Mushy brakes - what next?

[lutera]

Sorry I'm reviving an old thread to let everyone know about the importance of properly bleeding the brake system & also to thank those who posted here.

Background: In the last year, I had the local dealer install a brand new master brake cylinder, s.steel brake lines, new rotors, Speedbleeders and Project Mu NS Street brake pads + 2 flushes with Honda Dot 4 fluid and 1 flush with ATE Blue. All this to try and fix the soft brake pedal feel but, no resolution.

I trusted the dealer to do this job right (like the other jobs they did) but after a couple of PRIME members strong insistance, I decided to flush the brake system myself. I used the (standard) procedure listed at http://www.danoland.com:80/nsxgarage/brakes/bleed/bleed.html with my son doing the pedal pressing honors.

To my surprise, I found a lot of air bubbles in the system. Strangely though, the very first caliper to bleed (RR) continued to show 1-2 very tiny air bubbles even after 40+ brake pedal presses. So I moved to bleed LF, LR & RF calipers which all bled fine with no air showing after approx. 15 pedal presses. I came back again to bleed the RR caliper and just when it was beginning to show almost no air bubbles, I ran out of fluid. So I completed the job & went for a test drive. Well all I can say is "what a difference"! Pedal is now quite firm and brakes grab quick.

I'm going to bleed the brake system fully again once my new supply of ATE blue arrives and I'm confident that brakes will feel fully normal after that.

 

[baynsac]

Sorry I'm reviving an old thread to let everyone know about the importance of properly bleeding the brake system & also to thank those who posted here.

Background: In the last year, I had the local dealer install a brand new master brake cylinder, s.steel brake lines, new rotors, Speedbleeders and Project Mu NS Street brake pads + 2 flushes with Honda Dot 4 fluid and 1 flush with ATE Blue. All this to try and fix the soft brake pedal feel but, no resolution.

I trusted the dealer to do this job right (like the other jobs they did) but after a couple of PRIME members strong insistance, I decided to flush the brake system myself. I used the (standard) procedure listed at http://www.danoland.com:80/nsxgarage/brakes/bleed/bleed.html with my son doing the pedal pressing honors.

To my surprise, I found a lot of air bubbles in the system. Strangely though, the very first caliper to bleed (RR) continued to show 1-2 very tiny air bubbles even after 40+ brake pedal presses. So I moved to bleed LF, LR & RF calipers which all bled fine with no air showing after approx. 15 pedal presses. I came back again to bleed the RR caliper and just when it was beginning to show almost no air bubbles, I ran out of fluid. So I completed the job & went for a test drive. Well all I can say is "what a difference"! Pedal is now quite firm and brakes grab quick.

I'm going to bleed the brake system fully again once my new supply of ATE blue arrives and I'm confident that brakes will feel fully normal after that.

Hey Lutera,
Thanks for being a man and updating your thread with the correct information and update. Most people would just never admit they could be wrong. I am glad it turned out well for you and it will help others here for sure.
Thanks

 

[RON98]

i would check your brake pads.

if you got aftermarket autozone or pep boy brands, they might not grab as well thus the small delay.

 

[lutera]

i would check your brake pads.

if you got aftermarket autozone or pep boy brands, they might not grab as well thus the small delay.

I recently installed Project Mu NS Street brake pads and they are working fine so far. Not too much different from OE pads IMHO but I do not drive/brake the car too aggressively.

 

[nsxtech713]

I have had simmilar problems like this in the past mostly the continuing tiny bubbles in the lines. Since the brakes have been bled numerous times try activating the ABS, find a long straight SAFE place to accelerate and jam the pedal to actvate the ABS do this 2 maybe 3 times see if the pedal feel changes if not check to see if all the caliper guides are moving freely. A stuck or binding caliper guide pin will give you a soft pedal feel on the initial stroke if a second pedal application gives a better pedal feel this could be your problem.

Carl

 

[BladesNSX]

Thanks for posting this again Lutera.

A few years ago, I had carbotech brake pads, SS brake lines, and Mutol Brake fluid installed. Without a doubt, my tech made sure to bleed the brakes properly. That said, the car had WICKED bite. I mean I was MUCH more impressed with how my car STOPPED rather than accelerated. For the past year, ever since I had my engine rebuild, where the engine had to be removed and rear suspension as well, I've lost that "bite", or "grabbiness" of the brakes.

