4 x 4 system

Not sure if I should be starting a new thread or tagging this onto the one dated the 12th by myself. The issue relates to the 4wd system on my 2002 Jimny not working. I have ascertained that I have a vacuum to the front hubs on both vacuum pipes but the collars are not pulling on. I have removed the cover on the hub by removing the 6 hex bolts revealing the sliding splined collar inside. I can see how that operates and I can operate that manually and it seems quite free but it wont work via suction. This would indicate a lack of vacuum in the hub but not sure where the loss could be occurring. The strange thing is that both sides are not functioning. The wheel bearing is new so that shouldn't be a problem. Anybody ideas where the problem might be. Any advice would be greatly appreciated.

As I mentioned in your first thread read the guide Martin wrote in the forum. It explains it all in good detail better than snippets from us.

11/60 wrote: Take the flex pipes off the hubs one at once and very carefully clean out the ports in the hub with an air line don't go mad with it.

Do this with the black outer hub removed so the air has somewhere to go.

Usually changing the wheelbearing fills the small channels with grease and they don't work until cleared out.

Thanks for the advice given by you and other members ,I will use the air line as advised. Do the o rings and seal in the black hub that go over the end of the driveshaft in front of the bearing to create a seal ever need replacing Molecatcher

Hub cross section




The vacuum to engage the hubs passes through the hollow centre of the stub axle alongside the CV stub, and pulls the diaphragm (20) towards the CV splines. This needs the seal where the CV enters the hub, and the large thin oilseal working on the extended flange of the hub nut to be in good nick.

The disengage vacuum passes through the ball race, and needs the wheelbearing and seals to be in good nick.
Any obvious damage to the seals will help stop it working, there are bound to be some slight leaks with all the rotating parts though.
The teeny weenie ports block with grease when a new wheelbearing is fitted, and can't ever clear really, so have to be blown through (with the black outer hub removed)

Many thanks for the diagram and explanation provided which will be invaluable when fixing the problem. Really appreciate the advice given by everybody and I am well impressed with this site and members. Thanks again Molecatcher.