So after searching a lot here and talking with technicians I know I am getting several different opinions. Heres the deal: I have a 1959 Ford Fairlane Galaxie 500 4-door. I am trying to convert it to power brakes. I have front and rear drums. I have found on here that a 1967 Mustang master cylinder will bolt in. I found one after market that includes a booster. So the question here is, what all do I need to do? I have been told that since the Mustang that uses that M/C doesn't use a proportioning valve or metering valves that I won't need to either. Also, I have been told to get an adjustable proportioning valve or just add a normal proportioning valve, or change wheel cylinder to 67 Mustang cylinders, or put metering valves at each drum. Any thoughts for a plan of attack? By the way, I don't have an unlimited bank account nor do I really want to convert to disc brakes. Thanks in advance for any help.
as long as the master id a drum/drum there is no need for the adj valve. is the rod to the pedel the same?
59 ford wheel cylinder bore VS mustang Wheel cylinder bore. check that. Pedal ratio, need to change that.
Not trying to jack the thread but it got me thinking and my question is without disc up front what is the gain with the power ***ist? Are there any cars with power drum brakes? I would think that it would lock the fronts up and thats why they are saying you need the proportioning valve. I would probably try the adjustable one myself.
so far I have had a 63 grand prix, 66 gto, 66 buick gs, 67 firebird , 68 grand prix, 68 bonneville, all with power drum brakes. every single one of them stopped every time Many Millions more out there with power drum brakes.
Switching to a dual master with the same bore as your stock '59 will not change the brake operation (just makes it safer), so no need for any wheel cylinder changes or extras, except to add one 10 lb. residual valve to each axle IF the new dual master does not have them internally.(vintage drum brakes require residuals) Your manual pedal ratio has to be changed from it's present +/- 6:1 to a normal power ***isted ratio of about 3:1. You can modify the stock pedal, or find one from a factory power brake Galaxie parts car. Make sure the new master cylinder can be fully stroked before the pedal bottoms out, or a good bleed and the safety advantages of a dual master will not be attained. Avoid the small 7" single diaphragm boosters and use either a dual 7"-8", or a larger single booster.
"I have a 1959 Ford Fairlane Galaxie 500 4-door. I am trying to convert it to power brakes. I have front and rear drums. I have found on here that a 1967 Mustang master cylinder will bolt in. I found one after market that includes a booster. So the question here is, what all do I need to do?" The easy and cheap thing to do is just add a booster behind what you already have. You'll probably have to make longer brake lines and maybe redrill the firewall. Make sure the gap between the booster and MC is correct- about 1/8" Same for the brake pedal pushrod. Next best easy/cheap imo is to get a 4 wheel drum mc and booster, then bolt and plumb it to the firewall. You may have to drill new mounting holes in the firewall. They are available via the Internet for less than $200 Look in Rod and Custom magazine and you;ll see them. Some very good reading here - http://www.mpbrakes.com/technical-support/reference.cfm
Buick, Pontiac, Cadillac, Mercury, Lincoln, Ford chose one they all have power drum brakes at one time or another. The power ***ist is so that it doesn't take as much leg to make the brakes work. The only reason that I would ad a proportioning valve is if I raised or lowered it. A proportioning valve si to either change or maintain a certain brake bias. If you raise one you want less brake in the rear and if you lower one you can take advantage of more brake in the rear. If you rake one in either direction either tail dragger or california rake you want less brake in the rear.
Proportional valves were used to get the bias correct safely on a disc/drum system. The disc system requires a higher pressure to operate correctly than the drums. Too low of a pressure the discs won't work, too high of a pressure the drums would lock up. Metering valves were installed into combination blocks that allowed the rears(drums) to build pressure, when a set psi threshold was met the metering valve would open allowing the discs to operate. This allowed the drums and discs to operate together. The metering valve simply delays the activation of the front calipers. When four wheel drums were installed on a vehicle, be it car or truck, there usually wasn't a need for prop valves. The brake systems bias was calculated out and the appropriate size drums and wheel cylinders were used. Often the drums were the same size front and rear, the only difference was the size of the wheel cylinders. This is how the OEMs set the brake bias front to rear. If you have changed the bias of your stock system, changed wheel cylinders/drum size, altered the ride height, changed the weight distribution, or changed the wheel/tire size, then an adjustable prop valve can be used to help fine tune the brakes. But by no means are they a way to correct bias. A 'normal' or non adjustable unit is not an option on your car. There never was one. Each preset factory PV was set for a particular vehicle and its options. I would not use a 'preset' PV in any car other than the one it came from the factory with. Ideally the rears should never lock up. The rears locking up is dangerous as it can easily put a car into a spin. If you are going to use a MC from a four wheel drum system it should already have residual valves built into the MC and there would be no need to add them separately. If you use the Mustang unit verify that it is for the four wheel drum brake system. IIRC that year of Mustang had four different MCs depending on power ***ist and/or if it had discs.