Now, if I take the car to 120mph and stomp on the brakes, the brakes feel as though there's brake fade. In the past, I would be pressed up against the seatbelt. I've had new rotors installed, new carbotech brake pads, and still the same result. I was told that the master cylinder was fine. Now, I will see to bleeding the brakes properly. Perhaps there is still some air in the system. Would that lead to poor brake performance from hard deceleration from 100mph? Hmm, it's something I would really like to resolve soon.

 

[nsxtasy]

A few years ago, I had carbotech brake pads, SS brake lines, and Mutol Brake fluid installed. Without a doubt, my tech made sure to bleed the brakes properly. That said, the car had WICKED bite. I mean I was MUCH more impressed with how my car STOPPED rather than accelerated. For the past year, ever since I had my engine rebuild, where the engine had to be removed and rear suspension as well, I've lost that "bite", or "grabbiness" of the brakes.

Now, if I take the car to 120mph and stomp on the brakes, the brakes feel as though there's brake fade. In the past, I would be pressed up against the seatbelt. I've had new rotors installed, new carbotech brake pads, and still the same result. I was told that the master cylinder was fine. Now, I will see to bleeding the brakes properly. Perhaps there is still some air in the system. Would that lead to poor brake performance from hard deceleration from 100mph? Hmm, it's something I would really like to resolve soon.

Is it possible you have different Carbotech brake pads on the car now from what you had then? For example, maybe then you had their Panther Plus pads, which is a somewhat-streetable track pad (lots of squealing, but doesn't need much warmup), and now you have their Bobcat pads, which is strictly a street pad and won't stand up well to the heat of track use.

 

[MJK]

Now, if I take the car to 120mph and stomp on the brakes, the brakes feel as though there's brake fade. In the past, I would be pressed up against the seatbelt. I've had new rotors installed, new carbotech brake pads, and still the same result. I was told that the master cylinder was fine. Now, I will see to bleeding the brakes properly. Perhaps there is still some air in the system. Would that lead to poor brake performance from hard deceleration from 100mph? Hmm, it's something I would really like to resolve soon.

I agree - If the suspension was dropped and THAT is when brake feel went to sh*t, then I think I would try re-bleeding.

Is it possible you have different Carbotech brake pads on the car now from what you had then? For example, maybe then you had their Panther Plus pads, which is a somewhat-streetable track pad (lots of squealing, but doesn't need much warmup), and now you have their Bobcat pads, which is strictly a street pad and won't stand up well to the heat of track use.

I know Carbotech reformulated their pads a while ago. From personal experience, you can definitely cook the old formula Bobcats on the track. Once you do they lose some of their former 'bite', even after even after a caliper rebuild and fluid flush. That said, I seriously doubt you could cook them on the street.

As an aside, stainless lines did nothing to impact pedal feel.

 

[BladesNSX]

Is it possible you have different Carbotech brake pads on the car now from what you had then? For example, maybe then you had their Panther Plus pads, which is a somewhat-streetable track pad (lots of squealing, but doesn't need much warmup), and now you have their Bobcat pads, which is strictly a street pad and won't stand up well to the heat of track use.

Hmm, I ordered the Carbotech from SoS on the phone. I'm pretty sure I ordered the Panther Plus; however, it is possible that there may have been a miscommunication. If the bleeding does not show improvements, then perhaps I will go a new set of brake pads.

Edit: Now that I think about it, I recall either Chris or Greg(?) asking specifically which Carbotech brake pads I wanted. SoS makes sure you order the right set and asks what set you currently have on the car. Very diligent, as would be expected from SoS.

I agree - If the suspension was dropped and THAT is when brake feel went to sh*t, then I think I would try re-bleeding.

I know Carbotech reformulated their pads a while ago. From personal experience, you can definitely cook the old formula Bobcats on the track. Once you do they lose some of their former 'bite', even after even after a caliper rebuild and fluid flush. That said, I seriously doubt you could cook them on the street.

As an aside, stainless lines did nothing to impact pedal feel.

No, the car had been lowered a long time ago with adjustable Konis and Eibachs. The change happened after the engine work and the removal of the rear suspension.

To better explain what I experience: Let's say you just get on the track. You do an easy lap warm up. When you hit your first straight-away and get on the brakes at around 100+ mph. The initial response is adequate; however, you sense what feels a lot like brake fade as you are shaving off speed to around 50+ mph. I hope that makes sense :redface:

Until I can resolve this, I'm not putting her on the track. Just doesn't feel "right", compared to how it was before the engine removal. I think perhaps it is a result of air in the lines. Still, I don't know if that would cause such a premature feeling of brake fade.

