Brake pipe routing for rear pipes

Chris, the pipe runs through the rear crossmember. I believe the original was run before they closed it at the factory

Your drawings appear to show front brakes. The rears are a single line all the way back to a tee fitting.

Chris, some of the confusion may come from the fact that for reasons unknown, the brake proportioning valve is plumbed to limit pressure to the Pantera's FRONT calipers, exactly contrary to every other performance car known. In addition, it is non-adjustable and factory-set for stock brakes, tire and wheel sizes.

The above is why brake mods are one of the most common (and rewarding) changes done to the average Pantera.

Boss, Chris is working on a Mangusta? The main line for rear brakes goes to brake reserve on the frame rail. Then 2 lines exit going to rear wheels.

You're right. We currently have Cris posting in the Mangusta Forum and ChrisMel posting in the Pantera Forum. I thought it was the same guy with two different cars like you, and kinda got the subjects mixed. Sorry.

@forestg posted:

Your drawings appear to show front brakes. The rears are a single line all the way back to a tee fitting.

Belay this. I did not notice you were a Mangusta.

I installed a brake proportioning valve on my car, in the front. It limits the front brake, it is adjustable. It workd very well

You want to limit the brake capability of the brakes that lock because the tires have lost traction due to excessive brake force. On a Mangusta and a Pantera, or any mid-engine car it is in the front, not the back like a rear wheel drive or front wheel drive car.

@dickruzzin posted:

I installed a brake proportioning valve on my car, in the front. It limits the front brake, it is adjustable. It workd very well

You want to limit the brake capability of the brakes that lock because the tires have lost traction due to excessive brake force. On a Mangusta and a Pantera, or any mid-engine car it is in the front, not the back like a rear wheel drive or front wheel drive car.

I shouldn't be interjecting myself into this discussion since everything I know of Mangusta's is second hand but the significant review of them that still sticks is the term, "trailing throttle oversteer".

This was experienced in my 930 and was the main reason I ditched that in favor of a Pantera but it is next to impossible to learn to put your foot into the throttle in a sweeper when you feel it starting to go to pull it up. Kind of like pulling a trailer when the wind starts to whip the trailer and you need to use MORE throttle to pull it up in line.

The Pantera uses a '72 Mustang brake proportioning valve, with the brake warning light installed in it, but that thing proportions a set 75/25 into the brake system.

The additional "correction" in bias is designed into the size of the braking capability by the size of the pads, i.e., the clamping capability of the system.

I can't prove it at this points, simply because you can only safely test on a closed track, but I wager you that you can ALMOST eliminate the rears on the Pantera from this system.

You guys don't like to hear about Ford's involvement in the Detomaso's or even Shelby's association with it at all. Sure...it's pure Italian. Right. But what you want to do is forget about why there is a proportioning valve in the front, left to right, and install an adjustable proportioning valve in the system for the rear.

This was done on the 65 and 66 GT350's and I can tell you that it is virtually impossible to lock the brakes up at all.

In the Pantera, you are better off going to the Mustang replacement master cylinder simply because you have a greater variety of bore diameters to experiment with.

Generally speaking, on a Pantera, IF you are increasing the braking in front, leave the rears alone, and look for a larger master bore.

The stock Girling master is likely to make a monster out of locking the fronts because of the greater breaking capabilities and softer pedal. The larger bore, because of the greater pedal effort, reduces pressure to the fronts. In effect is a proportioning valve.

I already know that a bore of 1" is about where you want to be on that bore diameter BUT you could start as low as 3/4" and step all the way up to 1-1/4" by 1/16" increments. Let me save you the time and effort. 1".

If you want to stay metric, fine but you aren't going to find a 25.4mm bore. Euro thinking is this case is very limiting. Go ahead. Be stubborn.

What it will do is shorten the pedal travel, harden the pedal some and reduce the tendency of locking up the fronts in a hard panic.

That's what you do on a race car and when putting higher performance brakes on the car, you are really putting "racing brakes" on it with the exception of a softer, street, pad like the Porterfield R4s pad.

In many respects, the Mangusta is a 1.0 Pantera.

As far as the Mangust rear brake line routing, why is it important to replace the exact "factory" routing.

You are just going to have a single rear line splitting into a T at some point along the chassis. That's all that should matter?

My car did NOT have a proportioning valve, front or rear.

It is without a doubt the  most important thing that I have done to my car.

In the rear a single brake line comes into a T and than routes to the right and left calipers.

Same in the front. I put the adjustable proportioning valve ahead of the T, thereby effecting both front calipers.

