Stock Brake Problems

[240 2NR]

First my specs:

93 240sx SE fastback 63k miles
Stock calipers
Stock rotors
Stock lines
KVR carbon kevlar pads
ATE Super blue brake fluid (also used valvoline synpower, and stock fluid with same effects)
Stock MC, and brake booster

The Problem:
My brakes have never felt right.  When cold it feels like I'm squeezing two bricks against my rotors.  There is little bite, though they do slow the car, but it's nothing special unless I really stand on the pedal.  This is how the original pads felt as well (changed by previous owner, unknown type, 90% pad remaining, even wear so it's not a seized caliper) and the
motivation to replace all of mine with the KVR's.  Still the same feel.  

When I do depress the pedal hard it feels like I'm either flexing the pedal arm or the lines, as it will go a bit further, but feels more like play than additional stopping power (almost like it's pushing back).

The odd part is once the brakes reach a magical temperature they bite like crazy all at once and then hold that performance.  I've run these brakes at the track and love them once hot.  No fade so far, and insane grip from such
a puny braking system.  This problem is defintely not warm up time, though it may be increasing the symptoms.  I've been in other cars with these brakes and it doesn't take as long to warm them up.

I can find no leaks anywhere in the system, the fluid is fresh, the MC and brake booster look good, the pads aren't glazed, and the resevoir is topped off and doesn't go anywhere.  My only other thought is that the rotors are a bit scored.  Running my fingers over the rotor surface you can feel they
are uneven (condition that existed before the new pads).  Could this be the cause of my pedal feel/ poor performance?  I'm tempted to try new rotors (though mine are all at least 1.5mm over min spec) to see if that solves the problem, if not then I will try a new MC, but it seems like money wasted since I plan to get Z brakes next year.  At the same time I want to fix this if it's not rotor or pad related as it will still exist with the bigger brakes.  Eric Johnson has also driven the car and agrees that they don't feel right.

I'm ruling out lines as other 240's have felt better, and really starting to think it must either be the booster, MC, or the rotors.  Anyone know how to check the vacuum pressure?

Thanks in advance, <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>

[Tyler Durdan]

It sounds more like you rotors are causing the problems. &nbsp;Before you go out and buy new ones, you can take your rotors off, and just go to any local automotive store or shop to have them turned. &nbsp;This is what I'd do before anything. &nbsp;It's cheap to have them re-surfaced, and it should let you know if the rotors are the problem or not. &nbsp;Just my thought though. &nbsp; <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/satisfied.gif" border="0" valign="absmiddle" alt=':satisfied:'>

[240 2NR]

I've thought of that, though it seems like a lot of work and some money for rotors that will likely end up at or close to tolerance and probably be disfunctional after one track event, and I'll be needing new ones anyway. &nbsp;New brembo blanks are $45 each, and I'd guess getting the stockers resurfaced is going to be ~$20 each. &nbsp;I may stop at a shop on the way home and check. &nbsp;But still, won't it be at least 1mm of material removed? &nbsp; I figure with some decent rotors, at least I can sell them in a year and make back some money.

[HippoSleek]

Peculiar indeed. &nbsp;

Initially, I thought 100% pad issue - not enough heat/too aggressive. &nbsp;I know nothing about those pads, but I have a gut feeling that it is not fluid related and that is the type of thing that people bitch about when they have too aggressive a pad. &nbsp;But, since you know someone else running those pads, perhaps it is interface based.

Everytime I've heard of brake problems involving fluid, it involves pressure differentials. &nbsp;Too soft a pedal; need to pump; goes to floor; etc. &nbsp;Rarely do I hear that the pedal is solid, but the car doesn't stop. &nbsp;The only connection I might see is if the pedal is going to or near the floor. &nbsp;Obviously, there is an area of free play, bite, then bottom. &nbsp;If those are in about the right place - I'd think the hydraulic system is fine and it is a materials problem.

As for the scoring on the rotor - I don't know enough about those pads to say, either way. &nbsp;Scoring will definately reduce your cold brake stopping power, but does lessen as the pads get heat. &nbsp;I noticed this when I went from track pads to street pads on rotors that could double as a warped record. &nbsp;They sucked until they got hot... but not too hot.

I think you've made the only diagnosis I can think of.

