Boiled brake fluid or bad master cylinder?

[Cozmo]

I was on my way home from a car show on Sunday and got stuck in a 10 mile stretch of stop and go traffic after having been driving for about 30 minutes. I noticed my brake pedal felt funny and thought maybe I imagined it but a couple minutes later my pedal sunk to the floor. I pulled off the next exit and checked things out the best I could. My reservoir was still full. I pumped the brakes a few times and it was still soft, then finally felt normal again. There was no indication of leaks from any of the calipers or anywhere else under the car. The calipers weren't warm either.

I limped it home making sure to leave a ton of space between me and the car in front of me (pissing off lots of people in the process). The pedal sunk to the floor a few more times on the way home so it seems to me that the master cyl is dying on me.

Someone else suggested that maybe I boiled the fluid (which is about 1.5 years old). The right rear (SS) brake line is fairly close to the turbo which I suppose could've done it if I was driving slow for a long time getting very little air flow. I've never had any problems like this in this car before.

Anyway I ordered a new master cyl and will swap it out anyway. This is the first time my car has been "down" due to mechanical problems. :frown:

 

[mickeylex]

Sounds like master cylinder on it's way out. Check at the back of it where it mounts to the car. You leak is most likely there.

 

[Cozmo]

Since the fluid was still full I figured it was just leaking around the seals back into the reservoir.

 

[Cozmo]

The scary thing is I was giving family members some very spirited test rides the day before. If this had happened then I might have totalled my car or worse.

 

[e.pie]

Sounds like a master cylinder, I just replaced mine last month.

I got it from partsgeek.
http://www.partsgeek.com/catalog/1991/acura/nsx/brake/brake_master_cylinder.html

 

[pgilliam1]

Mine did the same thing. It was the MC. Fairly easy DIY in this car. I bench bled mine before the install. I recommend doing it on the NSX because it has a tendency towards being more difficult than other cars to get all the air out of the system. I got a rebuilt one on eBay and was very satisfied with the quality. Been in about a year with no problems.
Good Luck!

 

[Meeyatch1]

Sounds like a master cylinder, I just replaced mine last month.

I got it from partsgeek.
http://www.partsgeek.com/catalog/1991/acura/nsx/brake/brake_master_cylinder.html

I have one in the garage that I need to put on my '94 NSX. There was not a DIY that I could find on here. Does anyone have a link, or info to how hard this is to do on my own?

 

[CL65 Captain]

I have one in the garage that I need to put on my '94 NSX. There was not a DIY that I could find on here. Does anyone have a link, or info to how hard this is to do on my own?

It's very easy if you have small fingers. The hard part is the nuts on the inside of the car on the firewall. It is very cramped and you are in a tight space under the steering well on your back and then stomach and then yelling *&@)! because you can't reach the damn nut.

 

[goldNSX]

It's very easy if you have small fingers. The hard part is the nuts on the inside of the car on the firewall. It is very cramped and you are in a tight space under the steering well on your back and then stomach and then yelling *&@)! because you can't reach the damn nut.

You don't work on the inside for just the master cylinder. If you talk about the booster, then yes, you might be right.

 

[warrenw]

I have one in the garage that I need to put on my '94 NSX. There was not a DIY that I could find on here. Does anyone have a link, or info to how hard this is to do on my own?

Two nuts and two brake lines. Very easy. 10min tops. another hour to bleed the brakes afterwords. should be a DIY on bleeding brakes.

 

[Cozmo]

Yeah it took me longer to bleed the brakes than to change the master cyl. It was many times easier than changing the clutch master/slave.

 

[CL65 Captain]

You don't work on the inside for just the master cylinder. If you talk about the booster, then yes, you might be right.

ya, you're right. I did both together. Master is a piece of cake. Just have to make sure you bench bleed it before putting on or have one of those power bleeders that pressurizes the reservoir to get it going.