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Topic Review (Newest First)
06-24-2012 01:01 PM
PinkFiftySix
Quote:
Originally Posted by staleg
I had a h*** of a time trying to make my 45 degree double flare master cylinder fittings and fitting adapters to seal properly. What solved my problem was switching to banjo fittings.



Dont think I can use banjos. The port come strait out of the bottom of the master cylinder i am using. And i dont think there will be room because of how close the ports are to eachother. I'm thinking i might have to use a strait 3/8 24 to 3an adaptor if i end up going the single flare route.
06-24-2012 12:24 PM
staleg I had a h*** of a time trying to make my 45 degree double flare master cylinder fittings and fitting adapters to seal properly. What solved my problem was switching to banjo fittings.



06-23-2012 08:58 PM
PinkFiftySix also the MCPV-1 has a built in metering valve, With 4wheel disc I shouldt need one. Will I have to remove it? or can it stay in there and be ok?
06-23-2012 08:39 PM
PinkFiftySix
Installing new booster/master

here is what she's getting. Now if I can just get the flares to seal. The two fronts I had to re-do to get them to come up from the bottom. The stainless was a bear to double flare, especially trying to do it in the car. My buddy and I got it though, except they are both leaking.... Went with the CPP MCPV-1 with a 1" bore and a dual 8" Booster Chrome of course.
06-19-2012 09:00 PM
PinkFiftySix
Quote:
Originally Posted by cobalt327
There's a good chance that the booster- if sized for a disc/drum set up- is not large enough. For four wheel disc brakes you need a 7"-9" dual diaphragm or equivalent booster capable of 1200 psi. Usual vacuum required is 18 in/Hg although you might get by w/less, but pedal effort will increase as vacuum decreases. Vacuum reservoirs do not usually help very much; you can look into a vacuum pump if you have inadequate vacuum. But if this engine is basically stock it should be making enough vacuum.

You may need an adjustable proportioning valve, but other valves aren't really needed other than as a warning for system pressure loss, which can be plumbed separately.

From a post by powerrodsmike:

You can do a search for more.
I have been doing research, and finding out more about the car as I go. Today I found out:
**The rear end of this car came from a 2004 Mustang GT, so it has the OEM brake calipers.
**The Front end has D52 style GM calipers
**The proportioning valve was a Disc/Drum valve that was modified (as you said It had the fitting/cap between the two front outlets) I was told buy a custom brake specialist to huck that thing into the nearest trashcan.
**I was also told by this custom brake specialist that my problem is more than likely due to the size of the Master cylinder bore which is 1 1/8" He explained to me, and it makes complete sense after thinking about it. I have more volume flowing to the calipers than pressure. Pressure is what I need. He is reccomending that I go to a smaller bore Master Cylinder which will in turn give me more pressure. Thinking back that would explain why it seamed the master cylinder would "bottom out" it was filling the calipers with a large volume of fluid but not enough pressure.
**He also thinks that the 7" dual diaphram booster is right on the edge of being maxed out. I estimated the vehicle weight at 3400lbs, I found a websight that listed a 56 crown victoria with the thunderbird v-8 at 3400lbs, so its got to be fairly close to that. He says the 7" dual boosters are good for about 3500lbs.

I ordered a new combination valve from them and should be getting it tomorrow. But after hearing what he was telling me and thinking it over I was thinking about the CPP MCPV-1 with a 1 inch bore. That way I would get the Master Cylinder I need It has a built in Proportioning valve, its a lot prettier than a Cast iron Corvette Master, Less line and clutter. The Proportioning Valve I ordered was almost 90 bucks shipped. The CPP master seams like a killer deal at 199.00, Big Pretty bang for the buck.

As far as the booster goes, I'm not sure I can go with anything bigger due to valve cover clearence. With the 7" I don't notice any resistance like it is struggling, I might just stick with that.

Any Idea, comments, insight?

Thanks in advance
PinkFiftySix
06-18-2012 02:55 PM
PinkFiftySix I removed the complete valve , decided to disect it to see if there was any crap that was in the master cylinder in the valve. I didnt find ant trash but i did find there was no metering valve in the front brake portion of the valve. Please tell me there is supposed to be something in there and that has been the problem.

I ordered a new valve for disc/disc we'll see when it gets here i guess. Ideas?
06-18-2012 06:17 AM
PinkFiftySix I removed the rubber piston from the combi valve as per the CPP tech bulletin. still in the same boat, poor brakes. Going to look for a disk/disk combination valve and give that a shot.
06-18-2012 05:01 AM
cobalt327 There's a good chance that the booster- if sized for a disc/drum set up- is not large enough. For four wheel disc brakes you need a 7"-9" dual diaphragm or equivalent booster capable of 1200 psi. Usual vacuum required is 18 in/Hg although you might get by w/less, but pedal effort will increase as vacuum decreases. Vacuum reservoirs do not usually help very much; you can look into a vacuum pump if you have inadequate vacuum. But if this engine is basically stock it should be making enough vacuum.

You may need an adjustable proportioning valve, but other valves aren't really needed other than as a warning for system pressure loss, which can be plumbed separately.