[Natty]

I was about 30 minutes from ordering the KVRs from PDM before reading this. Now I don't know if they are going to suck for daily driving, which is all I use my car for &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>
About the rotors, don't waste your time turning them if they are bad. Napa does it for $12 USD a rotor. NOPI sells Brembo rotors up front for like $30 a piece. AutoZone has them up front for $23 &nbsp;:!:
Don't chance it. Get new ones.
You have ABS bychance?
Jeff

[Natty]

Oh, you did break the pads in, right?
Aside from this problem, do you like them better than what was on before?
Jeff

[240 2NR]

I don't believe this to be a pad issue as I stated it was a prexisting problem. &nbsp;Uiuc240 has these pads with his Z brakes and has no faults with them, and his rotors still look brand new smooth (plus his warm up time should technically be higher with more mass to heat up). &nbsp;I wouldn't hesitate to buy again (though in my case may try others just for comparison), the price is definitely right and they are fine on track.

The pedal is within spec for travel (measured the other night using specs in the FSM). &nbsp;The pads were bed properly as far as I know (repeated medium hard stops from around 60mph without a full stop about 1 minute apart after a 5 minute warm up and plenty of cooling time after). &nbsp;Again, they have been to the track and have worked fine once hot. &nbsp; I really think that it is either a vacuum problem (once they are hot, mechanical effort is enough to utilize a very sticky pad, but when cold there is not enough force), or a rotor interface issue (where at high temps more conformity is possible). &nbsp;I guess I will look into new rotors and hopefully it will fix the problem.

If I do get new rotors, are the pads reuseable if I sand/scuff them down?

Brembo blanks or KVR cross drilled?

[Natty]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (240 2NR @ July 21 2002,7:53)</td></tr><tr><td id="QUOTE">If I do get new rotors, are the pads reuseable if I sand/scuff them down?

Brembo blanks or KVR cross drilled?</td></tr></table><span id='postcolor'>
The pads should be okay. I do not know about the new rotors though. I would repaet your break in/bed process just for the rotors. I am not sure if rotors have to be broken in or not though. I am doing both rotors and pads at the same time....

I am facing the KVR vs Blanks too &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'>
It would be twice as much for the KVRs. They will look nicer (crossdrilled) and they won't rust. Probably won't do much for perfromance, they way my stock car is and how I don't really race. If you do the Z32 brake upgrade down the road, just get blanks. Can the KVR's be turned later on?
Alas, I may just get the Brembo blanks from NOPI or the generics from Autozone. I hate being broke &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>
Let us know what you go with. I'll be doing my brakes on my next day off for the first time. Heck for the cash I save, I could upgrade to the KVR's &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sly.gif" border="0" valign="absmiddle" alt=':sly:'>
Jeff

[guidot]

I believe it has been stated that xdrilled and slotted rotors cannot be turned.

[HippoSleek]

I think rotors are worth a shot. &nbsp;FWIW, When I took off my carbotechs 6 weeks ago, my rotors were SHOT. &nbsp;I put on the OEM pads for a couple weeks while I waited for another set of C-techs and new rotors. &nbsp;They could barely stop the car cold! &nbsp;Hot, they were okay - not stellar (OEM vs. Carbotech). &nbsp;When my new Carbos came, I put them on the a week (w/ new rotors) for a track event, then took them off and swapped in the OEM pads w/ the new rotors. &nbsp;MUCH better.

No problems using those pads on new rotors. &nbsp;Don't worry about griding them - just hit everything w/ brake cleaner. &nbsp;Also, there is no need to "bed in" rotors (you do it to pads to burn in/off the resins). &nbsp;

I am a bit more curious now that you say that the comparison for the KVR's is on z32 brakes, though. &nbsp;There may be some difference in compound (as there usually is for Moosetangs, Camaros and other heavier fast cars).

[bbp]

Here's my .02....

Theory 1: Are the rotors real shiney? Like glazed over? &nbsp;This is common when people run high temp pads on the street. &nbsp;They are designed to work at a higher operating temp, when run at low temps over a period of time will polish the rotor and reduce the amount of friction needed. &nbsp;Solution: &nbsp;lower temp pads and new rotors.

Theory 2: see #1

Try Hawk brake pads, they have a street/track and a street/autox compound.

[240 2NR]

Um, they're sort of shiny, no more shiny than the brakes on my parents accord (read: STOCK!!! and ridden lightly), though I have noticed when hot they almost have a blue hue to them and are def. shiny then.

I was looking around and found brembo blanks at NOPI for ~$26 each. &nbsp;Anyone buy from nopi before?

[240 2NR]

Also, I found out that getting them turned will cost $12.50 per rotor and will remove close to a mm (maybe more depending on how bad they are). &nbsp;I'm thinking for just a little more than twice that price I'm just going to get new rotors from Nopi. &nbsp;At the very least they'll last longer since if I remove 1 mm of material I'll only have 1mm or less until I'm to tolerance, and that's not a place I want to be at 100mph.

[uiuc240]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (240 2NR @ July 23 2002,09:27)</td></tr><tr><td id="QUOTE">Um, they're sort of shiny, no more shiny than the brakes on my parents accord (read: STOCK!!! and ridden lightly), though I have noticed when hot they almost have a blue hue to them and are def. shiny then.

