Brake Lock Up Questions

[NSXF1]

Questions for the brake experts,

Before the last Xpo I serviced the brake system, new rotors, (Bradi slotted), pads, (Project Mu race), and flushed with ATE supper blue. Car is a 92 with 83k. First I had problems with one of the rotors on the right rear, eventually found out it was not "finished", which made putting the caliper back on very difficult. After this was swapped out, problem was solved.

During the track event I had a re-occurring problem with the passenger side front locking too early. It would only happen at 9 or 10 10th's so I just braked easy for the event and had no problems but the confidence was not there, and it was a big distraction. I had removed the ABS relay from an early issue with the ABS pump that flushing the solenoids switching the solenoids, flushing etc etc would not cure. A few people I spoke to at the track said put the relay back in, that could be an issue. Did that and now the ABS seems to be working well again, ???? but premature lock up still continues. One thing that I will say was the bedding procedure was questionable as the roads around my house make it difficult to impossible. But after two bedding sessions, I never had the lock up. It didn't seem to show up until at the track.

Trying to figure out what to do next. Some have suggested new brake lines before I do anything else, which given the age of the car I agree with. This bring my next problem / question. Go OEM or stainless steel. Hard to go wrong with OEM, and I've heard a horror story or two about SS lines. Any advise? Car is mainly a weekend warrior and want to get to more track events.

What would be the next step in troubleshooting? Swapping pads side to side? Rebuild calipers? I've already removed that side twice and can't see uneven pad wear, sticking caliper, etc. Any advise appreciated.

 

[DanO]

What kind of tires are you running? Does/did the lockup occur significantly before the rest of the tires? Was the lockup occurring on mostly one area of the track, like just before a right hand turn or where there might be less traction on that side of the track? If you find a safe parking lot then you might be able to do some straight line braking to see if the problem persists. I’d bleed the brake system to see if that helps then swap front pads and rotors to see if the problem is following these components. I’d be surprised if a brake line was significantly contributing to the problem but it’s probably not a bad idea to replace these as preventative maintenance; lots of opinions about lines but sounds like the OEM lines have worked well for you over the years.

Keep us informed,

DanO

 

[NSXF1]

SO3PP 215 and 265. Lockup definitely occurs before the other 3 are even close, but you wouldn't know it on the street unless you did a panick stop. Doesn't seem to pull. But on the track it was very noticeable. Tried it on different roads same thing. Bled the brakes a second time at Xpo because that's where I replaced the defective rear rotor.

What's your opinion on the SS lines DanO?

 

[DanO]

What's your opinion on the SS lines DanO?

My opinion is that SS lines won't help or hurt your particular problem. Honestly, I don’t think there’s much difference in terms of brake feel between the rubber lines and the SS-coated rubber lines. I think the SS coating’s function is to protect the lines from debris and therefore minimize a hose failure during a race. Over time, I’ve heard that SS lines themselves can lead to hose failure because of abrasion to the rubber hose caused by debris between the SS jacket and hose. Some people think that SS lines help with pedal firmness. I think that these people had never bled their systems (ever) before the SS line install and are attributing the freshly bled firmness (a good bleed is part of a line install) to the new lines—an error in causality. I know when I switched my well-bled system from rubber to SS there was no noticeable difference at all.

So, it’s up to you. Go with cool looking SS-coated rubber lines but replace them occasionally, or go with OEM rubber and replace them every 10 years or so. Either way, you’ll want to have a 10mm flare nut wrench and four crush washers for the banjo bolts to do the line change procedure. For what it’s worth, I have SS lines on my car and I’m on my second set which I had custom fabricated by baker precision to match my particular brake setup.

I’d still swap front rotors and pads to see if the locking up problem moves with these components.

DanO

 

[Chuck]

So, it’s up to you. Go with cool looking SS-coated rubber lines but replace them occasionally, or go with OEM rubber and replace them every 10 years or so. Either way, you’ll want to have a 10mm flare nut wrench and four crush washers for the banjo bolts to do the line change procedure. For what it’s worth, I have SS lines on my car and I’m on my second set which I had custom fabricated by baker precision to match my particular brake setup.

DanO [/B]

I agree with DanO on this one but one advantage of SS lines that I found is when changing rear brake pads. I found with the stock line I had to remove the parking brake mechanism. With the SS lines I can move the caliper out of the way without messing with the parking brake. I'm just assuming the aftermarket SS lines were a little longer.

