Hello!

Looking for some assistance troubleshooting some excessive brake squealing after my first HPDE at Motorsports Ranch in TX.

I had the Hawk HP+ pads installed a week before the event (shop said that they bedded them) and while there was just a little bit of squeal when coming to a stop, it was really mild prior to the event (even enjoyable).

After two days on the track, the sound of the brakes engaging changed slightly. A soft "whisper" became audible, like I'm hearing the pad material "whisk" over the holes in the drilled rotors that wasn't present until after the first day of use on the track.

About 2 days after the event ended, the squealing became much more pronounced and is now persistent at any brake pressure. I'm getting lots of looks from people as it is extremely loud.

Will re-bedding my brakes following the instructions here likely solve the noise issue? http://www.zeckhausen.com/bedding_in_brakes.htm

I was wondering if the sound is an indication of pad wear, but the brake sensors are not being triggered which makes me think that it's not an issue with pad material.

Thanks for any help! I'm learning as I go.

 

I don't have any real suggestions with the pads other than going through the bedding procedure again as you suggested. I am curious about the MSR event though. Was this a Mini HPDE event? I went to one for Subarus sevral years ago at the MSR by Dallas and it was awesome.

-JL

 

I don't know if re-bedding will help (and wonder how the shop bedded them), but I got a lot of noise from bedded Hawk HP+ pads also. They also threw a lot of brake dust, and couldn't take the heat on track either. Hawk makes some good track pads, but I don't think the HP+ are very track worthy.

 

Nah, not a mini event. It was a Driver's Edge school. It was my first track event (though I've done probably 15 autocrosses over the last few years). We ran the full 3.1 which was freaking AWESOME.

I had decided to go with the shops recommendation of Hawk HP Plus instead of carbotech pads because they talked some serious **** about carbotech and said that they remove them from every car they put them on because they're such junk. The internet didn't seem to back that up so I went with Hawks to maintain a good relationship with the shop and because I didn't have enough personal knowledge to refute them.

I went ahead and did the re-bedding process and it definitely reduced the squeal to a manageable level. They're the first non-OEM replacements I've done so this has been a great education in expectations.

I wanted to ask that same question of the shop Jim. I don't know if they have a dyno, but if they do then I can see how they'd follow the procedure to get the right heat levels present.

What I'd love to do is get the tools I need to do a brake bleeding and pad replacement myself. But unfortunately, I don't live in an apartment with any space to do that kind of work and they're hawkish about people doing car work in parking spaces.

Anyone have any favorites they recommend for track use? I think I may try carbotechs next time around. (Also will replace the drilled rotors based on advice that drilled rotors can crack on the track)

 

Most track pads squeal (due to vibration) a bit on light application (as when coming to a stop for a traffic light); some much more than others. Most will also throw more brake dust than OE pads. They normally take some heat build-up before they provide their optimal slowing. They also wear faster, wear rotors faster, and cost more. What they do good is provide more torque during braking, and handle the heat from tracking better.

I've been using Performance Friction (PFC) pads for decades, but I don't track a MINI, so I don't know what to recommend. I went to the Mini Mania website to see what they sell for MINIs. They have EBC Yellow stuff, PFC 01, Hawk DTC70, and Carbotech XP8 and XP10 (XP6 probably won't work as well).

The best pads for you and you MINI may depend on how much track (braking) experience you have. In general, the highest torque pads are harder to modulate; thus, you may tend to over-slow for corners. They also tend to wear faster, squeal more off track, and cost more.

The pads I've been using (PFC 97 compound) provide only moderate torque, but are easy to modulate, provide quick release, and "are kind to rotors" (track pad words). They also squeal very little under an easy pedal off track. From what I've read, the Carbotech XP8 might be in the same moderate torque category, but I'm not sure.

Brake pads are fairly quick and easy to swap; I do it when switching wheels/tires for track. Only regular shop tools are needed.

Regarding rotors cracking. I've used all kinds of rotors; "drilled", slotted, and solids; both frozen and non-frozen. They all eventually cracked from heat, and none lasted much longer than others. One good thing about the drilled rotors I've used though; the holes are staggered on the rotor such that the cracks don't join as they extend.

 

I agree with Jim. Hawk HP+ are sort of an "aggressive street and light track" brake pad, which really means they're awful at both things. All the noise of a track pad, but fade like a street pad. They do have good bite but that's about it.

Hawk does make a few good track pads. I think the DTC-70's are a good choice for those with r-comps. The 60's might be better for street tires.

There are some big Carbotech fans out there, I've never used them.

PFC also is a good choice. Most of my brake pad experience is with regards to Subarus and EVOs, so I can't give very specific advice. Your track experience and tire choice are things to consider.

It's worth thinking about having a separate track pad though. It does make life a lot easier. Just my opinion.

- Andrew

 

+1

The noise, while incessant, is not abnormal. I always made a habit of changing pads before/after a track event (as well as flushing/bleeding brakes).

I used to be a fan of Hawk Blue for the track, though they will fade after a few laps if you are driving hard and have an otherwise good setup. I still like them for non-ABS/EBD cars because they're quite easily to keep near the threshold.

Porterfield Racing has highly recommended the Raybestos ST-43 compound to me for club racing. I haven't tried them yet as it's been a while since I've had a track car, but I trust Porterfield for many reasons (among them: they are stocking distributors for Hawk, PFC, Raybestos, and Porterfield; Andy Porterfield runs the ST-43 pads on his race beast.)

I pick up my first Mini next weekend, give the ST-43 a shot soon after, and report back with my thoughts

Yay, first post!

 

Yeah, I agree Andrew. That's probably what I'm going to be moving towards next. Have been considering something like the EBC red for daily driving. Thought I would go ahead and see what I'd be getting myself into with trying to find a good middle solution since I do 1 - 2 AX a month now.

Thanks for the advice Jim on the rotors, that's good to hear. I'll probably have a new Mini before I have to replace those rotors now.

 

My guess would be the heat from hard braking at the track has created a glaze on the pads that is causing the noise, and that you'll have to replace them to get rid of the squeal. HP+ pads are simply not built to deal with the heat build-up from repeated hard braking. My experience is that there is no such thing as a combo street/track pad. I used to go through the tedium of swapping out the pads for each event.

 

Big fan of Porterfield pads, both for the track and the street. Used the - what was it? - R4 pad on M3 for the track. Now I have Porterfield street pads on my wife's old Lexus RX300; with those pads, the car sorta, kinda stops now.

 

Ahhh, thanks Widmerpool! Something about that sounds right on the money with what I'm experiencing in comparison to when I first bought the pads.

I didn't have any excessive brake fade, but I think I need to bleed the brakes because my pedal feel has gotten softer and never came back to the original pedal feel, though modulation still feels good and my stopping power doesn't seem to be compromised.

I'm going to start swapping pads for track events and follow with your guys suggestions next time around.

Really appreciate the time and info gents!