Proportioning Valves - Disc Brake Valves  - Proportioning  valves are used in  disc brake systems. The valve provides the correct pressure for front disc and rear drums. Four wheel disc valves are also available. The valves available are listed below. 

Proportioning valves come in all shapes and sizes and vary depending on the car you are working on and any modifications to the braking system. 

The first year for disc brakes on GM and Mopar products was 1967 and Ford was 1966. All American cars built prior to this had four wheel drum brakes. Disc brakes were introduced as an option from 1967-1972. Starting in the 1973 model year, front disc brakes were mostly standard and front drums were no longer available. When the disc brakes were developed, so was the dual master cylinders. Therefore, all 1967 and newer cars came with dual master cylinders from the factory. Disc brakes require different line pressures than drums, so the master was divided into two halves to provide pressure to the front and rear separately. This also meant that if a front line blew out, the car would still have pressure to the rear brakes and vice versa.

All 1967-68 GM factory disc brake cars came with dual piston calipers. If the car is a 1969-72 car, it came with single piston calipers. All aftermarket sets come with the later 1969-72 single piston calipers, but this is not technically factory correct for the 1967-68 cars. The single piston setup will bolt on the 1964-72 GM A-bodies, 1967-69 F-bodies, 1968-74 X-bodies and function perfectly.

The next issue is the prop valve. Since disc brakes were new in 1967, the valve was still being worked out for the next few years. The 1967-70 valves could comprise of as many as three pieces, and the valves would not work properly without all the pieces. In 1971, the valve was finally worked out and the one piece combination valve design was used on most cars from 1971 into the 1980s. This is why it is important to know what is correct for your car.  We have comprised a listing that is easy to follow and will make picking a valve for your car easy.

Distribution Blocks - Inline Tube Exclusive

1967-69 GM F -Body Camaro / Firebird 
1968-72 GM X -Body Nova / Ventura
1967-70 Chevy / GMC Truck

Part Number - PR109        67-69 F-body Distribution Block (Camaro / Firebird / Z-28 / Trans Am)  $85.00 ea 
                                       67 Nova / Chevy II,  68-69 X-body Nova
                                       Mounted on the master cylinder stud drum and disc cars
                                       Front to rear brake line fitting orange 1/2-20 thread

Part Number - PR110        70-74  X-body Distribution Block (Nova)                                          $85.00 ea 
                                       Mounted on the master cylinder stud drum and disc cars
                                       Front to rear brake line fitting blue 9/16-18 thread

Part Number - PR111        67 Chevy / GMC Truck Distribution Block                                        $85.00 ea 
                                       Mounted on the master cylinder stud drum brakes

Part Number - PR112        68-70 Chevy / GMC Truck Distribution Block                                    $85.00 ea 
                                       Mounted on the master cylinder stud drum brakes

Part Number - BRK08       67-69 F-body Distribution Block (Camaro / Firebird / Z-28 / Trans Am)  $18.00 ea 
                                       67 Nova / Chevy II,  68-69 X-body Nova, Mounting Bracket

Details:
Now Available 1967-69 GM F-body Camaro / Firebird Distribution Block: This block was used on all cars, either disc or drum. The block is bolted below the master cylinder. This is not a proportioning valve; it does not hold off pressure. If there is a loss of pressure in either the front or rear braking systems, it will activate the brake warning light in the dash. From 1967-69 and 1970-74, this block was used on all drum cars and with the round hold off valve at the master on disc brake cars in 1967-70. In 1971, disc brake cars used a different one piece valve and the drum brake applications continue to use the distribution block. This block provides equal pressure to the front and rear brakes and is also great for 4 wheel disc applications.

Also available is the 1967 and 1968-70 Chevy / GMC truck valve. All trucks came factory with drum brakes until 1970. The only option available was power or manual brakes. In 1971 all trucks went to disc brakes. All 1967-70 had drum brakes and all 1971-72 trucks had disc brakes.

These valves are exact reproductions featuring a cast body, the correct mounting bracket, black die body and fully functional internals. You will also find with our current manufacturing procedures, the reproduction has no tool stamping marks and the edges of the part are much cleaner than the original.

