G50 Clutch Bleeding Problem

[skunkwerks]

I have struggled bleeding my clutch slave cylinder after a total engine rebuild. I have tried manual, vacuum, and pressure bleeding, yet still I only get 1/2 pedal pressure.

When manual bleeding, my helper held the pedal to the floor while I opened then closed the bleed valve. I didn't get air, just pure fluid.

I then added a pressure bleeder onto the reservoir and pressurized to around .75 bar. Again, holding the pedal to the floor, opening then closing, yielded no air. With the system pressurized, the pedal felt great! It was stiff all the way to the top, returned on its own, and I could feel the slave cylinder actuating the release fork from under the car. Once pressure was removed, the slop returned.

Does this sound like the master cylinder? I'm not sure what those symptoms would look like.

The only other change to this system is the hose from the slave cylinder to chassis tube was rebuilt by Amazon Hose with steel braided. I can't imagine the hose volume would change??

Anyone else experienced this or have suggestions?

[Dmitry at Pelican Parts]

Perhaps this tech article will be of assistance - there are some pointers when bleeding a G50.

https://www.pelicanparts.com/techarticles/911_G50_clutch/911_G50_clutch.htm

[john walker's workshop]

Pressure bleed with the pedal up. Just takes a few seconds for the air to exit. Just don't let the reservoir level drop below the outlet for the clutch hose.

[shrtshck]

If bleeding does not fix the issue, it could be your slave is done. Replaced mine during the top end rebuild as the clutch petal was acting up prior to pulling the engine.
Have had no issues since.

[rokemester]

Originally Posted by john walker's workshop

Pressure bleed with the pedal up. Just takes a few seconds for the air to exit. Just don't let the reservoir level drop below the outlet for the clutch hose.

Great Pro tip John. This helped, noting clutch pedal position and fluid level relative to clutch hose outlet. Thanks!

[GG Allin]

Is there any need to actuate the pedal at all as part of the bleeding process?

I'd using a Motive Pressure Bleeder.

I've flushed the old fluid out pretty good, pedal does not return like it's supposed to.

All new parts, clutch master, slave, TO bearing, PP, clutch & flywheel.

[aston@ultrasw.c]

Hope this link works

G50 Clutch Bleed Update...

These are my scintillating observations on a prior thread

[Tremelune]

Dunno what the pedal does when pushed in/out, but the procedure in the book says to do it slowly "several times" while the system is pressurized.

If the air is trapped in the cylinder at the wrong end, it might help to tap it with a hammer and raise the front of the car higher than the rear.

With regard to pressurizing: I ditched my Motiv and just used a brake res cap and an air line quick disconnect and hook it up to my compressor. No more $40 hand pump. No more $40 adapter. I just drilled a hole, screwed in the disco, and smeared it with silicone.

[faapgar]

I learned this method from repairing 928 and 944 cars.With the pedal up use an oil can for lube and connect a brake bleeder hose to the tip.Squeeze the oil can and push fluid to the tip of bleeder hose to remove air.Connect to slave and open bleeder screw.Pump about 20 times.It helps if you have someone watch the reservoir and tells you when there are no more air bubbles.Basically you are backbleeding the system.Ciao Fred

[skunkwerks]

Whoa, resurrected thread. I resolved this months ago. I eventually removed the slave cylinder and drained the fluid to reintroduce air to the system. Then I just bled it a bunch. Eventually I got a bunch of air that was trapped somewhere in the system to come out. It took several liters of fluid cycled through to get the trapped air out.

Good news is that I flushed the whole system really well! Pedal feels great!

[rokemester]

I used Frank’s clutch bleed tool today. Although I used it with the engine positioned below the car before reinstallation. It is a very slick bit of engineering. A real nice tool!! I can see how this would be a huge help with engine and transmission in car.

[Mervo]

I cut down a small wrench to fit the 7mm bleeder and connected a tube, put about 15psi through the system and bled it - clutch up BTW.

[rokemester]

custom wrench, small hands and expansive vocabulary required.