I was looking around and found brembo blanks at NOPI for ~$26 each. Anyone buy from nopi before?</td></tr></table><span id='postcolor'>
Steve, remember when I ordered that cap and rotor from Nopi like 2 years ago? &nbsp;It was the wrong rotor. &nbsp;And they didn't have stock on the cap. &nbsp;And the rotor looked 500 years old. &nbsp;I had to ditch it and buy all new stuff from the dealer. &nbsp;Hopefully your luck will be better. &nbsp;I think mine was weird because of obscure items. &nbsp;I say give 'em a shot. &nbsp;It's cheap.

Eric

p.s. Mark (Hippo), I know what you're saying about the difference in brakes between stock and Z, but Steve's feel WEIRD. &nbsp;I think this scored rotor thing must be the problem. &nbsp;They feel like what mine feel like after sitting outside all night and then trying to stop in the rain with wet rotors. &nbsp;That bad.

[240 2NR]

UPDATE-

My rotors arrived from Nopi yesterday (thursday) which is pretty quick turn around (ordered tuesday, standard shipping). &nbsp;I opened them up, and found I recieved Bradi rotors, which I had never heard of till I did a search. &nbsp;I'm still not entirely sure, but it sounds as if they are a sister company of brembo and still of high quality. &nbsp;Regardless i sent an email to Nopi questioning this and am awaiting a reply.

Has anyone used these before? &nbsp;Can anyone comment on their quality? &nbsp;I figure I'll probably just throw them on since I only plan to run them for a year or less and they were stupid cheap at $26 per rotor. &nbsp;I guess if you want real brembo's, the cheapest place is still Strano parts.

[HippoSleek]

ha ha - off brand rotors! &nbsp;I've seen Brombos and heard of Breembos. &nbsp;(along with Spoom wheels).

Cheapest place I found was Colletti (check out FAQ under parts sources).

Let us know if it fixes the problem.

[uiuc240]

Mark,

Colletti is gone. &nbsp;And Bradi is a Brembo sister...like Audi/VW.

Eric

[240 2NR]

I told Nopi (or maybe it was Nopy or Nobi) that I didn't like their practice of advertising a product they aren't going to ship. &nbsp;They said they would look into updating the webpage to reflect that. &nbsp;We'll see if that actually happens, but don't expect real brembos from them. &nbsp;

Colletti is gone as far as I can tell and the next cheapest I found for Brembo blanks was over $40 so I figure I'll suck it up and go with they sent me. &nbsp;A lot of suby owners seem to use them.

[HippoSleek]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (uiuc240 @ July 26 2002,11:21)</td></tr><tr><td id="QUOTE">Mark,

Colletti is gone. And Bradi is a Brembo sister...like Audi/VW.

Eric</td></tr></table><span id='postcolor'>
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/nervous.gif" border="0" valign="absmiddle" alt=':nervous:'> &nbsp;SH!T &nbsp; <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/nervous.gif" border="0" valign="absmiddle" alt=':nervous:'>

Good thing the 240 will be moving to street car duties...

[camppain]

steve if you suspect its a vacuum problem disconnect your line to your brake booster and see if you can stop better without it. you will need to push the pedal in harder now than before since its just working off of your leverage.

also in regards to turning your rotors you will only take about .005 of an inch to get them cut i usually cut rotors on a fast vcut at .003 and slow at .002 so you wont even be close to minimum specs after getting that done.

[240 2NR]

OK, I installed the new rotors on Friday and things are much improved , though I don't have enough time with them to accurately say how much.

Took off the old rust bucket rotors friday afternoon, reapplyed some anti squeal to my pads and checked to see if they were glazed (they're not). &nbsp;So I drenched the new rotors in brake clean to remove the protective oils and put them on the car. &nbsp;First impression is these look much better, though now the system looks smaller since they don't blend in with the dust shields.

Went for a short drive and at first the stopping was worse than the old ones. &nbsp;Got out to check and sure enough, I was still burning off oils. &nbsp;So I headed back after a short drive and per the directions, took it easy for about 100 miles. &nbsp;Last night I went out and bedded them in for real. &nbsp;When hot they feel about the same as before, but the performace says they do better as now my fronts lock before the rears (before just the rears would chirp when braking hard, now I can get the fronts to stop harder, though some of that could be the suspenion work as well, the last time I went out everything was done but the struts were still stock).

In anycase, today was the first day I drove them after bedding in and they had a chance to cool. &nbsp;Despite the rain, they already feel much better than before. &nbsp;Pedal feel is still off, but the cold braking performance is much improved.