Bello brake kit

[Stu]

Brakes were a terrible problem for me at CMP on Friday. It started after my first day with it at the track 2 months ago. Before that school, I put on new rotors/hawk hp+ and hps, and pressure bled them w/ate blue, I got a stiff pedal after doing this. I wasn't too hard on the brakes but the pedal was soft by the 5th session, and brakes were fading towards the end of each session.

I bled them (3x) before Friday, but I could not get a stiff pedal, it was soft even with pressure bleeding at 15psi. At the track, I had a soft pedal all day, and it was horrible after 5 sessions. After getting some heat in them, I would get 3-4 laps of good braking (still soft pedal though), and had lousy brakes thereafter. I had to shortshift, couldn't build too much speed because of the shitty brakes. I removed the iS lip and foglight panels, that seemed to help slightly. If I had the tools there to do so, I would have removed the brake backing plates and rigged up some sort of ducting, and maybe ran better fluid like Motul 600, these were Bello's recommendations to me.

My calipers are original, as is my MC (280k miles), but I am not getting any leaks. Any ideas why I couldn't get a stiff pedal after 1 trackday...even with the same bleeding procedure? I want to refresh the entire braking system before I track it again. An 11" rotor with fresh M3 calipers and HT-10's or something similar seems like it would work well.

Robert, thanks for the info on ducting. I really need to improve them as far as how well they grab and resistance to fade. I need less hp, really.

[ZackAH]

Yeah ok. Gonna post just this once.

Stu, I've had the same issues at CMP. Exact same symptoms you're describing. The last DE I did there with my dad (he drives a 325i Cabrio) I compared pedal feel. While my pedal felt mushy after one session, his felt like a rock. After multiple bleeds the brakes would be good for part way through one session, then it got mushy again. Since dad's car is heavier it seems that he would be using his brakes just as hard as me but he had consistent pedal. Fluid was ATE superblue so I don't think I'm boiling fluid.

Since braking is such a issue at CMP anyways, something had to be done. After lots of research I replaced my MC and removed the front backing plates. DE at ATL next month so we'll see how it works then.

Zack

[Gus]

Stu, not sure on your setup, but it sounds exactly what happened to me. turned out the rubber hoses had got owned.....a set of stainless fixed that right up

if you got new/stainless hoses, could be other things, MC, caliper...fun stuff. really

[Stu]

Gus, I do have SS lines on the car (all 6). Calipers/MC could be the problem, as many have told me, but I'd like to look into it more. Considering the mileage, the caliper seals and MC have to be able to benefit from being replaced--or so it would seem to me. I have a brand new MC from a V12 car that my dad gave me...so I may try that.

I do know that I will not be going back to the track with the current setup--it is almost dangerous and is not worthwhile to me to not be able to push the car sufficiently.

What do you all think of this?
-Replace MC with V12 unit
(I could use a stock one, but I have this V12 unit avail at no cost to me)
-Flush entire system and use Motul600 or AP600
-Remove all backing plates
-Some sort of ducting that runs from valance to center of rotor
-Rebuild calipers, and use better pads (HT10)
OR
-Rebuild M3 calipers, modify 11" rotor to fit E30 hub, fit caliper with re-location bracket

Damnit, I need your brakes Jordan

[rwh11385]

What do you all think of this?
-Replace MC with V12 unit
(I could use a stock one, but I have this V12 unit avail at no cost to me)
-Flush entire system and use Motul600 or AP600
-Remove all backing plates
-Some sort of ducting that runs from valance to center of rotor
-Rebuild calipers, and use better pads (HT10)

http://www.bimmerworld.com/html/brake-cooling-kits.htm
http://www.bimmerworld.com/e30_installation.htm

[Jordan]

FWIW.

Stock 1987 325iS 60-0mph time is 152ft

I did several passes, and wound up with 101ft.

For those too lazy to do the number crunching. 60mph to not moving in 7.11 my car lengths.

