Front center brake hose to pro valve

**jamjet** · 03/27/07, 01:27 AM

I have just purchased my first Bronco. Full resto 69 Frame 77 body and drive train, 351 EFI, Hydroboost, 4 wheel disk..blah blah. I inspected it, noticed what I thought needs replacement, its is currently being shipped so I do not have access to it. Anyway I am replacing all the brake lines, found a leak and the brakes were marginal.

If I remember the proportioning valve was attached to the inside of the frame when I inspected the Bronco. In looking at the 77 shop manual the proportioning valve is located on top of the frame. Was the proportioning valve mounted on the top of the frame through out the years? or did the early ones have it mounted to the frame.

Does the center brake line connect to the proportioning valve through a small segment of hard line as it seems to appear in the shop manual? If so any way around this and connecting the braided line direct to the valve?

Is there any reason why I would want to remount the proportioning vlave on top of the frame (purchased a new one with bracket)?

There is also an after market adjustable pro vlave.....is this typically used with the stock pro valve?

I am planning on braided from the MC to pro vlave...as I have read seems to be the way to go.

Great site
Thanks
Joe

**Apogee** · 03/27/07, 10:24 AM

I'm not sure if all years were mounted to the top of the frame, but I know my 1977 is. Most of the earlier 4-wheel drum setups were just a distribution block, not a combination/proportioning valve so that could explain why there is an adjustable added to the system. You should NEVER run two proportioning valves inline with one another. The results are unpredicatable at best.

There is a short hard line that goes from the combination valve to the front axle hose, which is normally attached to the inside of the frame. If you plan on running headers, it can be very tight. I moved mine to the outside of the frame and rebent the hardline to match.

**jamjet** · 03/27/07, 04:56 PM

It has headers so maybe the previous owner mounted the pro valve on the side of the frame. I just didnt kow if the pro valve used the same attachment point through out the years. It actually might be just a distribution block instead of a proportioning valve. As mentioned I purchased a new stock proportioning vlave (4 wheel disk)....is it recommended to use this pro valve or the adjustable pro valve that is already installed?

**Apogee** · 03/28/07, 08:58 AM

Quote:

Originally Posted by jamjet

...As mentioned I purchased a new stock proportioning vlave (4 wheel disk)....is it recommended to use this pro valve or the adjustable pro valve that is already installed?

No such thing as a "stock" proportioning valve for a 4-wheel disc application since no EB ever came from Ford without drums in the rear. Rather than deciding what you want to replace before you even have the rig, why not repair what needs to be repaired like the leak, replace the hoses if the existing ones are cracked and/or need replacement, and drive it. There are very few absolutes in the EB world, so asking what is recommended is a loaded question. I would run the adjustable and see if you like it for yourself. It's already installed and so long as you make sure it's safe first, it takes no additional effort on your part.

Since you haven't specified what rear disc conversion your EB has, it's tough to say, but you could just have mis-adjusted calipers in the rear which could explain why your braking is marginal.

Congrats on the new rig and enjoy it.

**jamjet** · 03/28/07, 01:07 PM

Understood
Rear disk are from a Lincoln Versallies.
I am replacing most of the simple brake items, all the hoses are rubber, going with braided. Since an adjustable proportioning valve is installed I need to make sure the previous owner used a distribution block instead of a dist/pro valve correct?
My other concern is that the front (rear brakes) resevoir of the MC is contaminated, as it is black as compared to the rear resivoir which is clear.
The hydroboost setup as I was told is a "GM" form what make of vehicle I do not know.

Thanks for your help!

**TOFIC** · 03/28/07, 01:24 PM

a couple of observations if I may
If this is four wheel discs , you dont need a prop valve "theoretically" As both reservoirs should exert the same pressure to both systems. If you really want to cut to the nitty gritty you dont need a prop valve or distribution block at all with an all disc system. Hook the back reservoir to the front brakes and the front reservoir to the rear brakes. An all disc master it doesn't matter which way they connect.

Get rid of the black bleed it out bad karma man don't need this.
GM master?? gotta be corvette or camaro. If not you are buying yourself trouble take the MC part number to the parts dealer and find out what it is. Either that or check and ensure both ports of the master have the residual pressure valves removed.

TOFIC

**Apogee** · 03/28/07, 01:40 PM

Quote:

Originally Posted by jamjet

Understood
Rear disk are from a Lincoln Versallies.
I am replacing most of the simple brake items, all the hoses are rubber, going with braided. Since an adjustable proportioning valve is installed I need to make sure the previous owner used a distribution block instead of a dist/pro valve correct?
My other concern is that the front (rear brakes) resevoir of the MC is contaminated, as it is black as compared to the rear resivoir which is clear.
The hydroboost setup as I was told is a "GM" form what make of vehicle I do not know.

Thanks for your help!

Certainly verify that that what you have is a distribution block. You can always open the adjustable all the way and it will behave like it isn't there too.