1967-72 GM A-body Distribution Blocks - Inline Tube Exclusive

Part Number - PR106        68-69 A-body Dist Block (Chevelle / GTO / Skylark / Cutlass)                $89.00 ea 
                                       Mounted on the driver frame rail of all drum and disc cars
                                       Front to rear brake line fitting orange 1/2-20 thread

Part Number - PR107        70-72 A-body Dist Block (Chevelle / GTO / Skylark / Cutlass)                $89.00 ea 
                                       Mounted on the driver frame rail of all drum and disc cars
                                       Front to rear brake line fitting Blue 9/16-18 thread

Part Number - PR108        67 A-body Dist Block (Chevelle / GTO / Skylark / Cutlass)                    $85.00 ea 
                                       Mounted on the driver frame rail of all drum and disc cars
                                       Front to rear brake line fitting orange 1/2-20 thread -  not pictured - No Mounting Bracket

Details:
Now available 1967, 1968-69, 1970-72 GM A-body (Chevelle / GTO / Cutlass / Skylark) Distribution Block: This block was used on all cars, either disc or drum, and is located down on the frame below the master cylinder. This is not a proportioning valve because it does not modulate pressure. If there is a loss of pressure in either the front or rear braking systems, it will activate the brake warning light in the dash. From 1968-69 and 1970-72, this block was used on all drum cars and with the round hold off valve at the master on disc brake cars from 1967-70. In 1971, disc brake cars use a one piece proportioning valve and the drum brake applications continue to use the distribution block. This block provides equal pressure to the front and rear brakes and is also great for 4 wheel disc applications. 1968-69 and 1970-72 are very similar valves except the fitting sizes change for the different year brake lines. This item is an exact reproduction featuring a brass body, the correct bracket, phosphate plating and fully functional internals. You will also find with our current manufacturing procedures, the reproduction has no tool stamping marks and the edges of the part are much cleaner than the original.

1967-70 Disc Brake Hold Off Valve - Inline Tube Exclusive

Details:
This item is an exact reproduction disc brake hold off valve. This valve was used to hold off pressure to the rear brakes so the front brakes would go on a split second before the rears. This was also considered a correction valve for the 1970 model year. During extreme braking conditions, this valve prevented the car from getting sideways and evened out braking loads. Inline Tube has reproduced this valve for every application. This item is an exact reproduction featuring a brass body, the correct bracket, phosphate plating and functioning internals. The reproduction has no tool stamping marks and the edges of the part are much cleaner than the original. When you expect the very best, Inline Tube is your first choice.

New Product - 1968-69 Hold Off Valve

Details:
This is the hold off valve that mounts on the stud of the master cylinder on all factory disc brake cars. It is used in conjunction with the distribution block mounted on the frame, which is the same on the disc and drum cars.  This valve holds off the front brakes to give time for the rears to activate. At a calibrated pressure, the valve allows fluid to pass and engages the front brakes. This all happens in a matter of seconds. This valve is the same on all GM cars, but the bracket is different for applications NOT listed below.

New Product - Brake Light lead wire

This is the connector and lead wire that is located at the top of the proportioning valve. 

71-81 GM Prop. Valve Bracket - F - X-body - Inline Tube Exclusive 

Part Number - BRK-05  1971-81 GM F - X-body Proportioning Valve Bracket     $24.00 

1971-81 GM F - X-body
Camaro / Nova / Firebird / Trans Am / Apollo / Phoenix / Omega 
Factory Disc Brakes

1971-81 F - X-body Disc Brake Bracket

Details:
This is an exact reproduction of the 1971-81 F-body, 1971-74 X-body & 1975 -77 X-body proportioning valve bracket. All F & X-bodies had this bracket for factory disc brake cars. In 1971, GM came out with the one piece proportioning valve and it was mounted using this bracket. All Camaros and Firebirds went to disc brakes, while on the Nova, disc brakes was still an option until 1975. Starting in 1975, all cars came factory with disc brakes. If you are converting your X-body to disc brakes, this is the bracket that mounts the valve in the correct location. This is a great restoration concourse item and can also be used to convert a 1970 F-body from the 3 piece valve to the 1971 one piece valve.

This item is an exact reproduction featuring the correct thickness of metal and silver zinc plating. You will also find with our current manufacturing procedures, the reproduction has no tool stamping marks and the edges of the part are much cleaner than the original. When you expect the very best, Inline Tube  is your first choice.