WOW, thanks for all the help guys. Mad Mike thanks for all the input, I guess there is a lot more research to do than to just throw the booster and M/C in it and call it good. I have lowered the front end about 2-1/2 inches, so would the metering valves be the best bet? At this point Im leaning towards 4 metering valves and an adjustable proportioning valve just to be over prepared than under prepared.
Just a basic understanding is needed, when you know how a brake system works, your less likely to cobble something together. A word of warning, I touch on the disc/drum system to better explain the purpose of a metering valve. Or you can skip it all, and go to the bottom. Something I didn't mention, and I should have. Metering valves were used to allow the rear drums to build pressure equalizing the pressure output between the front and rear brake circuits at the distribution block. This was done, because prior to discs some cars/trucks came with 'brake warning' lamps. Often the same lamp was used with the parking brake warning lamp. The device that operated the brake warning lamp is called a pressure differential valve. The PDV was simply a piston that would normally not move. In the event of a failure in one side of the brake system the pressurized side would push the rod towards the depressurized side and activate the brake warning lamp switch. The brake lamp warning light would come on, combined with a drop in pedal pressure, the driver would know there is a problem with the brake system hydraulics. ^This is a pressure differential valve. A misconception is that the PDV will block flow to the open line. This is not true. It is simply a light switch hydraulically controlled. Also if the MC fails and does not create pressure the PDV will not activate, nor if both circuits fail. If there is a difference of pressure between the two circuits it will activate. In the above diagram the PDV is the center portion of this combination valve called the 'Warning Switch'. The metering valve located in the 'Hold Off' section does two things. One it delays activation of the front brakes until pressure equalizes between the front and rear circuit is met. But it will not prevent front brake activation of the front brakes in case of rear brake failure. The metering valve opens ~300psi. Two the delay allows both front and rear brakes to activate at the same time. This is an anti-dive device. Without it the front discs would begin to grab before enough pressure was built into the rear drums. On a vehicle with low spring rates this would prevent the nose diving effect with the preset proportional valve. Proportioning The OEMs knowing they have to make a vehicle that will not allow the vehicle to do anything dangerous, in a normal operating capacity, have to err on the side of safety. So the proportional valves are preset conservatively. If the rears were allowed to lockup the car could easily spin. Now one can induce rear lockup on a factory system but under normal braking they never will. The preset prop valve does not allow for fine tuning of the system. An adjustable unit will improve the braking capability of the vehicle by allowing for better pressure distribution to the rear. The adjustable can also be used to improve braking when carrying a load. The increased weight allows for better traction to the rear, and more brake pressure can be applied. Here's the flow of fluid through a typical Bendix type combination valve found on mid 70s-mid 90s GM RWD vehicles. Pressure builds up on the inlet of the front/rear ports. Pressure builds up in both sides equally until the drums begin to activate, the metering valves spring is sized accordingly to allow pressure to overcome it and the metering valve opens. This allows both front and rear brakes to activate at once. Pressure increases equally until the PV kneepoint which does not allow full MC pressure to the rear drums, preventing lockup. Front discs are anywhere from 1000-1600psi normally operating Rear drums are anywhere from 600-1000psi normally operating *skip to here/ tl;dr* There is no need for a single metering valve, let alone four of them. There are a few ways to go about plumbing the brakes. The simplest for you would be to leave your current wheel cylinders as is, install your new four wheel drum dual reservoir MC and booster, plumb the brakes(usually on dual reservoir drum MCs the front port is for the front brakes and rear port is for the rear brakes) up and go driving. Test out the braking. If all is well you will most likely be fine. But if the rears lockup under moderate or hard braking you will need to reduce the pressure to the rear, this is where a PV comes in handy.
DAMN, thanks MAD MIKE, I think you just saved me a lot of time and cash. I think this was becoming one of those things that just get so over thought and become a nightmare. I really appreciate all the input on this. I just bought all my lines and now just have to start bending them up. Hard to believe how expensive brake lines have become and I get a discount for being in the parts business. Spent almost 50 bucks on lines, junctions, and tees. Thanks again for all the help.
I have another question for anybody that has done a M/C conversion; when I called my local supplier for pricing and the had no problem with the M/C, but when it came to the booster they asked me if it was the "twist-lock" style or "clamp" style. Any ideas or does it even matter since its not what the car came with? Again, I have a 59 Fairlane/Galaxie 500 and am trying to put a M/C w/booster from a 67 Mustang in my car so I can have power drum brakes. Any help is appreciated.
I tell everyone, try to get a dual master from a donor car that is close to the weight of your car. I'd rather go with a master from a '67 Galaxie. Bob
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