Manual Brakes will not lock up.

[CamaroJesse]

On my 67 Firebird i have The Right Stuff Signature brakes. 13 inch fronts and 12 inch rears. The system is manual with a 7/8 bore Wilwood master cylinder and Wilwood prop. valve. The car stops but not as well as i think it should. i am unable to lock up the tires even when its wet out. Even if i stand on the brake they wont lock. I dont know if it makes a differance or not but the pedal in the car is an automatic car pedal that was cut to work with the clutch pedal. the system bled fine and there is no air in the lines and all lines are brand new.

[GoodysGotaCuda]

Is your 7/8" wilwood master on the recall list? They recalled them for bypassing fluid, mine was sent in and rebuilt..

[dhutton]

Try a more aggressive compound on the pads.

Don

[cornfedbill]

Which hole are you using in the brake pedal lever? There are normally two holes, one for manual brakes and one for power brakes. The top is for manual, the lower is for power brakes. It changes the force at the master cylinder.

If there are not two holes, was the car a power brake car originally? If this is the case, you may need to change the pedal or drill the upper hole.

Just a thought.

[dhutton]

Hard to tell but those look like C5 front and metric (Cadillac) rear.

I had C5 front on a manual 7/8 Wilwood and I could just get them to lock up with a more aggressive than stock compound pad. Had LS1 rears on that car.

Don

[RobNoLimit]

If your pads are at a minimum of a 45 drag coefficient, it should stop fine on the street, and lock up. We need to stop confusing street systems with race systems, and understand what can be done for double duty systems. If everything in your system is installed, plumbed and bled correctly, you have a pressure problem. Or, lack there of. Here are some ideas to rattle around. 1. The use of the mythical "100 lb input" to map out a system is a joke. Stop using these numbers to compare with. Why? Go to the Gym, put 100 lbs on a leg press, sit in and lift it with just your foot/ankle. That's why. We don't press that hard on the street, even with a full hard stop. We're used to power brakes. We don't even drive like true GT drivers on the track. So, run your calcs with a lower number, and understand that this is the MAX, not the normal driving push (which is about half). 2. Do some reading to understand pedal ratios, and how to calc. them. It's easy. Yes, you may half to pull the pedal out of the car, but it's OK. BTW, stop looking at aftermarket "Race" pedal assemblies as the guide, you have a performance street car. 3. Understand that there is more than one way to skin cat, but not so with brakes systems, it's all math. Take a look at this chart, by moving the link mount hole appx 1/2" (givin a 14" pedal) you can add 200 psi to the output, with the same input. Yes, the pedal will not be as hard, but many times we find this gives the pedal more 'feel', and is easier to modulate.

[dhutton]

If your pads are at a minimum of a 45 drag coefficient, it should stop fine on the street, and lock up. We need to stop confusing street systems with race systems, and understand what can be done for double duty systems. If everything in your system is installed, plumbed and bled correctly, you have a pressure problem. Or, lack there of. Here are some ideas to rattle around. 1. The use of the mythical "100 lb input" to map out a system is a joke. Stop using these numbers to compare with. Why? Go to the Gym, put 100 lbs on a leg press, sit in and lift it with just your foot/ankle. That's why. We don't press that hard on the street, even with a full hard stop. We're used to power brakes. We don't even drive like true GT drivers on the track. So, run your calcs with a lower number, and understand that this is the MAX, not the normal driving push (which is about half). 2. Do some reading to understand pedal ratios, and how to calc. them. It's easy. Yes, you may half to pull the pedal out of the car, but it's OK. BTW, stop looking at aftermarket "Race" pedal assemblies as the guide, you have a performance street car. 3. Understand that there is more than one way to skin cat, but not so with brakes systems, it's all math. Take a look at this chart, by moving the link mount hole appx 1/2" (givin a 14" pedal) you can add 200 psi to the output, with the same input. Yes, the pedal will not be as hard, but many times we find this gives the pedal more 'feel', and is easier to modulate.

That grid is very useful. Thanks!

Don

[RSX302]

Just my 2 pennies but manual brakes have not worked for me on my Camaro that was 3800lbs with driver without going to high cF pads.(.65). System was 13" front rotors, 12" rear rotors. (front 4.03 sq in caliper on 3/4" a master, 8:1 pedal ratio) Medium pedal. This was with massive rotor wear and rear pad knockback

I currently run BP20 Wilwood pads ~.45 to .55cF (same brakes as above)on a hydroboost system with a 1.125 master that works well on a reduced car weight of 3700lb w/driver (4:1 pedal ratio, .75" pedal travel, light/medium pedal)

I'm thinking for a manual system to work on the street for me, the car would need to be 3200lbs w/driver. I would use 14" front rotors, 7/8 or 15/16" master with 6:1 ratio, 6 sqin area caliper, .5-.55cF pads. Kinda sounds like Ron Sutton's StopTech system!! Just need to be careful about rear brake pad knockback with the smaller diameter master..

[malibudave]

If it is wet out, you should be able to lock up a tire (unless you have some really good tires).

I would do the less costly stuff first before you change out any brake parts. The 7/8" bore master should generate enough pressure to make the brakes lock up in the rain.

Does your master cylinder hold pressure? If it doesn't, any brake change you make will be a futile effort to find out why your brakes do not get better. To test this, block off the outlets to the master cylinder using the correct sized plugs. Cycle you brake pedal. After a 2 to 5 cycles, the pedal should become rock hard. If it does not become rock hard, you master cylinder is bad regardless if it is new or not. If it does become rock hard, hold the brake pedal down for about a minute. If it sinks to the floor, it is bad regardless if it is new or not. If it holds pressure, move on to rebleeding the brake system.

Rebleed the system, but don't bleed the traditional way as sometimes not all the air will get pushed out. Bleed at each fitting in the brake system. Sometimes air will get trapped before the prop valve or right before the rear axle. In my opinion, you most likely have air before the prop valve (unless you have a bad master cylinder), but bleed at each fitting to make sure.
1. Bleed at the master cylinder outlets.
2. Before the prop valve
3. After the prop valve
4. Hose fitting on the frame above the rear axle
5. T fitting on the rear axle.
6. At each caliper following the RR, LR, RF, and LF bleeding pattern.

Also make sure your prop valve safety "switch" wasn't thrown (if the Wilwood prop valve comes with it). The safety "switch" will block off pressure to the front or rear depending on where the low pressure was. This "switch" is a safety feature in case you loose pressure in one half of the system, but will maintain pressure in the other half that didn't loose pressure. It may be that you are only using one half of your braking system. If you are getting pressurized fluid coming out at all four corners, your prop valve is set correctly.

Brake pads work well in a specified heat range. For the street, I would run a "street" pad that does not require a lot of heat to work well. The tradeoff to street pads is that they don't like a lot of heat and will start to fade with sustained high heat. If you take it to the track, install some track pads that work better when they are hot.

Let us know what you find.

[RobNoLimit]

Any fix on this yet?

[First Bird]

As Dave said, it's possible that your brake pads aren't getting up to temp. What kind are they? Have they been bedded in yet?