[hmedic]

OK guys this seems simple but not sure where to start..
- Installed Warn Free / Lock hubs
- Installed the caps supplied on the wheel housing and the other on the line on the truck.
- I believe 4x4 was working - never went off road tho, but light on dash came on
- yesterday tried 4x4 not engaging - NO LIGHT ON DASH either.
- Also noticed the vacuum pump that is always humming was not he other day when doing fuel filters
- another forum referenced to that pump as supplying the power to make the orig auto hubs work..
- do i need the vacuum to work to engage 4x4 now see i took them off
- is it supost to always humm?
- does the in cab switch run to vacuum or is it all electronic
- any thoughts on a starting point?

 

[drewactual]

man, I wish I knew more about this to help you out, but I do know this: The pump should only operate long enough to charge the system with pressure- continuous running indicates a leak. Mine likes to leak sometimes when it's really cold outside (like -20f or so) and during the first few (say ten to fifteen) minutes of operation, then whatever isn't sealed seals, and that's that...

 

[hmedic]

well now that it does not run all the time, I am wondering if I fixed a leak in the hubs when I capped the auto hub lines when installing the Warn manual hubs? seems logical - not figuring out where to start on the no engaging issue...

 

[fordsforever73]

Start with verifying the axle turns with the tire, when the hubs are locked. You can jack the front end up, lock the hubs and spin each tire. You should be able to see the axle shaft spin with the rotation of the tire. If that checks out ok, set the truck on the ground with hubs locked. Then reach under truck and try to spin the shafts with your hand or a small bar or screwdriver...they shouldn't spin (maybe slightly due to slop) much or at all. Check both sides!

Post your findings and I will add more...too long of a nightshift...need sleep! Lol.