the hubs Again.

Good afternoon all, after all the help i recd. from my last problem, i`m sure this will be a piece of cake!. Last week all was fine, this week she will not engage the front hubs. She being a 1999 model, manual transm... The 4wd green light is steady but the hubs are not engaging.After doing checks today i find the following.......no clicks from the hubs when engaging 4wd, but green light steady. All vac pipes are connected, i can find no leaks, small filter on vac system is clean, if i by-pass valve block connecting system directly to manifold depression i can hear hubs working both ways. Therefore my feeling is the fault is with a solenoid valve, OR, am i way off track.?? Just 1 more thing, after running engine, then turning engine off, then turning ignition switch on, if i select 4wd the green light does not illuminate !! where has vacuum from tank gone?? or is valve block causing this? Your thoughts will be much appreciated........I would like to retain the vacuum hubs, not go manual.

I had a problem with the valves sticking, search for my posts last year, or I will when I get home tonight.

Basically, the valves are 3 way affairs

The engine vacuum goes to both the normally closed ports and the tank all at once, the hub pipe goes to the centre and atmosphere to the lower port with a small filter on. When deactivated, the vacuum port is a dead end, and the centre and lower ports pass through. When activated, the vacuum and centre ports join together..

To activate the correct valve joins the centre port to vacuum for a few seconds, the other side of the hub has to be vented through the opposite valve. If the vacuum is held in the engage line the green light comes on.

A blockage in the pipes (unlikely as you tested the pipe) or a stuck valve would do what you say.

I squirted magic spray (GT85 likely) into mine and worked it about 500 times with a battery, and it started working.

so, next step would be to remove valve block assy, give it a good soak with freeing oil, then try connecting to 12v ??

That is what I did, although I just put a squirt of spray into the ports, rather than soaked it.

Sketch where the pipes and wires go go before you take it off.

IIRR, I had some trouble disconnecting the wiring plug from the valves, I think I had to lever a spring out.

thanks for the tips, i`ll try to get the valve block off tomorrow, and i`ll report back on findings..... Cheers.........

facade wrote: That is what I did, although I just put a squirt of spray into the ports, rather than soaked it.

Sketch where the pipes and wires go go before you take it off.

IIRR, I had some trouble disconnecting the wiring plug from the valves, I think I had to lever a spring out.

Yes I did too. I had to get a pick and lever out the metal retaining clip/bar on each.