 

[MJK]

No, the car had been lowered a long time ago with adjustable Konis and Eibachs. The change happened after the engine work and the removal of the rear suspension.

Poor choice of words on my part, sorry.

If the rear brakes were disconnected when the engine was dropped, and that is when the feel changed, then I agree that it is probably air in the lines. At least in my experience brake fade CAN feel like air in the lines. Missing small bubbles feels roughly the same as mildly cooked fluid to me. I'd try flushing the fluid. FWIW, if I whack the caliper a few times lightly with a hammer, bleed with clear tube, whack again, bleed again, etc it seems to get all the little air particles out faster.

If the calipers were never disconnected from the brake lines then I the above may apply but seems less likely to me. I would get in there and poke around for things that look odd like lopsided pad wear, fluid leaking from anywhere, torn piston boots, etc.

 

[ralph cerbone]

the best way i ve found to bleed brakes is with a MITY VAC pump, it is a hand operated vacuum pump,you can do it by yourself,the kit contains the pump and a plastic bottle , connect pump to bottle ,bottle to bleeder , pump till you develop a vacuum , then open bleeder and watch for air , close bleeder ,repeat untill there is no air entering bottle, just make sure master cyl. does not run dry, many times i watch people bleed brakes ,their helper will pump the pedal to fast and not let it come back all the way , fluid cannot enter the compensating port (in m/c) ,they keep bleeding and end up with a mushy pedal, when manually bleeding brakes ,pump slowly ,allow 10 sec. between each bleeding seq. , if you are replacing the master cyl , bench bleed it first, save you alot of time you can also use the mity vac to bleed hyd. clutches. brake fluid is hygroscopic(loves moisture ),keep container closed ,you dont want to create more problems .

 

[NSXDreamer2]

I agreed the fact that engine removal should have nothing to do with your brake system...

With that said, that "might" be one of your line got pinched by unknown reason in the process... I would at least wipe all dirt and moisture off the lines and caliper, then maybe exercise the brakes a little and try to see if there's any leak.

I have no luck with whatever shortcut way or tools the shop used. The Best ever system is the speedbleeder and one helper(speedbleeder made him/her optional).

 

[BladesNSX]

Thanks for the advice everyone. A buddy of mine, and fellow NSXer, purchased the speed bleeders and found it greatly improved his braking. He lives rather close to the "Dragon's Tail". I'm visiting him for a Dragon Run within a couple months so I will try this out with him, as well as the other advice given. The brakes are good for around town driving and perform well compared to most other cars. It's high-speed braking that I'm concerned with, so I will keep my driving at cruise speeds around town till I can get this looked at. Once again, thank you for all the advice. I will do a follow-up post once I get this resolved.

 

[MJK]

I agreed the fact that engine removal should have nothing to do with your brake system...

Depends on how it was dropped. If you dropped the whole rear subassembly then that would involve disconnecting the rear brakes, and potentially introducing air into the system.

A buddy of mine, and fellow NSXer, purchased the speed bleeders and found it greatly improved his braking. He lives rather close to the "Dragon's Tail". I'm visiting him for a Dragon Run within a couple months so I will try this out with him...

Speedbleeders don't change the feel of the brakes unless they just helped get air out. I have them. Post up if you all want to make some sort of meet at the Dragon. I know a couple NSXers local to it as well, and make it over there every once in a while myself.

 

[lutera]

My car has speedbleeders and they are made from brass. I just found out that they make steel version/s as well. Are steel ones better than brass?

 

[BladesNSX]

Depends on how it was dropped. If you dropped the whole rear subassembly then that would involve disconnecting the rear brakes, and potentially introducing air into the system. Post up if you all want to make some sort of meet at the Dragon. I know a couple NSXers local to it as well, and make it over there every once in a while myself.

Yes, I do believe the entire rear subassembly was removed. I had the top-end of the engine rebuilt, along with the suspension, since I had a bad 3rd gear synchro.

I debating on going around the end of March or Early April. I had just planned to drive up and spend those days with an NSX friend. However, I will post a new thread (assuming a Dragon Run thread isn't started before) when I'm more certain as to when I will go.

 

[NSXDreamer2]

Depends on how it was dropped. If you dropped the whole rear subassembly then that would involve disconnecting the rear brakes, and potentially introducing air into the system.

