Power Brake Booster Part # Comparisons

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CamarosRus

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Discussion starter · #1 · Feb 19, 2003

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Many people/media articles refer to the 9204 # as the correct booster for 1969 and my own research here suggest that 0426 is "correct" for 1970. For those not knowing these #'s are stamped on BACK side of that TOP TAB where booster halves mate together. The #'s on front side appear to be the julian date of mfg in that year(??). 1) I am LOOKING for a 9204 core for my 1969 AND a 0426 for my 1970 2) Would like YOU to submit your info on what #'s appear on YOUR 69 or 70 Booster 3) Also would like your Master Cylinder casting #'s such as 309 for 69 and 409 for 1970.
Booster Dewey(Portland,OR) sent me copy of 1992 General Motors letter stating that booster and M.C. reservoir cover were plated with Zinc Dichromate.
NOT the Cadmium 2 (gold) that I often hear about
Thanks, Chuck Sharin

 

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z28doug

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#2 · Feb 19, 2003

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Chuck,
I have a 02C build car with 9204 on the brake booster. 356 is on the front tab. 5468309 is the casting number on my master cylinder.
Doug

[ 02-20-2003, 06:50 PM: Message edited by: z28doug ]

 

JohnZ

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#3 · Feb 20, 2003

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My untouched original 02D '69Z has the 9204 booster, Julian-dated "55", and 5468309 "US"-stamped master cylinder. The boosters were zinc-plated and then dipped immediately in a dichromate wash, which imparted the "gold" coloration.

 

Jonesy

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#4 · Feb 21, 2003

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My car is 11B '69 SS350 has the 9204 booster, Julian-dated "300", and 5468309 "US"-stamped master cylinder. I had my booster replated like John's description.

 

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CamarosRus

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Discussion starter · #5 · Feb 21, 2003

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Thanks guys ......keep the opinions coming.....
John, do you believe that the prop valve brkt and distribution (brass) block support brkt and M.C. cover are also ZINC Dichromate or just Yellow Zinc....I dont know the difference but I'm guessing there is???

 

JohnZ

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#6 · Feb 23, 2003

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Yes, all three are plated - there is only one color of zinc plating - silver; the gold-shaded coloration came from the dichromate wash immediately after the parts came out of the zinc-plating tank (same way it's done today by the booster restorers).

 

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frankk

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#7 · Feb 26, 2003

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Anybody out there have any numbers for a JL8 booster and master cylinder?

 

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Steve Shauger

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#8 · Feb 27, 2003

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Frankk:
Used the same as front disc/rear drum cars, although proportioning assembly was deleted. 9204 booster and 309 master.

 

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Steve Shauger

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#9 · Feb 27, 2003

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my 3B Z has 9204 dated 065

 

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68z302

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#10 · Mar 1, 2003

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I believe that the JL8 Master Cylinders had a
1 1/8" bore where as the standard Disk Brake bore was 1".
I'm not 100% on that but I had a Delco rebuild kit for a '69 Master Cylinder with the bigger bore
and sold it on ebay to a guy with 4 wheel disk.
Same 309 Master Cylinder number.
Rob

 

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mjs-13

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#11 · Mar 2, 2003

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What about power "drum" brake cars. The boosters I have seen on power drum brake 69's is not a "9204" but a different shaped and maybe size.

What number booster is correct for Power Drum Brakes?

 

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bdzee

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#12 · Mar 2, 2003

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I HAVE A 69 Z BUILT THE FIRST WEEK OF JANUARY 69 AND IT HAS A 9204 BOOSTER. HOPE THIS HELPS.