Brake swap issue

[BAD67FUN]

Man... almost done with the swap and now I'm stuck. For those that don't know, I'm swapping
in front and rear disc brake kits from Baer. Everything has gone real smooth. No problems at
all.... until now.

My car came originally with drums on all four corners. I believe somebody did a brake job at
some point on this car and swapped in a dual resevoir master cylinder (MC) from what I'm guessing
was originally equipped with a single resevoir MC. This was probably done for safety matter.

The kit from Baer came with a proportioning valve for the rear brakes and a new MC. There are two
big differences in the MC's. First, the angle of the resevoir is such that when bolted to the firewall, the
resevoir does not level out with the ground. Even the fill line on the plastic container will be at a 20
degree difference. I don't like how that looks. Something smells on that one. The second issue is that
the ports coming out of the Baer MC are on the opposite side, towards the engine. As opposed to the
current dual MC which ports to the fender and the factory prop. manifold/valve. I'd have to bend new
lines out the Baer MC and then under the unit back to the factory positions. That sucks.

So here is my thinking. And where I'd like to here some good advice. I'm thinking there is nothing wrong
with my current (not original) dual MC. Why shouldn't I be able to use it? It has the same diameter bore
as the Baer unit. The lines are already there and connected... no muss, no fuss. So all I'd have to do
is find a good spot to mount the prop valve in the rear line (somewhere on it's was to the rear, most likely
on my firewall) and splice it in.

And be done with it.

How's that sound?

 

[67GTA-FB429]

why would the "brand" of MC matter? It is just a resevoir.

 

[mustang466]

I would say give it a shot with the ould master.But I think you might have to remove the factory prop.valve.Why dont you give the company a call and speak to their tech line. they should be able to answer all your ? They just might say they cant guarantee the performance of the system since you arent using their master cyl.Give it a shot and let me know how it goes.
Bob

 

[LanceMach]

I would probably give it a try - especially considering the bore size is the same, but you may have a residual pressure valve built into the m/c (I've heard you can remove them, but I'm not sure how).

If you have issues using that m/c, you can always swap in the one from Baer. You may very well end up having to do that (that dual m/c was probably designed for front disc/rear drum and may not work well). Bending lines isn't that difficult at all - just don't get stainless lines - they're a pain to bend.

 

[Loup-garou]

Most of the popular master cylinders for 4-wheel-disc installations (Mustang SVO/Lincoln LSC, Lincoln Mk VII) have the ports on the "wrong" side of the casting. Those are all traditional metal MCs (the SVO unit is supposed to be aluminum, but the service replacement is often cast iron and identical to the LSC part). Check out Ultrastang.com for some pics of an installation that might be of assistance.

You can't use the original MC with those rear disc calipers, they require more fluid volume than the disc/drum MC can provide.

Form has to follow function here. I'm not as familiar with the late-model master cylinders with the plastic reservoirs, but I believe the fittings on many of those do not match the brake lines of '60s Fords - some sort of adapter is needed.

Hope this stuff helps... let us know what your solution is.

 

[BAD67FUN]

Thanks guys.

I've discussed this with a few of my buds today and it seems that everyone agrees to give the existing aftermarket MC a try. It's already there and plumbed. The bowl sizes on the existing piece apear to be the same size as the piece from Baer (volume speaking).

I can always try the Baer if something doesn't feel right.

I just have to splice in the prop valve for the rear.

I'll post an overall project summary when I'm done. I'm really anxious to get the brakes dialed in so I can hammer down with my new gear ratio and locker!!

 

[bnickel]

bad67, the dual bowl master that is on the car now, is the correct one, starting in 67 ford switched to the dual resorvoir unit because it was federally mandated. since your car was originally 4 wheel drum it would have the residual valve on both ports. so you will have to remove those to make it work, otherwise you will burn up the pads QUICK, since the caliper pistons will not retract all the way, actually the 67 dual bowl MC is a popular master cylinder for 4 wheel disc applications. so once the residual valves are removed you should be fine, at some point you might want to consider trying the new unit to compare them and see which one you like best.

