Brake Theory 101 Question

[LL6]

I've always been hard on my cars, but I use quality parts and do the maintenance. Z-rated tires last me 30k, pads and rotors around 80k, and clutch every 35k-50k miles.

This question will be about disc brakes. The OE brakes that came on the car were the 11" cast iron fronts and 12" PBR rears. I drove this car for 85k miles in Germany, mostly on the A'bahn. They were good to 140 mph believe it or not. Now repeated high-speed stops caused pretty rapid fade, but I was mildly impressed. These babies would get so hot my rotors were blue. Ultimately they cracked and I had to replace them, but they never warped.

Now I'm driving in the states at mostly 75-85 mph and running Baer 12" Sports front and rear with ZR1 OE pads. The fronts are very similar to the 1LE setup and were purchased back in Oct 99. The Baer rear discs are slightly thicker with more vanes than the OE 12" vette-style rotors previously on there and were installed about 1 yr ago. I drive with about the same aggressiveness that I did in Germany, but obviously with 40-60 mph less speed. Under these new conditions I warped my rear OE rotors about 18 mo ago. I installed the new Baers and have warped them, too. Even my front Baers were slightly warped.

I have some suspicions but I want to hear your opinions first.

[Jaysz28]

Sounds like you are using too harsh or aggressive of a pad that is generating too much heat causing the warping. You may want to look into a softer pad. The downside to softer pads is more pronounced brake fade and excessive brake dust. I think this would help your situation.

You didn't mention if your rotors are slotted, crossdrilled, or both. I recommend using slotted rotors with a softer pad. The slots will help evacuate the gases giving you less brake fade and help them run a little cooler. Might also be time to flush your brake fluid. Not causing the warping, but it can't hurt if you haven't done it in awhile.....

[james85z28]

was there less traffic at high speeds in Germany?

When going to Las Vegas the traffic speed is about 85~90 MPH. But some people are afraid to drive more than 55 MPH and that causes people to slam on their brakes a lot because of the difference in speeds and the short reaction time to adjust accordingly. Maybe your high speed driving isn't as smooth/constant as it was over there due to all the blue hairs on the road where you drive.

since you have non-OEM brakes where do you get your replacement parts like rotors/calipers/bearings/etc. ?

[LL6]

I'll try to answer these in the order presented:

Jay, the pads I'm using are the least aggressive that Baer sells with their kits. They are stock ZR1 pads and they make a fair amount of dust. (FWIW our '00 SS has warped rears, too.) In Germany I was using everything from OE to semi-metallic Raybestos. Believe it or not the OE seemed to work the best.

The rotors are not slotted or cross-drilled. When the fronts were originally done in '99 I replaced all the fluid with Ford Z-rated fluid. When I changed the rear brakes I replaced all the fluid again. It's probably time again by the color of the fluid, but give me a break, I bet my fluid is newer than almost anyone else's here. tongue.gif

James, the difference is traffic speed was greater in Germany but there was less chance for a blue hair in the left lane. That's not to say two of the times I came closest to meeting my maker was on the rear of 18 wheelers. :eek: You figure 65 mph vs 150 mph. I suffered major brake fade both times. All in all they are better drivers over there and you might be less inclined to have to use the brakes. I did much less city driving while I was there. Almost all was on the A'bahn. My tires lasted almost 10k miles more there than here BTW.

As far as relacement parts the pads are ZR1. I suspect the rotors will be Baer/aftermarket/(maybe even 1LE) and the calipers are PBR so wherever or whomever carries that. The bearings I would suspect are OE, but I don't know for sure since Baer ships their kit already assembled on the spindle. The brake lines are steel braided Russells and the fluid Z-rated Ford stuff in the blue can.

[Jaysz28]

Well I flushed my brake fluid this winter. :D

That is odd man.... maybe you are just so confident in your brakes ability that you are overheating them. Its a possibility I guess. James had a good point about less traffic in Germany. I didn't think of that. I used to fly all over the A'bahns in my 79 camaro at 140 mph just because I could. I never had a problem with my brakes... Could be just the higher amount of traffic.

