36 replies to this topic

[Todd Green]

Y As I recall those had slightly thinner backing plates and worse yet holes in the plate exactly under the edge of the piston.

Sounds familiar...
 

[davew]

That is 100% from pad not being centered in the groove. No doubt in my mind. Installation error

[Jim Drago]

That is 100% from pad not being centered in the groove. No doubt in my mind. Installation error

agree

[davew]

Oh, by the way BEEN THERE DONE THAT

 

As have all of us

[Tom Hampton]

Yep. Notice the worn area (smooth and almost shiny) on the interior radial edge of the centering tab. That looks like where the tab got caught between the caliper and the caliper bracket.

[Todd Green]

That is 100% from pad not being centered in the groove. No doubt in my mind. Installation error

Explain how you run half a season on them before it happens if it is installation error?  Look at the pad wear, they are not exactly new.  Again these were run without the metal clips (per PFCs instructions).  No doubt something happened and something bound, but it wasn't from installation.

 

Edit: And again these are from 2012.  I run 14-16 races a year, plus 6 hour and 3 hour enduros.  Never had a problem before or since.  But I'm sure I suddenly forgot how to install pads for those two sets of PFCs.  Now, one could argue that not using clips is an installation error and I'd buy that since I use clips now and just get spares from RockAuto and replace them every time I swap pads.

[Tom Hampton]

Explain how you run half a season on them before it happens if it is installation error?  Look at the pad wear, they are not exactly new.  Again these were run without the metal clips (per PFCs instructions).  No doubt something happened and something bound, but it wasn't from installation.
 
Edit: And again these are from 2012.  I run 14-16 races a year, plus 6 hour and 3 hour enduros.  Never had a problem before or since.  But I'm sure I suddenly forgot how to install pads for those two sets of PFCs.  Now, one could argue that not using clips is an installation error and I'd buy that since I use clips now and just get spares from RockAuto and replace them every time I swap pads.

 

Stopping short of assessing blame.... Somehow that alignment tab got stuck between the caliper and the caliper bracket, and was in that configuration long enough to wear the surface of the tab smooth and almost shiny.  I'm guessing that takes more than a lap or two....dunno.  

I've done it...with PFC97s...while not running the clips...in 2012...multiple times. I still have 3 spare PFC97 front pads (yes, 1.5 pairs) because of it (I think).  **I** blamed myself (installation error) and began making a point of ensuring the pad was properly aligned and seated after swapping pads. I also starting checking alignment before and after every session, just to be sure.  I've never had a problem since.

 

I switched to Hawk DT60/30 last year when the PFC's were announced as going away.  Haven't bent a Hawk...yet.

 

Right or wrong...I still don't run the clips (I'm not asking for an opinion).
 

[davew]

The clips have nothing to do with what happened. The brand of pad has nothing to do with it. I have done the same thing with every brand of pads I sell. With and without clips.

 

The pic does not show it, but I bet the crack is pretty similar, in arc, to the caliper piston mark on the backing plate.

 

The clips help in preventing the installation error, as they hold the pad in place better than no clips.

 

Once the pad bends, the brakes work pretty normally. You lost 25% of one pad. My math works out to about 6% of total front pad area (4 pads, so 25% of 25%). Maybe 4% of total pad area. So yes, if you do not inspect your brakes often, it is very possible to run the pad through its usable life in that condition.

 

I am not putting you down. I did it last year to a car I was driving. It happens! How many pad changes do you think I have done in the last 15 years of Spec Miata. Sh it happens. Just admit that it happens and don't blame the parts.

 

Dave

[Jim Drago]

I am a member of this fraternity as well

[Tom Hampton]

FOBB (Fraternal Order of Brake Benders)

BBA (Brake Benders Anonymous)

 

Are there frat parties? 

Do they have hot chicks?

Will there be punch (and yummy snacks)?

[chris haldeman]

If there are hot chicks those could be considered yummy snacks 😇

[av8tor]

I read some where that according to the data derived from  dating sites that pilots and race car drivers are the most desirable men.  Therefore I would like to volunteer to be rush chairman for the new Fraternal Order of Brake  Benders.

[Tom Scheifler]

My fault or not, if I repeatedly experience bent pads with only one brand, I'm gonna stop using that brand.

[Steve Scheifler]

And though I generally defer to the massive experience of DW on such matters, we've been through a lot of pads over the years and had this problem with every set on both cars when using one particular generation of one brand, none before and none since. What ever the reason, that is not coincidence. If you want to speculate that I frequently screw up installation but all other pads have been able to handle it, that's OK by me, I'm not bending pads.

[Todd Green]

if you do not inspect your brakes often, it is very possible to run the pad through its usable life in that condition.

I inspect my pads every time I swap tires.  At that time it would have been 3 times a day (practice, quali, race).  In fact I remember it distinctly because the caliper was leaking fluid as the broken pad had ripped the dust boot and thus (presumably) allowed the inner seal to be damaged.  I rebuilt the caliper and switched to Carbotechs and haven't had a problem since.

 

If I screw something up, I'll be the first to admit it, but again since I ran several race weekends before the problem showed up, logic dictates that it wasn't an install issue.  The only counter argument that I can think of for that is that the problem doesn't manifest itself until the pads wear down enough for there to be sufficient play in the system. Also the law of averages would also say that if I were installing pads incorrectly then the pads that I've used 90% of the time would show an issue instead of the pads I used 10% of the time.  (Percentages guesstimated, I'm not about to go back and figure out how many pads I've gone through in the last 7 years on two cars.)  Especially after the first set cracked.  Don't you think I'd be extra, extra careful when I installed the second set?

 

But we each have our own experiences, believe what you want.

[SaulSpeedwell]

agree

 

Off topic, but my best brake install FUBAR was this - I back my car straight out of the trailer and onto the lift.  Do a bunch of stuff, including brake stuff, so the caliper pistons are squished all the way back into the calipers.  Do 100 other things, several days later I go to pull back into the trailer. 

 

NO BRAKES!  First pump - NOTHING.  Second pump - NOTHING.  Third pump - I stop 1 inch before the $2500 of aluminum cabinets in the front of the trailer.

 

Never made that mistake again!  Although - If the pads and rotors had been full thickness, this wouldn't have happened.

[SaulSpeedwell]

And though I generally defer to the massive experience of DW on such matters, we've been through a lot of pads over the years and had this problem with every set on both cars when using one particular generation of one brand, none before and none since. What ever the reason, that is not coincidence. If you want to speculate that I frequently screw up installation but all other pads have been able to handle it, that's OK by me, I'm not bending pads.

 

I know what generation of pad you are talking about, and you aren't wrong - especially for your tracks.  BUT - the other "bent pad" causes in this thread are very much real and probably a more primary cause in the present day if we subtract out the generation and compound of pad you are talking about. 

 

If I'm putting 2 and 2 together correctly, I didn't have the bending problem at Road America with the same pads - and I believe the reason is that I took extra care to minimize friction at the "ends" and "ears" of the backing plate.  The compound wasn't high-temp enough for that track - in my case, I was losing braking because the whole pad turned to cheese ... whereas in your case the ends may have been "jammed" while the center turned to cheese, thus resulting in bent pads?

 

I'm not defending, just trying to unscramble multiple causes behind what might *appear* to be the same effect.

 

Just a final thought:  There is no Runoffs, or $4 trophy, or spiffy driver patch for "Squarest Brake Pads at the end of a 45 minute race".  Unfortunately, the "fastest" brake compound combination required much more maintenance and earlier replacement than I preferred.  Same with my fastest engine and fastest diff setup.  Even my fastest exhaust was a DNF issue if I straddled a curb!