What happened to this brake pad?

[jmsanders78]

In changing my pads for an upcoming event, I found that the backing plates on the inner pads were bent. On the fronts, it was pretty exaggerated, see below. These are HP+ pads used with Dunlop Super Sport Race tires at Gingerman. I have Bimmerworld brake cooling ducts/hoses installed. Has anyone else seen this with these pads? At first I thought that they got a little hot, but switching to a race pad wouldn't stop the backing plate from warping, would it? Maybe I just need the metal caliper guides, but although I sometimes get a little uneven wear, this is pretty atypical.

Thanks for your thoughts. I'm puzzled.

[CodeMonkey]

Is the pad hanging up on the caliper on that side? Looks like the pressure of the piston bent the backing plate because of interference on the bent side. But that's a WAG.

[jmsanders78]

Good thought - I'll check for some binding. It happend on both fronts, though. It also happened on the rears, but both leading and trailing edges were bent a very small amount, nothing like this.

[traqrat]

Could it be that the backing plate is slightly too big and it gets caught on the caliper mounting bracket? It definitely looks like something obstructed the backing plate right at the edge.

[mcclaskz]

What do your rotors look like? Any signs of small cracks? Is the pad material flaking off on the edges? Are the dust boots in your calipers still intact?

[jmsanders78]

Could it be that the backing plate is slightly too big and it gets caught on the caliper mounting bracket? It definitely looks like something obstructed the backing plate right at the edge.

OK, I'll check it out. Two votes for something binding. Thanks for posting.

[jmsanders78]

What do your rotors look like? Any signs of small cracks? Is the pad material flaking off on the edges? Are the dust boots in your calipers still intact?

The dust boots are OK. I replaced the front calipers last year because I didn't have the experience/confidence to do a rebuild. This year they needed rebuilding, which I did in the spring. I check the dust boots now when I do pads and they're definitely OK.

I didn't check the rotors, but I'll do that. Thanks for bringing that up.

The pad material is flaking off at the edges, and there are cracks through the pads, but it's not as severe as before I installed the cooling kit. This is pretty typical for these pads when they come off of my car, with the exception of the bending of the backing plate. Brake cooling helped the pedal feel, the formation of pad deposits, and improved my pad life (some).

[///Mink]

Are you running solid caliper guide bushings? I know that when I still had the stock rubber bushings, I would get angled pad wear similar to what you can see on the non-bent part of yours. Perhaps caliper flex is what's causing your pads to bind?

[B.Watts]

What happened? It bent.

[vinnymac]

Are you running the OEM rubber caliper bolt guides? It looks like your calipers may be twisting under braking.

Try upgrading to the solid brass bushing guides. I did that recently and now my pads are wearing very evenly at the track.

[jmsanders78]

What happened? It bent.

Thank you Captain Obvious!! This contribution is the best so far!!

///Mink and vinnymac - These are with the OEM caliper guide bushings. I am considering the metal guides now. I assume the extra maintenance is lubricating them periodically?

[B.Watts]

Hey, the shot was there, so I took it.

[jmsanders78]

Hey, the shot was there, so I took it.

Future posts will be more guarded. Bring it on!

OK, now how about another shot. This time take aim AT MY PROBLEM (where by "my problem" I mean the specific issue with my bent brake pads and specifically with the reason for their deformation and specifically the possible steps that might be taken to remedy the deformation cited above, although these other guys may have already nailed it)!!

[mlytle]

brake pad "ears" are binding on the caliper bracket. every set of hawk pads i have used have required some filing of the ears a little to allow them to move freely in the caliper brackets. sure wish they would change their backing plate manufacturing design. add a drop of brake grease to the ears when you install the next set too.

[B.Watts]

What he said...

[NoSoup4U]

This is relatively on topic ...

Are these good to use that KO is selling?

http://forums.bimmerforums.com/forum...d.php?t=364095

i.e., are all solid brass brake bushings made the same, or, is some better than others?

[ScotcH]

Happend to me as well ... according to the brake manufacturer, the backing plate was good to about 1200º ... after that, it gets soft, and is easy to bend like that. It only happened with a set metal masters I had on ... different pads, no issues.

[jmsanders78]

brake pad "ears" are binding on the caliper bracket. every set of hawk pads i have used have required some filing of the ears a little to allow them to move freely in the caliper brackets. sure wish they would change their backing plate manufacturing design. add a drop of brake grease to the ears when you install the next set too.

This is good stuff. I haven't experienced this before personally, but it never occurred to me that the pads/backing plates would require some slight modification to work well. I quit using anti-seize because I thought people used it primarily to reduce noise. Which doesn't work with HP+ pads. I started thinking, what's the point?