If the master cylinder is functioning properly and you just have contaminated fluid, I would use a turkey baster or something similar to pull the fluid out of that reservoir and then refill with clean fluid and bleed/flush the system. There's really no reason to push all of that dirt down into your calipers and the lower points in the system if you don't have to.

I disagree with TOFIC about proportioning valves. Proportioning valves don't directly control the pressure ouput to the rear brakes, but rather the rate of increase of pressure to the rear brakes above a certain point. It all comes down to weight transfer under heavy braking which causes traction to decrease at the rear tires. Properly sized calipers and rotors for the system front and rear are necessary for a balanced system, but even a balanced system in a threshold braking situation will lock up the rears first without some sort of proportioning valve. Locking up the rears is not desireable since it's a great way to meet and greet whatever happens to be on the side of the road in a hurry...or worse, oncoming traffic.

Just my $.02, so take it for what it's worth. There's some good info about MC's here within the context of Hydroboost systems...scroll down to near the bottom of the page. http://www.hydratechbraking.com/prod...cessories.html

**jamjet** · 03/28/07, 07:35 PM

Great info thanks for the help guys. It is appreciated!!!!
Joe

**jamjet** · 03/28/07, 08:00 PM

One more question...
Received the front and rear brake lines. I am curoius as to the length. I ordered them from WH for a 3.5" lift. They measure out at 24". What length are stock? Could find the info doing a search.
Thanks again
Joe

**TOFIC** · 03/28/07, 10:21 PM

GAWD I love this forum, you can actually have a CIVIL disagreement with another member and no-one gets tense.
I still stand on my opinion of the all disc master does not require a proportioning valve. the differential is built into the MC so the valve is redundant, I am not saying not needed just redundant. If you are unsure of what is going on, take the Bronco to a reputable shop and get it looked at and set right in your mind.
This is where I really get on my soapbox about this, whatever you are doing think safety!!! this is the only system you have to stop 4000 lbs of moving metal. DO IT RIGHT if you don't like it get it looked at by the pros.
enough said.
TOFIC

**jamjet** · 03/28/07, 11:22 PM

Concur!!

76Broncofromhell · 03/29/07, 02:49 AM

Stock 77 valve assembly is a metering, proporting and adjusting valve. You can use it with 4 wheel discs but you have to take the metering function out of the front brake part.

The assembly has a small pressure valve in it that allows the rear drums to overcome the return springs and take up the play in the shoes before the zero play calipers engage.

Personally I would buy the $30 Summit Racing proportioning valve in the rear brake lines and adjust to your preference. I did that on the Bronco, GPW and Toyota. I despise the stock crap as it is made to fit too many needs and not adjusted to your specific rig.

**Apogee** · 03/29/07, 10:35 AM

Quote:

Originally Posted by jamjet

One more question...
Received the front and rear brake lines. I am curoius as to the length. I ordered them from WH for a 3.5" lift. They measure out at 24". What length are stock? Could find the info doing a search.
Thanks again
Joe

Stock length hoses are 16.625" & 17.57" front and rear respectively for a 1977 EB. The lengths will vary by maybe +/-.25" depending on what aftermarket hose manufacturer's catalog you look at, but that should be close enough for what you're looking for. With the super-flexy springs available now, you want the added length that the 24" hoses afford you.

I run a CAGE 3.5" lift and have 22" long hoses...but I am thinking about swapping them out for some 25" or 26" hoses when I do some more fender cutting because I think I might need the extra length. Also keep in mind that some of the manufacturers are selling hose kits that work for both the 3.5" and 5.5" lift kits.

TOFIC...you rock...and you are correct that there is a bias built into disc/disc master cylinders, typically in the 60/40 or 65/35 split range. This relationship is fixed and it is constant, regardless of pressure. The function of a proportioning valve is non-linear and primarily aimed at increasing safety in panic stops while allowing more initial rear brake bias for "normal" driving.

The metering orifice in the front of a combi-valve does not have to be removed when running discs...it just holds off the front brakes for a fraction of a second so allow the rear drum brakes to engage first, which would otherwise be slower to actuate. The rear brakes engaging first helps the vehicle stop straighter for simple geometry reasons. With 4-wheel discs, the function is still the same, but unnecessary as 76BFH pointed out.

**jamjet** · 03/29/07, 09:42 PM

Thanks for the info!! I think I have a handle on this now. At least I know what to look for to ensure the previous owner used the correct parts. Thanks for educating a newbie.

Joe

**jamjet** · 04/06/07, 12:23 AM

Got the Bronco.....the leak was at the H bolck, no proporting valve.

Question - Can you safely run with out an distribution vlave?

Tofic you mentioned that you could connect drirectly to the MC. It seems logical...I have 4 wheel disk, an adjustable proportioning valve....Although I do need to verify if the MC has proportioning built in.

Other than using the part number (which I plan on) how would one verify if a MC has bias?