Prop valve placement..

Topic: Prop valve placement.. (Read 3278 times) previous topic - next topic

Prop valve placement..

April 06, 2008, 02:19:34 PM

Okay, I am finally getting around to finishing the brake issue I have. 85 Tbird (TC) 8.8 rear, SN-95 brakes n rotors. I am going to keep the stock brake booster and buy a MC from a 1980 Mk 6 (per Chuck)

Some of the questions I have...

1) How am I going to connect the factory brake lines up to the SN-95 calipers?

2) I managed to get the E-brake lines installed but I think it is too tight. Whats the fix? (I was reading the sticky but still unsure)

3) Where do I put the Prop valve? I have seen some pics of people removing the stock PV all together and just running the lines to the aftermarket PV and then I have seen the 3-2 conversion kits and the aftermarket PV.

My plan was to keep the stock PV intact and just plum the aftermarket one in line somewhere. Is this right?

I have searched for "Prop valve", "PV" and "proportioning valve" and came up with nothing or some posts about sending units on 3.8's Please help me finish this project... Thanks guys..

Prop valve placement..

Reply #1 – April 06, 2008, 04:40:09 PM

Quote from: Uncleford;212830

Okay, I am finally getting around to finishing the brake issue I have. 85 Tbird (TC) 8.8 rear, SN-95 brakes n rotors. I am going to keep the stock brake booster and buy a MC from a 1980 Mk 6 (per Chuck)

Some of the questions I have...

1) How am I going to connect the factory brake lines up to the SN-95 calipers?

2) I managed to get the E-brake lines installed but I think it is too tight. Whats the fix? (I was reading the sticky but still unsure)

3) Where do I put the Prop valve? I have seen some pics of people removing the stock PV all together and just running the lines to the aftermarket PV and then I have seen the 3-2 conversion kits and the aftermarket PV.

My plan was to keep the stock PV intact and just plum the aftermarket one in line somewhere. Is this right?

I have searched for "Prop valve", "PV" and "proportioning valve" and came up with nothing or some posts about sending units on 3.8's Please help me finish this project... Thanks guys..

Do you have SN95 fronts? I will try to answer your questions, becuase I have already done this, I am just trying to figure out how to get it a little stronger now by exploring booster options. I have an '88 Sport, and our hardline fittings might be a little different.

1) On the front, I used the rubber lines that matched the SN95 calipers. On the rear, I "T'd" off of the original 1/4" line, and then fabricated new lines for the calipers that match the setup of an SN95.

2) Right now, my e-brake cable are zip-tied to the chassis because I live in Florida, with no hills, and dont need them for parking. If I am understanding all of the info I have ever seen though, you need Turbo Coupe cables from the middle of the car back. SOmeone may correct me on that though. I would like to hook them back up for "emergency" brakes though.

3) I am not familier with your factory setup coming out of the M/C, but I do know that when you convert to discs in the rear, you need to gut the stock PV, and add an adjustable PV that controls pressure to the rear. Ford motorsport used to make a plug for the end of the PV, the problem is that its now discontinued, and its nearly impossible to find. You may have better luck in your area, but I had to have the hole in the original aluminum plug TIG welded shut.

If you want pics of my setup, let me know and I can blast them up here.

Prop valve placement..

Reply #2 – April 06, 2008, 10:19:41 PM

Hey, Thanks for the help.

No, I don't have SN95 fronts. My front calipers are fox style (87-93) I am going to replace the front lines cause the ones I have are a little dry rotted.

When you fabricated the lines in the rear to match the SN95 calipers where did you get the fittings? What size line did you use?

My car is a turbo coupe so what I did was hook up the lines as is. It was an extremely tight fit and from what I remember I loosened everything up as much as possible. I will have to look again. I was from Florida also and never needed them but I am wanting everything functional this time around.

Okay, I think that answers my question as far as gutting the PV. I will gut mine this week. I bought the conversion parts a while back. (If you ever need the plug call Summit or Jegs. Thats where I got mine.

Yes, definately need pics. That always helps!

What master cylinder are you using?

Thanks!

Prop valve placement..

Reply #3 – April 07, 2008, 09:50:15 PM

I think your front rubber lines will work, but I am not 100% sure about that, because I changed over to the SN95s. On the rears, you have to make them bubble flares, because that is what the SN95 rubber lines use in the rear. I am using a master cylinder from a '94-95 SN95. I just got the MC to match all the calipers I am using.

Prop valve placement..

Reply #4 – April 07, 2008, 10:47:14 PM

Okay, how did you get the bubble flare? I have a flaring tool but the ones I have made weren't the greatest looking. They were sharp with no smooth area to them. Maybe i should look for another tool? What fittings did you use for the rear calipers when you made new lines.

Prop valve placement..

