I am ready to start doing brake lines/proportioning valve, etc. on the frame. i want to get it done before I put the cab back on. Now that it's really time to do that, I started doing some research and now I got all kinds of questions running through my head.
In case ya don't know my setup:
8.8 Rear axle from '97 Ford Explorer
Brake booster/master cylinder/pedal assy. from '91 T-bird
using 15" wheels, not sure on tires yet but more than likely standard height to lower profile.
I prefer to use a salvage yard proportioning valve, but depending on the feedback here, that can change.
I have read about setups where,instead of hooking up for front to front, rear to rear lines, some newer cars use a cross pattern where one front is connected to the rear diagonal: Left Front to Right Rear...Does anybody do that?
What is my Aprox. wieght? I have no clue whatsoever, and how close do i need to be on that?
I am hoping to catch Rhopper on this one because he just got his on the road and i think his is as close a comparison as i can get. But wanted to share this for other JAG users.
I just want to make sure i stop well when the pedal gets pushed!
Also I may be over-complicating this in my head like I sometimes do. I certainly am capable of double flaring and brake line work, just looking for help on the setup so i don't have too much trial and error...
i would use an aftermarket adjustable proportioning valve. they are relatively cheap. unless you can find a proportioning valve from a vehicle that has close to your weight bias, tire size and brake setup, an adjustable valve is the only way to go. very easy to plumb inline and easy to adjust properly.
i would stick with the traditional brake line routing of front and rear separate systems. most new cars have abs that will let the new routing system work properly. just stick with the old and proven method of routing the lines.
If the 91 Bird had 4 wheel disk the master cyl most likely has the porp valve built in.
Just my opinion the cross brake think brings to mind an Outhouse on Casters - Stuff flying everwhere with you in the middle.
I agree with the others. Use traditional brake line routing. Unless your name is Bosch and you design computerized ABS braking systems commercially, don't start messing with cross lines.
Using an aftermarket, adjustable prop valve on your rear brakes will allow you to dial in just the right amount of bias for your application. Way too much trial and error, and safety issues, involved looking for just the right junk yard part, if it even exists.
Weight will be somewhere in the neighborhood of 3200 pounds, depending on drivetrain and other options. Figure on a front bias of 55-60%.
Just saw your pm Jeff, been gone for a few days. My system is pretty simple. I have a dual diaphram power booster , 7" diameter for more room on the firewall, with a 1 1/8" piston "corvette" master cylinder. With the jag 4 piston calipers and rear explorer discs, we weren't sure which m/c size to go with, so we guessed the 1 1/8 and it's fine. It's alittle on the firm side, not mushy like alot of power brakes. I don't know if a 1" would have too much pedal travel. I used a roll of plain steel brake line from speedway to minimize joints and painted it yellow to match the frame. Rear lines run from the m/c back to the firewall, down to the frame, into the proportioning valve, then back to the flex line. The prop valve is just a hot rod store, **** type prop valve, but get the kind with the brake light switch. Wilwood, summit, etc sell them. I didn't get a switch prop valve and fabbing the lever light switch was a pita. For the rear axle, I used the stock explorer hard line and installed new flex lines. The flex line on the left side mates with the hard line from the prop valve on the inside of the frame. Just make a tab with a hole in it and duplicate a stock mount. To drill the hole in the bracket, get a step drill and go slow. The front line runs the same, to the firewall and down to the frame, T fitting to the left wheel, then forward to the radiator x member, across to the pass side and back to the right wheel. Same kind of tabs as the back to mount the flex lines. I bought new jag flex lines and used the jag fittings to mate to the hard line. Mount the flex line so you have enough slack. Because of the length of the line from the m/c to the frame, and the minimum number of clamps I used in that area, my local shop said don't bother with the spiral bends, there was plenty of room for the line to give. If you do spiral the line, do it horizontal rather than vertical so as not to trap air and make bleeding difficult. I bought the plastic coated steel clamps from speedway and drilled and tapped holes in the boxing plates for 1/4-20 screws. The fittings also came from speedway, 5 to a pack. Lay it all out on paper so you can order all the fittings because most parts stores are lost when it comes to them. If your m/c is below the floor, you will need residual valves, 2lb, but mine is firewall mounted so I didn't need them. BTW, with my hanging pedals, I switched to F1 round rubber pedals from the square ones. It looks great.
Last edited by rhopper; 07-04-2011 at 07:22 PM.
Thank you all for pointing me in the right direction!
