Air getting in hydraulic system
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
Air getting in hydraulic system
I have air getting in my clutch hydraulics. I bled it to death with a vacuum bleeder (hand pump) and have constant air in the system. Pedal goes to the floor without moving the slave cylinder / TOB.
Setup is 85 MC with Howe slave / TOB.
I isolated the master cylinder with a line that had the bleeder on the end. I bled it out, and with the bleeder closed, the pedal is stiff so I don't see it being the master cylinder. Sitting on the bench, it pushes fluid no problem without introducing any air. When connected to the rest of the system, bubbles come back up to the MC.
There are no visible leaks which is VERY frustrating. I have pushed enough fluid through this thing if the slave was leaking into the bellhousing it would be coming out between the block and bellhousing.
I don't get how air can get in but there is no sign of fluid getting out. Ever had it happen? Any good way to trace it? Can I put little AC oil dye and see if maybe I can find a trace of fluid getting out a particular fitting?
It pisses me off that I had it working at least a little bit (release and engagement were nearly on the floor) and then I discovered the hard tube to flex hose fitting I used was for low pressure applications. And went back to below setup.
Setup is 85 MC with Howe slave / TOB.
I isolated the master cylinder with a line that had the bleeder on the end. I bled it out, and with the bleeder closed, the pedal is stiff so I don't see it being the master cylinder. Sitting on the bench, it pushes fluid no problem without introducing any air. When connected to the rest of the system, bubbles come back up to the MC.
There are no visible leaks which is VERY frustrating. I have pushed enough fluid through this thing if the slave was leaking into the bellhousing it would be coming out between the block and bellhousing.
I don't get how air can get in but there is no sign of fluid getting out. Ever had it happen? Any good way to trace it? Can I put little AC oil dye and see if maybe I can find a trace of fluid getting out a particular fitting?
It pisses me off that I had it working at least a little bit (release and engagement were nearly on the floor) and then I discovered the hard tube to flex hose fitting I used was for low pressure applications. And went back to below setup.
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After pumping the clutch for 25-50 times, it firms up and works well. After driving or sitting, the clutch gets soft again.
I need to pull the slave off and see if there's anything leaking inside.
Any chance there could be tiny breaks in the line where air is getting in?
