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Discussion Starter · #1 ·
Fitted Strange Brakes and Master Cylinder to my build and after doing many searches here for tips on plumbing and bleeding and reading so many issues with bleeding and bad pedal feel I thought I would record my experiences for others to find in the future.

For reference, Car is a 2017 VF SS Commodore that I am building using the Copo Camaro as inspiration, as if Holden built a Factory Stock Race Car. (It will be powered by a 2650 Supercharged 412ci LS engine.)

Master Cylinder is Strange 1.125" Dual In-Line for use with front and rear 4-piston systems.

Rear Calipers are Strange Pro Series II brake kit ordered to suit the 40 spline axle offset and bearing ends.

Front Calipers were Strange Pro Series I, but I have since changed them over to Pro Series II Calipers. I bought the 2010-2015 Camaro Copo front brake kit for the car back in 2018, but will explain later why I changed calipers.

Fitment to the car was straight forward enough. I made up the adaptor for the firewall to adapt the Strange Master to the Holden Pedal system out of an earlier model Commodore that my chassis builder (SCF Racecars in Sydney) then adapted together. Pedal ratio worked out fine by modifying the pushrod mounting on the pedal closer to the pivot point.

I spoke to a few racers in our racing club about bench bleeding v's bleeding the car for new builds and no one had ever bench bled a new master cylinder. I remembered my last build 20+ years ago, I don't remember bench bleeding the master or having any issues. One suggestion that came up was to gravity bleed the master and I was surprised how easy it was!

Once I was ready to start bleeding the brakes I filled the master cylinder up with brake fluid and cracked the top bleed screws on all 4 x calipers. What surprised me is how quickly the brake fluid from the master cylinder came down to the closest brake caliper. Within 5 minutes, the first front caliper (RH side) was flowing out of the bleed screw. about 10 minutes later the other front caliper (LH side) was bleeding.

The rear brakes tool a little longer to self bleed and I actually started sucking on the clear hose I attached to the bleed nipples to help it move through the stainless brake lines. Once the fluid appeared in the hose I let it work through fully before closing the bleed nipples.

Obviously the gravity bleed isn't a full and final brake bleed, so I had to wait a couple of days for some assistance to bleed the brakes conventionally.

What surprised me is how easily the normal brake bleed went from there. Once the pistons moved to clamp the pads and within 4 or 5 pumps per caliper there was no air in the system and the brake pedal felt really really good. (Noting that I haven't driven the car yet, that will be a few months away yet.)

With the Pro Series II Calipers on the rear end, it was very easy to turn the wheels once the brakes are released (I have a ceramic bearing Dewco centre), however on the front wheels, I noticed that there was a significant amount of brake drag on the Pro Series I calipers. After some research on the Strange website and YB forums I worked out that the Pro Series II Caliper has a different design seal that pulls the piston away, so I ordered Strange B1950 4-piston calipers to do a straight swap on the front end.

With a quick 20min change over and brake bleed on the front end, there is now no brake drag on the Strange Copo hubs and the wheels spin for 30-40 seconds from a simple push. The different seal in the caliper made a huge difference to brake drag and while I haven't been able to do a back to back test on the track, I know now that when I do go to the track for the first time there wont be any significant brake drag to slow me down!

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Nice job but I question the use of the 1.25" bore master cylinder? 99% of all manual 4 wheel disc systems use a 1" or 1-1/16" bore master cylinder to develop required pressure for four wheel discs. The Strange master cylinder is based on the 1979-89 Dodge Diplomat 1-1/16" master cylinder Raybestos MC39034 or equivalent. If your system has a bad pedal or requires extra effort try the smaller bore master cylinder.
 

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Discussion Starter · #6 ·
Nice job but I question the use of the 1.25" bore master cylinder? 99% of all manual 4 wheel disc systems use a 1" or 1-1/16" bore master cylinder to develop required pressure for four wheel discs. The Strange master cylinder is based on the 1979-89 Dodge Diplomat 1-1/16" master cylinder Raybestos MC39034 or equivalent. If your system has a bad pedal or requires extra effort try the smaller bore master cylinder.
1.125" not 1.25" Master.

The pedal feels great, noting that I am yet to drive the car.

Strange recommend the 1.125" for 4-piston front and rear calipers, they recommend the smaller Master for 2-piston front and 4-piston rear brakes.

The 1.125" is the same as the Copo Camaro and they were pretty well tested before being released and modified by the racers (some who now run dual rear calipers.)
 

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Discussion Starter · #9 ·
Start a build thread of this car! Too clean and nice not too
Thanks mate, check it out on Instagram @copocommodore. Updating it there is enough work without duplicating everything here. especially doing it on my phone as well! lol
 
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