Jimmard

iTrader: (12)

Did anyone see this? I feel I have a valid point. What are you thoughts on this? I feel like nobody is reading this

Old burnt fluid will ruin your seals, and just make the problem worse. So by running new fluid through the system, you are also extending the life of your master/slave.

orangeapeel

iTrader: (18)

I learned the hard way that the Mity Vac will F your master up. Don't use it. You can actually blast the air out of the system by shooting it into the master and bleeding the slave at the same time.

NHRATA01

iTrader: (10)

What I did is when I changed my clutch, I cracked the slave just a hair, and let it drip gravity bleed, while putting fresh fluid in the master (I sucked out any remnant old stuff first from the M/C). After that I reinstalled everything and hit it with the Mityvac for a little bit, and removed any air that was left. Worked great for me.

Mr. Coop

Yes I did see it, but I had already run almost a quart of fluid through it and I had a new slave so I figured it didn't matter any more.

Phlip00WS6

iTrader: (7)

Alot of people are trying the mityvac with a new clutch install, so its probably fresh fluid to begin, but I wouldnt use the mityvac if the fluid was black.

Blackss99

iTrader: (1)

It doesn't matter what fluid clean or burnt you can still mighty vac it. Just keep doig it til the fluid is clean. Who would leave dirty fluid in their system with a new set up .

fusion_ta66

iTrader: (1)

Can anyone explain exactly how this works? Are you actually vacuuming the entire volume of fluid out of the master and line, letting the air bubbles escape, and then allowing the full volume back into the system? If anyone could explain this I would be appreciative.

ls1muscle

iTrader: (16)

I just installed a updated master cylinder w/ drill mod. We bench bled the master, and every step was done correctly. We pumped the clutch and then held the pedal down and cracked the valve and then closed it, we did this like 5-6 times. I got in the car and went for a ride to see how it was, the engagement point was really high and the pedal was softer.

So there is still a bunch of air in the system. I bought a mityvac, used about 15 hg of pressure, while pumping the clutch alot, and it pulled a bunch of air bubbles out.

SUCCESS

ls1muscle

iTrader: (16)

fusion_ta66

this is a helpful resource
http://mywebpages.comcast.net/buschm...utchbleed.html

425SS

Not sure if I understand why your engagement point would be high if you had air in the system. I would think air would compress during engagement and cause the slave to not compress the pressure plate as far. That should cause low engagement?
After having the tranny out and doing the drill mod, I had low engagement (~1" off the floor) and chatter when I tried to take off easy. I tried to bleed several times, but still low engagement. I had been using a socket and ratchet to loosen and tighten the bleeder screw. That caused me to have the bleeder screw open for a few seconds while I changed the direction of the ratchet. Recently I switched to a 1/4" breaker bar and 7/16" socket. That allowed me to open and close the bleeder screw very quickly (open for only about 1/2 second). I also jacked up the car very high on only the left side, thinking that may put the bleeder screw more at the high point of the slave cylinder. I have also experimented with the second person having the clutch pedal on the floor when opening the valve, versus having only pressure on the pedal and allowing it to move towards the floor while opening the valve. When they only put pressure on the pedal it went almost all the way to the floor in the 1/2 second I had the valve open. I believe it is important to open and close the bleeder valve quickly when bleeding the conventional way.
Whatever made the difference; this new technique resulted in my engagement point moving up a couple inches and the chatter going away. It also is much easier to shift quickly.

tim99ws6

iTrader: (31)

You had problems because you bled the system incorrectly the conventional way.

here is the correct way to bleed the system.(need 2 people)

-Get under car, crack bleeder open with clutch NOT pressed in
-push clutch pedal to floor
-close bleeder valve
-get clutch back up off floor, and repeat



This should not take more than 4-5 times of repeating this process, and all air will be out of system. Obviously, make sure you don't run out of fluid.


I think the reason people resort to this Mighty Vac idea, is because the correct way to bleed a system is not known. Its actually extremly easy, and doesn't take longer than 5-10 minutes at most. Now worries about screwing up your hydraulics either.

wkniffin98ss

iTrader: (1)

The vac was used on my ls7 clutch and the clutch constsantly sticks to the floor, and its really spongy. I have bled the system twice with the mity vac and have gotten the same results. Im guessing that it did damage my master cylinder.

425SS

tim99ws6: I think my results agree with your thoughts. I suggest a couple additions/changes to your procedure:

-Have a second person apply light pressure to the clutch pedal
-Get under car, crack bleeder open and closed very quickly
-Clutch pedal should move towards floor, but not all the way there
-Pump clutch pedal and repeat

This should help assure air can't re-enter through the bleeder valve.

02BLK-SS

iTrader: (1)

oh snap, Ive mity vac at least twice a month for two years now and had no issues with master seals. ive made a quick remote bleeder cable which is hard line from throw out bearing then converts to short flex line with bleeder. easy access at bottom of tranny. attach mity vac to bleeder and purge old fluid. continue vacum and draw new fluid from top master. then attach mity vac from master cyl - top in center hole and keep vacum on for the night to remove air bubbles. pre track maint.

richieg

iTrader: (1)

My last clutch change, I changed out the master and slave, and drilled out the line. I put the mitty titty in the hole at the bottom of the fluid resovior, pumped up 20 vaccum, filled the resovoir with fluid, then pulled out the mitty titty quickly. Watched the resovior quickly drain dry, then repeated once more. After that, put the mitty titty in one more time, pumped up 15 vaccum, Let it sit for 15 minutes, then done. Just figured everyone has there way, there's mine.

lovin myls1

iTrader: (4)

GM issued a service bulletin,01-07-31-002A, telling dealers to use the mighty vac as an improved bleeding procedure.I doubt it's harmfull since they endorse it.

gun5l1ng3r

But what is the Maximum reccommended pressure(vacuum)?

lovin myls1

iTrader: (4)

Had to go back and read it;GM says 15-20hg of vacuum,then repeat if needed until no bubbles are seen.

gun5l1ng3r

I know, but I have had my new master up to ~26 psi.

I replaced my clutch and slave, and flywheel. The new slave has not seen above 15psi. And it still has a notchy feel to it.

buschman

Back a few years when the MCleod MC was new we were having a lot of problems with it. 90% of the stock MC guys weren't having problems bleeding their setups the conventional way, but 90% of the McLeod guys were. The write is just me battling through the same problems most of the Mcleod guys were battling with at the time and how I fixed it. Someone smarter than me thought of the idea to use a Mity vac on the Clutch system. But everyone had an opinion on how it should be done. So I took what made sense to me and sort of blueprinted a plan that got my Mcleod to work right. I sruggled with that MC for like a year of inconsistant pedal pressure and moving shift points. But since employing the mityvac and using the write I've had consitant shift for over three years now. I haven't even had to touch the system since then other than like two times and that was after disconnecting the lines to pull the tranny. Both times I just did the last step(in car bleed) after a few days driving. Not that I noticed problems to begin with, but it can't hurt once you have the MityVac.

I'm not saying my write up is the only way to go. if a conventional bleed works for you, then by all means use it. But the method seems to help anyone that experiences difficulty in the bleed process. Maybe overkill for some.

Best of luck guys. Glad to see this page is still helping people out.

Mike