QuestionHi-
I just purchased a 1977 Chevrolet Stepvan Truck (Boyertown); 8 cylinders, 5.7L, 4BL 1 ton, forward control chassis, rear drum brakes.
I drove the vehicle directly to the mechanic for inspection because only 50 miles had been put on it since the last inspection in 2000; only 40k original miles.
The mechanic inspection report stated that the master cylinder was wet.
So...my boyfriend purchased a replacement master cylinder and installed it. Afterwards, without starting the vehicle he had me pump the brakes a few times. The brake pedal never really depressed.
Upon starting the truck...there were no brakes and the pedal seemed to be locked in an up position. He says it needs to be bled properly. But since the brake pedal won't depress at all...he tried to bleed the vehicle from underneath...unsuccessfully.
He now states that the brake booster is sticking and not pushing brake fluid to the vehicle and that I need to purchase a new brake booster.
Please help...it didn't seem like the booster was the original problem. Does his trouble shooting sound accurate? How do you properly bleed these brakes? Is there a way to adjust the booster so as not to purchase a new booster?
I appreciate all insight. Be blessed :)
AnswerGOOD MORNING SHAR,IF I WERE YOUR BOYFRIEND I WOULD REMOVE THE MASTER CYLINDER AND PUSH DOWN ON THE BRAKE PEDAL TO SEE IF THE PEDAL MOVES LIKE THIS..IF THE PEDAL MOVES LIKE THIS THEN I WOULD THINK HIS DIAGNOSES IS NOT CORRECT. WE HAVE TO BACK TRACK HERE AND FIND WHAT THE CAUSE OF THIS IS.SO WITH THE M/S NOT ON AND THE BRAKE PEDAL NOW MOVES WE HAVE TO ASSUME IT IS IN THE REBUILT M/S.HAVE HIM TRY TO PUSH THE PISTON OF THE M/S IN AND SEE IF IT MOVES LIKE THIS. IT SHOULD NOT MOVE IF THIS IS THE PROBLEM..ALSO DID HE BENCH BLEED THIS BEFORE HE INSTALLED IT..THIS IS VERY IMPORATANT. BECAUSE WHEN THIS IS MOUNTED ON THE TRUCK IT IS TIPPED FORWARD FROM THE FRONT, CAUSING TRAPPED AIR IN IT.SO BENCH BLEED THIS BEFORE INSTALLING IT..AIR IN THE SYSTEM WILL NOT CAUSE A HARD PEDAL... [[[[IF THERE IS AIR IN THE LINES THE PEDAL WILL BE SOFT AND DROP]]]].SO FIND OUT WHAT IS BINDING THIS AND GET THIS REPAIRED EITHER BOOSTER OR M/S.CHANCES ARE IF THE PEDAL WAS OK BEFORE THE NEW M/S I WOULD THINK THE M/S IS AT FAULT..BUT TRY WHAT I SAID FIRST.
GET BACK TO ME ON WHAT YOU FIND AND IF YOU NEED MORE INFO ON BLEEDING THE BRAKES[[WHICH YOU SHOULD NOT HAVE TO DO ONCE THE M/S IS BLED CORRECT..]]GOOD LUCK TO YOU,,TOM
PS/PS/PS/////JUST THOUGHT I WOULD ADD THIS TO MAYBE HELP YOU,YOU DO KNOW THAT THE BRAKE PEDAL WILL BE HARD TO PUSH DOWN WHEN ENGINE IS NOT RUNNING,,THIS IS NORMAL,BECAUSE THE IS NO POWER ASSIST LIKE THIS..BUT YOU STILL WILL BE ABLE TO PUSH THE PEDAL DOWN IT JUST WILL BE HARD..IT WILL NOT BE LOCKED UP HOWEVER...HOPE THIS HELPS,,TOM
