4wd system

My 4WD system does not work and a Suzuki garage who came well recommended have told me it is uneconommic to repair.  I have looked at YouTube videos about rebuilding the ends of the axels etc and it looks straight forward so I am unsure what the problem is but if they are correct will fitting a pair of manual free wheeling hubs restore the car to 4wd?
Any advice welcome and appreciated.

There are numerous points of failure but things like the vacuum lines across the front axle - which rust merrily - apparently require genuine (expensive) Suzuki parts as they are not the same size as brake piping.  If the hubs aren't sufficiently airtight they can also require a total rebuild.

Basically, it is hard to narrow down the problem so most people plug the vacuum lines under the battery box and fit manual locking hubs.  The loss of convenience is not huge, as it is no real issue to drive in 2WD with the hubs locked if your journey varies between slippy and grippy surfaces.

i am quite sure that i should get it to work with other near same dimension pipes and hoses as long as it is approx the same volume and air tight. Cant see why not.
I like the vacuum hubs and do not miss having to dive into the mud or snow to engage the manual hubs on my SJ.
I am not put together so that I would remember to engage them before the need would occur more than once every leap year.

I read somewhere else it was 8mm pipe, screwfix do an 8mm copper pipe, no idea if it's suitable or not, but it might be with an investigation, I use it on my kitcar as fuel line.

I think (from memory) it is 4mm internal diameter pipe. My vacuum lines became blocked last year and after wasting hours trying to free them off I bought manual hubs and have never looked back.

Suzuki's arrangement of metal pipes and several flexible sections is horrible and I was going to get some lengths of coloured pipe, then put the T-piece at the top and run a separate pipe for lock/unlock to each hub in the summer so I could go back to vac hubs, but just didn't get round to it.

The pipe is very easy/cheap to get on eBay.

Robin

I took mine off the axle and made a copy with standard copper alloy brake pipe, it worked perfectly, IIRC, brakepipe is a slightly larger diameter, but the rubber hoses still push on ok. The difficult part is the Tee junctions, brake pipe Tees are expensive, so I made some up and brazed them on, I was brazing the fixing plates on anyway..

I have an idea that the old pipes are behind my toolchest, I'll have a look late and measure the diameter if they are.

You can replace the entire vacuum hose system with a better and more durable solution for under £15.
Buy 10m of 4mm id hose (I use PVC, some prefer more expensive silicon), 2x 4mm hose tees and a pack of cable ties.
Run the hoses from the vacuum solenoids around the engine bay, along the brake lines and down the brake flexis to the hubs. This is far preferable to the original convoluted and exposed hose routing.
Its a simple job that takes less than an hour.

If its the vacuum hubs themselves that are the problem (uncommon but it does happen) a working pair can be obtained cheaply and easily from anyone who has fitted manual hubs. The same goes for the vacuum solenoids.

Another simple option to get 4wd working is to permanently lock the vacuum hubs by driving a 20mm long self tapping screw through the centre of each hub. This pushes the collar into the engaged/locked position and holds them there. They then operate in the same manner as old fashioned drive flanges, or manual hubs being left in the locked position, with 2wd and 4wd being selected using the transfer case lever/buttons as normal.