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| | | | Joined: Dec 2003 Posts: 299 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2003 Posts: 299 | I was thinking of putting in discs later on, but can I put a power MC for disc/drum in now with some sort of metering valves? I just don't have the time or money to do it all at the same time.Or do I just have to wait or pawn off my familly and do it all now?I have a 53 1/2 ton chev with drums all the way around. | | | | | Joined: May 2005 Posts: 1,624 Shop Shark | | Shop Shark Joined: May 2005 Posts: 1,624 | The problem is the size of the piston in the master cylinder. Drum type master cylinders run a smaller size piston (3/4" to 1") than a disc type (1-1/4" or so). This is due to the higher operating pressures and less volumn than discs. If however, you have a nice fat booster, say 8 inches plus, then you can get away with it. I would forget about this metering valve. You will need higher pressures for the drums and a metering valve is not going to help. Good luck.
Six volt guy living in a twelve volt world
| | | | | Joined: Oct 2006 Posts: 4,983 Master Gabster | | Master Gabster Joined: Oct 2006 Posts: 4,983 | Pawn the family! That would save a bunch of money! 
~Jim
| | | | | Joined: Jan 2008 Posts: 41 Apprentice | | Apprentice Joined: Jan 2008 Posts: 41 | You probably can, just add an adjustable proportioning valve for the rear drums. When you convert to 4-wheel disks, remove the valve. | | | | | Joined: Dec 2003 Posts: 299 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2003 Posts: 299 | that's what Iwas thinking 55stepside, but I wasn't sure, Beltfed, do you think I should forget it?Do you think that an 8 inch booster would work?
Thanks guys, Lothar
| | | | | Joined: May 2005 Posts: 1,624 Shop Shark | | Shop Shark Joined: May 2005 Posts: 1,624 | I am thinking that if you are careful, do your research, and purchase a disc/drum master cylinder with a smaller size piston, you will be sucessful. I assume you are doing a fire wall mount where the physical size of the booster will not present a problem (under floor setups can get tight). I would not go less than 8 inches. You may want to look for a donor car/truck to cut your cost. Please remember, you have to have good brakes! Get help from someone who can lay eyes upon it if you are unsure of what will work. Good luck.
Six volt guy living in a twelve volt world
| | | | | Joined: Dec 2003 Posts: 299 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2003 Posts: 299 | Any idea what proportioning vale to use ? | | | | | Joined: Jan 2008 Posts: 41 Apprentice | | Apprentice Joined: Jan 2008 Posts: 41 | Any idea what proportioning vale to use ? Any drum/disk prop valve will do the trick. Your local speed shop, or favorite online speed shop, should be able to help with the valve and fittings. | | | | | Joined: Mar 2004 Posts: 3,068 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 3,068 | You don't want to use a prop valve until the disc brakes are installed. Drum/drum brakes use equal pressures front and rear, hence the old single line masters. If you want to plumb one in while installing the dual res master, be sure it's an adjustable one,
Scott | | |
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