Balky dc brush motors

[junkhound]

In the category of "I should have know that!"

or at east tried it - technique to temporarily fix dc brush motor. 'foster child' (18YO) of son's family had borrowed my land rover. would not start for him at work, so called AAA I went down to wait with it till with AAA card till AAA showed up to tow. Told the dispatcher is had bad fuel pump (which I'd replaced 3 years ago) as had no fuel pressure at injectors. So AAA guy shows up with service truck but no tow truck, all busy and restricted to on road due to hot weather breakdowns. Tells me he probably cannot do anything I've not already done when he see I still drive an '84 truck, Show him my fuel gauge on injector rail shows no pressure and that I'd checked the fuse, etc, etc. . Says he: sometimes this works, and hauls a big wonkin' plastic mallet and ground pad from his service truck and whacks the fuel tank a few wollops. Wallah! fuel pressure shows, so I turn the key and she starts up. Told him that was a new trick for me, that I had whacked balky starters a few times in the past, but had never tried it on a fuel pump - assume enough shock wave in the fuel to move the brushes slightly I suspect. Gonna replace the fuel pump anyway.

 

[drcampbell]

Percussive maintenance is effective on a wide variety of technologies.

 

[electricman2]

I may be wrong but I would think that motor would be brushless.

 

[retirede]

I may be wrong but I would think that motor would be brushless.

Agree.
This was common on ‘80s vintage Chevy trucks. Whack the fuel tank and it starts. I had presumed that the issue was probably gunk in the pump that the blow would dislodge or relocate enough to get the pump moving.

 

[junkhound]

I may be wrong but I would think that motor would be brushless.

I would have thought the same thing.

Was at an elec machinery conference where I asked small dc motor company when dc brushless would totally displace brushless. His reply was 'erneve all the automated production machinery wears out" Cost of small brush dc motors is less than 50 cents over cost of raw materials that go into one.

Economics indicate that small brush motors are here for a LONG time yet. 12 v brushes in gasoline are not an ignition hazard .