Disc Brakes

[1949P17BC]

In the process of the swap. What changes if any are needed to the standard 47 master cylinder (rebuilt).

[55 Fargo]

Others have added residual valves, 10 psi for the rears, and 2 psi for the front brakes. Also proportioning valves have also been used.

Or you can eliminate the single jug MC and get a bolt on dual MC conversion, these mount where the existing MC mounts.

Go on the search section and type in Disc Brakes, there are a ton of threads/posts on there......................Fred

[Suddensix]

You must remove the residual valve from inside the stock master cylinder otherwise the front brakes are partially on all the time.

[eric wissing]

You must remove the residual valve from inside the stock master cylinder otherwise the front brakes are partially on all the time.

Are you sure about this? (don't mean to doubt you but I am feeling stupid) I never did that maybe that could cause my problems. Eric

[Norm's Coupe]

I changed over to front disc brakes and kept the old original master cylinder. All I had to do was install the residual valves Fred mentioned. Did not modify the master cylinder at all. Have no problems with the brakes working and releasing properly. Others have done the same without modifying the master cylinder too.

I've only heard of a couple of people on the board that claimed they had to modify the original master cylinder. Most have done only what I did, regardless of who's kit they used.

[eric wissing]

Good, I have only driven mine a few blocks since putting in the brakes, and the front didn't drag. Still have some power issue but that will have to wait for the Spring. Eric

[Suddensix]

Are you sure about this? (don't mean to doubt you but I am feeling stupid) I never did that maybe that could cause my problems. Eric

My car would hardly move until I took that valve out. The reason being that disc brakes only run with 2lbs pressure on them while drums brakes have 10lbs. As the built in valve in the stock master is 10lbs there is too much pressure on the discs consequently the brakes drag, at least mine sure did.

[Don Coatney]

My car would hardly move until I took that valve out. The reason being that disc brakes only run with 2lbs pressure on them while drums brakes have 10lbs. As the built in valve in the stock master is 10lbs there is too much pressure on the discs consequently the brakes drag, at least mine sure did.

Is what you removed called the valve assembly in this exploded view?

[Don Coatney]

Good, I have only driven mine a few blocks since putting in the brakes, and the front didn't drag. Still have some power issue but that will have to wait for the Spring. Eric

Eric;

Norm has only driven a few blocks too:D

[rearview]

Is what you removed called the valve assembly in this exploded view?

I pulled the the sealing part of that valve out. I thought it would soften the spring too much without the canter "hub" piece. Works like a charm now.

Thread hijack:

Why isn't there a collective FAQ or stickey about disk brake conversions? This is probably the most beat horse around here, and it's always the same folks posting the same info.

[55 Fargo]

I have heard of cases like yours, where th front discs have locked up, and required this valve to be removed from the stock MC, so on the otheres that did not require this, what was different, is everyone using the same calipre assemblies, could that have anything to do with it. Would the residual valves in the lines to the fronts and rears, compensate for the fluid force and allow it to function. Is every one using the same style MCs, ie the dual outlet on the MC,or are some using a single outlet MC to a splitter somehow.

I am not trying to stir the pot, but would like to know exactly how this should be done, as I wan to do the change inmy Car someday. IU would like to use the stock MC, but in reality, it might be worthwhile to spend another $500 for the dual MC.

The other thing might be this, the valve in the stock MC might not work as well on some as the others, mine, when I apply the brakes, holds slightly for a second , as you can hear the brakes slightly touching in the back when you take off afetr applying the brakes. Or unless my return springs are to weak..................Fred

[55 Fargo]

Great Idea

Thread hijack:

Why isn't there a collective FAQ or stickey about disk brake conversions? This is probably the most beat horse around here, and it's always the same folks posting the same info.

[eric wissing]

Eric;

Norm has only driven a few blocks too:D

Don, did you remove the valve in yours? And did it suddenly leave your driveway? , really, I am serious about this valve removing business. Eric

[Don Coatney]

Don, did you remove the valve in yours? And did it suddenly leave your driveway? , really, I am serious about this valve removing business. Eric

Eric;

I installed a new kit in my master cylinder when I did my disc conversion a few years back. If the valve was part of the kit then I installed it.

In other words I dont remember.

[eric wissing]

Don, I think you will be safe from any further prosecution. You may now step down. Thanks, Eric

[rearview]

I am not trying to stir the pot, but would like to know exactly how this should be done, as I wan to do the change inmy Car someday. IU would like to use the stock MC, but in reality, it might be worthwhile to spend another $500 for the dual MC.

The other thing might be this, the valve in the stock MC might not work as well on some as the others, mine, when I apply the brakes, holds slightly for a second , as you can hear the brakes slightly touching in the back when you take off afetr applying the brakes. Or unless my return springs are to weak..................Fred

I will look for the parts I removed from my MC when i get home from work and let you know. I'm pretty sure the first MC I removed only the rubber piece, but on my new MC I think I removed all of it because it still hung a little (parts were machined much better and bled back too slow for my liking)

I agree 100% about the valve maybe not holding as well in some. It is a very primitive valve and could easily leak through. My rear brakes drag a little also, and I know my return springs are weak.... I really don't want to mess with a working item though.

