I am buying a new clutch soon and spoke to slp today about their clutch package for a 95 lt1 and they said I need to upgrade my slave cylinder to GM part number 12557509. Anyone have any info on this and why they suggested to do this? I am leaning more towards a spec stage III, but would I need to do this for the spec III also?? Thanks in advance

 

that part # should be the factory slave/master cylinder unit with lines. they all come together. however, it would be a good idea to replace this with a new clutch. i believe mine is going out right now so i will be replacing mine soon too. i believe some clutches are harder on the cylinders and lines due to the fact that they are stronger clutches. so maybe they meant just replace your old unit and you will be fine with a new unit.

 

im not gunna replace mine.. and im doing my clutch tomarow.. *slp* and im not doing the slave.. if it gets gay on me. then ill replace it.. if its not broke dont fix it

 

This was not a original part it is suppose to be a better slave unit
I guess GM might of change to a better piece than what was in there. Anyone else know anything?

 

do they have another part # for a similar unit then? heck i don't know. i was just told by people on here that was the part # so i assumed it was the factory one. maybe they redid the part or maybe they were having problems with the factory one do made this. sorry, can't help you much there.

 

12559912 is the number i got from Dal for my '96 T/A. it's also about $40 cheaper than 12557509.

 

does anyone know the difference? is one stronger?

 

i'm not 100% sure, i think what Dal said is that the 9912 is a refinement and a little softer, but it moves quicker...AFAIK the parts are interchangable.

 

He told me one is longer than the other. Not distinguishable by sight though. I think the newer one has a bit more travel from the slave cylinder rod. Have to add that Dal is great. I got the hydraulics overnight saturday delivered for less than $130. You can't beat that. Local dealer wanted almost $150 and said it would be a week.

 

brian, which one did you end up getting?

 

Dang, I can't remember the part number, but it was the newer style. The old one was about $50 more, and Dal said the new one was all that he ever sells anymore. Put it in and still have a problem though. Hopefully I have found the issue. I've had the flywheel turned twice and I bought it used, so it may have been done before. Went to a local machine shop the other day and he had some flywheel shims. Picked one up and I'm gonna try it today. Wish me luck!

 

let us know if that works. and good luck!! also, when you say that the newer unit, 9912, is a little softer and quicker, do you know if one can handle more power or if they are similar? thanks

 

There is a mod for that unit involving opening up the oriface to allow more fluid to move faster for better engage/release of the clutch. It was on the board before but the thread was short lived. Anybody done this mod latelty?

 

I'm surprised that no one offers an aftermarket "stand-alone" slave cylinder for the LT1 T56 with how popular that combination is (or at least was) in swaps. I'm going to have to find something to work with the Street Twin, since the stock master/slave system isn't going to work with my firewall.

Then again, I'm surprised that no one offers an SFI-approved bellhousing for the LT1 T56. Lakewood has an LS1 model, and the recent articles I've read on McLeod's one-size-fits-all version stated that it wouldn't work with the LT1 T56 because it has no provisions for an external slave cylinder on the bellhousing. So much for one-size-fits-all.

At this point, I'd like to figure out how to convert my LT1 T56 to a hydraulic throw-out, if possible. It would make a number of things easier, including exhaust routing. I think someone on the Impala forum posted information on this at one point. If I can find it, I'll post it, if anyone is interested.