Help Bleeding Clutch
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
I'm not sure if the '91 slave bleed screw is on the bottom of the system like it is on the LT1 cars.
But if it is...
I came up with an easy bleed method that puts fluid in from the bottom so that you're not fighting the air bubbles' buoyancy.
Drain the system from the bottom as normal. Pull the bleeder, clean it and wrap 3 layers of Teflon tape on the threads only. Reinstall it but leave it a few turns open as if you were bleeding it. Attach a hose to the bleed screw and run it to a fresh bottle of brake fluid securely taped to a stool above the height of the master reservoir. Remove the filler cap and moisture barrier. Use a mighty-vac or the off-brand clone to suck the air from the system at the hole in the bottom of the inside of the reservoir. When the fluid reaches the bottom of the reservoir, close the bleed screw and fill the reservoir to just below the low level mark and reinstall the moisture barrier and cap. That should bring the level to the full mark.
But if it is...
I came up with an easy bleed method that puts fluid in from the bottom so that you're not fighting the air bubbles' buoyancy.
Drain the system from the bottom as normal. Pull the bleeder, clean it and wrap 3 layers of Teflon tape on the threads only. Reinstall it but leave it a few turns open as if you were bleeding it. Attach a hose to the bleed screw and run it to a fresh bottle of brake fluid securely taped to a stool above the height of the master reservoir. Remove the filler cap and moisture barrier. Use a mighty-vac or the off-brand clone to suck the air from the system at the hole in the bottom of the inside of the reservoir. When the fluid reaches the bottom of the reservoir, close the bleed screw and fill the reservoir to just below the low level mark and reinstall the moisture barrier and cap. That should bring the level to the full mark.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
^huh?
And why is bleeding this not like bleeding brakes?
Push clutch, open valve, hold pedal down until the bleeder is closed again. repeat.
The reason you may feel that it is not working is, because the pedal never gets firm like on a brake system.
Just get your buddy or GF to pump the pedal for you. Pump a bunch of fluid through the system and be done with it.
And why is bleeding this not like bleeding brakes?
Push clutch, open valve, hold pedal down until the bleeder is closed again. repeat.
The reason you may feel that it is not working is, because the pedal never gets firm like on a brake system.
Just get your buddy or GF to pump the pedal for you. Pump a bunch of fluid through the system and be done with it.
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
On the brakes, the bleeder screw is at the highest point on the slave. On my clutch slave, and all ZF LT1s, the bleeder screw is at the lowest point in the system.
The FSM proceedure has you remove the slave from the bell housing, rotate it 180 degrees, hold it level, bleed, then reinstall. The FSM also says not to twist the hydraulic line. The two goals are mutually exclusive.
The FSM proceedure has you remove the slave from the bell housing, rotate it 180 degrees, hold it level, bleed, then reinstall. The FSM also says not to twist the hydraulic line. The two goals are mutually exclusive.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Hahahaha
That is classic!!! That almost makes my day!!
but just asking questions..........you are running under the assumption that the air bubbles are able to move freely within the fluid.......like in water or 7-Up. That fluid is thick and the air bubbles travel along with the fluid and right out the bleeders when you pump it. Otherwise air bubbles would never go "down" the brake lines from the MC when bleeding brakes the normal way...
So my question is, wouldn't the fluid carry the air bubbles out the bottom of the Slave bleeder valve?
That is classic!!! That almost makes my day!!
but just asking questions..........you are running under the assumption that the air bubbles are able to move freely within the fluid.......like in water or 7-Up. That fluid is thick and the air bubbles travel along with the fluid and right out the bleeders when you pump it. Otherwise air bubbles would never go "down" the brake lines from the MC when bleeding brakes the normal way...
So my question is, wouldn't the fluid carry the air bubbles out the bottom of the Slave bleeder valve?
Last edited by jhammons01; Aug 9, 2008 at 12:52 PM.
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Team Owner
Joined: Aug 2004
Posts: 22,303
Likes: 213
From: Sussex,Wi
2023 Corvette of the Year Finalist - Unmodified
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The Tech section has numerous ways to bleed a system easily.
I found the easiest way to do it is this; (pointed out to me in the tech section)
Remove the slave from the bell housing, remove the cap from the master, make sure the master is full, and has a rag underneath it.
Take a large philips screw driver, and push the piston in on the slave.
You'll hear air escaping thru the master. Refill master, push piston in again.
No air in system.
Reassemble.
done.