Brake master cylinder replacement/line fluid capacity question

[Chris Yewdall]

About to drop a new master cylinder in this coming weekend as the brakes are soft and there is fluid leaking around the servo now - picked up the 11-2800 from Cardone so I'll be swapping over the reservoir from the old to the new one. While I'm stripping down the brakes, I'll flush out the lines and put some new DOT4 in. I read the brake bleeding wiki and see that the brake bleed order is RR, LF, LR, RF however I was wondering how much fluid is needed to flush and fill the lines. Anyone know how much fluid is needed for a line flush? Also, since I'm removing the master cylinder, should I flush the old fluid out of the lines before I remove the old cylinder or should I leave the lines as full as possible with the old fluid so that there is as little air as possible in them after I replace the master cylinder?

 

[Larry Bastanza]

Have a QT on hand. Bench bleed the master before installing it. No need to flush prior to the change.

HTH,
LarryB

 

[Chris Yewdall]

Thanks Larry - if I'm using a pneumatic brake bleeder connected to my compressor, do I still need to bend bleed the master cylinder? Looking around online, it looks like you have to buy two of the master cylinder bleeding kits to get the job done since most appear to only come with one of each of the different sized brake pipe adapters and there are two on the NSX cylinder. One reviewer on Amazon even pointed out that he hadn't bought the master cylinder kit to bleed the brakes on a unicycle.....

 

[xxxdominion]

Thanks Larry - if I'm using a pneumatic brake bleeder connected to my compressor, do I still need to bend bleed the master cylinder? Looking around online, it looks like you have to buy two of the master cylinder bleeding kits to get the job done since most appear to only come with one of each of the different sized brake pipe adapters and there are two on the NSX cylinder. One reviewer on Amazon even pointed out that he hadn't bought the master cylinder kit to bleed the brakes on a unicycle.....

Bench bleeding the MC is a must like Larry pointed out.

I just installed the RL BBK and used the 25 dollar hand pump bleeder from harbor Freight. Worked like a charm and comes with a 100 ml cup that attaches to the vacuum lines. I bled RR - RF -LR- LF twice over and got a firm pedal.

To do a flush you'll want to attach the MC to the Booster fill with new fluid (id recommend using the blue fluid if you can get your hands on ithttp://www.amazon.com/ATE-706202-Or...sr=8-1&keywords=super+blue+racing+brake+fluid). That way, when you begin the flush you'll know when you've flushed the lines when you start pulling blue fluid into your vacuum reservoir cup. do this on all four corners until you're pumping new fluid, then bleed all four corners according to the manual being careful to avoid completely draining the MC reservoir, or you get to re-bleed your MC.

Unfortunately, I need to replace my brake booster and MC after already installing the BBK as I have developed a hiss on the back of the MC which is allowing fluid to seep into the booster and on to the diaphragm. Cheers, hope this helps!

 

[htmachine]

Chris
I got the Cardone unit also. There was bench bleeding fittings in the box with hoses. I'm finished with them. If you still need them I can pop them in the mail to you.
Vince