Brake problem - pedal depresses all the way

[Sudesh]

Well took the car out today for a run, all was fine up until a couple of hrs ago when the brake pedal lost all pressure, the ABS light and hand brake light came on and stayed on. So I pulled back into the office and had a look round, the brake fluid was low, so I topped it up and the started the car again, warning lights all went out ok, but the pressure didnt return to the pedal. So I'm having a look round now for any signs of a leak but cant see anything so far?

Question now is, how do I get the pressure back in the system?

[Kaz-kzukNA1]

Hi, Sudesh.

First of all, I’m glad you managed to park the car after loosing the brake pressure.

Brake is a hydraulic system so if you are not getting any pressure at the pedal, you have trapped the air somewhere in the system when the brake fluid level was too low.

As your hand brake light came on, the fluid level was way too low and thus, it is very likely that you have trapped the air inside the brake master cylinder and somewhere in the brake line.
You need to bleed the system to recover the solid feeling.
You may require extra time to push out all the air from master cylinder unless you use pressure bleeding.

I’m quite sure you are trying to find out why the brake fluid level dropped so low. As in your post, so far, you haven’t seen obvious leakage.
I think you will be looking at the brake callipers, piston boots/seals, brake hoses and so on.

Addition to these, please check the base of brake master cylinder. I have seen lots of NSX with leaking brake master cylinder. When the leakage is small like this one, it is hard to see.
5698


The leakage will be small but if it was left without being noticed, it would cause rust on the master vacuum power case and would look like this.
5699

Just feel for the wet fluid at the base of brake master cylinder or at the bottom of brake vacuum master power case.

Although the rubber parts for the brake system have been improved significantly over the past years, I personally recommend servicing the brake callipers and master cylinder at regular interval.


Hope your NSX will be back on the road soon.


Regards,
Kaz

[Sudesh]

Kaz,

Thanks for the reply and info!!

I will ahve a closer look now at what you mentioned for leaks.

Can you tell me what is the best way to bleed the brake system?

[Sudesh]

Kaz,

I had a look round the master cylinder and its bone dry and looks quite new with no signs of rust anywhere.

However after you mentioned checking the calipers and brake lines, I got the car raised and there it was, leak on the front passanger side, which I assume is coming from the black brake line that I pointed too in the second pic.

http://i77.photobucket.com/albums/j77/icongroup/NSX/000_0020.jpg
http://i77.photobucket.com/albums/j77/icongroup/NSX/000_0022.jpg

[Sudesh]

So I'm after a set of brake lines/hoses now. Do you guys recommend the braided type? I seen these "GOODRIDGE" hoses on ebay, what do you think?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=270402852730


I'm also going to bleed the system and was looking at this write up

http://www.danoland.com/nsxgarage/brakes/bleed/bleed.html

[Kaz-kzukNA1]

Hi, Sudesh.
Glad you managed to find the leakage point.

Nice coilover kit you have. Looked like Zeal from Endless in Japan…Slightly different mounting shape from the one I just worked with.

Regarding the braided hose (or PTFE hose with stainless braided cover), I use them but requires regular inspection as you can’t detect any symptom of damage/leakage unlike the OEM rubber one.
I use the one with stainless steel end fitting and not the zinc plated one.

Although I used Goodridge products through my business many times, I never used it on NSX so recently, I visited one of the member here to have a look at the build quality of their NSX brake line out of the box. He bought one set and it was still in the box.

It looked quite good with very good flexibility. The reason is, recently, I noticed one of the products from US didn’t have this flexibility and causing splice on the outer cover.

On Goodridge one, the hose bracket was made out of some sort of plastic. The price was very competitive compared to the one I use.

As mentioned above, braided line will require regular inspection and although people believes that it will last forever, in fact, some of the manufactures are recommending to replace them every 3 years. I overhaul the callipers every 2 - 3 years so it makes sense to replace the hoses at the same time any way for me.

The procedure from Dan is great. He also wrote very nice procedure for ABS service.
Some additional tips for you.

If I’m not pressure bleeding the system, I prefer opening the bleeder plug as minimum as possible and not like 1/4 to 1/2 turn. I have never measured it but I think it is something like 1/8 turn if you torqued the bleeder plug at correct spec in the past.

When I start the bleeding process and If I can press the brake pedal with ease, I’ll stop there and close the bleeder plug a little until I can feel some resistance and yet being able to push out the fluid.

If I’m doing the brake pedal method and not pressure bleeding, I normally press 20 times for the Rear and 10 times for the Front. As I need to press the pedal reasonably hard, I’ll be sweating at the end of bleeding process. I'm getting old these days...

Unless you have some sort of tool to top up the reservoir automatically, keep eye on the fluid level during the process. Otherwise, you'll need to start the whole process again.

Just take your time especially when lifting the pedal if you are doing the process on your alone. Also, tap on the callipers with plastic hammer to release any air bubbles from the internal wall of the callipers but may be I'm asking too much.

On the workshop manual, the bleeding order on Right hand drive NSX prior to Bosh style ABS system is different from the one on Dan’s diagram.

His procedure is for LH drive car.

It is RL, FR, RR, FL for UK and JDM NSX.

On the later model with Bosh style ABS (controller built into the accumulator), the manual states to start from the Front. I think it is something to do with the Proportioning Valve but not sure.

