J52 brakes - master cylinder date code vs. brake booster date code?

[Dave69x33]

I would like some feedback from owners of cars with J52 front disc brakes that have their original date coded booster and master cylinders. 

My Norwood 05A (1st week of May, 1969) Z28 has its original #9204 booster with Julian date “108”, or April 18th.  My “309” casting master cylinder is a replacement with Julian date “297” or October 24th.  At the time of my restoration, I ran across this October date MC and had it restored.  I would like to search for a correct dated unit for my car, with Julian date between 091 and 120, or April 1st – April 30th.

In the AIM, pp. 359-360 covering the J52 disc brake option, it shows Cylinder ASM #5468165 as the booster and MC as one preassembled unit.  So was the “165” preassembled brake assembly sent to the assembly plant this way from Delco Marine?

What are common date codes on the boosters vs. master cylinders? 


JohnZ,
I recall from a related discussion on master cylinders, that your “309” MC is dated “45”, or Feb. 14th and within about 2-weeks of your 02D build date.  If you still have your original booster, what is the date code?

Thanks!

[JohnZ]

JohnZ,
I recall from a related discussion on master cylinders, that your “309” MC is dated “45”, or Feb. 14th and within about 2-weeks of your 02D build date.  If you still have your original booster, what is the date code?

Thanks!

My (original) booster is dated "55" (February 24, 1969), about 4 days before the car came off the line.

The Assembly Manual shows the master cylinder and booster as an assembly, but that's not how the parts were received; they arrived separately, and the master cylinder was installed on the Chassis Line, and the booster was installed on the body on the Trim Line. The master cylinder was secured to the booster studs after body drop.

[sixt9x33rs]

Where are the Julian date codes located on the parts?

[mark x22]

John was the complete front chassis assembly and rear end with springs and brake lines installed on  a fixture and filled with brake fluid before body drop ? If so how did they bleed the brakes ?

[KurtS]

Where are the Julian date codes located on the parts?

http://www.camaros.org/suspen.shtml#Brakecomp
M/C date is on the side of it.

[Dave69x33]

Thanks JohnZ.  

So was the #9204” brake booster P/N-5468156, or was this the part number of the preassembled booster/MC unit as show in the AIM?

Anyone else with their original units care to share their date codes vs. the build date of their Camaro?   The date codes on these units appear to be very close to the build date of the car.

sixt9X33rs,

The master cylinder’s Julian style date code is cast as a two or three digit code, in the driver's side of the 5468309 casting reservoir.  In ’69 the power brake booster, commonly used with the J52 disc brakes, has “9204” stamped on the tab directly above the MC at the 12:00 o’clock position (not sure if it’s the same unit for ’67 and ’68).  On the back side of this tab you should find a Julian stamped date code.  See pics for ref.  It is stamped upside down when the unit is viewed in the car.

[JohnZ]

John was the complete front chassis assembly and rear end with springs and brake lines installed on  a fixture and filled with brake fluid before body drop ? If so how did they bleed the brakes ?

Yes, it was, with an evacuate-and-fill system. An adapter clamped to the master cylinder with two probes that sealed to the two compensating ports in the bottom of the reservoirs. The machine drew a very high vacuum in the system, held it for a few seconds to check for gross leaks, then injected brake fluid through the probes at 40-50 psi with the system still under high vacuum, then filled the reservoirs; none of the bleeders were ever touched. The fill adapter was removed, and a test adapter was clamped on the rear of the master cylinder which applied pressure directly to the rear piston, bringing the system to 1800-2000 psi and monitoring system pressure for any decay, which would indicate a leak.

Prior to 1968, brakes were bled using 40-50 psi fluid pressure in the master cylinder and tubular wrenches at the bleeders on hoses connected to a vacuum source.

[sixt9x33rs]

My M/C looks like it is stamped either 65 or 85 for a 03D car. The booster looks like either 60 or 80 again for the 03D car.

Is is raining here and cant get the car outside for a good picture. The car is parked below another on a lift so just cant get good light.

I will try tomorrow and report back a sure date.

[mark x22]

Thanks John , have any pictures it would be neat to see that set up ?

[JohnZ]

<<Thanks John , have any pictures it would be neat to see that set up ?>>

Don't have any of the Camaro Chassis Line, but here are two from the Corvette plant taken in the 70's. One shows the master cylinder after bleed and test, supported by a tool from the steering gear, and the other shows a view across the line with the 500-gallon aluminum tote-tanks of brake fluid next to the fluid processing equipment.

[mark x22]

Thanks John