Vacumm Hubs Just For a Change

Hi, my Jimny has stopped engaging into 4x4 just now. The light has stopped coming on on the dash when I press the 4WD button I hear a click under the dash  make a noise then 3 secs later another click but nothing happens, if I press 4WD-L it beaps 3 times .I just changed the king pin bearings and checked the metal air intakes on hub and was able to blow air through them. If I pull the electrical plugs of the 4x4 near the actuator the green lights come on the dash.
I'm puzzled what this could be.

From what I understand when you press the 4x4 button, the transfer box moves first, then the solenoids initiate the vacuum to move the hubs.

This makes sense, it would be less likely to create a problem when moving if the transfer box had connected the front drive shaft first and certainly with mine, when in 4x4 the drive shaft is connected, it's the hubs that aren't moving.

It's much warmer here today, at one stage when trying the 4x4 the transfer box would engage and then the green light would flash. If I tried it again, I would get steady green, I am pretty sure the hubs didn't lock. I still think the vacuum is working on mine, it's just the lines are blocked/frozen or may be split and blocked.

I ordered AVM manual hubs this morning, we have a forecast for snow and I have a trip to make in a weeks time, so need to have 4WD working and this is going to be the fastest way.

I now you can leave the manual hubs engaged and switch between 2 or 4WD using the transfer box, but I guess it is best to stop first with manual hubs engaged, otherwise the front shaft and gears inside the transfer box will get a load shock?

Robin

For no 4WD light have a look here

www.bigjimny.com/mediawiki/index.php/4WD...ult_finding_overview

If there is no light or flashes once, the fault finding guide suggest a fault in the transfer box, transfer box switch or the fuse. If this happens, it returns the transfer box to 2WD and doesn't try the vacuum.

Finally my problem from the same guide, I might have faulty or sticking hubs, this would be great news if it is, but I really want to get 4WD working again and new manual hubs is still the answer even if I go back to vacuum hubs at a later date, or for the summer/normal driving and switch to manual hubs for the winter or when at an event.

Ok thanks for that Robin.I will go through what it says in problems 1 to 4 and see if it shows up anything similar to what it says. I've already checked the fuses and there all good.

Dr. Robin, it certainly sounds like you have a blocked hose. When you do come to replace the hoses I recommend routing them around the engine bay and down the brake hoses rather than the replicating the somewhat vulnerable standard route along the radius arm and then along the axle. To help keep track of which hose is which when doing this I cut the ends of the lock hoses at 90 degrees and the un-lock hoses at ~30 degree. It saves more problem solving when your hubs are clicking opposite ways, or when you have to pull the hub off at a later date.

Thanks for the advice, I will make sure I mark them up and route carefully.

Just out of interest how far do the hoses go back along the radius arms? I wonder if I might have trapped a hose when I fitted radius arm protectors?

If I replace the hoses, I assume it is best to put the T-piece joint at the top and run four hoses down, rather than putting a joint down below?

My AVM manual hubs are to be delivered today, but I have been going back through all of the tests I did and if it isn't the hose which is blocked I think both vac hubs might be stuck.

The problem is the existing hose is difficult to see and involves a lot of lying down under the car, whereas the hubs are relatively easy to change. I don't mind having a spare set of [manual] hubs, but need to get 4WD working for Xmas.

Robin