Where to put it was a simple decision although I knew that rear drive cars had them in the rear. In my case, the front brakes would lock up under hard braking. so I put it there. It works very well.  Add that to the softest brake pads that you can get from a race supplier and you will have great brakes.

I have not done it but I think that adding a residual valve to each caliper would be a big improvement.

Has anyone done that to a Mangusta?

DICK RUZZIN

Does the Mangusta use the same calipers as the Pantera?

Nø, Doug. I've seen small iron three piston calipers on a few but mostly what Mangustas have are large two piston aluminum calipers. Same as on big-block Cobras and a few other '60s sports cars.

I never got to drive my basket case Mangusta. I'd say that Johnny Woods' method of eliminating rear bump-steer from suspension bind in the Mangusta is the best alteration one can make for that car. Once altered, the Goose rear suspension and handling is identical to a that of a GT-40. Most of my driving experience is 40 years in the Pantera and I approached its front brake locking problem from a different angle.

Instead of perfecting the non-adjustable prop-valve in the Pantera's front brake circuit, which reduces its stopping power, I put an adjustable valve in the rear brakes and rebalanced the whole system so the fronts were working more efficiently without a front prop valve. This was quite a bit more trouble -probably why Ford didn't do it- but it then allows phenomenal stopping power. Especially with big tires like the GR-4s used without a prop valve.

The lack of a Heims joint on the outboard end of the outboard upper link to the hub carrier is a real mystery. No other De Tomaso car does that. Also, the rear bridge being soft mounted to the subframe makes no sense, it allows a tremendous amount of flex that must allow camber change as well. I have looked at the GT40 rear suspension. Maybe they are theoretically the same in a kinomatic drawing but they are executed in a very different way, note the outboard upper hub carrier link and the rear bridge.

In my picture see my new bridge hard mounted to the frame with the transaxle soft mounted to the bridge. I drove the car five feet and felt the difference.

Dick Ruzzin

@bosswrench posted:

I never got to drive my basket case Mangusta. I'd say that Johnny Woods' method of eliminating rear bump-steer from suspension bind in the Mangusta is the best alteration one can make for that car. Once altered, the Goose rear suspension and handling is identical to a that of a GT-40. Most of my driving experience is 40 years in the Pantera and I approached its front brake locking problem from a different angle.

Instead of perfecting the non-adjustable prop-valve in the Pantera's front brake circuit, which reduces its stopping power, I put an adjustable valve in the rear brakes and rebalanced the whole system so the fronts were working more efficiently without a front prop valve. This was quite a bit more trouble -probably why Ford didn't do it- but it then allows phenomenal stopping power. Especially with big tires like the GR-4s used without a prop valve.

My preference would be to put the adjustable valve in the rear system and leave the fronts at full pressure. That is how I understand the system.

I suppose that you could put one in the front but you would need to examine how the existing master cylinder proportioned pressure to the rear  before you did anything. Production cars tend to become uncontrollable under sever braking because the rear locks up and starts to come around. Not the other way around.

At one point there was also resistance to putting better tires on US cars from "Detroit" because they were afraid of people using that potential and they didn't want to be "Naderized" as making race cars and putting them on the street. That I think is a result of the ass backwards views projected by the "legal team"?

Jack, did you play with the bore of the master cylinder or stay with the original? You can reduce the front lock up or eliminate it by going to a larger bore. That's what was done on the 65-6 GT350's along with a Shelby version of the Corvette adjustable rear valve and you just can't lock the system up.

I think what happened with the Mangusta vs. the Pantera was that Ford was running Pantera production ALMOST from the beginning with US engineers assigned to Detomaso in Italy.

The procedure at Ford has always been to take something that works out of the existing vast array of parts already produced.

That simply didn't exist with the Mangusta.

How and why that Pantera front proportioning valve came to be is just a mystery to everyone now because it is simply counter productive.

I CAN envision a scenario though where it's possible "Ford" felt that the braking on the Pantera WAS TOO GOOD for the average driver in the US market and killed it a little?

The lawyers always want to be in control even if it shows that they have their heads up their asses...as usual. Now they have to protect you from yourself. It seems to be their moral calling?

Doug, over time I replaced the entire stock Pantera braking system and plumbing. It all started with the ridiculously small, heavy rear calipers & limited front brakes. A few years after we bought it in 1980 I added ATE's Porsche 911-S aluminum 2-piston front calipers to the rear along with what Wilwood called their 'cable operated spot brakes'-popular on go-karts, for legal e-brakes on custom brackets. My rotors are early Porsche ventilated. To balance the altered system, I removed the stock prop valve and added a Corvette/Kelsey-Hays adjustable prop valve in the rear plumbing, adjusted to lock the fronts first. Still works great.

