particleeffect

I have stock brakes and an ATC extreem clutch with SS line on the clutch alone. The clutch pedal has a bit of travel, like the line is building pressure before movement starts, the brakes are, for the lack of another FD to test, factory feel.

I'd like to tighten up the clutch disengagement and if possible make the brakes a little more touchy.

I remember reading something about the 929 master cilinder swap? Would that do it for me, or would I need some type of new clutch slave?

What should I expect to pay in labor for a master swap assuming i sourced one from a junkyard?

And if need be what would the costs be for a new slave and swap.

-woops, mispelled brake in title.

FormerPorscheGuy

The way to "improve" your clutch feel is to replace your clutch pressure plate with a stiffer unit. While you are in there, replace your entire clutch with a stiffer unit. Different clutches have different levels of stiffness, talk to people and try to sit in cars with different types of clutches to find out which one is right for you.

As for the breaks, try replacing your stock brake lines with stainless steal units. This will probably accomplish hat you want for minimal cost.

From what I have read the 929 master cilinder swap will achieve larger fluid capacity, not stiffness.

NorthwindHost

From what I remember, the 929 master cylinder upgrade will hold more brake fluid, but it will not help stiffness.

People usually do this upgrade when they do the big brake upgrade as they need more fluid to help cool down the huge brake.

It wouldn't help the stiffness however.

Honestly, I think its kinda stiff as it is. Factory that is. Any stiffer and you will be making very sudden stops. =)

FormerPorscheGuy

Sorry to tell you this but you have been misinformed. Brake fluid has nothing to do with brake cooling. Brakes are a hydriodic system. The brake fluid works as the hydriodic fluid in the system. when ever you press down on the brakes the pedal activates the spring loaded hydriodic pump (A.K.A. the master cylinder) which forces fluid through the brake lines and into your calipers causing the pistons in your calipers to expand outwards. This expansion is what compresses your brake pads onto your rotors. Taking your foot off of the pedal releases the brakes in the reverse order.

the_saint

The fluid does not contribute to brake cooling. Rather the larger pistons/increased # of pistons require more fluid to move the same distance, hence requiring a larger master cylinder that moves more fluid.

particleeffect

I already have a stiff clutch (act extreem, 450lb tq capacity, 59% stiffer pedal pressure), the issue is in the stock hyrdolic system needing to build pressure before it actually moves the clutch to disengage. i can think of atleast Vosko who's swapped a new clutch slave in, maybe i should pm him.

but the 929's bigger master cylinder, moving more fluid should make the brakes more responsive if i'm thinking correctly. (more volume per inch of push on the stock breaks = more touchy pedal feal. which is what i want on both pedals)

FormerPorscheGuy

Your logic is unfortunately flawed. If I am reading your statement correctly you are either assuming that the brake fluid is compressible (which it is not) or you are assuming that the higher brake fluid volume offered by the 929 master cylinder will improve fluid flow volume in and out of your stock calipers (which it will not).

Take my advice earlier and buy a set of stainless steal brake lines. This will accomplish what you want by replacing the stock expandable rubber lines. By eliminating the expansion point you will experience heightened brake sensitivity.

particleeffect

so then what would a new clutch slave do for me? i know that the fluid isn't compressible, my thoughts were just that with more fluild being sent out, it would move the parts sooner. a new master cylinder doesn't make the pedal throw's longer, but it moves more fluid per pedal movement.

i probably should throw some SS brake lines in but i'd still like the clutch pedal to feel more linear, instead of reall easy at the top and then stiffer as it goes farther. i gues that's a job for a different slave?

Sled Driver

iTrader: (9)

If your goal is for more sensitive brakes with less initial force, switch out your brake pads with the hawk blue pads.

Did you install the ACT clutch? there are instructions on lengthing the clutch master cyclinder input rod (from the clutch pedal) to eliminate all the freeplay between the clutch pedal & master cylinder. This will give you more clutch travel & the pedal will release closer to the top.

sirjury

bigger master cylinder=more volume=less mechanical advantage at the pedal, so to move the same amount of fluid requires less pedal travel but is harder to push. a smaller master will give you a softer pedal but easier to push. if your clutch pedal feels soft try bleeding it. also stainless lines dont expand as much as stock ones so you might try those. changing your slave will only help if yours is leaking.

particleeffect

no, i didn't install the clutch, i had it put on while my engine was being rebuilt. is lengthening the clutch master cyclinder input rod something that's doable from under the car or would i have to disconnect the transmition?

now i understand the master cylinder thing, thanks. noted brake pads and ss lines.

Sled Driver

iTrader: (9)

the clutch master cylinder input rod is adjusted inside the passenger compartment.

Using your hand, can you feel any freeplay when you push down on the clutch pedal?

See the rod, connected at the top of the clutch pedal, that travels through the firewall?

Break the jam nut loose & rotate the rod until you have no free play (don't preload it). Tighten the jam nut & your all done.

CrispyRX7

iTrader: (139)

The basic clutch question aside...try adjusting the clutch pedal free travel as noted above. You could also try a SS clutch line. Most clutch feel is all in the pressure plate though.

As for the brakes, most of the above reasoning WRT the 929 master cylinder swap is flawed. The 929 MC **WILL** change the pedal feel. It will make the pedal feel much stiffer/harder. This is because the 929MC moves more fluid for a given amount of brake pedal travel. If nothing else is changed at the caliper end it therefore take less pedal travel to move enough fluid to engage the brakes. Consequently once the brakes are "engaged" it take less pedal travel also to apply more brakes. The brakes are basically working on pedal pressure not on pedal travel and therefore will feel stiffer with the 929MC.
And all this crap about better cooling, phooey...nonsense. It's all about pedal feel.
It is true that those who have installed upgraded front calipers (like me: AP's) which have a larger than stock caliper piston bore, it takes more fluid pushed into them to get the brakes to "engage" hence the need for the 929 MC to be able to push more fluid "to them" and reduce the pdeal travel necessary. Bigger bore on the caliper end requires bigger MC on the other or be faced with a long pedal throw.
(agreeing with: sirjury)
Want more details:
http://www.negative-camber.org/crispyrx7/929.htm
Also DO NOT use Hawk blues on the street! (Sled Driver - what kind of advice is that?) This is a track only pad. Poor cold braking...if any, nasty dust, will eat your rotors in a few weeks, and the will squeal like crazy. Stick with a street pad.
SS brakes lines is always a good idea too.
HTH,
Crispy

GTUDRIFTER

ahh, unfourtunatly for me, there is less than 1/4 inch in play before the clutch pedal get's to work. I guess the problem is in the pressure plate then, (a pedal feel problem of course, the clutch is great) and the way it progressively get's softer on the pedal the farther out it gets from fully depressed. it's like a marshmellow under my foot for the 1st 1 inch or so, with the clutch still pretty much fully engaded, but it's not 1 inch of free play, it's pushing the piston. and i had a ss clutch line installed with the clutch.

oh well, thanks for the help.

particleeffect

sry that was me posting as GTU ^