Possible master cylinder upgrade for 67?

[protraxduner]

So my brother stops by today he is working on his rock crawler and upgrading brakes, he said everyone told him to use 74 lincoln master cylinder. I told him should have came by I have 2 he could use(67-68). Neverless he looked at what I had and said that is same thing he had . So he showed be what he got and it is probably almost twice the size of stock one in my 67 and direct bolt-on to booster (will have to reroute lines but doesnt look difficult). So I think i will upgrade to this, he said it was only $20-30 new at parts store with core. We both guessed that it is bigger because of 4 discs? Just a guess. I plan on putting rear discs on so I think it will be perfect. Any reason not to use? I was going to replace anyway.

[Dan Szwarc]

There is no reason to think that a bigger master cylinder will stop the car better. Just because it holds more fluid, doesn't mean it works better.

If the MCs have different bores then you will be changing the dynamics of the system as designed by Ford.

I say stick with the correct MC. It stops the car well, doesn't it? It sure works well on my 66.

[protraxduner]

So why more fluid then? Anyone happend to know the bore of the 67 vs 74. I plan on going 4 wheel discs.

[76MarkIV]

So why more fluid then? Anyone happend to know the bore of the 67 vs 74. I plan on going 4 wheel discs.

Why? The brake system on the car is more than adequate. Getting into a 4 wheel disc conversion can be like opening up a big can of worms unless you're hydraulics and mechanical engineer enough to get all aspects of the system properly matched.

[jleonard]

Both '67 and '74 Lincolns came with 1" bore master cylinders. The '74 master is not designed for rear discs and doesn't have enough fluid volume to handle that conversion well. The '74 was designed to deal with the LARGE bore (over 3" diameter) calipers used, so it has a larger fluid volume in the front brake reservoir.

Basically, there's no benefit going to that master on your '67. If/when you convert to rear discs, you would still need to replace the '74 master.

- John

FWIW, I am a mechanical engineer...

[protraxduner]

Thank you, So when switching to rear disks do I need to upgrade the master cylinder at all? I plan on putting an adjustable proportioning valve to adjust the bias, course seems like i remember it already has one but either way I will have one to adjust the bias. thanks

[protraxduner]

Well i think I have decided to go with this for brakes as I planned on upgrading everything, plus it looks nice, and i like the idea of integrated proportioning valve. The say they have put them on continentals with success. So i probably set myself of for some opinions.

http://cgi.ebay.com/ebaymotors/Chevy-Fo ... 0267681708

[Dan Szwarc]

The size of the MC reservoir determines the capacity of the system as the brake pads wear and the pistons in the calipers move outwards.

Disc brakes have inherently bigger pistons and require more fluid. That's why the MC is bigger for front disc and 4-wheel disc systems (assuming the bore size is the same).

Dow what you need.

[76MarkIV]

Yup, you'll get opinions alright. First one is you'll end up being a lot happier if you buy from Gearhead Engineering instead of trying to piece together a bunch of street rod junk not designed for any specific usage in hopes it will all work out. But it's your project and you can do what you want. Chances are you'll discover you've got a mess on your hands before you get the job done and on the road. All that glitzy chrome plated crap will not guarantee function, and that is the most important issue. As the old saying goes: "Pay me now, or pay me later." I'm sure Gearhead will be happy to sell you a system that will work, as one specifically designed for the car should, at a later date.

[jleonard]

Tony,

That's a pretty cool looking master cylinder/booster combo. The 7" diameter booster seems a little bit small for one of our heavy cars, but in reality it probably provides at least as much boost as a stock '61-'64 booster. See if CPP will give you an estimate of the fluid pressure you can get from that setup - in a typical hard stomp on the pedal and the maximum acheivable.

