Unusual Fix Technique

I have a question. My daughters ranger wouldn't start and of course she is in another state. It was running fine when she parked. Then wouldn't even click. I had her try and jump it, she said they let it charge for a while and still no click. So i call roadside assistance to get the truck back to where she is staying. The tow truck driver listens to her symptoms and agrees it's the starter. Then he steps on the bumper and bounces up and down. Truck starts right up. He says that confirms the starter is bad. :confused: I could see moving the truck causing the position sensor, or neutral safety switch to move, but how does bouncing the truck prove the starter is bad?? (But cant argue with the results...)

The older Ford starter uses an actuator arm for engagement. It works from an electro-magnet pull. His bouncing got the arm to move so that it could engage more easily. Either there is a problem with the magnet or the arm itself. You can get a rebuild kit for the starter and fix it yourself, buy a rebuilt starter or buy a brand new starter. But before all that, take the starter into a parts store that can test starters. They will be able to tell you if it is good. The problem may be a relay that the bouncing jostled and not the starter, or something else.

DC motors armatures go "off center" when they wear out- this creates a dead spot- tapping on the starter (or blower motor- or fuel pump ) moves the armature back to center and it activates. I tapped on my chevy starter 6 times in 2 years before I replaced it when I had the money.

I've saved numerous tow truck tows by whaaaaaping the fuel tank to start a dead fuel pump this way. Blower motor do the same- but at least you can drive without a blower motor operating.