Can a Disc/Disc master be used with Disc/Drum?

cdnpont · Canadian Poncho Superstar!

Can a Disc/Disc master be used with Disc/Drum?

2drpost · Uber Guru

i remember years back removing the residual valve from masters that were sold to work with drum/drum or disc/drum. you could possibly install a valve in the rear port...

DANO65 · Poncho Master!

As is the master won't work.
You need the residual valve to keep the cups seated in the wheel cylinders, so adding one will cure that. With you adjustable proportioning valve you should be able to dial down the volume going to the rear as discs require more volume than drums.
It may take a little playing around with the prop valve to find a nice balance. Find a nice big empty parking lot to play in.

Or you could look though a jobber brake parts book and find a disc/drum master with the same bore as your vette master so it will supply the right volume to those vette calipers, the drums are usually close enough not to matter.

-- Edited by DANO65 on Thursday 21st of April 2011 09:01:45 AM

cdnpont · Canadian Poncho Superstar!

Thanks for the replies guys.

Good info! Sothe wheel cylinders need some pressure to keep a seal, and to keep the springs from retracting the shoes. If not I assume you'll have a pedal travel issue as it moves to take up the shoes travel.

Since I already have the master, I think I'll just order a Wilwood inline 10lb residual valve.

As far as line placement goes, does it matter where the valve goes? Should it go before the proportioning valve or after?

I have this Valve already...

And will order this...

DANO65 · Poncho Master!

Residual valve should go between master and prop valve, stock ones usually incorporated in the outlet port of the master.

cdnpont · Canadian Poncho Superstar!

Thanks!

cdnpont · Canadian Poncho Superstar!

Took your advice dan, bought and mocked up a 10lb residual before the valve.

DANO65 · Poncho Master!

Looking good Mark. biggrin

One of these days I have to go pick up my disc brake spindles, they've only been waiting oh about 8yrs, still on the front of a 69 I believe in a friends yard. He always reminds me that they are there and how many times he could have sold them wink . Soon, then I can try out the vete rotors like you did.