 

[BAD67FUN]

Residual valve.... what the heck is that? And where is it? Can I just remove it?

Hey, another thing I noticed. When we were bleeding the system.... my buddy noticed that the firewall/MC unit flex when the brake pedal is pushed hard. Is that normal?

bad67, the dual bowl master that is on the car now, is the correct one, starting in 67 ford switched to the dual resorvoir unit because it was federally mandated. since your car was originally 4 wheel drum it would have the residual valve on both ports. so you will have to remove those to make it work, otherwise you will burn up the pads QUICK, since the caliper pistons will not retract all the way, actually the 67 dual bowl MC is a popular master cylinder for 4 wheel disc applications. so once the residual valves are removed you should be fine, at some point you might want to consider trying the new unit to compare them and see which one you like best.

 

[bnickel]

the residual valve is designed to hold pressure in the line at all times, but only enough to keep the brake shoes from moving away from the drum too far, without it you would have way too much travel in the system and the master cylinder wouldn't have enough pressure to apply the brakes properly. they are located in the ports where the brake lines go into the master cylinder, however i have never removed them myself, so i can't tell you how to remove them. i came across a web page once that described how to do it, but i didn't bookmark it. the search i used was something like "versailles rear swap" or "4 wheel disc conversion" but i'm sure someone else will chime in on how to do it, also i can't remember for certain but the 4 wheel drum master cylinder may only have a residual valve for the rear brakes, but i think it has one for front and rear.

 

[BAD67FUN]

Okay.. thanks for the info. I think what I'm going to do is run the car for awhile and do an inspection afterwards. Baer sent specific instructions along with the kits on how to properly season and bed the pads.

I'm going to go thru all that and just get a "feel" for how the car works with the new brakes. I have a ton of options it seems. So I'll just get a baseline before I decide on any changes.

 

[bnickel]

oh i forgot, the firewall flexing some at that point is normal, it is only sheetmetal afterall. some people have built reinforcement plates that bolt in between the firewall and the master cylinder, and i have even heard of people putting them on the inside of the firewall.

 

[BAD67FUN]

If you happen to know of a place that sells those plates... I'd be grateful. Thanks.

oh i forgot, the firewall flexing some at that point is normal, it is only sheetmetal afterall. some people have built reinforcement plates that bolt in between the firewall and the master cylinder, and i have even heard of people putting them on the inside of the firewall.

 

[bnickel]

i don't think anyone sells them, all of them that i ahve seen were owner built, out of like 1/8" plate or something.

 

[66fastback]

bnickle is right. drum brake mc's (should) have a residual valve inside them, and your dual-drum mc should have one in each port. If you have the mc out of the car, look down into the ports on the side. you will probably see a rubber flapper (typically orange) in each hole.

the flared brass piece that the brake lines seat against is pressed in, and normally people remove them with a large screw that will just barely screw in a little bit, and a little bit of wiggling and pulling and they pop out, giving you access to the residual valve (the little rubber piece) behind it. Be careful not to scratch up the flare (fluid will leak), or mangle the piece with excessive force, and be sure to put the brass fittings back in when your done.

You've spent a lot of $$$ and bought some killer brakes, make sure you either remove the valves from your old mc, or install the new one. You WILL BURN UP THE PADS or even WARP THE ROTORS if you don't make sure, and that would really kill the joy.

and yeah, the mc's move around alot on these cars....that firewall is pretty thin.

I'm kinda suprised they still let me in here, I haven't logged on since dec of 02.....gee I'm getting old. Rottsa Ruck. Doc.

 

[corpse]

I thought I'd bring this thread alive a bit as I'm starting my brake project at the moment.

Now, I read through some of the stuff on the master cylinder, and still not 100% sure on anything. So you all know, the fronts and backs have the 4 piston wilwood calipers. It WAS front disc/rear drum.

For starters, it sounds like the lincoln master cylinder is what I need, right? I read some stuff about the residual valve, but I'm all confused. If I just buy a new m/c, like for a lincoln or cobra, is this somethign I need to be concerned about? And same thing for the prop valve...