I think I'm just gonna check my front and rear brakes for drag, and if there's not any I'll roll with what I've got. If there is, I'm kinda thinking about that Dodge truck MC and no proportioning valve.
Guys... Think about this reasonably. Have you ever done a brake job on a drum brake? Rebuilt a piston? This can't be right. I can't think of anything in a Maverick piston that needs pressure. I have never cracked open a bleeder on a cylinder and had it pressurized. They just dribble via gravity like a caliper. And we all know that the pressure is held on the shoes by the star wheel. I think this residual pressure thing is a myth. Otherwise you wouldn't need a star wheel. Also, disc brake pads drag slightly. Ever try to take a caliper off without collapsing the pads slightly? It don't work... They drag as you pull them off. I rock the caliper slightly to get them to pull back, which pushes the pads away from the rotor. If they weren't dragging, you could pull the caliper straight off every time.
First off the adjuster(star wheel) is used to keep the shoes adjusted so that the application of the pedal doesnt have to take up the space betweeen the shoes and drum. Giving a low pedal. Has nothing to do with the wheel cylinders. Wheel cylinders do not make up for brake adjustment. The reason for a small amount of positive pressure is to keep the lip seals in the wheel cylinder tight against the bore and the cylinder pistons against the shoe contact. Yes calipers will pull off a rotor without pressing them in. If they dont pull off its because of the ridge on the rotor or a part failure. Otherwise how could you remove a caliper with an integral Ebrake? As for the bleeder thing your right. Sort of. The pressure held in the system will release the instant the bleeder is cracked. 10 psi is very low in a brake ciruit. The volume is so low you wont get a stream shooting out of the bleeder. Its far from a myth its brakes 101. Do a front disc swap and leave the drum master on it and I guarantee you will burn off the front pads.(assuming the resiual valve works) Disc brakes dont drag. They do have some resistance when turning the rotor but not enough to damage the pads. The only thing that releases disc pressure is the slight run out in the rotors and in our cars the piston knock back created by the bearing adjustment. Anyhow the link was posted to help with conversions. It is brakes 101 and far from a myth.
You make my arguement right there... Even if after all these years, your brakes still hold that 'massive' 10 psi, that isn't enough to hurt your disc brakes. Correct me if I am wrong, but when you push the brakes, the pressure is on par with many hundreds, if not thousands, of psi... 10 psi isn't going to hurt anything. That is the sort of pressure a party balloon may have in it.
Your right its not going to lock the calipers on by any means but it is enough to hang the pads and burn them off. When it comes to hydraulics its a big difference in force applied comparing a wheel cylinder at 10 pounds per square inch vs a caliper piston at 10 psi. The surface area of a wheel cylinder piston is is less than 1 square inch=less than 10 pounds of force on piston against the return springs. The caliper piston has more surface area guessing around 2.5 inch diameter that puts the surface area around 5 square inches=50 pounds of force applied to piston and pad. Big difference. Hope my amth is close. Just tried it on my car after the swap. Bled the calipers with the old drum master as an experiment. The front pads definitly drag. Feels similar to a car that has the sliders seized up. Interesting thing is that the drag lessens after it sat for about 5 minutes. I assume the residual valve slowly bled down in pressure. Master looks pretty old. Put on the disc master and the drag is normal. Considerably less. I could have got fancy and checked the turning torque with and without the drum master but no torque wrench at home. It was noticeably less with the disc master. I'm sure the pads and rotors will last a lot longer with the disc master over the drum. Anyhow the car stops a ton better with the disc now. Well worth the time and money.
Darren.. or anybody.. What then, is the best choice of M/C for a Granada front disc and rear disc Exploder on my Comet? I just put the Granada discs on the front and am researching discs for the rear. I know this thread is ancient, but I have spent hours reading threads here.. My car is a 72 drum drum with 14" Granada steel disc wheels. I am looking for a 8" 5 lug rear to repalce my 4 lug and then to convert to disc with Explorer discs or Ebay conversion kit... Thanks!!!
I'm using a stock 74 Maverick disc brake manual master cyl with the Explorer discs and I had the front 75 Mav/Granada brakes in the front, now I have dual piston 99 Mustang calipers with the same master cyl and they work great.
What spindles do u have to use on the Mav w/ the dual cyl calipers? Is it worth the effort to make the dual over the single setup as far as noticeable improvement in stopping pwr? Finally, what's the min. "dia." size whls u can rum w/ that setup? I like it.
75 Maverick spindles, custom caliper mounting bracket, drum brake hubs, 95 crown vic front rotors. There was an improvement in stopping power but I think the biggest benefit is a much better choice of pads and rotors. I'm running 16X7 American Racing TT2's, but I think a 15X7 will clear depending on the wheel. I have a 15X6 as a spare from an Explorer and it fits. I had the Mav/Granada front brakes previously with the Explorer rears and it worked very well also. A friend gave me the calipers and brackets from the Mustang for free so I figured, "why not?". here's the link for the original custom bracket setup with the Maverick rotors:http://www.woodyg.com/fairlane/finfo/discs66.html
Since this thread's come back and my brake setup's changed a little bit, thought I'd mention that I'm now running a non-cruise, non-proportioning 96 Explorer master cylinder with a 1" bore, along with a Maverick booster. Best I can tell, the stock "combo valve" below the master cylinder on my car is just a junction block. So I'm not running a prop valve and my master cylinder has no residual valve. The only reason I changed cylinders is to get a firmer pedal when I replaced my booster. Brakes still work wonderfully under every condition I've encountered.
Has anyone, IN FACT, found and removed the residual valve from a M/C. There. It's been said. My front end is now completely redone with 'Nada discs and Moog. I found a nice 5 lug x 4.25" 8" rear end from a 65 Fairlane. It is 58" wide, drum face to face, vs. the 56.5" 4 lug 8" I have now. It's going in as I type. The drum brakes are 10" compared to the 9" I had, and are virtually brand new. Seems a shame not to run them. But then there is the nagging M/C issue, as I have the drum/drum M/C. IF I could remove the residual valve from the front of the M/C ... but that would just be too simple I guess.. If I can find discs for the rear I might keep the d/d m/c and d/d p-valve, and if I do go d/d some day then buying a disc /drum m/c will be a waste of money.
