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TX '90 ZR1
02-14-2022, 07:12 PM
Found a PBR master cylinder to replace the original on my '90. It was beginning to seep a little out of the cylinder bore. The new one is exactly the same as original except the PBR logo font is a bit different. It also does not have "Made in Australia" cast into the housing as the original did. The box it was shipped in does indicate it was made in Australia.
Would like to repair my original, but am having no luck on locating an overhaul kit. Does anyone know if any have become avasilable?
Thanks Guys & Gals !!
:cheers:

Z51JEFF
02-22-2022, 06:49 PM
I would think this is easily available considering how many C4s were produced.

TX '90 ZR1
02-22-2022, 07:59 PM
I would think this is easily available considering how many C4s were produced.

Jeff, I would have thought so myself!
Steve from Crossed Flag Performance and I have been looking all over for a few years. NAPA used to have them, but that was before I was checking around. And yes, I did check about stock on individual store shelves to no avail.
Just feel fortunate to locate an OEM replacement.
:cheers:

Edit: I did a quick check again for an overhaul kit. Appears Eckler's may have some. Everybody else shows not available.
The kit from Eckler's is $169.99!! Wow! Think I will disassemble mine and see what parts it needs. I have repaired some cylinders in the past just by matching the seals.
No hurry I don't guess. Doubt anyone would know the one on my car is not original except me.
:cheers: (again)

Paul Workman
03-01-2022, 02:40 PM
I have had good luck with the M/C & slave combo from Rock Auto. Both (mine) are cast iron (not the Chinese or that tubular steel junk).

For (anyone's) information:

The '90s clutch line between the MC and the slave was a solid steel line. And, if you ever need to replace it, it is a "bear" to weave it around between the (what have you) and the MC and SLAVE. Furthermore, the bleeder on the slave is on top of the 90 slave cylinder; a real PIA to try to bleed the clutch (system) of air or to change fluid, etc.*

But! The clutch line for the 91+ years has a flexible section in the middle which makes it easy to install and orient to the respective cylinders.

And! The slave for the 91+ has the bleeder on the bottom side of the cylinder which avoids the access issues when manipulating the valve when purging the system. I installed the '91 line & slave on my '90 with NO issues!

(Hint:) I purchased a kit from [U][Mytivac/U] containing a bottle and adapter that fastens to the open MC. With that setup, you can cycle the rod in and out and open/close the bleeder w/o being distracted by having to keep filling the MC while purging the system. (or worse...NOT filling the MC reservoir in time and accidentally sucking AIR into the system and having to start the purging process over again! BTDT!)

I wrote an article for HOTB (Registry member's quarterly) with more detail and photos on the whole MC/Slave installation, if interested.:)

The bottle from the Mitivac kit shows how it looks when mounted to the reservoir of the MC.

The SLAVE is the TOP view of the '90. I recommend** purchasing a slave from the 91+ years. (The bleeder valve is opposite to the one pictured (the '91+ are on the bottom instead of the top)).

*The traditional method of bleeding the system involves two ppl: one to pump the clutch pedal while the other opens/closes the bleeder valve. Or, the alternative calls for pumping the clutch pedal and monitoring the fluid lever in the reservoir. This requires several dozen pumps of the clutch pedal, but good results (and patience) is sometimes elusive!

(IMO) the better/easier way to bleed the air out (especially) is to install the Mytivac bottle with ample fluid and then pushing/releasing the slave (throw-out bearing) push rod, while operating the bleeder valve between the "in-out" cycles of the pushrod. This method can be done w/o an assistant, and only requires (about) 3 to 5 cycles to bleed out all of the air and end up with a firm pedal (IOW, NO AIR in the system!):thumbsup:

**if/when you convert from a '90 to a '91+ slave, you will need to purchase the '91+ clutch line too. I think you'll find the new one much easier to install than removing the old '90 hard line!