2G Changed the master clutch cylinder... didn't expect this

[kteare]

This winter I noticed my master clutch cylinder was leaking inside the car (1997 GST, 125k miles). I bought a Nabco replacement and installed it. Install went fine and the line bled normal. I didn't expect this: My clutch pedal, after pressing halfway, is going to the floor and staying there. I don't recall removing a return spring (don't see one) and I'm not sure why this is happening. I'm really scratching my head on this one. Included a picture showing clutch pedal to the floor. Help anyone?

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[ThunderChild]

Did you bench bleed the master cylinder? I do believe there is a small return spring, but it won't be able to pull it back if you don't have the system bled properly.
Also, can you pull the pedal up by hand?

 

[kteare]

Thanks for the reply!! I didn't see anything about bench bleeding on the YouTube vids I watched. The pedal pulls back just fine. It's like after pressing halfway, it sucks to the floor. Really weird. Check out the vid to see what I'm talking about.

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[DSMPT]

Assuming it's installed/bled properly. Try to replace the slave cylinder, too. This sometimes happens when you replace only one cylinder or install a higher pressure plate. You get higher pressure in the line and it would finish the weaker side.

 

[spyderdrifter]

There is no return spring on a 2G clutch pedal. It returns to position via the hydraulic fluid being pushed back to the master cylinder when the clutch pedal is released. If you didn't bench bleed the cylinder before installation, it would be best to remove it from the car, bleed it, reinstall, then bleed the clutch system. If you don't want to take it back out again, prepare for a very long and slow bleeding session.

Here are some videos from Jafro, he's very informative, and definitely someone to watch.

Clutch Bleeding: He's bench bleeding the slave cylinder, but the master cylinder is the same process.

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Clutch Adjustment:

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[kteare]

Assuming it's installed/bled properly. Try to replace the slave cylinder, too. This sometimes happens when you replace only one cylinder or install a higher pressure plate. You get higher pressure in the line and it would finish the weaker side.

Installing the unit was one of the easier projects I've done on this car (2 nuts, 2 bolts, pin w/ clip, and 1 clamp). I pumped a cup of fluid through the system (using the same method I use to bleed brakes) so I'm very confident it is bled correctly.

I ordered a slave unit. Thank you for your assistance!

 

[pauleyman]

Do not throw your old slave away. Check and make sure the slave you bought and your old slave have the same bore diameter. I don't remember if there are two available on FWD but there definately are two available on AWD. Don't remember why. Could be a 1g/2g difference.

 

[kteare]

There is no return spring on a 2G clutch pedal. It returns to position via the hydraulic fluid being pushed back to the master cylinder when the clutch pedal is released. If you didn't bench bleed the cylinder before installation, it would be best to remove it from the car, bleed it, reinstall, then bleed the clutch system. If you don't want to take it back out again, prepare for a very long and slow bleeding session.

Here are some videos from Jafro, he's very informative, and definitely someone to watch.

Clutch Bleeding: He's bench bleeding the slave cylinder, but the master cylinder is the same process.

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Clutch Adjustment:

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Thanks for the vids... who'da thought a replacement would be this tedious.

 

[kteare]

Since I'm replacing stuff, I'm going to add the SS line. Any recommendations where to get one? It's been a while since I've bought good aftermarket parts for my DSM. Big thanks.

 

[kteare]

Will do. Thx for the advice!!!

 

[camocorvette]

I've fought with non oem MC and autozone/napa ones to get them to bench bleed. Sometimes it doesn't work the first time.

https://www.extremepsi.com/store/Ex...-to-Master-Cyl.-Mitsubishi-Eclipse-95-99.html

 

[kteare]

Thanks for the link!! I absolutely stay away from the junk parts from the chain auto part stores. I'm not trying to act/be snooty. I used to work for one of them and the lifetime warranty sounds good in theory, but watching customers repeatedly taking a part off to exchange it gets rather expensive time-wise not to mention the hassle factor.

Update: I let the car sit for a few weeks cap off simply adding fluid when needed. Bled one last time and the pedal was "normal" again. I'm sure it had to do with not bench-bleeding it.

Thank you everyone for your help, deep DSM knowledge, and for this site to keep these cars on the road.

 

[1990TSIAWDTALON]

Thanks for posting an end result so that this thread is a useful one!
Marty