I'm wondering if anyone has any words of wisdom for me. This past weekend I replaced the stock front pads and rotors with hawk HPS and TX speedwerks rotors. Bedded them in per instructions. Now, when I brake hard the ABS seems to kick in sooner than before, and the car does not stop as well as it used to with the stock set-up on all four corners. My guess is that the braking is now biased to the rear, and the ABS kicks in to prevent these from locking up. In support of this, I am pushing he pedal harder/lower than before the brake change, to get the same stopping power. So, the fronts apparently need more brake force to stop, but this same force is too much for the rears. Unfortunately, the ABS seems to affect not only the rears, but the fronts, so the overall stopping power is less. Under normal driving there is no problem, but I'm a bit concerned about emergency situations.

So, have I violated a cardinal rule by having stock pads on the rear and aftermarket on the front? Or is this something unexpected?

 

yes you violated a general rule...

when you replace pads, you should keep the same type of pad front and rear...
UNLESS you are trying to modulate brake force F-R.
(I know several people who do exactly that, different compounds F&R to balance the brakes after an upgrade or for track duty).

you have 2 options at this point:
1) put stock pads on the front.
2) buy Hawk HPSs for the rear.

Don't forget to bleed the calipers.
New pads mean more friction material = thicker pad than your worn ones...
This will push the brake pistons in and cause your brake pedal to ride higher than before the job (unless you bled the brakes...)

HTH!

 

As stated above you've got two things working against you here. The fact that you only replaced the fronts means they're stopping harder (Which means more weight is shifting to the front, which means 2 wheels are doing 90% of the braking now). If you replace your rears it will cause the car to "Squat" while braking and spread the force to all 4 wheels.

As far as ABS kicking in sooner, it has a lot to do with more weight moving to the front during braking now, but your ABS is GOING to kick in sooner with better brakes. ABS kicking in means your brakes are doing their job (Stopping the wheels). Contrary to popular belief, it's the tires that stop the car, brakes just stop the tires (Which isn't always a good thing if they're not in full contact with the ground at the time ).

Sounds like you need to get some rear brakes, and upgrade your tires.

Pushing the pedal lower, you may want to replace your fluid, and stainless steel lines will make the brakes feel less "Squishy".

 

That there's the troof people. As I understand it, at least.

mb

 

i have the TCE/willwood 13" bbk and TCE larger rotors w/ relocated stock calipers in the rear. i used to run BP-20's (track oriented, but very streetable) w/ stock rears. i had no ABS issues. when i switched to larger Hoosier track tires i went w/ poly h's up front and porterfield R4's in the rear for thr track. the poly h's have a much higher cf but still no ABS issues (unless i overcook a corner!). do you know which end is trying to lock up? i believe that you can disconnect a fuse to disable the ABS (plus DSC/ASC and possibly something else i cannot remember). stickier tires or a better suspension set-up will make this go away. not that you need my help spending your money. upgrading one thing often points out the new '"weakest link". i don't think that pad mismatch is the issue here. just the opinion of one who loves to outbrake others on the track.....

edit: one of my friends ran that same combination on the track at Homestead a month ago. he had no ABS probs, but he cooked the Hawks before the weekend was done....almost no (1/16") compound remaining and an interesting lasrt session.

 

Replacing the pads and not bleeding will not affect the pedal height at all....That's what is so great about using disc brakes....constantly adjustable to the width of the pad and roter to keep contact optimum and the further out the piston goes, the more fluid that goes from the reservoir to essentially behind those pistons as the pads are used up. Don't believe me...replace your pads that are worn and watch the fluid go up in the reservoir backward with the master cylinder in the "bleed through" position(pedal not pressed). Only thing that I have seen that would affect the height of the pedal was either mechanical or air in the lines from opening the system, making the pedal low. Seen them high too, due to a improperly adjust rod on a Master cylinder not letting the fluid get back into the reservoir and release pressure.

Now old drum brakes on the other hand didn't adjust all that well most of the time and that was a gap in between the show and the drum. This made the pedal lower due to the fact that the show had to move all the way towards the drum before and friction(ie, hard pedal) was felt.

Not saying that replacing your fluid isn't a good idea though

 

Thanks for the input, everyone. The situation above is kinda what I figured, but it's nice to get confirmation. The idea of pulling the ABS fuse also seems like a worthwhile experiment. BTW, the unpressed brake pedal height is unchanged, I just need to push it harder. Also, the tires are considered reasonably sticky for street: Pirelli P zero.

