Is it normal?

[gabkwong]

I just replaced the slave cylinder, bled the clutch and fill up the master cylinder reservoir to the max line. After driving for one day, the fluid level in the master cylinder reservoir is now only half full! Is there something else is broken?

Gab

[POS Racing]

Sure doesn't sound normal, any signs of a leak?

[driftdevil]

check the soft line running into the slave. I replaced mine with the ss braided line.

[Titus]

You may need a dose of penicillin.

[sammm]

Probably needs to be bled.

[Sharpie]

Probably needs to be bled.

Air in lines, that would be my first check.

[black roadster]

There are two parts to the hydraulic clutch system. The slave cylinder which you replaced and the clutch master cylinder.

I'd bleed the clutch again until I'm confident there is no air in the system making sure to keep the fluid full as I do. If after that you still lose fluid, replace/rebuild the master clutch cylinder.

[trickyrix]

Double-check for leaks, for sure. However, it's possible that any air you did have in the line bubbled up into the master cylinder, causing the reservoir level to go down a bit.

+1 on re-bleeding just in case. That, and keep a close eye on the level and watch out for leaks. Does the clutch work okay now?

[gabkwong]

The clutch paddle actually feels better than before. Just than it engage a little closer to the floor. Today the level drops to the middle between max and min line again. I guess it may be air in the line as I don't see obvious fluid on the ground even I pump the paddle several times om the driveway. I will keep an eye of the fluid level the next couple of days. I will let you guys know in a couple of days.

Thanks for the help!

Gab

[trickyrix]

One thing you might want to try is to have someone pump the clutch pedal while you look under the hood at the reservoir with the cap off. If there is air in the line, sometimes you can see it bubbling up into the res...

As for leakage, you probably want to get in there and check all your connections to make sure they are dry and clean. The fluid could be pooling somewhere and not making it down to the ground. I don't know for sure where the slave cylinder is on the Miata, but they're usually on the top/side of the trans so the fluid would have a little ways to go before it hits the pavement.