Large quantity dealer pricing is also available.

71-72 GM Prop. Valve Bracket - A-body - Inline Tube Exclusive 

Part Number - BRK-04  1971-72 GM A-body Valve Bracket     $22.00 

1971-72 GM A- Body
Chevelle / LeMans / Cutlass / Skylark / El Camino / Grand Prix / Monte Carlo
Factory Disc Brakes

1971-72 A-body Disc Brake Bracket

Details:
This item is an exact reproduction of the 1971-72 A-body disc brake bracket. All factory disc brake cars had this bracket to mount the proportioning valve to the frame. Drum brake cars did not have this bracket, only the front disc cars. If the car is being converted to disc brakes, this item is a must to place the valve in the right location so the factory lines will bolt into the correct location. Disc brake conversion companies use the wrong bracket that mounts the proportioning valve up by the master cylinder. All 1968-72 A-body cars mount the valve at the frame. The valve will only mount correctly with the use of this bracket.

This bracket may also be used if converting a 1964-70 A-body to disc brakes using the GM 5 port valve. Since 1964-66 cars were not available with disc brakes and 1967-70 used a two part valve one piece mounting on the frame and a second part at the master cylinder, this bracket does mount the valve in the proper location on the frame instead of up by the master cylinder.

Application List
Buick

Cadillac

Chevrolet

Chevrolet Truck

Oldsmobile

Pontiac

GM Valve Notes:
1964-66 cars all had a single master cylinder with drum brakes. There was no proportional valve and no disc brakes available in these years. The tee block that mounted to the frame served as the distribution block. When converting to disc brakes, the system will need a proportioning valve. This aftermarket valve mounts on the frame similar to the 1967 cars.

1967 was the first year for disc brakes for GM and Chrysler and 1966 for Ford. 1967-69 cars all had a dual master cylinder and were available in drum. If the car had drum brakes, there was a distribution block with a built-in brake warning switch. If the car had factory disc brakes, it used the drum distribution block in conjunction with a disc brake hold off valve, which made the disc cars a 2 part valve. For disc brake conversions, replacement aftermarket one piece valves are available, see listing above. This valve will NOT plumb into existing factory lines. 

If converting any of the above disc/drum cars into 4 wheel disc, Inline Tube offers a disc/disc valve that is identical to the disc/drum valve. This valve is metered for 4 wheel disc pressures and is $99.00.

Proportioning valve brackets are also available for all cars and trucks with disc conversions for $18.00.

Mopar - Jeep

Ford Truck

Disc Brake Conversion Valves & Lines

Street Rod

Street Rod Valve Notes:
The 5 port valve works great on factory cars that have been converted to disc brakes. The adjustable valve is designed for scratch built street rods and conversions using factory front brake lines. This valve is mounted in the front to rear brake line and controls only the pressure to the back brakes. The front brakes get full pressure and the rears are turned down until they do not lock up and provide a smooth stop. Adjustment depends on tire, caliper or rotor size and is different for all cars. Adjustable valves can also be used on factory or race cars to fine tune the rear brakes from locking up because of rear disc or mismatched components.

Residual Valves:
These valves are used in brake systems where the master cylinder is mounted lower than the calipers, typically under the floor. This is a check valve that keeps either 2lb (disc) or 10lb (drum) of pressure in the system to prevent the fluid from running back and overflowing the master cylinder. These valves should be mounted as close as possible to the master before the proportioning valve. These valves are not needed on firewall mounted master cylinders. 

Quick Tip - Prop. Valves

Different valves are used on different cars. If you are working on a production car (Chevelle, Camaro, GTO, Impala), the brass 5 port valve is usually the way to go. This valve is available for the disc/drum or disc/disc applications. It is intended as either a replacement valve or a valve for disc brake conversions. Adjustable valves are used in street rod applications (1930-50 cars) where heavy modifications have been made to the braking system, or for conversions that use the factory front line set. Adjustable valves are also used to tune in rear disc brake applications on production cars. (If your rear brakes are locking up, this valve allows the pressure to be reduced to even out braking.) Residual valves are only used when the master cylinder is mounted under the floor.  Two valves are required: one in the front and one in the rear.