So I guess it makes sense that heat + imperfect backing plate design = bent pads.

I didn't realize that the solid guides were made by several manufacturers. I'm also curious to see if anyone has experience with other companies.

Thanks to all that contributed! But I shouldn't leave out BMWRacerITS, so thanks to you too.

[JS154]

On the fronts, it was pretty exaggerated, see below. These are HP+ pads used with Dunlop Super Sport Race tires at Gingerman.

Here's what happened. You're running a high performance *street* pad on a heavy car with race tires at a track that is hard on brakes...and you're running your pads all the way down to the backing plate.

>>>>This is from Korman's website:

Brakes - Brakes are the Achilles Heel of the E30 M3. On the track, street - performances pads have actually melted and stuck to the rotors so that the brakes dragged all the way around the track. The drag was so great, the engine couldn’t pull over 5000 rpm in 4th gear! The heat build-up ruptured the caliper seals resulting in total brake failure. If you value your car (and your good looks) use only the very best racing brake pads available. Some racing pads are made for sprint racing. They slow the car rapidly with surprisingly light pedal pressure. They feel great, but make so much heat they destroy rotors and the pad gets so hot the backing plate gets soft and bends. When the backing plate bends, the brake material fractures and departs suddenly, leaving you metal against metal to slow for the next corner. That won’t last long because when you get down to metal to metal (backing plate to rotor) the piston comes so far out of the caliper bore that the seal comes out, followed by most of the brake fluid. By this time the rotor is usually hot enough to ignite the brake fluid. Recommendation: when you leave the road, try to crash near a corner station where a fire extinguisher is available. Or better yet, use an endurance type racing pad that can handle the demands of the M3. None of the above are hypothetical or ‘what if’ speculations. They are all actual E30 M3 on-track experiences!

________

Now bear in mind your car is about 500lbs heavier than an E30 M3, with race tires you're carrying a bunch of speed out of the corners.

Suggestion: Use an appropriate brake pad (think Hawk HT10) *and* don't run them down more than halfway, let alone all the way to the backing plate.

Either that or let me know the next time you're going to the track so I can nominate you for a Darwin award.

[jmsanders78]

Use an appropriate brake pad (think Hawk HT10) *and* don't run them down more than halfway, let alone all the way to the backing plate.

Either that or let me know the next time you're going to the track so I can nominate you for a Darwin award.

Point taken. Thanks.

[B.Watts]

I, personally, would, and do run them WAY below the halfway point (on my old 325 ITS car, my Spec Miata, my Formula Mazda, and our CMod M3) unless I was running to win a very competitive race where absolute braking consistency is necessary. You can run them all the way to the point that the pad material is the same width as the backing plate without any real problems.

You've still got a problem with the pad sticking anyway. It's obvious that the backing plate bent way before the pad material got really low based on the thickness of the pad material on the bent portion.

[mlytle]

what he said......

[vinnymac]

///Mink and vinnymac - These are with the OEM caliper guide bushings. I am considering the metal guides now. I assume the extra maintenance is lubricating them periodically?

Yes, the "extra" maintenance is minor. All you need to do is remove a circlip and apply anti-seize and/or grease the bushings.

It looks like your backing plate got too hot as the pad thinned out and your caliper twisted resulting the pad bending like that. I noticed my pads were wearing unevenly at the track with the OEM rubber bushing guides, and my current set of brake pads are fine with the upgraded brass bushings.

[jmsanders78]

BMWRacerITS - thanks for the counterpoint. I thought that was pretty typical, but I also hadn't seen the Korman perspective. I know several people that run HP+ at the track without any trouble other than fading and pad deposits (but then again, I don't know at what pad thickness they toss them). But clearly some have had major trouble with incorrect equipment, and that's something I'll keep in mind.

mlytle - thanks for... uh... i'll have to get back to you.

vinnymac - I think I'll pull the trigger on these when I order my next set of brake pads. This time proppapads.

Be cool guys.

[jamesclay]

Nothing wrong. I used to have a Dodge Neon that I raced for a season in Showroom Stock. The front brakes were terribly underpowered in that car. My pads would come off looking like bananas. The problem is the car is heavy, you are really hard on the brake pedal because you probably need a track apd at this point to get the bite you want, and because the caliper is a single piston design, all the force on the inside pad is in the center 1/3, leaving the ends to hopefully go with the center of the pad. Unfortunately, with this much pressure, it doesn't happen and it is easier for the backing plate to bend. The fact that you got your money's worth out of the pad doesn't help either - that is probably when most of it happened. Try to change at about 3/16" min left - that last little bit is kinda like the first 1/2 of the tread on a DOT R tire - useless and should be removed.