Master cylinder leaking

Amack1970

Active Member
I just noticed I have a small fluid leak between the back of my master cylinder and the brake booster. I used a 2010 cobalt SS as my donor. Do I have to use the same master cylinder from that car, or can I us a LS model. None of the local parts guys have the SS one in stock, but they have tons of LS ones and there cheaper. Let me know what you guys think
Thanks
 

Desert Sasqwatch

Goblin Guru
Anthony, can someone tell you if there is a difference in the piston size between the two MCs? The other significant difference could be brake pedal stroke ratio that could affect pedal travel and the MC piston travel. I don't want to ask if you have checked the local boneyards, since the last time I looked it was easier to find a Corvette than a Cobalt SS in any of them.
 

Parson Green

Well-Known Member
I just noticed I have a small fluid leak between the back of my master cylinder and the brake booster. I used a 2010 cobalt SS as my donor. Do I have to use the same master cylinder from that car, or can I us a LS model. None of the local parts guys have the SS one in stock, but they have tons of LS ones and there cheaper. Let me know what you guys think
Thanks
A "correct" SS master cylinder will have, on the plastic reservoir, an extra, clutch-operation-related nipple.

That fact makes them atypical and hence more expensive and/or difficult to source.

Is the presence of said nipple the only difference between the SS ones and the LS ones? Methinks yes but YMMV.
 

Karter2026

Goblin Guru
A "correct" SS master cylinder will have, on the plastic reservoir, an extra, clutch-operation-related nipple.

Is the presence of said nipple the only difference between the SS ones and the LS ones? Methinks yes but YMMV.
I have a LT donor that has the clutch nipple. Here are some bore size differences for the master Cyl.
SS Cyl

Base Cyl
 

Amack1970

Active Member
A "correct" SS master cylinder will have, on the plastic reservoir, an extra, clutch-operation-related nipple.

That fact makes them atypical and hence more expensive and/or difficult to source.

Is the presence of said nipple the only difference between the SS ones and the LS ones? Methinks yes but YMMV.
Oh, that's right. So I get to bleed the clutch too. Awesome!
 
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