From a post by powerrodsmike:
Quote:
It is easy to tell the difference between a combination valve for disc/disc and one for disc/drum.

The rear outlet looks much the same, but on the disc/drum combination valve between the 2 outlets for the front lines, there is a small screw in fitting with a button that sticks out, usually these are covered with a rubber boot. That is part of your metering valve. The disc/disc combination valve does not have this.
You can do a search for more.
06-18-2012 04:55 AM
PinkFiftySix
Quote:
Originally Posted by HotRodMan
Would the wrong combination valve cause poor braking. Yes Here's why.

The disc brake pad is normally in contact with the disc while the drum brake shoes are normally pulled away from the the drum. Because of this the disc brakes are in position to engage before the drum brakes, when the brakes are applied. The metering valve compensates for this by making the drum brakes engage just before the disc brakes. The metering valve does not allow any pressure to the disc brakes until a threshold pressure has been reached.

I suspect with your set up you are getting most of your braking action to the rear brakes and very little to the front.

Try this. Put the car up on jack stands. Have someone apply the brakes with the brake pedal all the way down. Go around to each wheel and try turning the tires. You should not be able to turn any of the wheels by hand. Check to see if the front wheels are easier to turn than the back wheels.

Is your master cylinder on the firewall above the level of the calipers, or has it been relocated to the floor level?

You say you saw some rust in the old master cylinder, you may have some rust in the calipers as well. Did you get clean fluid when you re-bled the system?
Thanks for the reply. The MC is located on the firewall above the calipers. I have had it on stands and all four wheel will come to a stop when spinning them and applying the brake. I have notice when wiping it down for a show, the rear wheels are the only one tgat seem to have any brake dust on them. And yes I used new fluid and got clean fluid to all calipers. I did find while searching around more I think on cpp's website a way to modify a disk/drum combi valve to a disk/disk, it says there should be some type of rubber or plastic piston that I can remove for a disk/disk setup. I will be trying that this morning. Then I guess i'll go from there. Really hope that is it. Can't see it being anything else.
06-17-2012 11:22 PM
HotRodMan
Combination valve problems

Would the wrong combination valve cause poor braking. Yes Here's why.

The disc brake pad is normally in contact with the disc while the drum brake shoes are normally pulled away from the the drum. Because of this the disc brakes are in position to engage before the drum brakes, when the brakes are applied. The metering valve compensates for this by making the drum brakes engage just before the disc brakes. The metering valve does not allow any pressure to the disc brakes until a threshold pressure has been reached.

I suspect with your set up you are getting most of your braking action to the rear brakes and very little to the front.

Try this. Put the car up on jack stands. Have someone apply the brakes with the brake pedal all the way down. Go around to each wheel and try turning the tires. You should not be able to turn any of the wheels by hand. Check to see if the front wheels are easier to turn than the back wheels.

Is your master cylinder on the firewall above the level of the calipers, or has it been relocated to the floor level?

You say you saw some rust in the old master cylinder, you may have some rust in the calipers as well. Did you get clean fluid when you re-bled the system?
06-17-2012 08:32 PM
PinkFiftySix
Having brake issues since day one.

Ok First post here so Hello to everyone.
A little information on what I'm working with here. The car I am working with in my Grandfathers. He's got the money, I get to drive it and show it. I have been taking the car to shows for about a year now. Its a 1956 Crown Victoria, powered buy a modular 4.6 blown by Kenne Bell, Fatman Fabrications Mustang II stage 3 Front end, Ford 8.8 rear. The car has been fully restored/customized for about 3 years now. Since day one the Brakes have never been right. We have a disk/disk setup on it and the car barely wants to stop with your foot pressing as hard as possible. Between him and I we have put 570 miles on it in the past 3 years, and as stated above the brakes have never been right. Friday I pulled the system apart making sure everything was setup right, as far as the brake pedal, linkage, booster pin, brake line hookup and routing, etc. was all OK. Everything seams to be in correct order.

One thing I did notice was when I pulled the master cylinder off and pressed the brake pedal the booster pin would come out just over an inch or so, when I put the MC back on the booster and press the pedal it will only go in about half the distance like it was bottoming out. I have come to the conclusion there is nothing wrong from the pedal to the Booster. So I figure there has to be something wrong with the MC or the combination valve.

Saturday I pulled the MC to check it, The fluid looked pretty rough, the piston seamed to hang up a bit when pressing it in, after I dumped out the fluid there was quite a bit of rust crud in the bottom of the MC so I ran to the store and got one. By the way it is a dual diaphram booster with a C3 GM master cylinder. I bench bleed the new MC install it and bleed the brakes. Take it for a run, and nothing seams any different. My Grandad came down and told me that when he bought that conversion kit, the car was to be set up with a disk/drum setup. By the time the car was finished it had disk/disk because they ended up using the 8.8 rear end out of the donor mustang.

Now after doing some research I see there are Disk/drum and disk/disk combination valves. since he ordered that kit as disk/drum I am assuming it may have the wrong combination valve in it. Would having the wrong combination valve cause extremely poor braking? Any suggestions? He's getting irritated. And I'm the one to fix it. Here are a few pics for you guys. Thanks in advance

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