[Gideon911]

I just tried to do this bleed tonight. Filled the Reservoir. Clamped the overflow line. Closed reservoir cap. Hooked up a tube to the bleed line with a bottle attached, and had my wife ready to pump the clutch pedal. I’ve got my 7mm wrench and I say, “go ahead and pump it 3x..first pump the slave explodes and brake fluid all over the floor lol

I am an idiot lol. This one I had to laugh at..after a few minutes..yep, that’s what that cylinder is suppose to do. Oh did I mention the slave was not hooked up to the trans? Lol

I might be to first guy to do this lol. Now I’m curious, is it even possible to bleed without the slave bolted up? I doubt it, but I’m wondering if I had my thumb pressing firmly on the end..would that have worked or does it just have way too much pressure? I’m sure I need to buy a new slave since the spring and whatever else sprung out like a clown out of a box.

[Quicksilver]

Originally Posted by Gideon911

I just tried to do this bleed tonight. Filled the Reservoir. Clamped the overflow line. Closed reservoir cap. Hooked up a tube to the bleed line with a bottle attached, and had my wife ready to pump the clutch pedal. I’ve got my 7mm wrench and I say, “go ahead and pump it 3x..first pump the slave explodes and brake fluid all over the floor lol

I am an idiot lol. This one I had to laugh at..after a few minutes..yep, that’s what that cylinder is suppose to do. Oh did I mention the slave was not hooked up to the trans? Lol

I might be to first guy to do this lol. Now I’m curious, is it even possible to bleed without the slave bolted up? I doubt it, but I’m wondering if I had my thumb pressing firmly on the end..would that have worked or does it just have way too much pressure? I’m sure I need to buy a new slave since the spring and whatever else sprung out like a clown out of a box.

I've bled my clutch a couple times where I wasn't getting results so I unbolted the slave so I could hold the slave so the bleeder was at the top corner of the cylinder. No problems as the piston is held in with a circlip. (It is really hard to remount the slave under the car though. Hand strength and cussing is involved.)

How much pressure did you put on the system? I can't really imagine the circlip blowing out of the slave until a WAY higher pressure then would pop the reservoir like a balloon? Something sounds off with the cylinder.

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Full disclaimer: My system is slightly non stock as it has a separate clutch reservoir which is nice to keep everything separated. No need to clamp off a vent tube.

[Gideon911]

Originally Posted by Quicksilver

I've bled my clutch a couple times where I wasn't getting results so I unbolted the slave so I could hold the slave so the bleeder was at the top corner of the cylinder. No problems as the piston is held in with a circlip. (It is really hard to remount the slave under the car though. Hand strength and cussing is involved.)

How much pressure did you put on the system? I can't really imagine the circlip blowing out of the slave until a WAY higher pressure then would pop the reservoir like a balloon? Something sounds off with the cylinder.

------------------------------------------------
Full disclaimer: My system is slightly non stock as it has a separate clutch reservoir which is nice to keep everything separated. No need to clamp off a vent tube.

Oh I bet it’s a PITA trying to bolt the slave while trans is still in the car. I did not use a motive or any power bleeder. I thought I could do it the old Fashion way by just having a helper press down on the clutch pedal.

I was under the impression you have to clamp the overflow line. I think I read Kevin made a mess as one point by not clamping it.

I plan to just order a new slave, but now I’m curious. Can these pieces be put back together in the slave that the circlip, spring, etc blew out of?

To be more clear, engine and trans have been out of the car for a few weeks. Clutch, and brakes had not been touched until my wife pumped the clutch the one time. She pressed the pedal normal, and not very slow..maybe that was the problem? Or is it possible min was on its way out anyway?

[Tremelune]

For bleeding I use a reservoir cap that I lodged an air compressor quick connect into...I fill the res and pressurize the system to 10-15psi (this is why people clamp the overflow tube) and bleed (making sure not to let the fluid run too low). Pumping under pressure might help get out finicky air bubbles, I dunno.

If I'm not mistaken, I can let you borrow it at GVBC. It's a janky piece of kit, but it works...

[Gideon911]

Originally Posted by Tremelune

For bleeding I use a reservoir cap that I lodged an air compressor quick connect into...I fill the res and pressurize the system to 10-15psi (this is why people clamp the overflow tube) and bleed (making sure not to let the fluid run too low). Pumping under pressure might help get out finicky air bubbles, I dunno.

If I'm not mistaken, I can let you borrow it at GVBC. It's a janky piece of kit, but it works...

I see, that makes sense. I ended up buying a motive bleeder this morning. Figured I might as well have one so I don’t need a helper for brake/clutch bleeds in the future.

Thanks for the offer to let me borrow yours! Have not been making it up there Friday mornings since it became a zoo haha