I saw my car was leaking brake fluid on the rear brake half of the master cylinder. after some poking around i found the thing is junk, so forget all the leaky leaky nonsense. so because i can get it to my house in relative speed, what r the physical differences of the 23mm mc vs the 19mm (rod size fitting placement etc) i relize the potential pedal hardness issues but im not that worried in this case. ps if anyone has a 19mm mc they could ship to me at 98406 by friday pm me

New grommets are available for $4.25.

http://www.pelicanparts.com/cgi-bin/ksearc...ion=90135592900

Not easy to install with the master cylinder in place. I would take the strap off of the reservoir and unbolt the master cylinder from the pedal set. pull it down a bit to get in new grommets. There is also a washer the does under the grommet.

If you dont know how old the master cylinder is, then you need to inspect it very closely, you want to pull up the pedal board and see if you have brake fluid in that area. If the MC is suspect at all then replace it.

If you are just replacing the reservoir grommets, Bruce is right, it's a tight squeeze, and difficult to get the lines in the MC with the grommets on them. My trick is to use put the seals on the feed lines, and the use a flare wrench and an open end wrench to push the grommet into the boss.

The thing is 6 months old and come to find out its completely broken outside of that leak. Now, because its crunch time, i need a new mc now amazon can get me a 23mm one in 2 days and considering i have boxster calipers it would probably not b so bad. new question is how identical are the mc's (ie fitting placement rod size etc)?

I had a 23 mm Mercedes master cylinder in my 911 hot rod track car which had turbo brakes. It will physically bolt up. One of the lines has to be bent as the port orientation on the 23 is slightly different. It worked great with a firm pedal.

Charlie

I'd get a 19mm

What brand master were you using? Never seen one break. Use the same size in a quality brand. The correct master size depends on which calipers you have at all four corners. Using too large a master will give a hard feel with little modulation. Too small and you will have a lot of brake pedal travel.
So it is back to what size is in there and is it acceptable to you ?

yeah that would b ideal more research neds to b done

Tons of research done via the common practice of using a 19mm Ate 911 master cylinder. 17mm would be the best for stock brakes.

My Cap'n Crusty comment: Go it on your own, and you can write a ton of threads on how you are trying to get something different to work, and your car is still on jack stands. You can probably find a 30mm master cylinder somewhere off something and get it to work on your 914, or you can just employ the good advice you've solicited.

I've got a 23mm that I am planning on putting on with 4 pot brakes. I am anticipating it to be very firm with little modulation. But thats what I am hoping for as well. I have never had this car stop very well.

i meant of my own lol, not trying to offend

No worries I've been in "Star Trek Zone" (where no man has gone before) a few times and at least half the time I kick myself and say "should've done what they told me"

lol i live that zone, i wanted to do a 19mm i just couldn't get one shipped in time but i could get a 23mm in time thats why i asked but i found a 19mm "used" the thing is literally brand new in sealed packaging off amazon shipped to my house next day! Crisis averted