Drift4

iTrader: (12)

Replaced Master Cylinder today, bled all four corners, NO MORE spongy brakes.
The first seal for the Rear line failed, causing fluid to leak back into the resevoir.
FYI the master cylinder is made by BOSCH. Part# MR977088 is for cars with ABS, for non ABS Evolutions RS use MR977089 with built in proportioning valve.

As of now no rebuild kit available yet, I will sending the unit to Bosch and see what else could have been cause of failure, and if they can warranty it, or rebuild.

Max Power

iTrader: (1)

Well crap... I'm having a similar problem. Was yours pretty consistant? Mine seems like it comes and goes. Went to a "driver's education" event again, and the brakes are just not predictable (this was after another thorough bleeding).

What fluid were you using and how many miles do you have? Also, about how much does that MC cost? Thanks a bunch.

Drift4

iTrader: (12)

Max Power, I used the ATE Type 200 Super Gold, it has an amber tint, same as the ATE Super Blue. http://www.raceshopper.com/brake_fluid.shtml

I paid 225.00 from the dealer retail is $302.00...crazy, I currently have 21,000 miles on the car.

Yeah I gave up after going through almost 3 liters brake fluid.
As soon as I instaled the new master, after 2 cycles per brake bleeder nipple..the pedal was FIRM...the only thing is that the pads I replaced the factory with was HAWK HPS, but the rear pad backing was noticable shorter than the Brembo and have friend tell me that if you leave the brake dust sitting on the wheels they will rust .

So every time I would back up the rear pads would make a clicking sound...which is not design to do. So I skimpped a little and went with the Project MU NS...which states to be a Street/Sport pad...but the graph show it to be more for street use.

Not really up to par with the factory compound (medium to hard) but initial bite is good but you can tell its an entry level brake pad (soft compound).
The nice thing about it is the dust build up is like 4 days compared to a day you get with the O.E. pads

So my next thing is I need to find out is what the other have to say about this model brake pad. I guess you get what you pay for. Hope this helps

Max Power

iTrader: (1)

Thanks Drift4... I'm running ATE Super Blue and Hawk HP+ at the moment. It actually happened when I flushed it with Blue. I've heard from a couple people that this fluid acts a bit weird. I'm hoping it'll go away when I flush with Motul RBF 600. The funny thing is mine doesn't do it all the time. It seems to happen on warmup or drill laps when I'm not really on the brakes. Once I start getting into it, the pedel seems to recover a bit. Is this how yours was or was it spongy 100% of the time?

Boy I hope the RBF works... I'm trying to save for a turbo kit, I think the car might be trying to spend my money on other stuff so I don't go through with the kit

Drift4

iTrader: (12)

I have been using this fluid on my porsche also with brembo...never had a problem. Mine got spongy after I pulled the hawks out and apllied anti seize on the section where the pads rest on, tried to eliminate the pads from sticking. after the pads were in place.

I went in the car and stepped on the brake pedal so the pistons would seat up against the the pads, then I heard that spring sound I was talking about...ever since the pedal travel was slightly past the throttle pedal and was spongy initially when the brakes were applied, but if you pumped it the second time, it would firm up then eventually sink.

Did you experiece when opening the rear only bleeder screw 1/2 turn, the screw feels loose like it is ready to come out? Yeah I just got some new Advans myself. I might buy some speed bleeders, because the is some sweat coming from the base of the bleeder screw after driving the car....

I read somewhere in the forum a guy also had the same problem......this is mostly why the clear coat on the caliper peels over time...check the rubber cap for the bleeder the ring that goes around the bleeder screw in the bottom. sorry for the long post.

Max Power

iTrader: (1)

Thanks a lot for the post... it'll be a good post if other people have this problem.

I'm not noticing any weeping from any of the bleeders. I'll keep an eye on them. I didn't have a spring sound when I first flushed the brakes, but I did have a groan coming from the MC which I thought might be normal. The only difference I'm having than you is that my brakes don't sink and they aren't always spongy. That's why I'm hoping another flush will take care of it... if not a MC bleed and hopefully I can spend the money on go instead . How bad was removing the MC?

Thanks again and have a good holiday.

Drift4

iTrader: (12)

Did you remove the rubber cap completely...I mean the cap in your hand and inspect the the base of the rubber cap if it is wet...you won't see it if you just expose the cover for the nipple and leaving base still attached to the bleeder screw.

The groan went away after I replace the master cylinder, and started bleeding the brakes, that was a good sign. But you will hear a faint hum which is coming from the diaphram of the boster which is normal because you are relieving the system of the air that is built up.

To R&I the part was like 15 minutes, no need to remove the strut brace, only the battery, I you have a hydraulic or fluid evacuator to suck up the fluid in the resevoir before removing the master would make it less messy....and put clean rags under just to catch any dripping fluid. I did not bench bleed the new master since I was going to re-flush the entire system anyhow.

Remove the hose that leads to the clutch master cylinder. The master is held by (2) 12mm nuts on to the booster, you'll need six point deep socket with an extension.
Use a 10mm flare wrench to remove both brake lines from the master, if you don't have one a regular 10 will work but care must be used (don't slip) when using that type of wrench. Install is reverse...and torque nuts and line to factory spec....and don't forget to bleed the clutch

HAPPY EASTER

kyoo

iTrader: (29)

good info here - does everything start leaking as soon as you disconnect?

interesting that you installed dry and power bled - how is that different from air being trapped in the MC and bleeding?

Fast_Freddie

iTrader: (50)

I really think I have a bad Master Cylinder after reading this... i have bled and rebled brakes multiple times and I am having the same symptoms... Tried different fluid everytime...

kyoo

iTrader: (29)

replaced mine... but the pedal is getting an intermittent pop... any ideas?

4whlbst

iTrader: (2)

Well from a mechanics point of view and common sense I would think that the top of the master is above the last outlet valve. So if you don't bench bleed it, you will still have air. It's a five minute process to bleed and a five minute removal of the master. Really no reason not to. If o was questioning my methods I would start with the basics. I have an apprentice that *****es about doing "hard" jobs. I tell him if you shut up and worked you would have done and or eliminated the concern in the same amount of time as questioning and complaining. So sometimes
Best to eliminate all options before.

kyoo

iTrader: (29)

thanks I did bench bleed it. must be something mechanical. going out of town the next couple days so I'll check when I get back