Question about NSX brake pedal feel

[zmt]

Hey everyone,

I've been trying to get behind the wheel of a few different NSXs to see what I like and dislike about the cars (manual steering feels better than EPS, etc) and I've noticed something on both cars I've driven...

<flame suit>
The brake pedal sucks
</flame suit>

The pedal effort at speed is super high, like freakishly so. I would have chalked it up to a fluke or bad brake booster but both cars exhibited the same behavior. I've owned 5 different honda/acura products produced over 20+ years and a bunch of other cars from different makes and I've never felt brakes like these cars had on a normally functioning car.
The two cars I drove were a 95 T with 36k miles, and a 91 with 74k.

Any help on what could cause these cars to behave like this? Is it a known issue, or did I just get really unlucky and have two cars that share the same malfunction?

In other news, the shifter makes me miss my S2000 (meaning it's great), and the engine note is probably the best I've heard in any car I've ever driven/thought about owning.

 

[ChrisK]

What do you mean by high effort? You mean you have to press really hard to get the car to slow down? Could be just the type of brake pads those NSX's have because I have owned a lot of different Honda's and Acura's and the NSX brakes don't really feel any different too me. Pedal pressure is firm not soft, and I while I haven't been up to speeds like some members here I have taken my NSX from 100 MPH to 40 MPH to take a left hand turn with little to no effort.

 

[Hugh]

Something is not right. As Chris mentioned the normal pedal effort is firm but definitely not hard as you describe. The brakes should be very easy to modulate but when stomped on will stop the car like a battleship anchor was thrown out of the trunk.

If you can find a stretch of road to do this safely, take the car up to 60 or 70 mph, take your hands off the steering wheel and stand on the brake pedal. The car should come to a very fast stop while maintaining a straight track.

 

[pgilliam1]

If the brakes were really hot (were you doing a bit of spirited driving?) you may be experiencing brake fade. Old fluid or cheap pads can cause fade to happen at lower temps. Ask the owners what maintenance they've done on their braking system. The type of pad makes a huge difference in these cars. Could be, they both had air in the lines (the NSX is the most particular car of any that I have owned for this).

 

[Hugh]

Air in the lines would make the pedal feel mushy, not harder. A hard pedal is more often than not related to a booster issue / vacuum to the booster issue or one or more faulty calipers.

 

[pgilliam1]

True, but wouldn't it also make you press harder on the pedal to slow down.

 

[Hugh]

True, but wouldn't it also make you press harder on the pedal to slow down.

 

[nsx_2k]

The pedal feel you describe as requiring high effort to slow the car down is not normal. As Hugh pointed out the NSX has very easy to modulate brakes. It should easily bring the car to a standstill without any drama and little effort.

 

[PHOEN$X]

I have not heard any complaints about this before, so I did a search and found only one prior thread where someone complained about brake pedal feel:

http://www.nsxprime.com/forum/showthread.php?t=46468&highlight=brake+pedal+feel

Most of us have other cars so if this was a common issue, there would be a lot more threads discussing the subject. I don't know how you lucked out driving two NSXs with bum brake pedal feel.

 

[zmt]

I have not heard any complaints about this before, so I did a search and found only one prior thread where someone complained about brake pedal feel:

http://www.nsxprime.com/forum/showthread.php?t=46468&highlight=brake+pedal+feel

Most of us have other cars so if this was a common issue, there would be a lot more threads discussing the subject. I don't know how you lucked out driving two NSXs with bum brake pedal feel.

Yeah, I did a lot of searching before I posted because I thought the chances of me finding two cars with similar/identical brake issues was probably out of the realm of possibility.

These were both stock cars with as far as I could tell stock brakes. There definitely wasn't an air/fluid compression problem because the pedal was as firm as firm could be. Not the master cyl either because there was no pedal-to-the-floor behavior or anything like that.

The best way I could describe it is like driving a car w/o assisted brakes (think dedicated track car, etc), or a car with super aggressive pad compound that needed to be heated up before really grabbing. Low speed braking felt mostly normal if you didn't need to do any serious slowing or stopping, but any higher speed braking or wanting to shed any kind of speed in a hurry meant you had to mash the hell out of the pedal to get the car to respond.

As my wife put it, "it feels like there's a midget under the pedal pushing back up at me." She only drove the '91, but if you blindfolded me and asked me to use the brakes on both cars, I couldn't have told you which was which.