 

[titaniumdave]

Clean your rotors well with scotch brite, hose them with brake cleaner and swap front pads from side to side. See if the lock up follows the pads. If it does there is a chance you got some brake fluid on the pad that is sticking. I have had the problem with other cars when I had a leaking cylinder, get a bit of brake fluid on the pad and the wheel locks like crazy! No cure I know of but to throw out the pads and start with clean new ones.

I would be surprised if the issue is a caliper.

 

[NSXF1]

I pulled off both front tires last night to get them balanced to fix a vibration ever since Xpo, (tires really do rotate on the rims under hard repeated braking when new), and found the usual drag on the drivers side, but the passenger side, (the one with the problem), was almost free spinning. Hit the brake and the drag was the same on both. Can't find any fluid leaks??? Should this tell me something? Master cylinder? Air in the lines? The car had been sitting for almost 2 weeks.

So, who has the best SS brake lines for a stock 92? Seems like the big SS line failure I read about, (besides the lines not being secured properly and rubbing through), is the swaged-on ends coming loose. Does any one make a set that has the better Earls, or Aeroquip fittings? I'd like to replace these before I do any more brake bleeds or troubleshooting. Thanks for the help.

 

[NSXF1]

Finally got a chance to swap pads. (Tough when you go from a nice garage to working in a storage locker with NO room.) Cleaned the rotors with a "Corner Kat" sander and scotch brite pad, lots of brake cleaner afterward, swapped pads and sure enough the lock-up switched sides. This is the strange part, while bedding the pads again, doing stops from 80-20 I could see 1 or 2 sparks go up past the top of the roof on the drivers side! I remember seeing the same thing at NSXpo when I had the wife drive the car and told her to brake hard while I was hanging out the window to make sure it was front passenger side. ( Ya, it was as stupid as it sounds) At the time I remember thinking, well, their track pads and very aggressive, so that must be normal. But the other side doesn't do it, so there must be a problem with the pad. Not a cheap fix, but better than rebuilding the caliper. Thanks for the advice. Still on the fence about the SS or OEM lines.

 

[Taj]

.........Still on the fence about the SS or OEM lines.

I installed the SOS SS brake lines and it came with the clear plastic cover over the SS braid to prevent debris from imbedding between the braid and the rubber hose. The installation is simple and no mod is required. It is a direct bolt on. It also firm up the brake pedal.

 

[BITeR]

Finally got a chance to swap pads. (Tough when you go from a nice garage to working in a storage locker with NO room.) Cleaned the rotors with a "Corner Kat" sander and scotch brite pad, lots of brake cleaner afterward, swapped pads and sure enough the lock-up switched sides. This is the strange part, while bedding the pads again, doing stops from 80-20 I could see 1 or 2 sparks go up past the top of the roof on the drivers side! I remember seeing the same thing at NSXpo when I had the wife drive the car and told her to brake hard while I was hanging out the window to make sure it was front passenger side. ( Ya, it was as stupid as it sounds) At the time I remember thinking, well, their track pads and very aggressive, so that must be normal. But the other side doesn't do it, so there must be a problem with the pad. Not a cheap fix, but better than rebuilding the caliper. Thanks for the advice. Still on the fence about the SS or OEM lines.

I have the same issue as you do. My front left locks up way early.
So your solution was to change pads? Meaning buy new ones? Can I solve this by any other method?

 

[SaberX]

I have the same issue as you do. My front left locks up way early.
So your solution was to change pads? Meaning buy new ones? Can I solve this by any other method?

I installed SoS stainless lines, new rotors and pads, got some new front tires and had a master NSX tech look at my ABS system. He said everything is fine, and that its just an old system and not as sopisticated as newer ones. After doing all that, it did get somewhat better - but its still not like I would expect.

 

[juejaimon]

I have the same issue as you do. My front left locks up way early.
So your solution was to change pads? Meaning buy new ones? Can I solve this by any other method?

Do you have stock brakes or aftermarket?

 

[juejaimon]

I installed SoS stainless lines, new rotors and pads, got some new front tires and had a master NSX tech look at my ABS system. He said everything is fine, and that its just an old system and not as sopisticated as newer ones. After doing all that, it did get somewhat better - but its still not like I would expect.

Saber... does one of your fronts lock up early?...

 

[BITeR]

Do you have stock brakes or aftermarket?

mine are stock. both pads and disks.

 

[SaberX]

Saber... does one of your fronts lock up early?...

Indeed it does... I'm at a loss as to what causes it. My car is corner balanced and aligned and all that goodness....