1994 GMC Suburban

DIESEL K2500 SUBURBAN. INJECTION PUMP SUFFERED A PROBLEM WITH INTERMITTENT FUEL CUTOUT. SOLUTION WAS REPLACEMENT OF INJECTION PUMP. REPEATED DEALER ATTEMPTS TO DIAGNOSE EXACT PROBLEM WAS NOT SUCCESSFUL. SEAT MOUNT FAILED. THIS CAUSED SEAT TO TILT ON BASE & TORQUE REMAINING MOUNTS. THE WIPER MOTOR CUT OUT AT RANDOM. GM ACKNOWLEDGES THIS PROBLEM FOR OTHER MODELS, BUT NOT FOR MINE. THIS WOULD CAUSE FAILURE OF MOTOR FUNCTIONS (IN MY CASE, THE WIPER WOULD NOT START IF PARKED, BUT WOULD START IF PULLED OUT OF PARK POSITION). BRAKES ARE THE MOST INTERESTING PROBLEM. WHILE THERE MAY INDEED BE A PROBLEM WITH PEDAL SUDDENLY GOING TO THE FLOOR I THINK THE ACTUAL SITUATION IN MOST OF THOSE CASES MAY ACTUALLY BE AS FOLLOWS. I HAD TO BRAKE FAIRLY HARD IN UNEXPECTED TRAFFIC, AND THE ANTILOCK BRAKE SYSTEM FIRED. I WAS MOVING NOT FASTER THAN ABOUT 50 MPH AT THE TIME, BUT IT TOOK (MEASURED) 642 FEET TO STOP THE VEHICLE. AT NO TIME DID I RELEASE THE ANTILOCK SYSTEM BEFORE THE VEHICLE STOPPED. DURING THIS TIME, I WAS ABLE TO STEER QUITE SUCCESSFULLY AROUND TWO STOPPED VEHICLES, AND TO RUN UP ON A GRASSY SHOULDER AND BACK ONTO THE PAVEMENT. I HAD THE FRONT BRAKES RELINED AND TRUED, AND THE FLUID FLUSHED AND REPLACED, AT A LOCAL SHOP SHORTLY AFTER PURCHASING THE VEHICLE USED (WITH ABOUT 56,000 MILES). APPARENTLY, GM KNOWS THAT IT IS NECESSARY TO CYCLE THE ANTILOCK MOTOR SO THAT ALL THE PISTONS ARE AT THE RIGHT POSITION BEFORE BLEEDING THE BRAKES. IF THE BRAKES ARE BLED WITH THE MOTOR NOT CENTERED, THE EFFECT IS THAT FULL MODULATION OF THE BRAKES DOES NOT OCCUR, FOR SOME OR ALL WHEELS, WHEN THE ANTILOCK SYSTEM FIRES. HOWEVER, THE DUMP-VALVE FUNCTION RELIEVES ALL BRAKE PRESSURE WHILE THE MOTOR IS RUNNING. THE RESULT IS THAT ONLY PARTIAL BRAKE APPLICATION IS EFFECTIVELY BEING MADE -- THIS MIGHT BE ALMOST ANY ARBITRARY PERCENTAGE OF A 'NORMAL' FULL BRAKE APPLICATION -- AND THIS MAY GREATLY REDUCE THE AMOUNT OF DECELERATION SEEN IN CRITICAL SITUATIONS.

HAD FAILURE OF BOTH REAR BRAKE LINES AND FUEL DELIVERY LINES/SENDING UNIT DUE TO HEAVILY RUSTED/RUPTURED METAL LINES. FORTUNATELY, THE FAILURES WERE OBSERVED IN MY DRIVEWAY, LEAKING BRAKE FLUID AND GASOLINE. THE VEHICLE REQUIRED TOWING TO THE LOCAL MECHANICS GARAGE.TOTAL COST OF REPAIR (ALL RUSTED LINES AND FUEL SENDING UNIT) AT LOCAL GARAGE WAS $875.00.*AK