Author Topic: 346 Master Cylinder  (Read 7763 times)

melav8r

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346 Master Cylinder
« on: August 19, 2008, 07:29:20 AM »
I picked up a Cardone 10-1423 Master cylinder from an Autozone about 7 years ago. It is a '346 casting with no identifiable stamp on it, i.e. US etc... It came up as a replacement for a 69 396 Camaro w/ front discs (the 69 Z28 master he pulled was a tall Bendix type).
The box says its a reman'd unit, couldn't pass on it for $14 at the time. I'm now considering installing it but noticed it doesn't seem to have the rear residual pressure valve installed.
Does anyone know if these are reproductions. Shouldn't a 396 Camaro with front discs also require the rear RPV? Why does the 69 Z28 master Cardone sells as a remanufactured unit resemble a bendix type master? Any suggestions would be appreciated.

JohnZ

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Re: 346 Master Cylinder
« Reply #1 on: August 19, 2008, 02:32:50 PM »
Shouldn't a 396 Camaro with front discs also require the rear RPV? Why does the 69 Z28 master Cardone sells as a remanufactured unit resemble a bendix type master? Any suggestions would be appreciated.

Yes, the master cylinder for ANY disc/drum application should have an RPV in the outlet for the rear (drum) system; if Cardone doesn't understand that, they shouldn't be selling master cylinders. Dunno why the one they sell for the Z/28 is the tall Bendix type - they sell "functional" replacements, not necessarily rebuilt originals, but they should also understand that there's no difference between a '69 396 power disc/drum master cylinder and a '69 Z/28 power disc/drum master cylinder - maybe they're assuming that all Z/28's had JL8 4-wheel discs, which don't use RPV's at all.
'69 Z/28
Fathom Green
CRG

melav8r

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Re: 346 Master Cylinder
« Reply #2 on: August 19, 2008, 05:26:48 PM »
Thanks John, I sorta assumed, whether valid or not, that the Z28 master cylinder was intended for a JL-8, since the part number I described calls for "ALL 69 front disc Camaros except Z28".
I confirmed no check valve (RPV), by using the blunt end of a 7/64th drill bit, I should probably consider installing one before using this master cylinder.
The 69 Chasis Service Manual makes a strong emphasis on the correct secondary piston. Short of disassembling the main cylinder, is it safe to assume that I have the correct secondary piston installed? Are the aftermarket or replacement pistons marked or grooved correctly as the originals for identification?

JohnZ

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Re: 346 Master Cylinder
« Reply #3 on: August 20, 2008, 05:03:23 PM »
The 69 Chasis Service Manual makes a strong emphasis on the correct secondary piston. Short of disassembling the main cylinder, is it safe to assume that I have the correct secondary piston installed? Are the aftermarket or replacement pistons marked or grooved correctly as the originals for identification?

I don't know if the aftermarket secondary pistons are marked the same as the originals or not; if you can see through the compensating port (no seal blocking the port), you're probably OK. You definitely need an RPV in the rear outlet port.
'69 Z/28
Fathom Green
CRG

melav8r

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Re: 346 Master Cylinder
« Reply #4 on: August 20, 2008, 06:01:40 PM »
Just picked up a Napa kit UP-501 and comes with 2 check valves. the seats in the kit both mic at about .435" in diameter, the front port on the master cylinder is 7/16" thread, which would seem to work with one of the seats although don't need to pull out that seat since its for front discs, the rear port however is a 1/2" thread, not sure if the .435" seat will work. +Are the seats the same on both ports or do I need to find a larger seat, .500", for the rear port?
thanks.

Steve68

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Re: 346 Master Cylinder
« Reply #5 on: August 20, 2008, 10:53:37 PM »

melav8r

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Re: 346 Master Cylinder
« Reply #6 on: August 21, 2008, 04:55:13 AM »
Thanks Steve, actually I did read your posting before starting my thread. Did you notice if both seats were the same size or not in your master and kit? Don't want to pull out that rear seat before I know if one of the seats in the kit will fit.

Steve68

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Re: 346 Master Cylinder
« Reply #7 on: August 21, 2008, 10:51:48 PM »
Valve seats are same size.

Steve

melav8r

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Re: 346 Master Cylinder
« Reply #8 on: August 23, 2008, 06:15:48 AM »
Thanks Gents, pulled the rear seat and it was the same size as both seats supplied in the kit. So although the rear port on the master takes a larger fitting than the front port the seat diameters are the same.

 

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