A hard pedal is more often than not related to a booster issue / vacuum to the booster issue or one or more faulty calipers.

That's what I was thinking; is brake booster/vacuum loss a common issue on the NSX?

If the brakes were really hot (were you doing a bit of spirited driving?) you may be experiencing brake fade. Old fluid or cheap pads can cause fade to happen at lower temps.

What we felt was there from startup and felt pretty consistent through the test drives. I even tried to put some heat into the pads to see if they were using a more track-oriented compound, but I never felt a change.

I guess we'll need to find a third car to compare. I'm coming to terms with the clutch engagement (not bad necessarily, just different from all my other car experience), but I don't think I can live with brakes like we've seen.

 

[ChrisK]

Like everyone has said, this is NOT normal. What cars do you have experience with in terms of brake performance if you don't mind me asking. I just want to get a feel of what you are familiar with. For me, the feel of the NSX brakes are virtually identical to any other Honda/Acura I have owned. The performance in terms of stopping power feels better though because the NSX is so much lighter than most cars that it stops very easy. I also have experience with my old E46 BMW, which I feel had great feeling brakes as well. Now, the Lexus cars I've owned too me feel like it has over boosted brakes. I don't like how grabby and touchy they feel when you tap the brakes lightly. The Honda/Acura and NSX brakes IMHO feel more linear.

Anyway, I think virtually every NSX owner here has driven and owned multiple cars of other makes and brands and the only complaint I've ever recall hearing was from a few that track their car and complain about brake fade. However, that is understandable as track use takes a toll on most any stock brakes.

Also, the NSX definitely doesn't feel like someone is pushing back on the pedal. The only time I've remotely experienced anything that could be similar is when I activate the ABS system.

 

[A.S. Motorsport]

Well it's hard to describe and compare with out actually seeing or feeling the car.

But i do understand your point if I drive in a french car for a few hours than get back in to my Legend the difference is huge, much more pedal force needed (stainless brake lines and bigger brakes) Although it's much more predicable and very easy to modulate.

 

[zmt]

What cars do you have experience with in terms of brake performance if you don't mind me asking.

We currently own a 2007 335i coupe, which has brakes I think some people would call overboosted. they definitely require little pedal effort. We've also got a 2001 MR2 spyder and 2006 town and country. Both NSXs I drove required what I would call orders of magnitude more pedal force than any of our current cars to exhibit the same speed reduction when braking.

I've owned and either tracked or at least driven spiritedly the following cars:

'81 honda prelude
'91 acura integra
'95 acura integra GS-R
'98 acura EL (can't say I ever flogged this one)
'02 honda S2000
'08 Subaru STi

we've also owned an '01 saturn SC1, '95 Rav4, and an '03 Toyota tacoma.

Definitely not brake fade, and definitely didn't feel the ABS kicking in. Until I find another car to drive, I'm going to have to chalk it up to brake booster/vacuum issues with the two cars I drove.

 

[ChrisK]

We currently own a 2007 335i coupe, which has brakes I think some people would call overboosted. they definitely require little pedal effort. We've also got a 2001 MR2 spyder and 2006 town and country. Both NSXs I drove required what I would call orders of magnitude more pedal force than any of our current cars to exhibit the same speed reduction when braking.

I've owned and either tracked or at least driven spiritedly the following cars:

'81 honda prelude
'91 acura integra
'95 acura integra GS-R
'98 acura EL (can't say I ever flogged this one)
'02 honda S2000
'08 Subaru STi

we've also owned an '01 saturn SC1, '95 Rav4, and an '03 Toyota tacoma.

Definitely not brake fade, and definitely didn't feel the ABS kicking in. Until I find another car to drive, I'm going to have to chalk it up to brake booster/vacuum issues with the two cars I drove.

I had a 91 Integra too. I also used to have a 89 Prelude as well as a multiple Acura Legends. All of those cars IMHO have similar brake characteristics as the NSX brakes. In fact the Legend brakes are very similar to the NSX brakes. The NSX should feel like a Honda. Anyway. Good luck and hopefully you do get to drive an NSX with no suspected issues.

 

[PHOEN$X]

Until I find another car to drive, I'm going to have to chalk it up to brake booster/vacuum issues with the two cars I drove.

Yeah, I'd say that what you experienced was not definitely normal. If it were, all the car magazines would have written about it, in addition to substantial buzz in the Honda & NSX forums, and no such thing has happened. In fact the top result for a google search about NSX brake feel leads back to this thread, which should tell you that the issue is an anomaly rather than a normal occurrence.

