4x4 light flashing

Iv just used a mite vac at the hubs the hubs have locked but I can't get them to unlock I tried swapping the mite vac on the other pipe of the hub but it won't hold a vacum

Wheelbearings shot :huh:

If you can't raise a vacuum in the unlock pipe (the one buried under the brake calliper) the wheel bearing has gone and is leaking air at the inboard side.
If you can get a vacuum, but nothing happens, the pipe is blocked with grease from fitting a wheel bearing. Remove the hub and blow air down the pipe to clear it.

Remove the hubs and you can push the splined centre towards the outside, when it will click into place. You can then replace the hub and it will stay free.


For info:

The unlock pipe is under the brake calliper. It comes out between the wheelbearing and the hub seal on the inside, so the vacuum sucks through the ball race :ohmy:

The lock pipe is at the front half way down, and exits on the wheel side of the CV bearing. (if you nicely grease the CV bearing it blocks the pipe ) the vacuum sucks along the splines of the CV joint.

Is it the seal at the back of the bearing causing the problem

Yes, but usually the seal lasts forever unless something has got caught in it or the wheel bearing has gone.

You need a special tool with 4 pegs to undo the hub nut to get the hub off to check.

The 4x4 light has stopped flashing when the kingpin bearing was done the vac pipe must have been put on the wrong way. There is grease on swivel joint both side and both won't unlock If the bearing had gone would I not hear it humming

I've no idea what is wrong, you will have to check all the pipework carefully.

Start with the hubs locked, and turn off the engine, they stay locked.

Try and turn the hub, it should go a little each way taking up the play in the axle.
Remove both pipes, and attach your mittyvac (I use a 100ml syringe) to the spigot under the calliper (unlock)
Suck away and the hub should release, the wheel is free to turn. If it doesn't, and there is no leak (a vacuum is maintained) there must be a blockage or the hub is stuck. Remove hub and see if both spigots are free to blow down, or suck through.
If there is a leak, it has to be the rear oil seal or between the FWhub and the wheel hub.

Once one side is working, move round to the other side and check that one.


If both hubs check out reattach the pipes and start messing under the bonnet. Against the bulkhead are 2 metal pipes with rubber pipes attached that go to the vacuum solenoids. Attach the mittyvac to each of the metal pipes and see if the hubs operate, if not, check all the axle pipework for leaks.
If they do work, you can mess with the solenoids.

There is a vacuum pipe from the manifold that goes to the centre spigot of both solenoid valves, and to the vacuum reservoir. Suck away and see if you can get a vacuum in the tank. If not the tank is holed or the solenoids are leaking. (don't forget to check the one way valve is the right way round and working.)
The lock solenoid has a tee piece to the vacuum switch and to the lock pipework, the rubber pipes should be coded with white splodges of paint: mine was.
Turned out my lock solenoid was leaking when it was off, so I couldn't raise a vacuum in the tank to pull the hubs off, they would go on because the lock solenoid didn't leak when it was energised and the engine could suck a vacuum in about 5 seconds, giving me a 5 second delay between selecting 4wd and the light coming on,