Master Cylinder Brands and 19mm vs 17mm (again)

[DuckRyder]

First, those that have been following I have the pedal cluster out. I am concerned that the master is leaking, so I want to replace it.

For my autocross class I have to keep stock calipers, but can change the master, so I am assuming that 19mm is the way to go from reading past post and the good doctor’s book.

I prefer ATE for BMWs and have had problems with other brands. Is that constant with you guys experiences for Porsche as well?

Any one know what brand Pelican carries? I tried to call but its too late, I would like to get it shipped ASAP.

TIA

[sean_V8_914]

19mm master will require less pedal travel but greater foot pressure to stop teh car. 17mm will give longer pedal travel with less pressure required to stop the car. IMO 17mm gives better foot control of teh quantity of braking desired. I have had good luck with the Brazilian brake parts Braga or Burgos or ...starts with a B

[red-beard]

I am in total agreement with Sean. The 19mm "seems" to give you better brakes, but in reality is reduces brake effectiveness.

[John Rogers]

Good rule of thumb: stock calipers, 17mm; 320i in front then 19mm; 320i all around or 911 fronts and 320i in back then 23mm.

[Jim Smolka]

Of course one could go for the fun route which is to retro fit to a dual MC setup .

[skline]

Funny how most of the replies so far are from San Diego area, Not that there is anything wrong with San Diego. Post 912

[Dave at Pelican Parts]

Either the 19mm or the 17mm is fine in a 914. The 19mm one does require more pedal effort to get the same clamping pressure (about 25% more), and the travel is less (about 25% less). I don't know of anyone who has had too much trouble modulating the brakes with the 25% pressure increase, and I don't think many people will have difficulty pushing a little bit harder...

It's a matter of taste, really.

--DD

[woodman]

Has anyone succesfully rebuilt a stock MC? I know the kit is half the price of a new unit, but I'm curious. Besides, I've long since spent my budget...

[sean_V8_914]

320i callipers in the back? hhmmm?

Scott: did you have teh Volvo callipers on Ol Yeller in Baja?

[sean_V8_914]

yup. rebuild that puppy. piece o cake

[mike_the_man]

I rebuilt the MC in my car. Was pretty easy, although getting some of the seals on was a little tricky. Took about an hour, and it seems to work.

As far as upgrading to a 19mm, I'd have to agree with Sean. Everything I've read indicates that a 19mm MC isn't required for stock brakes. But it probably wouldn't hurt anything, and it is cheaper, so you be the judge.

[DuckRyder]

Thanks guys, I've got one coming!

[sean_V8_914]

since you have a known good unit coming, you have nothing to loose by trying to rebuild your old one, but you might gain the knowledge of the rebuild and a spare MC
what size did you deside to use?

[sammyg2]

I refer the 19mm master cylinder, but I have a big ole fat leg that doesn't mind pushing a little harder in order to get a nice firm pedal.

When it comes to rebuilding a master cylinder you need to determine what is worn out. If the rubber seals are all that is worn, rebuild that bad boy and it will work fine (assuming you do it right).
If the cylinder bore is worn or pitted, all bets are off. You can hone a little bit but honing isn't supposed to repair the bore, just clean it.
I'd suggest taking it apart and inspecting it, then make the decision on whether to replace to rebuild.

[DuckRyder]

I got a 19mm ATE coming. I prefer the the pedal to be firmer.

I may pull the other one apart and see it it is rebuildable as a spare, but the car has done a lot of sitting so who knows.......