Ford Motor Co., still reeling from last week's recall of 1.5 million Pintos and Bobcats, was hit again yesterday with an announcement that it is the subject of two more federal safety investigations.

In addition, the National Highway Traffic Safety Administration said it also was investigation steering problems with certain Fiat 128's and X-1-9's.

One new probe involves possible engine compartment fire hazards from alleged leaky fuel lines in 568,000 1975 and 1976 Ford Granadas and Mercury Monarchs.

A second investigation was announced into a suspected steering mechanism problem in 1.3 million 1973-1975 Ford Pinto and Mustang II models as well as Mercury Bobcats from the same years. The problem can result in a loss of steering, NHTSA said.

The Fiat cars are being looked at for possible front wheel bearings problems Some 21,000 vehicles are being investigated for the alleged hazard, which could result in loss of vehicle control because of wheel looseness, lockup or separation.

According to Data given the agency by Fiat, the Italian automaker has received more than 900 complaints about the bearing problem, although no deaths or injuries have been reported.

Fiat also reported 11,000 warranty claims regarding front wheel bearing failure, with replacement data revealing a failure rate of 31 percent on the bearings.

The Granada-Monarch fuel leakage problem can occur at the point where a small rubber hose connects the metal fuel line to the fuel filter, which in turn, is connected to the car-burator.

The Pinto-Mustang-Bobcat steering problem involves the steering coupling flange, which can loosen and allegedly allow the wheel to turn freely without turning the car wheels.

Drivers have complained that abnormal slippage appears first, and the steering is lost shortly thereafter. NHTSA's announcement said.

The point of the NHTSA announcement is to alert the public to look for these problems if they own the cars in question. No recall will be ordered until the investigation is complete.

Comsumers experiencing pr oblems can call NHTSA at the agency's tollfree hotline. 800-424-9393.