I like the integrated proportioning valve idea - definitely cleaner looking than the OEM stuff. Couple of things to consider: mounting pattern and proportioning valve ratio. I'm not sure about the '67, but the earlier slab sides use an unusual mounting bolt pattern for the booster. Aftermarket boosters require drilling in the firewall. Also, check the length of the pushrod (when combined with the optional clevis end you will need). The Lincoln pushrod is shorter than most aftermarket push rods so you may need to get creative during the installation. As for the proportioning valve, I'm not a fan of universal proportioning valves. The amount of pressure required to the rear depends upon a lot of factors, and a one-size fits all approach doesn't really make sense. See if CPP will tell you the relative pressure drop for the rear circuit. At the very least, find out if the proportioning valve is designed for rear drums or discs.

- John

[protraxduner]

Thanks John, I have an email out to them with questions. Although it does look pretty the main reason i like it is the integrated proportioning valve and it is all new ,aluminum not iron, and i can clean up my plumbing. And since I am not real up on brake stuff did a little research myself. I thinking the 7" booster would be adequate for disk/drum rear but probably would need to be bigger for 4 wheel disk not saying the 7" wont work. I have asked about the mounting, but I am less concerned about it. My understanding is the proportioning valve is adjustable, which is exactly what i want, that way i can adjust it for my particular setup depending on how the rear disk setup turns out. So when are you going to come out with a rear disk kit for the 67? Not sure when I will get to the rear end but will be fabricating my own unless something becomes available before then.

[protraxduner]

Can someone tell me what size booster and how many diaphrams is on my car. I have a 67. Do they go bad? I really dont mind it but want to paint it to look pretty But since my car is not running how do i know if it is good. They are relatively inexpensive (my guess is for generic ones) and dont mind doing a little fabrication to make a new and/or chrome one work just need to know what size to get.

[vert1966]

Both '67 and '74 Lincolns came with 1" bore master cylinders. The '74 master is not designed for rear discs and doesn't have enough fluid volume to handle that conversion well. The '74 was designed to deal with the LARGE bore (over 3" diameter) calipers used, so it has a larger fluid volume in the front brake reservoir.

Basically, there's no benefit going to that master on your '67. If/when you convert to rear discs, you would still need to replace the '74 master.

- John

FWIW, I am a mechanical engineer...

Sorry for resurrecting an old thread but wanted to see if any opinions have changed on whether the 72-73 Continental MC is a viable alternative (not upgrade) to the 67-71 MC? I, like most owner's, of pre-66 Continentals want to upgrade my car to a dual master setup/combination valve. I have read a ton (but still need to read more) about other user's experiences/outcomes/recommendations before attempting this upgrade.

After reviewing ton's of pictures online of a variety of master cylinder/combo valve upgrade "kits" (Mopar/GM/Ford) they all seem to include some form of the following:
1. Dual MC (or reuse if you already have one)
2. Combo valve (typically a PV2)
3. Some type of bracket (one that mounts to the side wall of engine bay, "side mount" off booster stud, "undermount" off booster studs, "adjustable" which mounts to left stud and allows valve to be mounted underneath)
4. Pre-bent lines from master cylinder outputs to valve inputs (for the more popular setups, mustang, Camaro, A/X body, etc).

I think it would be a more economical/easier to plumb/cleaner look if I was able to use one of these readily available kits. The first immediate issue I see is the location of the output ports (side and bottom) on the 67 MC. Every other Make/Model/Year MC has 2 left side ports, so all the available kits are set up for those locations. I think the reason the 67 MC has the lower output port is to accommodate the bleeder valve on the side. Is there any other reason that Lincoln would put it there? I can't think of one. Please let me know if I'm wrong.

I reviewed the technical specifications of the 67-71 MC to the 72-73 side by side and they appear to be almost exactly the same. I also called and confirmed both specs with a technical specialist at Centric Parts (I basically was told the only difference is the output port location, and the swap "should" work fine). I understand from a previous post in this thread that the front reservoir is on the 72-73 is larger and wouldn't help the performance of the brake system. To reiterate, I'm not disparaging the use of the 67-71 MC at all, not looking for upgraded performance, I'm more interested in another alternative that would allow the use of off the shelf parts that weren't available 20 years ago. Thanks!