[Norm's Coupe]

Eric;

Norm has only driven a few blocks too:D

Actually, I've put on at least a couple hundred miles since the brake swap to disc. No hanging up on the brakes. Prior to installing the disc brakes I had the master cylinder rebuilt by an auto service shop, when all four were still drum brakes. So, it was rebuilt with the valve in it. The master cylinder has at least 500 to 600 miles on it since the rebuild. Everything in the rear brakes is new except the return springs and they are working fine.

My driveway has a hill in it. With the disc brakes I can stop on the hill, release the brake pedal and the car will roll down the hill with ease. Since the street is also on a hill, if I don't hold the brake on out there the car will roll down the street.

That said. If you guys want, you can download the old forums before we switched to the new forum format. There are lots of discussions on there about others who have switched over to front disc brakes. Not one of them complained about having to remove the valve from the master cylinder, or their disc brakes dragging/hanging up. Also, in the instructions that came with my disc brake kit, it said nothing about having to remove the valve in the master cylinder.

[Young Ed]

Norm you better slow down or there will be nothing left of that thing to pass onto the next generation I've done 5-600 miles in a weekend.......

[Norm's Coupe]

Norm you better slow down or there will be nothing left of that thing to pass onto the next generation I've done 5-600 miles in a weekend.......

Ed, not to worry. We've already told our kids that we are spending their inheritance.

As for driving the coupe. Well...........it's usually in the garage when I want to go somewhere, and the van is sitting outside. It's easier to just get in the van and go, so that's what I do. That said, even the van only gets a couple thousand miles on it a year. Don't really keep track. I burn about 10 gallons of gas about every three to four weeks in the van. Gets around 25 MPG on the highway. Never tracked the MPG in the city though. So.........really I'm just guessing at how many miles go on the van. It's a 95 Lumina with only 80,000 miles on it. I'm doing my part to help close the ozone hole that good old Al talks about.

[55 Fargo]

Wow Norm, I burn at least $100 worth of gas here every week, my truck and the wifes van, gas is 4 bucks a gallon, so about 25 gallons per week minimum.

The wife has an hour commute to work, 20 minutes to the outskirts of Winnipeg, and another 30 to 40 just from the outside of the city to her work location in the south central part of the city. I go 25 miles each way to work, all country highway.It is getting expensive for transportation just for work...........Fred

[Norm's Coupe]

Fred,

I use to put about 30,000 to 40,000 miles on the one car every year until the early 90's. Did that from about April 1968 until then. So.........burned a lot of gas back then and went through a lot of cars at the same time. So, it's sort of nice not to have to do that anymore. Not only do I save on gas, car repairs and car replacement costs, but I don't have to fight the traffic anymore.

All that is one reason you will seldom hear me complain about the cost of gas today. Don't burn that much to be that concerned about the cost or the MPG. Use my wifes little 02 Kia Spectra for trips because it gets between 36 & 38 MPG on the highway and rides as good as a large car. Even that car only has about 37,000 miles on it now, so it doesn't get that many miles on it either. I think she only fills it up about once a month around town.

Lately I've been thinking about going down to just two cars. Would keep the wifes car until she needs another new one. My only problem is, don't know which of the other two to get rid of, the van or the coupe. Like them both for different reasons. The coupe for obvious reasons. However, the van has the creature comforts like AC, etc., plus I can haul stuff around with the van. So.....it's a tough decision because I don't need both of them. Have toyed with the idea of getting an old pickup that's ready to go and getting rid of both the van and coupe. Or, a ready to go 50's or 60's car with AC and get rid of the coupe and van. Guess it will depend on if something pops up that's a real interesting deal and my mood at the time it happens. In the meantime doesn't cost me anything to keep what I have.

[martybose]

Norm,

You should probably sell the van, use some of the money to put airconditioning in the coupe, then buy a small box trailer for hauling stuff around behind the coupe!

Marty:D

[Norm's Coupe]

Marty,

That's what I've been thinking too. Of course I wouldn't get that much selling the van. It's a 95 Lumina APV. Nice van, but they are selling pretty cheap now. It's worth more to me to keep it than sell it. Plus, I really like it too.

Really don't like trailers. Had a small utility trailer when I owned my 87 reliant. It was one of those 8 foot fold up trailers. Worked ok, but just don't like pulling them around behind me. Plus, even though it folded up against the wall in the garage, the space in the garage is gone now. So, would have to park it in the yard and don't want to do that either.

So.........now you see my plight.

[Paul Beard]

I put front disc on my pickup and used the stock MC. My understanding is that valve is to keep the fluid from flowing back into the MC not hold pressure.

Everything I read said that without that valve in the MC the fluid would back up in to the MC and you would have to pump the brakes to stop everytime you tried to stop. I am using my original MC with a proportioning valve only and will continue until I find a dual Mc that will fit between the Steering box and rear cross member.

[rearview]

Here's most of the parts from the outlet side of the MC... missing is the sealing washer, imagine it to the left of the valve disc. My old MC I only removed the rubber washer that is not in the picture (I dropped it and rolled under the bench.. all gone) My current MC I removed the rubber washer and the disc on the left of this pic. If you wanted to still run the valve disc you could either notch it slightly or ding it so it doesn't sit flat but still gives a base to the spring.