I suspect this may improve further as the outer most 3mm ring of the front rotors havent been introduced to brake pad yet. Pads need to bed in just a bit more.

[rwh11385]

Care to list what all other factors could come into account besides just brakes?

[Jordan]

Well. As already mentioned a wider, stickier contact patch of rubber is the #1 factor.

Caliper clamping force, and rotor diameter is #2 and #3.

The larger the diameter the more mechanical advantage the caliper has over the wheel.

Of course terrain also matters. I tested on what I consider "average" road.

Flat, level, faded tar. No pitting etc, still smooth.

Also, for the sake of throwing it out there.

If a stock 87 325iS and I line up side by side @ 60mph and slam on the brakes...

I come to a stop, and he will continue on for 3.6 more e30 car lengths.

[rwh11385]

Bingo, #1 was the first thing i was thinking of. Too bad you can put your tires and wheels on a stock 325is and compare. Damn variables.

I was also thinking have you dropped weight too?

[Mystikal]

I did several passes, and wound up with 101ft.

If that's accurate, it's incredible.

[cunninglinguist]

The stock 1987 325iS 60-0mph time is 152ft -- on 1987 era tires?

[ZackAH]

This a follow up for any who are interested.

Just got done with a DE at Road Atlanta. Had a BLAST! Great track! Anyways no brake issues whatsoever this time. In my previous post I had issues getting a solid pedal. No issues now! Even after braking from 110 (indicated) down to 40ish every lap.

I belive the new MC solved my issues. I have removed the front backing plates. Have stock front brake ducts. Carbotech panther + pads (nice pads btw) on the front with Hawk HPS on the rear. Vavoline brake fluid from autozone. 25mm MC also. Great fun. Nothing quite like braking and knowing they'll be there.

Zack

[Stu]

This a follow up for any who are interested.

Just got done with a DE at Road Atlanta. Had a BLAST! Great track! Anyways no brake issues whatsoever this time. In my previous post I had issues getting a solid pedal. No issues now! Even after braking from 110 (indicated) down to 40ish every lap.

I belive the new MC solved my issues. I have removed the front backing plates. Have stock front brake ducts. Carbotech panther + pads (nice pads btw) on the front with Hawk HPS on the rear. Vavoline brake fluid from autozone. 25mm MC also. Great fun. Nothing quite like braking and knowing they'll be there.

Zack

Good to hear Zack. I've decided to go ahead with the 25mm MC, and atleast ducting before I go back to the track (might not to bigger rotors just yet). Going to replace caliper guide bushings as well, should I get solid-brass for these, or OEM?

Plan for ducting: Cut a 3" hole in the front part of the stock backing plate. Weld tabs to attach 3" hose to....attach hose at valance. This should direct the air to the rotor veins, but I won't know until I have the stuff right in front of me. $245 for aftermarket backing plates is just not in the budget. ;)

[ZackAH]

Guess I'll post my thoughts on the larger MC here too. Saw some other thread about it and would like to give my feedback. Basically like others have said most all pedal movement is gone. Like pressing on a brick wall. It WILL build up your leg muscles. It takes alot MORE pressure to stop the car the same amount as with the stock one. This is probally why people say it yields less performance. No idea if it does though. I think it's basically the same. Just requires more force for the same amount of braking. Not for girly men. ;)

I had looked at the solid caliper guides too but after some research have found that they probally won't be suited for my daily driver/some track car.

http://forums.bimmerforums.com/forum/showthread.php?t=329182&highlight=solid+caliper+guide

To sum that up for those to lazy to click on the link "The pins need to be lubed with some good high-temp brake grease at least like every 2 months or so . . ." So you COULD daily drive them but I dunno if it'd be worth the trouble.

The ducting sounds good. I'd love to rig something up that'd make my pads last a little longer. Yeah $250 seems a bit high for now. :( Maybe after a rollbar and harnesses.

Plan to make the November or December DE at CMP Stu? So far it looks like my dad and I will wait for the December one. Free food! :)

Zack