blackrat

I've been having ongoing problems with my set up and not being able to shift at high rpms. I ended up getting an adjustable master cylinder from futral to compliment the ls7 clutch/aluminum flywheel combo to hopefully give me a little more seperation.

When I tried to mityvac the resovoir with my stock master I didn't get anything out, even when I did a pull to 20 hg.

Now that I am trying to vacuum the adjustable I won't STOP pulling out air bubbles. I put it at 15 hg and let it sit for 30 minutes, excersizing the clutch periodicaly and I would continuously get the same damn 6 air bubbles plooping out of the resovior into the catch on the mityvac. Occasionally it would come out in two large bubbles. They are perfectly timed it seems. The fluid will rise up the tube slowly to the same damn point, at which moment the air bubbles will come up and ploop at the top, bringing the level back down.

This pattern happens over and over. You can almost set a watch by it.

There can not be THAT much air in there. I stopped after an hour of screwing around with it, thinking I'm doing something wrong. It was still sucking up the same amount of air as when I had first started. I've also tried pumping it without the vac on, with the cap on and the cap off, just to try to get some circulation. If anything, it feels worse now.

I called futral and the master was already supposed to be bench bled, and it did come with fluid already in the resovoir. Thing I did notice though is that before I went to pull a vac, the fluid was clean, like it came even though I've been driving it around for a week before the bleed. After I started bleeding it's gotten murky.

Any help would be much appreciated. I've followed these instructions to a t.

http://performanceworks1.com/ls1_clutch_bleeding.htm

The PAT WS6

iTrader: (14)

i have been there and done that and have had the same problem with that damn mity vac first try bleeding it with a buddy under the car and opening and closeing the bleeder valve while u press the clutch. www.installuniversity.com has a setup on doing this when doing the drill mod. speaking of drill mod go ahead and try doing that to found on that web site. what i ended up doing was taking my car and gettin it pressure bled with a buddy that has a pressure bleeder. dont knw what to tell u if u aint gonna find a pressure bleeder.

The PAT WS6

iTrader: (14)

also ive seen mity vacs ruin slave cylinders so be carfull on how high u pump that up.

kenkaru

I had the same prob with the mity vac. One thing I did notice though is that the pedal will be better after you fire the car up. I'm guessing it's because the centrifugal force make the pressure plate snug against the slave or something. It sounds wierd but I've experienced it several times with two different clutches.

BIG_MIKE2005

iTrader: (116)

Never had a problem with my mighty vac. I never pumped it up that high. Only to 12 like the write up says. Maybe its still doin it from too much vaccum??

I bet thats how others have messed things up also.

blackrat

Well, I Started Off Only Doing A 12 Inches Pull On It. It Was Only After I Kept Pulling Air After 15 Minutes That I Increased The Vacuum. Ill Try It Again Today.

blackrat

Oh Yeah, Forgot To Add That IIRC Even In A GM Advisory To Mechanics That It Told Them To Pull Over 15 Inches. I Realize Your Fear Though, And I Still Wouldnt Pull Over 20inches. i dont get what you mean by too much vacuum creating more air though. i mean, how would air enter unless theres a leak or the resivoir runs dry.

BIG_MIKE2005

iTrader: (116)

I have heard that you can do damage to the seals inside the master by using too much pressure. I wouldn't personally know since mine worked fine @ 12.

Mike44138

iTrader: (3)

Here's what I do....

Hook the master up to the slave. Use the normal "crackiing the bleeder" procedure to fill the slave with fluid and push all the air out.

Remove the master cylinder. Connect the reservoir and fill with fluid and cap the reservoir. Rotate the master and place it in different orientations until you don't see any more bubbles come up from the bottom of the reservoir. Occasionally pump the master. You'll have all the air out of the master when you can no longer depress the master plunger. (This is essentially a bench bleed)

Install the master with the reservoir attached, full and capped. Re-Bleed the slave if necessary.