Wrecker Mystery

[bobr2004]

The boom on M-816 Wrecker just up and quit!? Can't find any thing broken in the drive shaft, no sign of any oil leak in the system and everything else works just fine. No boom action at all -- no rotate, extend, up/down nothing. Any clue here guys as to what it is?

 

[doghead]

Water in the oil, frozen?

Stuck open pressure relief valve?

 

[m816]

Check to see if the PTO is fully engaging. At all the connection points.

 

[bobr2004]

Thanks doghead, won't work in warm weather either. Where is pressure relief valve?

 

[doghead]

Well, the control valve body has a recirculation/relief valve on it. item 27 in this pic from the TM.

Have you read the -20 TM for troubleshooting the wrecker controls (I'm guessing it's covered there).

 

[doghead]

And to test the pressure,

 

[73m819]

sounds like the power diverter is out of gear to the crane pump, does the rear winch work when in gear, if it does, look at the shift to the diverter, then work towards the pump, is it making noise, if not, start from the transfer case pto back, see what is not turning

 

[dmetalmiki]

OIL level. Pump divider properly in gear (mesh) listen for "engine drop" when engaged in cab and on deck. (deck clutch ENGAGED?) Sometimes a "smart" pull on the engage lever gets it in mesh. NO FORCE just good HAND pull.

Make sure RPMs are up to speed. Underneath check shaft rotation. power divider drive.

If no result "crack" a hydraulic pipe connection. "check oil weep, spurt, flow."

if pump rotating Hydraulic relief valve.

Keep us posted.

 

[Csm Davis]

Bet it is a shaft not turning. I don't like it but you will have to get under the truck while it is running and look for turning shafts please watch and don't get to close to the turning shafts! There's a keyway in the shaft between the splitter and the first constant joint box, had me scratching my head for a few days.