 

Those tires are hard as a rock compared to what I run .

Your pedal modulation is likely changed due to improper bedding/bleeding of the system. Are you sure you got all the air out? When I bed in pads, I do 10-15 60-10 mph stops, then drive around for 5-10 minutes to cool the whole system off.

 

Having simular problems. Hawk HPS pads all the way around and StopTech Slotted roters. Pedel is softer and must be depressed further to get hard brakeing accomplished. ABS bearly kicks in...
Bedded the brakes twice and I have bled the breaks twice and not much/if any differnce.

 

Update, Seems to be getting better with miles... So these may just have a long break in period. FYI I used the Hawk procedure and the StopTech procedure to bed in the pads...

 

I like rustboy155's answer - tires. If you speak with Todd at TCE he'll tell you how important tires are in the braking equation.

I had the Wilwood 12.4" kit on my car with two different pads choices. Obviously the track pads are way too much for typical road going fare, but I tried the combo once. The intitial braking torque caused the ABS to kick in immediately as the tire's grip was exeeeded. Not so at track level speeds with R compound tires.

I've also grown to really dislike those entry level sport/track pads; they do not like cold weather, the are not abrasive enough to keep the rotors clean and therefore leave a lot of material on the rotors causing that nasty pulsating we associate with warped rotors.

Pads are easy enough to change out for track events...I like stock on the road and track dedicated pads for the track. Of course, this is just another opinion.

 

Tires are all too important. Too many people slap on a Big brake kit with their stock tires and wonder why their car's not stopping any faster. If you can lock up your wheels with the stock brakes, then brakes aren't your problem . Really all big brake kits do is increase the number of times you CAN lock up the wheels.

Some pads are a good compromise for the street, Hawk HPS pads do a decent job at stopping the car, good initial bite, high temperature tolerance, and almost no dust (Compared to stock). Once you start getting into some of the more dedicated track Pads (HP+, Mintex CTek 1144-1166, some of the more agressive pagid and porterfield pads, etc, it's difficult to double duty them. I run 1144's on the street right now, and they're fine for stopping (HARD initial bite, ridiculous temperature tolerance) but they dust like mad, and they squeal like a banshee.

It all depends on what your level of tolerance is for noise and how meticulous you are about keeping your car clean .

 

Wrong. Big brake kits SHOULD allow for far more precise modulation at or near threshold. Smaller brakes will still lock up, but they will go from an 8 to a 9 VERY quickly. Big brake kits allow you to precisely brake at a 9.9 each and every time (10 being lockup). .......as well as doing it repeatedly with far less change.

 

I recently replaced brakes all around with Brembo anodized, slotted rotors, f/r, Hawk HPS front, Mintex red box rear, and Tyrol bushings. Replaced brake fluid with good valvoline stuff. I bedded the pads best I could - repeated high speed stops (almost stopped).

I have found that the HPS barely dust the wheels at all. However, the stopping power is much less. I can stomp on the pedal and not get into the ABS, whether pads are cold or warm. From my personal experience, I can not recommend the HPS. I am considering going with TSW Porterfield R4S, but they are pretty pricey at $145 plus shipping for one set. Any other recommendations?

I want to do occasional track days too.

 

Hey meb,

Would you place the wilwood bp-20 in that category?

mb

 

Sorry, I'm obviously not in a position to make a pad recommendation, having also made the Hawk HPS mistake. The HPS has gotten many glowing reviews on NAM, but it is interesting find others with an experience similar to mine. Apparently, the stock pads have much higher friction than many of the aftermarket, so if you dump the OEM you may also think about adding SS braided lines to keep the firmness at the higher pedal pressure required.

In my case, HPS front and OEM rear gives a strong rear bias that causes the rears to lock up way before the front. How long have you had the new pads on? I think the HPS have improved a bit as they break-in, but then again I may just be deluding myself.

 

I'm not meb but I've tried the BP-20 on the track. No thanks won't do that again. Wear out very fast, poor pedal feel and poor initial bite. I've gone to the Play-b's and am very happy with them.

However, I thought I could get through this weekend with the pads I have on. But since the sessions are about 10 min longer then usual I'm going to need pads after 1-2 sessions tomorrow. The store at the track has Performance Friction 97's in stock for a decent price (shocked as this place is normally expensive). I'm going to pick them up in the AM insuring that the pads on the car now will last all day. If I don't buy them the pads will go away after a session and someone else will have bought them. I'll post my thoughts if I use them.

