[Slurpee]

I am changing my master cylinder on my ZL1. When removing the old master cylinder, I could not remove the nuts with my hand. Had to use a wrench the whole time.
I cannot for the life of me get the new master cylinder on at all. The springs in the brake booster are all the way forward, and no matter how hard I push, I cannot get the master cylinder far down enough to even start threading the nuts.
Am I missing something?

[ctrlz]

Do the old and new parts measure identically, particularly diameter of piston?
EDIT: Just looking on ebay, all the pulls seem to include both the master cylinder and the booster as a unit. So, maybe you were not supposed to separate them. Sounds like you may have been battling threadlocker to remove the MC.
At any rate, Master cylinder/booster combo units go for about $100 on ebay (for gen6 ZL1)

[Slurpee]

Originally Posted by ctrlz

Do the old and new parts measure identically, particularly diameter of piston?
EDIT: Just looking on ebay, all the pulls seem to include both the master cylinder and the booster as a unit. So, maybe you were not supposed to separate them. Sounds like you may have been battling threadlocker to remove the MC.
At any rate, Master cylinder/booster combo units go for about $100 on ebay (for gen6 ZL1)

I also cannot get the old MC back on. It's the same issue as the new one.
When removing the old MC, when I removed it from the booster, I heard a click, definitely sounded like a spring. I tried pushing in the booster push rod and it will absolutely not move. The pedal is all the way back in the car.
EDIT: according to the manual I have, it does not say anything about having to replace both. It does say to pump the pedal before installing to remove vaccum, which I unfortunately forgot to do, but I removed the vacuum line with the booster.

[DeuceCam]

Not familiar with the Camaro setup, but from past experience with other cars, sometimes the pushrod length on the booster needs to be adjusted. However, if the masters are both identical, I don't see why that would be.

[ctrlz]

Originally Posted by DeuceCam

However, if the masters are both identical, I don't see why that would be.

Agree. If parts are identical, next step may be pulling the booster and mating MC and booster off the car.

[Slurpee]

The service manual I have shows that when installing the brake booster, the master cylinder isn't installed on it yet.
Is it possible the push rod from the booster fully extended and that's why I can't push the new MC in? If that's the case, is the only solution to buy a new booster?

[ctrlz]

Originally Posted by Slurpee

The service manual I have shows that when installing the brake booster, the master cylinder isn't installed on it yet.

Mine shows the same thing. But since you can't line them up on the car, it might be easier to pull the booster and see what's going on.
EDIT: Links to separate listings for a ZL1 booster and an MC. Multiple photos in each. Looks to me like the male end of the MC has indentations suggesting it is "keyed" in a certain way.
https://www.ebay.com/itm/156735410667
https://www.ebay.com/itm/296955578275

[Slurpee]

For anyone that comes across this, you have to remove the reservoir in order to get everything lined up. Then put the reservoir on once the MC is bolted to the booster. You do not have to remove the booster

[ctrlz]

Originally Posted by Slurpee

For anyone that comes across this, you have to remove the reservoir in order to get everything lined up. Then put the reservoir on once the MC is bolted to the booster. You do not have to remove the booster

Thanks. Glad you got it on.
Now if only they would mention stuff like that in the service manual...