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05 cavalier clutch

My daughters clutch goes to the floor. The mechanics replaced the master cylinder which did not fix the problem. They are now telling her that the slave cylinder must be replaced. I do not understand how the clutch pedal can be going to the floor if the master cylinder is working and there is no leak. What am I missing? I am in Thailand and so am not able to investigate on my own.

It’s quite possible for a clutch to be inoperative if the slave cylinder is faulty.
Generally speaking, it’s a good idea to replace both master and slave at the same time even if one or the other is not defective. Replace the bad one and this often knocks out the other.
The leak is often internal, which means it’s leaking past the seal inside rather than out onto the ground.

The exception might be on slave cylinders that are integral with the clutch assembly and require removal of the transmission to replace that particular part. In a case like this it’s replace the master cylinder and pray. If that fails then it’s time for a slave cylinder and a new clutch assembly because one would not want to pull a transmission and leave an old clutch assembly in place. Hope that helps.

Thanks, her car has the slave cylinder that requires the transmission removal. The part I am puzzled about is where the pressure goes if there is no leak. Does the master cylinder work differntly than a brake master cylinder?

A brake master cylinder may act up in the same way. Pressure bleeds back past the piston seal and takes the route back through the fluid line into the resevoir.

With the slave cylinder being mounted internally I can understand why they did not change the slave at the same time. Changing the slave cylinder in a case like this needs to come down to a have to situation and unfortunately, that’s what it sounds like now.

I started servicing hydraulic clutch mechanisms many decades ago and it did not take me too long before it got to the point where both were recommended. There were too many instances of changing the master and the slave would fail a day or a month later or the scenario would repeat in reverse with the master failing after the slave only was replaced.

I don’t quite understand because clutch pedals always can be pushed to the floor. Is your daughter relating that the pedal goes to the floor and does not return? Alternately, is she relating that the pedal goes to the floor but the clutch still does not release?

BTW how long ago and how many miles are on this clutch?

A clutch master cylinder can leak internally and not show a leak. But if a clutch slave cylinder leaks it shows. Because it’s just a cylinder with a piston. a rod, and a seal.

It sounds like all the air hasn’t been bled from the clutch hydraulic system.