Upgraded to 19mm Master Cylinder, Brakes are hard - not mushy!! Options

[vesnyder]

Just upgraded my my brake system along with a major front end overhaul and I am really impressed by the difference in the feel of the brakes. They are as hard as a rock - reminds me of my 911! I did not change anything else other than bleed the lines real well and they went from a mushy VW feel to rock hard secure feeling! I read a bunch about brake upgrades and one of the recommendations was not to upgrade the MC without changing out the calipers - but in my case it made a world of difference.

[thesey914]

19mm master cylinder is not really an 'upgrade'. (IMG:http://www.914world.com/bbs2/html/emoticons/poke.gif)

[Mueller]

hmmm, replacing old parts with new parts along with new fluid....you better have an "improvement" (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

mostly it is a psychological effect 'cause you went "bigger" (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

[bondo]

I've used both, and consider 19mm to be an upgrade. In fact I used both on the same car as vesnyder. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

(The 19mm one started leaking so I had to put the 17mm one back)

Some will say that with a 19mm MC you get less PSI of pressure for every pound of pressure you put on the pedal. They're right. But on the other hand, you have the capacity to move more fluid. That means for every inch of pedal travel, you're pushing more fluid out of the MC. This means that it takes less pedal travel to get the pads into contact with the rotors, so your pedal will end up farther from the floor than with the 17. It also results in a firmer pedal feel, and any swell of rubber brake lines will have less of an effect. It also means you have more pedal travel "left over" in case something goes wrong. As far as stopping ability, either one can lock the brakes. I think most people are strong enough to lock the brakes with a 19mm MC (It will take more pedal force, but it's still reasonable)

[seanery]

I like my 19mm mc, both of my cars have them, but the biggest thing that I noticed was a harder pedal with a little less "feel." I wouldn't go back because I'm used to it, but modulation is different.

[lapuwali]

It's a personal preference thing. I find I can't lock the wheels with a 19mm MC, as I just can't push the pedal hard enough (I'm a wussy). Once I finally, totally, bled the brakes with the 17mm MC, I didn't find them to be mushy at all, I just had to push the pedal a little farther, which is expected.

Have you tried this new 19mm MC with a really hard stop? That's the real proof in the pudding for me.

I still wonder how much of an effect the flexing floor has on the feel.

[sean_v8_914]

IMO I think the 19mm MC on stock callipers puts teh pedal too high for good heel toe transition

[ArtechnikA]

QUOTE (sean_v8_914 @ Jan 7 2006, 02:01 AM)

IMO I think the 19mm MC on stock callipers puts teh pedal too high for good heel toe transition

this is why the brake pushrod is adjustable...

[vesnyder]

I have not taken it out on the road yet - that twill be theh real test. I had the 17mm on my '67 911 and had the excact same feel as I did on my 914 and I did not like it? I was alos concerned about the heel-toe ability, but was able to adjust it where I think it will work.

Bondo - It is coming along! Tried to post pics of my upgraded front end but size limits prevented me. I am making you proud (I hope?). If I can find your email I will foward some pics!

[sean_v8_914]

duh..which way did he go george?
nothing worse than a slap in teh face with the obvious. I still prefer teh feel of the modulation over greater travel

it boils down to preference

[bondo]

QUOTE (vesnyder @ Jan 7 2006, 09:14 AM)

Bondo - It is coming along! Tried to post pics of my upgraded front end but size limits prevented me. I am making you proud (I hope?). If I can find your email I will foward some pics!

Heck yes! I never thought it would get such royal treatment. You're doing an amazing job, and getting it done pretty quickly! Gonna bring it to the WCC? (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[shadygrady]

All this discussion is very intersting to me and shows how little I know. I changed my 17 to a 19 and put bmw 320i calipers and wow what a difference. Then 2 years later, I swapped the 2.0L-4 for a 3.0L-6. Now I figured I needed larger brakes and more rubber on road, so we put 911 brakes on the car. Then we cut the fenders and added flares. That worked fine, but then I got to thinking again, which by the way is dangerous. I put on 4 piston calipers all the way around. I then figured I needed a bigger master cylinder now because the car the brakes came off had a power booster. So I bought a 23mm racing mc. Just put it on, but haven't driven it yet. A test will tell whether all of it works. The shop said I needed a proportioning valve, so I bought that, too. It will go on next.

Got to get it all done, because we go to Roebling Rd next weekend for DE event.

All this to ask you experts what you think?

Grady