
 
Drives: 2012 Porsche 911 C2S
Join Date: May 2010
Location: Toronto

Posts: 1,246
iTrader: (0)

Garage List
That is some seriously weird pad wear. I've sent you the vendor information via email.

I know it's highly unlikely, but could it be piston failure or jamming? It almost looks like only the bottom piston in each caliper is working properly.
sawzall is offline   Canada
0
Reply With Quote
      11-06-2012, 08:29 PM   #21
Jaypod
Brigadier General
 
Jaypod's Avatar
 
Drives: Frozen Silver M3, AM V8V
Join Date: Nov 2008
Location: Toronto

Posts: 4,916
iTrader: (7)

Quote:
Originally Posted by shizzle View Post

I know it's highly unlikely, but could it be piston failure or jamming? It almost looks like only the bottom piston in each caliper is working properly.
At first I wondered the same thing until I realized it wasn't just one pad. Maybe those pads just have some serious initial bite...

I am curious to find out what the issue is. Hopefully Max will get it sorted soon.
Jaypod is offline   No_Country
0
Reply With Quote
      11-06-2012, 09:37 PM   #22
MaxL
Captain
 
Drives: E90 M3, Cayenne T, 991 GT3
Join Date: Jun 2007
Location: Bay Area

Posts: 935
iTrader: (0)

Just had the first long drive on Alcons with street pads (only used track pads so far), and damn the brake feel is awesome. It's so smooth and almost telepathic - like I'm stopping the car with my hands while wearing those lambskin mittens that high end car washes use. I'm sure that company that can engineer that, sure should know how to make brake pads wear normally as well. I'm sure I'll figure that out.
MaxL is offline   Canada
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 08:27 AM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST