LS2-240z

Has anybody found a clutch slave that doesn't make the master cylinder fluid turn black? I'm tired of having to bleed it al the time.

BlackScreaminMachine

iTrader: (17)

Which ones have you used?
What have you done to insulate the line?

LS2-240z

I have only tried stock, what about you? I haven't tried to insulate line. I know it is discussed all the time, but that is bull. My line is far away from my headers - I can grab it with my hand and it isn't even warm to touch. To test the heat hypothesis, I put fluid in a skillet and cooked it until it burst into flames (makes blue flame by the way). It became progressively more brown - never black. The problem is clutch dust.

01ls1v8

Probably coming from the black rubber hose breaking down just my 2 cents

studderin

iTrader: (28)

is your bell housing all sealed up? I haven't put a ton on miles on, but I went the quicktime bellhousing, with the access window in the bottom. And ran that without the cover on the window, and cut the block safer plate a little so its open in the front around the starter, and near the oil filter. After about 600 miles didnt really have any dust in the clutch area, it all just blows out under the car. I run a twin, and a little dust came out I think inside the discs, and inside the floater plate, but the slave was pretty clean of dust. Didn't have any dust sitting inside the bell, or in the t56 front ribs.
I'd try that, I put some pics on the bell in my build thread, and the install writeup I did on it. And jermeryF did a thread on it too.

https://ls1tech.com/forums/drag-raci...h-diet-36.html

https://ls1tech.com/forums/manual-tr...-teh-diet.html

LS2-240z

Studderin-thanks-that's awesome. Did the improved dust ventilation keep your hydraulic fluid clean from contamination? Is your throwout bearing the McLeod part or a regular GM throwout bearing? I wonder if I could get away with removing the block off plates from around the starter and oil filter, then cut the window in my bell housing open a bunch?? I could do those things pretty easily.

SPEEDYws6

iTrader: (9)

What clutch are you running? I believe the clutch material to be a lot of the problem as well.

I always take the dust covers off my cars, but the stock clutch in my firehawk will have the fluid contaminated in no more than a tank of fuel worth of driving.

LS2-240z

Stock, factory 2006 GTO clutch. The thought of an alternate material had crossed my mind. Something with a larger dust molecule so that it doesn't get into the fluid so easily. I'm taking recommendations. My GTO bell housing doesn't have a cover, thinking about taking a saw to it.....

Gary Z

I've installed a new GM slave each time I've replaced my clutch - four slaves total. Two of these, including the original, quickly turned the fluid black. The other two, the fluid remained clear for more than two years. Stock GM slave cylinders are lubricated with black grease, probably molybdenum disulfide. This grease is isolated from the clutch hydraulic fluid only by a rubber seal that moves with the piston. If grease gets past the seal the fluid will turn black. This and other theories are discussed here: https://ls1tech.com/forums/manual-tr...rns-black.html

LS2-240z

Hmmmm. Have you had any of the problems that I have had with unreliable clutch disengagement at the track? I wonder if anybody has ever cleaned out the moly grease and regressed with lithium to test that theory. This calls my entire premise into question. Gonna go study that link-thanks.

LS2-240z

Im considering this.... How much moly grease? Unless there is an endless supply? Wouldn't we eventually wash it all out with our fluid flushes? However, the clutch provides an endless supply of carbon. The sleeve is aluminum, corrosion produces aluminum oxide which is also black and of endless supply. Do ony of the aftermarket slaves have stainless or plated sleeves? In terms of heat, could this be why GM used a plastic bearing support collar. Why does the GM slave use a spring when neither the McLeod, tilton or quartermaster do? What does the spring accomplish?

Gary Z

It's good and greasy in there. I don't think it takes much to turn the fluid black. If all of the grease were washed away the slave would probably bind and fail. I think the spring just keeps the bearing pressed against the release fingers so it doesn’t rattle.

LS2-240z

If I wind up giving a new GM slave a try, I volunteer to clean all the moly grease off and apply a white lithium grease. Thanks for pointing me in a direction and giving me something that I can at least test. Is the grease inside the bearing or on the tube/sleeve that the bearing slides on?

studderin

iTrader: (28)

https://ls1tech.com/forums/manual-tr...ur-clutch.html

LS2-240z

Awesome. This is gonna happen this weekend. With a stock clutch, how much room do I have between the inside of the bell housing and the rotating assembly? I'm not afraid-I want to take a hole saw to the bellhousing. Just don't want to drill into something important.

Gary Z

Not a good idea - your cast aluminum bellhousing is important.

LS2-240z

Well, it is done. I removed platic covers on front of bellhousing cut 2 holes in my bellhousing big enough to put a 2X4 thru. Cleaned and cleaned with compressed air and brake cleaner. You could eat off it. Replaced Model 75 Tilton master cyl with Model 74 Tilton master cyl in order to use the bosses for a firewall/clutch master brace. Bled and bled and bled with Motul RBF 600. It was great to be able to inspect the slave for leaks and inpect for any broken springs or anything else. Looks pretty good in there, clutch operating properly by visiual inspection.. Need to figure out how thick my clutch disc should be - looks pretty thin. I look like a tar baby and will probably die young from black lung. Will give feedback as I have it.

Reject

iTrader: (24)

Nice!

LS2-240z

OK. The hammer, dremmel and cutoff saw continue to be my most valuable tools since I did this motor swap. Got busy and made an inspection/service/vetilation window in the bellhousing. Started with filthy fluid, starting this test with clean fluid after yesterday's work. Based on the advice of a T56 drag racer on LS1tech I decided to let the bellhousing breath a little. I removed the dust covers behind the starter and oil filter and cut (2) 2X3 holes in the bellhousing. Will it effect strength?-time will tell, nothing ventured nothing gained. The front hole lets me see the flywheel, pressure plate and clutch disc; the rear hole lets me see the throwout bearing and the hydraulic lines.

First of all, no leaks. The pastic dust covers near the flywall side were filthy. I put just a pinch of the clutch dust in a bit of clean hydraulic fluid an perfectly reproduced the gunk I keep getting in my master cylinder reservoir. Look at the picture that shows one of those covers and the pieces of aluminum I cut out-the aluminum at the bottom of the bell was totally clean (you could eat off it). Found that weird. However, the throwout bearing sleeve (visible only when my daughter pressed the clutch pedal) was packed with clutch dust. There is a little recess at the base of the sleeve that may act as a funnel for the collection of the dust. If I wind up replacing my throwout bearing, I will modify it to remove the recess and let the dust blow elsewhere. Used compressed air and brake cleaner solvent to clean things as much as possible - my garage is a mess and I looked like a tar baby when I was finished. Swapped my 1" Tilton series 75 master for a 7/8" 74 series in order to gain the extra mounting bosses to attach a firewall brace to. That is next week's project. Took a lot of bleeding, using a combination of gravity, mighty vac and old-school bleeding to get a great feeling pedal. I did need to extend the adjustment rod out a long way. But it feels great. With the old series 75 1" master, the pedal stroke was very firm and at the bottom of the travel, the pedal was really easy to press. With the new master, the resistance is constant from top to bottom, just like my S10 pickup. Started car on jackstands and clutch fully engages with no rear wheel rotation. Next issue is about 3/8" of firewall flex, thought the smaller master bore might decrease that, but it didn't. I may eventually have to address the fact that the clevis hole in the clutch pedal has ovalized due to wear.

Gonna due a little rear suspension work and try to test drive before the day is done. Then we'll see if I can keep clean fluid and stop having shift refusals.

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LS2-240z

How do I check my air gap? Now that I can see my clutch disc and pressure plate, I'd like to check to make sure the pedal is moving the pressure plate enough. Please give all related specs. I have searched forums and have checked my service manual.