For the uninitiated the diff-locks on a Syncro are an essential part of the off-roading toolkit that could be specified on a Syncro - they provide massively improved traction off road and enable that wonderful wheel-waving that is so characteristic of a Syncro when it's 'on one' off road.
The lockers are actuated by vacuum servos. These have a feed and return that are switched by the pull-out knobs on the dashboard. When one is actuated the actuator pushes in the pin, push the knob on the dash back in and the return pipe sucks to assist the spring to pull the locking pin back out. Dead simple and pretty damned effective..... if only they'd just used steel instead of steel and alloy on the locking pin...
Anyhow, if at any point you need to service the lockers, or remove the gearbox or front diff it's safest to remove the actuator and brackets. This means you won't snap the vacuum feed pipes or bend the brackets etc.
So, here's how to remove the little blighter:
First off gently pull the vacuum pipes. Make a note of which one goes on the outside of the van and which is pushed onto the inside of it - this is very important, or you will find your locker is on when the dash knob should be setting it to off!
There are two long 7mm headed bolts that you need to undo and pull out. This will release the body of the actuator, but NOT the pin! Both of the bolts are half undone in this picture:
when you've undone these bolts *gently* pull out the actuator until the piston is fully extended. It will stay in this position once pulled out.
Now what you've got to do is knock out the 3mm roll pin that is securing the locker actuator. At this point you may pull out the actuator and find it comes away in your hands! This means that someone's taken it off before and not known about the roll pin, go buy another actuator from VW and join us later...... sorry.
Here's the roll pin as you'll first get sight of it:
This is what it looks like if the rubber shroud is missing (don't cut it if it's intact!):
Again, be *gentle* with the roll pin - it should tap out easily.
After losing one of them what I do is put a magnetic pick up tool on the pin as I tap it out, this makes it very tough to lose! Do it something like this:
Now there are two 10mm headed M6 bolts that secure the bracket and.... HANG ON, come back, there's a circlip you've to remove,too. Here's the bracket with the bolts removed and circlip pliers in there getting ready to ping the circlip across the garage. The holes where the bolts were are arrowed:
You may find that the bracket isn't too keen to leave (see alloy/steel comments above). Gently moving it around and worrying it to and fro will release it after a while. Now there's just a packing plate to pull off behind this - looks like this:
Remove this and then drop the gearbox/diff. Both the front and rear lockers are pretty much the same. Annoyingly on the back locker you will probably need to remove the driveshaft to get the damned thing off, but that's one of those things that makes Syncros so special and makes us love them so..... or something.
Refitting is the reverse of removal, as they say.
As ever, comments and clarification requests welcome.