On one trip to 'Vegas, Judy suddenly lost both front brakes in the stock master cylinder to wear. Except for a long travel brake pedal, the car drove normally in town & on the highway, using only the ATE rears. After we got home (550 miles!) due to cost at the time, I fixed it with Don Byers' GM power brake adaption. I removed the 'keep-alive' ball-check valve in GM's master cylinder for less pad drag. That master cylinder is dual bore size, neither one being exactly the same as OEM. GM's dual stage vacuum diaphragm is larger as well as being lighter overall. At that same time, I replaced the front Girling calipers with Wilwood Superlite lls that were 1/2 the weight with equivalent stopping power.

I also added dash-3 Aeroquip hoses & aluminum fittings for the entire car including the clutch. On gauges, I see 1150psi in the front brakes & around 1000psi rear in panic stops. All this actually fits together; I run 245-50 x 15" BFG Euro T/A front tires & 295-50 x 15" Pirelli P-7Rs, both V-rated, on 8" & 10" x 15" Campys, with Porterfield R4-S pads all around. Sadly, some of this stuff is no longer commercially available.

Chris, here is the setup on #1010....not the original lines but basically where they were located. Regards to all, Nate

Here is 1046, as Denis points out going thru the lower rear crossmember...(you can just see it...)

Nate, every time I see glimpses of your car I think its going to be fabulous...Chris, note that the clear tubing Nate used around the frame attach is original.

The brake compensator was common for performance Italian cars--at least, the same part was used on Ferrari and Miura.

(btw, the picture of the oil pan is with the skid plate removed, but its the thing hanging underneath the crossmember in the other photo)--Lee

@bosswrench posted:

Doug, over time I replaced the entire stock Pantera braking system and plumbing. It all started with the ridiculously small, heavy rear calipers & limited front brakes. A few years after we bought it in 1980 I added ATE's Porsche 911-S aluminum 2-piston front calipers to the rear along with what Wilwood called their 'cable operated spot brakes'-popular on go-karts, for legal e-brakes on custom brackets. My rotors are early Porsche ventilated. To balance the altered system, I removed the stock prop valve and added a Corvette/Kelsey-Hays adjustable prop valve in the rear plumbing, adjusted to lock the fronts first. Still works great.

On one trip to 'Vegas, Judy suddenly lost both front brakes in the stock master cylinder to wear. Except for a long travel brake pedal, the car drove normally in town & on the highway, using only the ATE rears. After we got home (550 miles!) due to cost at the time, I fixed it with Don Byers' GM power brake adaption. I removed the 'keep-alive' ball-check valve in GM's master cylinder for less pad drag. That master cylinder is dual bore size, neither one being exactly the same as OEM. GM's dual stage vacuum diaphragm is larger as well as being lighter overall. At that same time, I replaced the front Girling calipers with Wilwood Superlite lls that were 1/2 the weight with equivalent stopping power.

I also added dash-3 Aeroquip hoses & aluminum fittings for the entire car including the clutch. On gauges, I see 1150psi in the front brakes & around 1000psi rear in panic stops. All this actually fits together; I run 245-50 x 15" BFG Euro T/A front tires & 295-50 x 15" Pirelli P-7Rs, both V-rated, on 8" & 10" x 15" Campys, with Porterfield R4-S pads all around. Sadly, some of this stuff is no longer commercially available.

I admire your courage to go this on your own, so long ago. I went more traditional, if there is such a thing.

For me, there were few to talk to, which is why I talk to myself so often. I'm the only one who listens to me.

Without a closed track, to test safely, I'm concerned with adding more rear braking. The rear of the Pantera seems to be kinda' like a trailer you are pulling and you don't want it pushing or pulling back on the tow vehicle?

A dual bore size master is too complicated for me to conceive of. Even though Byers has credentials, I don't like being forced to accept others engineering decisions that I don't know what the repercussions of are? "Here, try this". Seems to sound like a drug pusher to me?

I appreciate the sharing of tech info such as the pressure readings BUT I should have taken stock readings first before I made changes.

I'm not sure I want to be able to lock up the fronts? I suppose that it is no worse then any other US production vehicle? The jury is out on that and I'm sure that is just an ever developing story as far as I go? Same as it ever was.

Engineers (which I am not BTW) have changed their views on braking in the last 20 years. I remember then era where front pads needed to be changed every 10,000 miles and the rears wether they were drums or rotors would last another 15.  Now a days manufacturers have changed the bias and usually all 4 corners are somewhat due at the same time.