Reply #5 – April 08, 2008, 08:14:43 AM

I dont remember what exact fittings I used for the rear, that was about 2 years ago, and I had several project going at once. If I am remembering correctly, bubble flares use metric fittings, what I did was take my new rubber lines down to the parts store, and had them match it for me for bubble flares. You have to have a special bubble flare kit to make them on the hard line, you probably have an inverted flare tool, and that wont work. Spend the extra money on a quality kit though, it will save you tons of aggrevation for only about $30 more.

Prop valve placement..

Reply #6 – April 08, 2008, 09:05:45 AM

When did they switch to bubble flares on the rear hardlines? I don't ever remembering having to spec metric fittings for rear hoses on the SN-95 brake kits. All the one we put together with Goodridge were Std INF fittings.
What's stopping you from using TC rear hoses? Not much from what I can see. There isn't that much difference in the rear calipers.

Prop valve placement..

Reply #7 – April 08, 2008, 10:31:23 AM

Like I said, I dont remember 100% if they are metric or not, my rear calipers and rubber lines are from a '96 Mustang GT, and I know for sure that I had to build them with bubble flares for them to seal right, because there are no inverted flare cones inside the part of the rubber line that bolts to the body.

When you say "put together with Goodridge", were they building new lines for the caliper to the body for you?

Prop valve placement..

Reply #8 – April 08, 2008, 10:49:39 AM

As in, when I was at KB and we were working with them putting together line kits....

At some point they changed the way the rear lines were ran. Before there was on flexible line between the body and the axle and a flex line at each caliper. It was this way on the 94-95 cars. Later, they switched to 2 flex lines between the body and the axle and just T-ed the hardline on the body. They never changed the calipers.

For what he needs to do, keep the flex line to the axle, run new hardlines on the axle with std fittings and use TC hoses at the calipers. I prefer to use braided lines, but if you are just using rubber, the TC (or even the SVO/Lincoln) should work.

Prop valve placement..

Reply #9 – April 08, 2008, 05:39:27 PM

Well, I just thought the flexible SN-95 caliper lines were metric and my hard lines (original 85 TC) were standard. I was thinking I needed to cut my hardlines to put standard threads on it and then flare it to work. If they will simply fit then I will just screw them in on the rear driver side and then try to figure out some way to connect on the rear passenger side.

Prop valve placement..

Reply #10 – April 08, 2008, 09:11:24 PM

I see what you are saying now Chuck, that would be the easiest way to do it. I would have preferred to use braided lines as well, but when I put it together I was on a budget because I had a kid on the way and needed a way to move him around other than my motorcycle. Basically I copied the line setup of the car that I took my axle from. It was a '96 Mustang GT, that had one hard line coming to the rear, it then went to the passenger side of the car, where the softline had a built in bracket on the body, and a Y style fitting. The main hardline went into that, and then came out of the other Y, and went over to the driver's side and connected to that soft line. Those were still bubble flares though, to match the soft lines, I used new because the old ones were dry rotted, I just cant remember if they were metric or not.

Prop valve placement..

Reply #11 – April 16, 2008, 12:01:51 AM

Well, I bought the fitting conversions from Matt's page but strangely enough they do not fit. It almost seems as if the fittings (from the T-Bird drum ...line) will fit the SN-95 soft lines. I am a little nervous to try it cause I am not really sure what to do if it doesn't work.

AutoZone doesn't carry the fittings and two online shops I called didn't have a clue. One of them said they would make me a new custom bent line but they couldn't tell me what size threads they were going to use. Ha. what now?

Oh, almost forgot, what to do about the parking brake? thanks for your patience

Prop valve placement..

Reply #12 – April 16, 2008, 08:51:55 AM

What do you mean by this?

Quote

It almost seems as if the fittings (from the T-Bird drum ...line) will fit the SN-95 soft lines

The fittings on the hardline on the axles that go into the old drum wheel cylinders are 3/8-24INF threads. It's possible the the SN-95 disk hoses are 3/8-24INF as well. Is the bottom of the fitting on the hose convex (raised up)? if so, and the threads are the same size, then yes, they will probably work. If the holes in the hoses are larger and have the domed bottom, they are most likely 7/16-24INF, which is common as well. You can find adapter fittings for those pretty easily.
It's really hard to say without seeing what you have, or being there. I don't use rubber hoses on my brakes any more, so remembering what was "stock" is not easy.

Prop valve placement..

Reply #13 – April 24, 2008, 12:00:02 AM

Okay, now that I've had a little time to look at things...Yes Chuck, the stock hard lines will fit into the soft lines of the SN-95 calipers. However, I think that the soft lines have threads that are too deep for the hard line fittings. Make sense?

At any rate I will venture to Napa shortly to see if they can help me out on some new lines and fittings. I need to figure out how to get the junction on rear to work with the soft line junction or bypass the stock one.

Prop valve placement..

Reply #14 – April 27, 2008, 11:22:56 PM

Okay, need some help on a connection. I got the correct fittings and made a new hard line across from the left rear caliper to the rt rear caliper. (I am using the SN-95 soft lines) I am trying to figure out how to connect the rt rear soft line to the main MC line. Any suggestions?