Master Brake Cylinder ?

[WB9MCW]

OK we know the 90-91 have a dual cups.

The 92 & 93 a single cup and a hose going to the cup.

And the 94 & 95 have a single cup (but no hose? right)

The ? is what is the hose on the 92-93 for?

BTW no stock in at Rock Auto and all the other catalog houses on 92-96 MC's.

Even used are hard to find but I did have luck with

http://www.justcorvettes.com/

[VetteMed]

FWIW, I sent my master in for a rebuild, to Cardone (via RockAuto). Pretty quick turnaround, and no complaints since.

[WB9MCW]

Originally Posted by VetteMed

FWIW, I sent my master in for a rebuild, to Cardone (via RockAuto). Pretty quick turnaround, and no complaints since.

Yes PETE suggested I do this with mine as well once I install the used one from Just Corvettes. The Cardone rebuild via Rock does seem to be the best deal. This way I will have a good to go one in stock should my used one go down. Maybe I will luck out and the used one will last a good while. But just in case I think I will do the Cardone rebuild so I have a spare.

This way if any of the FAST gang get in the same pinch I am in now I can offer to help out and let them install my spare and return their Cardone Rebuilt via Rock to me and not have any down time.



This is why I was wondering about the hose on the 92-93 and why no hose on the 94-96.

It is strange that the used part shops point this out but others do not - they lump them all as 92-96???

To HOSE or Not to HOSE that is the ?

WHAT IS THE BLACK PART FOR?
AUTO BREATHER OF SOME SORT?

[scottfab]

I'm curious. What is the failure on these that need to be rebuilt?
What is the symptom of the failure?

[WB9MCW]

Originally Posted by scottfab

I'm curious. What is the failure on these that need to be rebuilt?
What is the symptom of the failure?

Spongy brakes - even after a bleed down and a new tight pedal - 15 days later (next time out) back to the spongy blues.

The MC is sucking air in upon each stroke.

Common known failure with all C4 MC's.

[VetteMed]

Originally Posted by WB9MCW

Spongy brakes - even after a bleed down and a new tight pedal - 15 days later (next time out) back to the spongy blues.

The MC is sucking air in upon each stroke.

Common known failure with all C4 MC's.

Agreed. I couldn't get a hard brake pedal no matter how much bleeding I did.

[WB9MCW]

Brake Hose May Cause Low Pedal

How to diagnose a sinking, low or spongy brake pedal.

1. Begin by isolating the master cylinder. Remove the lines from the
master cylinder and insert blocking plugs into the ports. Press on
the brake pedal. If the pedal is firm and hard, the master cylinder
is good. If the pedal still drops, either air is in the unit or it is
bypassing internally. Bleed the unit or replace as necessary.
Reconnect and bleed the system.

2. With a properly bled master cylinder test the brake hoses. Using
a proper tool, carefully pinch off all the rubber brake hoses as
close to the master cylinder as possible. Release one brake hose
at a time. Press the brake pedal. If the brake pedal is firm and
hard, move to the next circuit. Repeat until the circuit containing
the defective component is located (the brake pedal will be soft
or sinking). Replace defective components as necessary.



3. Flush the system thoroughly with fresh brake fluid from a sealed
container according to the manufacturer’s service procedures.

[WVZR-1]

Originally Posted by WB9MCW

Yes PETE suggested I do this with mine as well once I install the used one from Just Corvettes. The Cardone rebuild via Rock does seem to be the best deal. This way I will have a good to go one in stock should my used one go down. Maybe I will luck out and the used one will last a good while. But just in case I think I will do the Cardone rebuild so I have a spare.

This way if any of the FAST gang get in the same pinch I am in now I can offer to help out and let them install my spare and return their Cardone Rebuilt via Rock to me and not have any down time.

This is why I was wondering about the hose on the 92-93 and why no hose on the 94-96.

It is strange that the used part shops point this out but others do not - they lump them all as 92-96???

To HOSE or Not to HOSE that is the ?

MAYBE YOU JUST USE YOUR OLD RESERVOIR ???

The GM service M/C does/did '92 - '96MY BUT to use it on '94MY and earlier you needed to transfer the reservoir or buy new and reuse the level sensor or buy new. The hole you indicate as for hose is actually the level sensor port. That is NOT an open port it is a "pass-through" for the level sensor. That image might likely do '92 - '96MY.

The only oddity here is that in '95MY base car MC changed BUT the ZR-1 used the reservoir and level indicator that was used for the previous years '92 - '94MY. If you check a '95 - '96MY base car you'll see no level sensor.

[scottfab]

Originally Posted by WB9MCW

Spongy brakes - even after a bleed down and a new tight pedal - 15 days later (next time out) back to the spongy blues.

The MC is sucking air in upon each stroke.

Common known failure with all C4 MC's.

It maybe a common failure but I've never experienced it in 15yrs of ownership and 92k miles. Maybe it's in how I flush and bleed them.
Don't know. I learned on my 72 vett not to just push a lot of fluid through the system. And to flush every few years even if the pads are ok. I'll be doing that service again this fall. We'll see if my luck holds.

[BOB HDZ]

I know a guy who's addicted to brake fluid. He says he can stop any time.