Speedbleeders don't change the feel of the brakes unless they just helped get air out. I have them. .

most likely, you have air trapped in the system, with speedbleeder, MJK was right, it shouldn't helped on performance by itself, it just make the bleeing process easier and minimize human mistakes..

This works extremely well, have someone only spotting the brake cylinder, make sure they refill before it's empty, that should be a very easy job, even a 4 y.o can do if he/she is paying attention.

release the farthest speedbleeder, just go ahead and stomp brakes, so it's Right Rear, then Left Rear, right front, left front... I will then do LR, RF then RR and LF and check if you got all clean fluid and no bubble.

now if you have anyone at work or your household need some exercising... :wink:

 

[lutera]

I'm posting on this old thread again because it may prove useful to some one.

I read on NSX Prime somewhere lately that air bubbles may get stuck to caliper wall/s and, they (calipers) should be tapped during the bleeding process.

Honestly I was a bit skeptical as the last 2 flushes did not find any air in the lines. However, I had a litre of fresh ATE blue brake fluid laying around, so I did it any ways. To my surprise, air bubbles came out of RF caliper. Others were O.K.

However, it has made noticeable improvement in brake pedal feel. It's firmer and bites quicker. What's remarkable that the difference was more than any other change I made (read above). Now I'm wondering if new brake pads such as HP+ will make the brakes bite even faster :wink:.

 

[GreyHoundSteve]

I'm posting on this old thread again because it may prove useful to some one.

I read on NSX Prime somewhere lately that air bubbles may get stuck to caliper wall/s and, they (calipers) should be tapped during the bleeding process.

Honestly I was a bit skeptical as the last 2 flushes did not find any air in the lines. However, I had a litre of fresh ATE blue brake fluid laying around, so I did it any ways. To my surprise, air bubbles came out of RF caliper. Others were O.K.

However, it has made noticeable improvement in brake pedal feel. It's firmer and bites quicker. What's remarkable that the difference was more than any other change I made (read above). Now I'm wondering if new brake pads such as HP+ will make the brakes bite even faster :wink:.

Thanks for revisiting this because i am having the same problems you had. I first installed new cross drilled rotors, ss brake lines, new oem pads all around and had my calipers rebuilt and pc'd by SoS and used Motul rbf600. The brakes sucked afterwords. I had them bleed three times by two different places. I just bought a new master cylinder and am having it installed now. If they are still mushy then i am going to try the tapping the caliper bleeding thing. I don't know what else it could be?

 

[ChopsJazz]

Bleeding the brakes is a time-consuming task. But it should be done carefully and IN THE RIGHT ORDER, starting with the caliper furthest from the reservoir (ie. the RR.) and progressing in that manner. FWIW, I've never tapped the calipers during the operation, but it doesn't sound like a bad idea.

I'm glad this thread has come back too. :wink:

 

[lutera]

Thanks for revisiting this because i am having the same problems you had. I first installed new cross drilled rotors, ss brake lines, new oem pads all around and had my calipers rebuilt and pc'd by SoS and used Motul rbf600. The brakes sucked afterwords. I had them bleed three times by two different places. I just bought a new master cylinder and am having it installed now. If they are still mushy then i am going to try the tapping the caliper bleeding thing. I don't know what else it could be?

FYI I mainly followed the procedure listed at http://danoland.com/nsxgarage/brakes/bleed/bleed.html. As I mentioned in my post/s above, it took me 40-50 brake pedal presses to clear one particular (right rear) caliper. Some tiny bubbles kept showing up even after 5-10 clear pedal presses. It would be good to have 2-3 litres of fresh brake fluid (it's relatively cheap). I had my son help me with pumping the pedal while I tapped the caliper. Even though I have speedbleeders installed, I tightened the valve/s a bit after every pedal press, just to make sure no air can go back (a box spanner works best). I had the fluid bottle sitting higher than the caliper so that the tube is always full of brake fluid. Also it may be nice to have a rubber mallet/hammer for tapping. I used a normal/steel hammer and had to be careful not to damage anything on the caliper. Make sure there is bright light while you bleed e.g. a floodlight. Certain light angle can help see the bubbles better. Some of the air bubbles were so tiny, they were hard to see in regular light. As many have said before, pump, pump & pump again until no bubbles can be seen at all. Good luck & hope this helps clear your brake issue.

 

[Briank]

Also pump slowly, rapid pumping just mixes air into the fluid which takes forever to flush out.