Would this then mean that those of us with rear disc brakes need to find a 4-disc master cylinder that fits a Maverick?
Funny you should ask that. I started another thread on that exact topic to see if anyone who has the rear disc has a dragging brake issue or not. I assume it works fine or someone would have realized the rear brakes are dragging by now.
I would hope I'd notice that... I don't think I noticed a drag of any kind when I first swapped from drum to disc. I just did a little quick and dirty research on autozone.com, for whatever it's worth... A 1995 Explorer has the same rear disc brakes that are becoming a popular swap on Mavericks, but they were optional that year. After that year they were standard, but in '95 you could still get drums. I confirmed this by looking up pads and shoes; they both show up. Then I looked up master cylinders for that truck, and it did not list different ones for disc vs. drum. Only options on master cylinders are with/without cruise, and with/without proportioning valve. Then I looked up a '97 Explorer... Pads listed, but not shoes. Disc brakes only, as I thought. Master cylinders for that truck come in flavors with and without cruise control. No mention of prop valve. Part numbers matched the '95 master cylinders without the prop valve. So... Drum rear Explorers had a proportioning valve, disc rear Explorers didn't. Not even separate from the master cylinder, there's just not one listed. What's all that mean? I don't know. Just stuff to think about.
Neat. good research. based on what you found and this excerpt from Darren's article I would say that constant pressure is going to the rear disc that isn't necessary. I don't know if it is enough to engage the brakes. It says disc also need more pressure than drums. Maybe the residual pressure isn't enough to engage. that being true, with the disc/drum m/c, one might not be sending enough bf pressure to the rear disc to optimize stoppin'.
when i did my disc/disc. conversion i used the maverick disc/drum master cyl. one day i noticed drag on the front wheels...i cracked the bleeder valve and it released...i now have a Strange M.C. and. ...no prop.valve...everything seems fine...
Why not get a Versillies master? As for the prop valve, it just keep the rear from getting as much stopping power as the front. Therefore a drum/drum valve should be the ticket on disc/disc. The valve will keep the appropriate distribution needed for brakes in front and rear with equal standing. To use disc/drum valve should send too much of the braking force to the rear for discs, I would think.
+1 on the Versailles. Wouldn't the drum/drum cause residual pressure in the hopes of keeping the non-existent wheel cylinder for collapsing, only or POSSIBLY causing the discs to engage on all four wheels?
The residual pressure valve is in the master, not the proportion valve. That is why the Versillies master might be a good option. No residual valve would be in that one, garranteed. Or maybe the residual valve(s) are located in the fittings on the side of the master. If so, you could just remove the valve and use your stock master.
so summary for disc/disc upgraded cars: disc/disc Versailles- probably good to go Drum/Drum - good to go if you can turn down/remove residual pressure valve which is located in the mc. ....?
One snag... If the Versailles master is the same as the Granada disc+disc master, which I think it is, it's gonna be for a hydroboost setup and have the wrong mounting flange.
when i was researching for my Disc/Disc setup, i read where the...residual pressure valve... is only used when the M.C. is...frame mounted, even or below the calipers... ...Frank...