I will forget the crossing line thing, i hadnt heard of it until starting this research anyway...
As far as the aftermarket prop. valve with the light switch? are we talking a prop valve that goes into the reaer line only? or a valve that all line get connected to?
Rusty Thanks a million! as i said before i think your setup is as close as i can get for comparison. I didn't even remember you also had tha same rear axle as me! that is great to hear, for me. I will print this one off as soon as i know the right type of prop. valve. i assume you mean that the front brakes don't get tied into the prop. valve but someone verify that for me!
Ah you guys are great help! Thank you so much!
Okay after reading back through this, I got it! I need a single line prop valve to the rear only, an adjustable one with a switch built in. Got it!
Off i go to price the parts! you guys, again, are so appreciated for answering my questions! Have a great day!
How about the e brake? I used the stock handle with a lokar cable. Ford cars of that era used the same handle so I think I'm using the 48ish sedan cable. I'm using the stock cables on the rear axle routed up the left side of the frame, mated to a fabbed T bar then to the lokar cable. You can also get a complete lokar cable assembly that I believe runs up the middle of the frame if you don't have the stock explorer cable. The handle does need a pretty good tug to set the brake, however. I think a lever pulled by the handle, which then pulls the axle cables would be a better way if you're just starting. It's a lever used to increase the leverage kind of thing. I'm sure someone will be able to explain it better or draw a picture, but it's sort of what the stock system did.
whaddya need brakes for jeff ????? that's what you got bumpers for , to use on other vehicles to slow you down . the 91 in question was my parts car had rear drums , and if you go boneyard jeff find one for a 4 wheel disc bird , cougar , no mark 8 as they are anti lock period . my reasoning is one they are 3600 lbs just like my 53's weight , the got the same nose heavy weight bias as i can, and other owners can attest too as our trucks , so i reckon they'd work ........ oooopps never mind i see you got a new one .
My opinion: Many have used the factory prop valve when the weight, brakes and tires are the same as the prop valve donner vehicle. Adjustable prop valves came out for the hot rod crowd when they started putting bigger and wider tires on the rear end. More rubber on the ground had a hugh difference. The adjustable rear prop valve comes on slightly to keep the vehicle tracking straight ahead as the weight moves forward and is slowed mostly by the front brakes. If you use a adjustable rear prop valve check the adjustment in a large parking lot using heaving braking to see if the vehicle swaps ends or tracks straight ahead until stopped. Next time when it rains do the same test. Sometimes the dry road test is ok, but the wet rode braking test can be a thrilling ride as it changes ends like you are on ice. Be careful, chuck
okay! dumb question!
on factory proportioning valves: I always thought that the electrical connection was for a brake warning light. if pressure is lost front or back, some type of slider piston would slide to the non pressure side and make an electrical connection thus illuminating the brake warning light.
on an aftermarket prop. valve the elec. connection: seems to me that it is to be the switch for the brake lights? or is it a brake warning light also?
Jeff you are right. The early combo valve has a metering valve, a diff valve and a proportioning valve. Four wheel disc don't need a metering valve. It is for drum rear and disc front. The aftermarket should have a combination diff valve and a adjustable proportioning valve. When you buy one please confirm how it works and how it is plumbed. Have a great day,chuck
ok let's confuse me more!
I was at a Good Guys Show last night.(Paradise Casino, East Peoria, IL)
I found one '49 F1 he lives 15 mins from me.
I was chattin with him about his brake stuff.
MII front suspension(disc),
9" rear axle(drum brakes)
He said he did not use a prop. valve, said it didn't need one...
there really is no Standard here, it seems?
well i am gonna have one, regardless but, it's never the same story twice!
kinda makes me wonder why I ask! LOL
I will keep ya posted on what I get. it may be a week or two.
Have a great day!
Jeff, there is always going to be in anything, someone, who goes the different route and has zero problems. Maybe he drives slow, maybe he has never had to do any max braking to see what would happen. City traffic vs small town traffic. Who knows. I would read up on the internet about the subject and do what is safe for you and your family riding in the truck. I see nothing wrong with using a disc/disc combo valve assy and see if it works under heavy braking. You could always replace the valve with an adjustable valve after testing. Many people in the past have put big wide tires on the rear of a car and never had a problem. The truck rear end is lighter than a car and the rear weight shifts forward and leaves the truck rear end weighs even less as you heavy brake to a stop. The manufacturers put the system on cars and trucks for a purpose. Be safe. chuck
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