Interesting to know what kind of brake hose you were using when it leaked. Looked like OEM bracket but not attached to the coilover body. Zeal comes with tyrap for the front, I guess.

If you need further information, just let us know.


Regards,
Kaz

[Sudesh]

Well, I have ordered the GOODRIDGE braided hoses from a local supplier, and just wondering what is the best method to replacing the hoses?

I take it that, I replace the hoses first then bleed the lines?

Also as I have aftermarket suspension, what is the best was to attach the hose to the shock body?

Some of the guys on prime reckon that as the hose was not attached correctly to the shock body that, it could have aided in the hose being damaged.

[Sudesh]

Hi Kaz,

Thanks again for the great info and help.

My car does have Zeal suspension fitted! The hoses are OEM and as mentioned above, they were not attached to the shock body and I couldnt see anywhere they could be attached, so I'm guessing I will have to make something up or as you mentioned, they are more than likely cable tied.

[Kaz-kzukNA1]

Hi, Sudesh.

Not sure whether I understood the point of your question correctly or not but yes, you are right in saying to replace all the hoses first and then bleed the system.

When you replace the hoses, always start at the calliper side.
5702
This is to avoid any stress or twist on your new brake line after installation. Use new banjo washer and torque the bolt to the spec and then move onto the chassis mount side.

First, clean the nut and brake pipe close to the chassis mount area like in the photo.
5700
You will have lots of debris there. The nut should slide up and down for a few cm over the brake pipe and you don’t want to trap any sand or debris inside the fitting of new brake line.

Be very gentle to the brake pipes and pay extra attention to the torque especially when tightening the nut into the brake hose fitting. If you look inside of your new brake line, there is a conical section at the chassis mount fitting. This will be attached to the end of your brake pipe so if you over-torqued the nut, you’ll widen or even splice the edge of brake pipe mounted on the chassis side. You may be able to repair it but in the worst case scenario, you’ll need to replace the brake pipe which will require some juggling and head scratch moment. Make sure to use flare nut wrench for this process as it is so easy to round off the edge of the nut with other tools such as spanner.

Without looking at the actual leakage point, it is difficult to say whether the hose was damaged by external force/scratch or not. As you mentioned, it was OEM rubber one so it could split with long long usage. It will normally first expand though. The bracket was designed to hold the hose away from other suspension area parts and to reduce the vibration so if it was not fixed to anything, it won’t be a good thing any way.

If you still have the OEM damper kit, you may be able to modify the original front hose bracket but they are in black. You may want to design your own bracket to match the colour of your nice coilover kit or go down the route of high temperature spec tyrap like this one.
5701

PS. nice tyre you have... BS 010? Couldn't read the week and year info from the photo...


Regards,
Kaz

[Sudesh]

Kaz,

Thank you very much for the geat info! Was a great read and will definately help when I replace the hoses, hopefully this week or weekend as I'm waiting for them to arrive into stock. I dont have the OEM dampers so not sure what the original front hose bracket looks like? Have you any pics as I might be able to fabricate something similar to fit? Failing that the high temperature spec tyrap will be the other solution. I cant remember what the tyres are on the front lol.

[Kaz-kzukNA1]

Hi, Sudesh.

Couldn't find the drawings so only the photo. It may help you to look at the workshop manual as well. It's in the suspension (Front Damper) section and in other areas as well.

Some of the photos from my archive.
5728 5729 5730

At the bottom of this photo, you'll see the Bilstein damper.
It has simple tab as brake hose bracket.
5731

Regards,
Kaz

[Sudesh]

Thanks Kaz for the pics!

I seen the brackets in the parts book, I was going to order new ones and have them painted to silver to match my zeal suspension.

Will the OEM hose brackets fit the zeal suspension ok?

[Kaz-kzukNA1]

Hi, Sudesh.

I think you'll struggle to use OEM bracket on Zeal.

As you can see from the photos below, Honda designed the bracket so that it will make D-shape rather than O-shape to avoid any movemens around the damper body. The damper body has small recess to accomodate this flat line by the bracket bolt.
5736 5737

On some of the Koni dampers, they have simialr recess on their body so they can use OEM bracket.

For Zeal dampers, I think it is best to make your own bracket or use high temperature spec tyrap. I prefer the ones from T&B.

Regards,
Kaz

[Sudesh]

Hi, Sudesh.

I think you'll struggle to use OEM bracket on Zeal.

As you can see from the photos below, Honda designed the bracket so that it will make D-shape rather than O-shape to avoid any movemens around the damper body. The damper body has small recess to accomodate this flat line by the bracket bolt.
5736 5737

On some of the Koni dampers, they have simialr recess on their body so they can use OEM bracket.

For Zeal dampers, I think it is best to make your own bracket or use high temperature spec tyrap. I prefer the ones from T&B.

Regards,
Kaz

Yeah I see that now! Good pics Kaz!

I think I'll have to try something else, or just use the tyrap.

[Sudesh]

Brakes all sorted!! new Goodridge Hoses, complete bleed and flush and all went pretty smoothly. Only one issue and that was one of the rear brake line nuts that goes into the brake hose, was over torqued and the nut head was stripped, so the flare wrench wouldnt event catch the nut head. But I managed to get it off ok with vise gripes. I have to say I noticed an improvement right away with the way the brake pedal feels and car stops. The Goodridge hoses were well put together.
Thanks Kaz for the help and the danoland write up was great help too.