brakes staing on

Do you have any issues with the front wheels locking up on hard braking or when braking and cornering? The reason I ask, is I am considering installing the prop valve on the fronts to prevent this reported occurance on cars with narrow front tires. I haven't personally experienced it, but mine will have much more rubber on the rear than the front. I'm running rear drums, front discs, and I believe it's a mustang master for disc, drums. I'm not real worried about anything else in my system, as designed. If anyone else can provide any wisdom on this topic, don't hold back! There are many theories and opinions, I like to hear experiences to help put it into perspective.

 

I have not done an hard braking yet and the weather today was not good for driving the T. I will have to wait until the weather improves to find out if I have the problem you suggest. That ma be awhile, the Wisconsin weather is unpredictable.

 

Fletch: my advice is try it without any 'valves' in the system first; you can always add one later, and many of the guys in St Louis have no problems running without any.

 

Hey Spanky. Where in St. Louis. I'm in Hazelwood. Perhaps we can meet up sometime and compare rides. My wife likes to cruise Forest Park.

 

I have slid all 4 tires before and I get about the same reaction from front & rear.....If I am on a loose surface then the fronts will lock up first if you stand on the brakes but if you don't get crazy they work fine....This setup works so much better than the disk/drum combo I had before.....I do not have any prop valve or Check valves in my system..........

Think about it this way folks, a brake system is a closed system and for anything to return to the Master there will have to be air somewhere in the far end of the system......If you have air and when you apply the brake pedal then you would see a fluid leak.....If you push the pedal with a check valve in the line then it would do what a check valve is supposed to do and not let the pressure to be relieved and the brakes would be LOCKED UP!....Does that not make sense........or is my common sense gone away.......

 

The force applied to the brake shoes/calipers comes from your foot pushing on the pedal, which is connected to a piston in the MC. This piston pushes a column of brake fluid through the lines, and restricting the flow at some point in the line reduces the force applied at the shoe/caliper, which is what the proportioning valve does. When you take your foot off the pedal, it returns to its original position, and the piston withdraws from the MC allowing the fluid to move back through the lines into the MC as the shoes/calipers retract. If I'm lyin' . . . I'm dyin' . . .

 

I might have to respectively disagree. If you are talking about the transition period while applying the brakes then you would be correct. But if you are talking about a steady state condition, then the pressure would be the same everywhere in the brake system.

 

From the CPP (Classic Performance Products) web site:
"The proportioning valve reduces the pressure to the rear brakes. Whichever type of brakes your vehicle has, the rear brakes require less pressure than the front brakes.
If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up."

 

Sorry if I misunderstood you! I took it to mean without a proportioning valve, a restriction would reduce the pressure.

 

No problem; sometimes I misunderstand myself!

 

Something that I haven't seen in this discussion is how a proportiong valve works , it's not simply a valve , it's a spring loaded valve [i.e. a regulator] that,s adjustable....so it can raise or lower the line pressure to the circuit it supplies....

 

I haven't seen any that raise the line pressure; all they do is lower the line pressure below the level of the circuit that you want to be dominant - in my case, the front brakes.

 

If the line pressure is 100 & the reg is SET at 50 , you would be able to raise or lower the pressure....[some things are lost in verbage LOL]

 

Just a thought.... maybe the answer is not to drive like a maniac in an over powered car.

 

Aw, Fred . . . where's the fun in that??!!

 

I agree, why have 400+ hp and not let em run a bit, lol...

 

Fred is the one that ran over a cop car! Lol

 

Maybe that is why my car's brakes work so good is my little 180 horse 289 is just right too NOT get me in trouble...........Damn I buy much less gas and get to the gas station right along with the Big Boys too......LOL...

 

I think the issue is more that these cars are so light, and most of these brakes are designed for cars that weigh triple.
It just makes things a little more touchy.

 

Rubicon...sounds like you found your problem.
Don't overthink things and take the fun factor out.

The old "you need them, you don't need them" argument about PV's and RPV's is silly.
There are so many variations within these homebuilt Hot Rods that the argument is totally pointless.
Some, like me, will find the need and make good use of the parts...others will have absolutely no need for either!

You CANNOT file all these cars into the same folder and make the blanket statement that the parts are either 100% required or 100% not required.

There are soooo many small differences between similar cars that there is no simple, easy answer.
Tire diameter, tire width, rubber compound VS road surface, rotor/drum diameter, self or non-energizing brakes, coefficient of friction of pad/shoe material, pad surface area, caliper style....it just goes on and on.

Put the car together with quality parts and test.
IF you need something added its not rocket science to make the change.