CRG Discussion Forum
Camaro Research Group Discussion => Decoding/Numbers => Topic started by: crobjones2 on March 26, 2008, 03:19:30 AM
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Does anybody know what is the difference between a D3 and a D4 master cylinder?
Thank you
Chris
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From previous posts, D7 and D14 have been identified as foundry pattern numbers for master cylinders 5459467 (manual disc)
and 5460465 (power drum). I would assume that D3 and D4 are also foundry pattern numbers.
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Does anybody know what is the difference between a D3 and a D4 master cylinder?
Chris -
Check out this CRG thread... http://www.camaros.org/forum/index.php?topic=3228.msg20954;topicseen
Paul
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Does anyone know which pattern # was correct for the camaro?
Thanks
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Any of them. It was just a casting thing....
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Does anyone know which pattern # was correct for the camaro?
Thanks
It would be interesting to confirm whether or not each Camaro master cylinder part number has a discrete foundry pattern number particular to it, for example D7 for manual disc and D14 for power drum. I don't know if that information exists anywhere.
In any event, there are at a minimum 4 possibilities; manual drum, power drum, manual disc, and power disc. The master cylinders for power drum or power disc brakes would have bleeders incorporated into the master cylinder due to the master cylinder being mounted at an angle; whereas the manual drum and manual disc brake master cylinders do not have bleeders since they mount horizontally.
In addition, the master cylinder bores are different between drum and disc brake cars.
One other difference - quoting a previous post from JohnZ: "ALL factory drum brake master cylinders have RPV's (Residual Pressure Valves) behind the seats in the outlets, as do the rear outlets on disc/drum master cylinders. The RPV's maintain 10psi at the wheel cylinders to overcome the initial tension of the shoe pullback springs and get the shoes out close to the drum surface to minimize pedal travel when depressing the pedal."
Also, see the following: http://www.camaros.org/suspen.shtml#Brakes
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Rich, I too think it would be an interesting investigation. Also, with regard to your quote,
One other difference - quoting a previous post from JohnZ: "ALL factory drum brake master cylinders have RPV's (Residual Pressure Valves) behind the seats in the outlets, as do the rear outlets on disc/drum master cylinders. The RPV's maintain 10psi at the wheel cylinders to overcome the initial tension of the shoe pullback springs and get the shoes out close to the drum surface to minimize pedal travel when depressing the pedal."
I would offer a word of caution to those who may have not read this post (http://www.camaros.org/forum/index.php?topic=2938.msg18849#msg18849) on master cylinder RPV's. Remember what John is talking about are "factory" mc's. Not all the replacement ones available in the auto stores today will absolutely have the RPV's in them. Be sure to ask before you buy one to make sure you are getting a mc that has them if your application calls for it. :)
Steve
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It would be interesting to confirm whether or not each Camaro master cylinder part number has a discrete foundry pattern number particular to it, for example D7 for manual disc and D14 for power drum. I don't know if that information exists anywhere.
There is no correlation between 309 master cylinder foundry pattern numbers and their ultimate application. High-volume castings used multiple pattern sets, and the raw castings were all the same; the differences related to the car application were created during machining and assembly of the internal components, all of which was done well after the casting was poured.
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Does CRG have any database on patern #s? is there any trend?
I keep seeing D3 and D4 for the 309. Was the 309 used for any other year other than 69?
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No, not tracked in the db. Because it's just a casting and any pattern could show up and my time is limited. :)
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Well i just got info about another 1967 manual disc brake M/C. I have 3 now. All have the AD on front pad. All have the 6 rings on the piston shaft. All 3 have # 5459467 with 1" . The 3 different date codes are 262/318/87
The 318 and 87 dated ones have foundry of D7 and the one dated 262 has foundry of D2. Also the 318 and 87 M/C stamped AD are in the same location on pad. The 262 is in the center of the stamped pad. All three have the rear pull off valve for the rear brake port. Hope this helps. The one dated 262 came off a NOV 67 car SS350 convert. The one dated 318 came off a July L78 car. The one dated 87 i don't no.