 

Yes but Brembo's in the front with a high torque race compound and Hawk HPS pads in the rear with OEM disks and calipers is going to result in a nosedive whenever you hit the brakes, and the car is going to transfer all the weight forward, with very little braking in the rear.

On the track I run stock brakes with upgraded pads (As do all the other people I race with) and we've never had any issues with brake modulation. I can modulate the brakes fine .

 

I've been tracking for 4 years using the stock MINI brake system with top shelf brake fluid, bronze guide bushings, Ferrodo 2500 pads front and rear, and regular maintanence. I added home made air ducts 2 years ago. No problems what so ever. Good pad life. No modulation problems that others report with their BBK systems. Can brake as well as or better than any MINI I've seen on the track. A number of my track rat friends report the same experience with their relatively stock systems. Those with Hawk pads seem to wear out rotors pretty fast, though.

Big brake kits seem to offer a braking advantage to full race MINI's and offer a cosmetic advantage to all MINI's. Not for me. I'd put my BBK money into high quality struts, springs, tires and wheels.

Regards,
John Petrich in Seattle

 

That post was in reference to your saying: "If you can lock up your wheels with the stock brakes, then brakes aren't your problem." Drum brakes all around would lock up the wheels,...doesn't really mean that brakes aren't your problem. I myself am on stock JCW brakes AND pads and find the modulation offered with this setup to be sufficient,...but a bigger (quality) kit would definately offer me more precise fine tuning at or around threshold. ...and yes, I'm sure your a very late braker.

 

"How long have you had the new pads on? I think the HPS have improved a bit as they break-in, but then again I may just be deluding myself."

I've had them on about 2 months. Put them on as part of a full break setup I bought from k-huevo on this board.

The HPS work a little better once they get warmed up. However, at the track recently (my 1st time - streets of willow), I did not feel secure with them. The instructor commented that I needed to check my pads, and was surprised I had just recently replaced all the pads. The pedal dropped pretty low, but was brought back somewhat with bleeding the brakes when I got home.
I think I have to put the stainless brakelines on too cause the brakes now seem a little mushy. I think the heat of the fluid might have softened the brake lines, but I'm not sure.

Petrich - how are the Ferodo's on the street? Have you heard how they compare to the Porterfield R4 and R4-S which Texas Speed Werks recommends highly?

 

double post

 

Steve S,

I am a minimalist and I try to keep things simple so as to reduce the risk of error. Hence, I run my Ferrodos both on the street and at the track. The maintenence involves regular caliper bleeding and checks for pad wear. The Ferrodo pads seem to work perfectly on the streets in the Seattle area. Plenty of bite with normal driving in all types of weather, no noise, and minimal rotor wear. After 38K miles, the rotors are still within tolerances. Both my son and daughter have new MINI's and the brake action is indistinguishable to me between the Ferrodos and their stock pads on the street.

Comment: The stock pads fragmented with even minimal track use. The Ferrodos in my car seem on a par with anyone else's brakes judging from observations in the braking zone. The Ferrodos wear evenly across each pad due to the bronze bushings. No pad carrier twist. And the pads wear equally front to back due to the stock brake balance and brake distribution system software. I go thru 2 sets of pads per year. (It's those track days.)

That's about it from me. The air ducts to the centers of the rotors stabilize the heat to the braking system and contribute to the consistency of braking from lap to lap. It's hard to beat the stock system when it is properly set up.

John Petrich in Seattle

 

Update.
My problem was the rotors.
Hawk Pads are great, Very Hard Rotors (Slotted) are bad. Put the two together and you have a mini that barely stops.

I went back to OEM rotors and life is much better

Thanks to WMW for helping me get to the bottom of this...

 

To Petrich:

I always appreciate your posts.

Haven't you taken off the factory backing plates and replaced them with Z-3 aftermarket which have 3" duct flange?

LDG recommended against just removing the factory backing plate

"There is an opening between the caliper and the rotor where the cooling air enters. The backing plates do not need to be removed and they actually serve as heat shields to the wheel sensor and tie rod end as well as the lower ball joint. The setup that we use for the track are the two piece floating hubs on the front. This way the heat in the rotor is not transfered into the wheel hub bearings and caliper." from post 17 of this thread:

https://www.northamericanmotoring.co...=backing+plate

What are your thoughts on that?

Do you have a suggested vendor for a good price on Ferodo DS2500. and brake lines?

Thank you.