Here are some slotted 1LE rotors on ebay. Slotted 1LE Rotors (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1822402540)

[88WS6TA]

Maybe you're riding the brakes like an little old lady. tongue.gif

[LL6]

Thanks for the input thus far. Here's one of my theories, at least for the rears warping...

The e-brake. Both SSaSSy (in her '00 SS) and I are ardent users of the e-brake and don't leave it in gear. I'm wondering since where I work (and she used to) isn't a quarter mile off the Interstate, if the brakes haven't had a chance to cool down before I clamp on the old e-brake. Comments?

[WS6 VERT]

I think thats a very good possiblity. When I get off the interstate only to sit at a redlight, I kick the shifter up into N so that I can let off the brakes. Kinda like a blacksmith, get the metal real hot, then add pressure. Can't be good for it. When I drive a manual car, I don't use the e-brake, I just leave it in gear. I only use the e-brake on steep inclines where there is a chance of it popping out of gear.

[LL6]

Yeah, I've already been experimenting with that and recently had a friend at work tell me there's a problem out in the parking lot with my car. I run out there and it has rolled half a car length out of the slot. redface.gif

Thank god it stopped. :eek:

Needless to say my clutch is obviously slipping and will have to replace it sometime soon. At least this time I am prepared and already have a new CF Dual Friction just waiting to go in, just got to find the time to do it. :(

[WS6 VERT]

Where are your vehicle's chock-blocks, soldier? Thats part of your Basic Items Issue, you better get your car back up to 10/20 standards, before it gets deadlined. :eek:

[CraigSkiles]

Originally posted by LL6:
I bet my fluid is newer than almost anyone else's here. tongue.gif Hate to tell you, fresh fluid as of yesterday ;)

[WS6 VERT]

Damn Craig, I was going to chime in, but you got me by a month. Oh well. :D

[LL6]

Showoffs... http://www.theunholytrinity.org/cracks_smileys/otn/mfinger/pokeeye.gif

[CraigSkiles]

yeah, but you know my car isnt quite road ready just yet graemlins/devil.gif

[ April 23, 2002, 22:09: Message edited by: CraigSkiles ]

[Jaysz28]

I never use my ebrake in any of my cars. Mainly because my beater rear calipers keep sticking and I can't stand the smell of fried brakes. Sad part is that I have replaced both rear calipers and still have the problem.

But your theory does make sense. I like BT's description of the blacksmith. But my brakes suck. Sad when our new 4x4 truck will stop quicker than my Z from any speed! :eek:

[LL6]

Jay I've actually found that if you don't use your e-brake that it causes brake problems like you've described. While stationed in Germany we had access to a brake dyno. Almost to the car I could predict the outcome of the rear brake test of those that didn't use their e-brake.

I think the moral of the story is if you think your brakes are hot, park it in gear or up againt the curb. This should still be infrequent enough so that you can use the e-brake and it will work if you need it.

[Jaysz28]

Mine will stick wether hot or not. It is a documented design flaw in the caliper itself. I try to use them often. Didn't seem to help. I also used a high temp grease for the sliders. I know about the brake test machine. Part of the yearly inspection. I haven't forgotten that headache! Wish I still had access to one so I could find out what is the deal with the rear brakes on my Z.

[Skweezn87]

Very interesting Mike...

I use my E-brake ALL the time when I park.. just habit .. and mines an auto... I have not had any of the problems your expierencing...

Just seems quite weird that you went w/ a better quality brake system..and having problems?? Have you contacted Baer about this to see what their thoughts are on this??

Rick

[LL6]

I've had conversation with Baer tech line before on a different subject and came away less than impressed. I guess I could try them again.

[Skweezn87]

That doesnt surprise me.. but I was just curious if you had called them or not.. Im sure it wont be any different now from back then... :rolleyes:

Rick

[LL6]

FWIW I sent them an email this time. I'll wait and see what their response is...