All Plymouth Volares, Dodge Aspens, Chrysler Lebarons and Dodge Diplomats built before Sept. 23 - some 1.2 Million cars - are being recalled by Chrysler Corp. to correct potential brake defects.

The nation's third largest auto maker said Monday there were no injuries or accidents in 20 reported incidents in which cars lost their front brakes.

Chrysler said one defect involves acid leaking from the battery and eating through the brake tubes, causing a loss of brake fluid. The company said its dealers will replace the brake tubes if necessary and install a protective shield between the tubes and the battery cover at no charge.

In a second problem. Chryslers said front brake hoses which run from the tubes to the front wheel brakes may become brittle and crack in prolonged cold weather.

If trouble develops in the front brakes, the rear brakes will be enough to stop the car, Chrysler said, adding that owners should inspect brake tubes for signs of corrosion at the rear of the battery cover and inspect the brake hoses for visible cracks.

Meanwhile, Ford Motor Co. is recalling nearly 70,000 1977 and 1978 cars and trucks to replace faulty hose clamps and steering gear attachments, and British Leyland Motors is recalling about 5,000 1975 and 1976 TR-7 autos to replace defective accelerator cables.

Ford said the problems could create "the potential for an underhood fire" or a loss of steering. The company said no accidents or injuries have been reported because of the conditions.

Ford said the faulty hose clamps might be on about 49,700 Ford. Mercury, LTD 11. Cougar and Thunder bird passenger cars and Ranchero and F-Series light trucks with 351-and-400-cubic inch engines. Another 5,300 units in Canada and 600 in export markets were affected.

Ford said owners should return the vehicles to dealers for free replacement of a fuel line hose clamp adjacent to the carburretor fuel filter.

On some of these vehicles there is a possibility that improper hose clamp assembly could cause fuel leakage, creating the potential for an underhood fire," said Stephen Geoffrey, a manager in the parts and service division.

The problem was discovered in predelivery inspection of one of the models.

The British Leyland recall was generated by a U.S. National Highway Traffic Safety Administration investigaton of problems with the accelerator cable, which links the accelerator and carburetor.

"A partial cable failure may cause the accelerator to stick in the open position," said agency administrator Joan Claybrook. "A complete failure will result in the loss of engine power.

"Either failure is extremely dangerous," she said. "Drivers experiencing the partial failure should shift into neutral or turn the ignition off."

The agency said there have been four reported accidents associated with the cable defect, but no injuries.

British Leyland already has replaced 15,000 cables under a quality assurance program. It decided to launch the safety recall program after the agency began its investigation of the defect.

Claybrook warned: "I am advising the motor vehicle industry that any attempt to avoid a statutory responsibility for conducting a safety recall by conducting a less rigorous product improvement campaign will be considered a violation of the safety act and may result in injunctive sanctions and civil penalties."

Robertshaw Controls Co. is recalling about 20,000 demand valves because they have "potentially dangerous defects."

The valves often are used in resuscitation unit to control oxygen Pressure to a Patient. The firm said some may have leaks and if used could make it impossible for a patient to breathe through the valve.

The company said it sells the device across the United States and abroad for use by hospital, rescue squad, police and fire department resuscitation units during emergencies.

Thus far, Robertshaw said, no injuries have been reported from use of the defective valves.

A company spokesman said the leak was found during laboratory testing and that distributors and users of the device were being notified of the serial numbers of the defective valves.

The valves being recalled bear serial numbers above 28170.