 

[A.S. Motorsport]

I had a 91 Integra too. I also used to have a 89 Prelude as well as a multiple Acura Legends. All of those cars IMHO have similar brake characteristics as the NSX brakes. In fact the Legend brakes are very similar to the NSX brakes. The NSX should feel like a Honda. Anyway. Good luck and hopefully you do get to drive an NSX with no suspected issues.

Integra, Legend and NSX are nearly identical.

 

[s14_tat]

When I first got my car years ago, I thought the brakes sucked on the stock pads. the pedal was nice and firm and easy to modulate but it required more effort to get it to stop. I swapped out the pads to hawk hp+ and it made a night and day difference. The freaking thing just stops with very very little effort and I had to relearn to stop smoothly while retaining the stock firm pedal feel that I love about this car.

 

[dirtbag]

How you're describing it, I think it's designed this way. At least on the other zero-travel (or near zero travel) brake systems I've driven are pretty firm and requires slightly extra pedal effort with the "applied force to stopping power" being very linear. However it's much more consistent and allows you to modulate the brakes a ton easier than a system with an oversize booster.

For example, when I mean more effort, typical daily driven passenger cars/minivans that have monster brake boosters you can lock up the brakes using a single big toe. The NSX (& Viper) it'll take almost all your toes. This is of course given if you were to use the same pad comparing both systems. Usually recommended pads are different between a minivan and extreme sports car where sports cars you'll have to bring them up to temp for optimum bite.

So in short, stock for stock the brakes in my NSX & Viper react very similar to each other, but drastically different than my Saturn and Integra.

 

[HockeyGoalie]

How you're describing it, I think it's designed this way. At least on the other zero-travel (or near zero travel) brake systems I've driven are pretty firm and requires slightly extra pedal effort with the "applied force to stopping power" being very linear. However it's much more consistent and allows you to modulate the brakes a ton easier than a system with an oversize booster.

For example, when I mean more effort, typical daily driven passenger cars/minivans that have monster brake boosters you can lock up the brakes using a single big toe. The NSX (& Viper) it'll take almost all your toes. This is of course given if you were to use the same pad comparing both systems. Usually recommended pads are different between a minivan and extreme sports car where sports cars you'll have to bring them up to temp for optimum bite.

So in short, stock for stock the brakes in my NSX & Viper react very similar to each other, but drastically different than my Saturn and Integra.

I think dirtbag is right. His answer is probably correct......

If not, I have another theory, the brake fluid on the two NSX's was never changed or not changed in years.

Car nuts like us change our brake fluid every 2 years (factory recommended). The public never changes it and both cars you drove are 17 and 21 years old. The fluid may be very low in both cars or not functioning properly due to age.

 

[PHOEN$X]

If not, I have another theory, the brake fluid on the two NSX's was never changed or not changed in years.

Car nuts like us change our brake fluid every 2 years (factory recommended). The public never changes it and both cars you drove are 17 and 21 years old. The fluid may be very low in both cars or not functioning properly due to age.

I suspect this could very well be the case. Many owners (guilty myself :redface often forget to change the brake fluid frequently as recommended due to the low amount of miles we put on them.

http://www.nsxprime.com/wiki/Schedule_(Maintenance)

I need to do my transmission oil as well probably. Maintenance...fun stuff...

 

[dquarasr2]

If I may throw my $.02 in here . . . .

When I first got my NSX and tracked it I had a hell of a time with the brakes. The pads would contact the rotors only near the hub, so when they started cooling the rotors would crack due to the centers being very hot and the outer portion of the rotors radially cooler by comparison. The pads would wear crooked, too.

In spite of lubricating the caliper slider pins with fresh high-temperature synthetic grease, since I didn't know what the problem was, I didn't completely clean out the caliper grease. Turned out that the grease in the caliper was like putty, almost like glue. The calipers were in serious need of rebuilding. I also wonder if the pistons were starting to seize.

While I didn't rebuild them (I found a complete set of 2001 brakes for my '91), I am sure my problems were lack of maintenance or previous use of improper grease. The slide pins were galled as well.

So, I'd say that it could be an easy fix with a good caliper rebuild, fresh fluid, new slider pins, and a appropriate street compound. Unless as others have noted, the brake booster needs some help, too.

No, high pedal pressure is not normal on an NSX.