mercman from oz
Well-known member
Unique Tail Lights on the 59 Mercurys
Someone cut a big chunk out of the driver's side inner fender apron to fit the brake proportioning valve.![]()
Seemingly the public was also moving away from all the chrome and fins and fancy stuff. So the 1959 Monterey, with all its style and largeness, had fallen out of favor rather quickly.
Oddly enough, this is an example of where scarcity does not dictate value and NADA pegs these cars with rather conservative value estimations.
... hmmph ...
Does it have a FRONT DISC BRAKE CONVERSION?
No, looks like drum brakes all around. I suppose then it isn't a proportioning valve, more like a distribution block. Its mounted on a bracket that's bolter to inside of the the driver's side front frame rail, just below the master cylinder.
Here's a pic. You can see where the fender apron is all cut away (outlined in red).
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Now that is gnarly ...
It is a COMBINATION VALVE. I can see the METERING VALVE (FRT) and the center is a PRESSURE DIFFERENTIAL VALVE. I can only a$$-u-me it also has a PROPORTIONING VALVE (PPV) along with a DISC/DRUM MC.
Someone must have been planning on a FRT DISC SWAP. That setup is possibly going to get you into trouble at some point.
... Now that is gnarly ...
... That setup is possibly going to get you into trouble at some point.
I make no claim to be a brake system plumber. This is just a 'sight unseen' first guess.Please elaborate on the impending doom or all around headache I can expect with this setup. ...
Please elaborate on the impending doom or all around headache I can expect with this setup. It doesn't look newly installed, but when I saw it I was curious about the conversion, especially when I saw the hack job on the fender apron.
I would a**ume it is a takeoff from some late(ish) model donor car. I was kind of impressed that someone was even able to do this. I know a lot of the older cars have single reservoir master cylinders, In I consider a dual bowl setup preferable over single pot.
Following the k.i.s.s principle... a better solution would be to use a more correct drum/drum master cylinder and eliminate the compensating/proportioning valve.
IMO, an as-original single bowl brake setup with new or properly rebuilt parts would be much safer than what a previous owner has done.
.
... whew ...
1) The MC style is INCORRECT (DISC/DRUM on a DRUM/DRUM car) ...
2) A PPV (PRORTIONING VALVE) and in this case a COMBINATION VALVE is not used on FORD DRUM/DRUM ...
3) The METERING VALVE holds off front brake pressure (DISC) until the rear brakes (DRUM) have a chance to apply (@ approx 30 lb line pressure) ...
4) The PRESSURE DIFFERENTIAL VALVE (PDV) (free standing) can (and should) be used on a drum/drum application w a DUAL RESVR DRUM/DRUM MC ...
5) The PROPORTIONING VALVE (PPV) is used on a DISC/DRUM to gradually limit rear DRUM BRAKE line pressure so as to prevent rear wheel lockup as the FRONT DISC becomes overly aggressive at high line pressure leading to rear brake lock-up.
6) You need to know what year the system came off of as a system later than 1971 will not have a RESIDUAL PRESSURE VALVE (RPV) in the drum circuit.
7) If you are considering going to a DISC/DRUM setup, the present system may be OK. If going to stay with four wheel drum, it is a good way to get hurt and invite a civil lawsuit (IMO).
I'm no brake expert, but it looked pretty hokey to me when I first saw it, but I thought maybe it was just a weird retro-fit for some junk yard setup that happened to be available to the PO.
Let's see - point for point so I don't get lost:
1: ok, I need a MC with two same-sized bowls.
2: so this concoction can be ditched whenever I replace the MC with a proper Drum/Drum unit? (more questions regarding the replacement MC below)
3, 4 & 5: So the combination valve I have has a built in Metering Valve, Proportioning Valve (PPV) and a Pressure Differential Valve (PDV)? Again, I'll toss the unit when I get a correct Drum/Drum MC installed.
If I buy a new MC, will it come with the needed valve(s) built-in, or is this something I should expect to have to add to the circuit?
6: I've heard of some MC with a built in Residual Pressure Valve. Any suggestions on a MC that might be a good fit for the 1959 Mercury Monterey? I've heard that early Maverick MC have the build in residual valve and work on Mustangs, not sure about old Mercuries.
7: No, I'll stay with all drum brakes for now. I don't have any plans to modify the braking system, except now it seems I will be changing out the MC for a more suitable Drum/Drum unit.
Lastly, for this drum/drum setup, I need a dual bowl MC with bowls the same size, a Residual Pressure Valve and a Pressure Differential Valve? Whew...