Diff-lock brackets come in two varieties, front bracket 40mm externally from the face of the bracket (that sits on the packing plate) to the top of the “legs” Late brackets are either front(shorter) or rear (Llonger) but the early can be used on either.
A medical syringe with needle full of plus gas gets it right where you need it, at any angle. You can also push it through the rubber boot so potetially could free a reluctant diff lock with out any dismantling. Just make sure to put the cap needle when not in use, I’m sure a vein full of oil wouldn’t do you any good!
Syncro starter motor
You need to remove the actuator to get the starter motor out basic order is thus inner CV unbolt. There may (should) be a 2 part rubber boot covering the plunger push it back to reveal the roll pin (3mm X 8mm). Drive out roll pin to release plastic body with friend holding other end with mag pickup tool or have a spare handy have a white sheet on the ground to prevent the pin bouncing off into oblivion. Remove bolts holding on actuator etos has them as M4 X 55mm. Remove the 2 “shackle”, bolts and remove circlip. Recover packing plate behind.
Starter motor as per 2wd except less space to get to bolts with the tight access of petrol tank.
Diff-Lock Actuator Parts:
* Vacuum Actuator (Throttle) Unit 251 711 822
* Vacuum Actuator (Throttle) Unit Bracket (Retainer) 094 301 142 £18-92
* Long thin bolt (2) secures Diff-lock unit (Throttle unit) to Bracket M4x55 N 100 538 01 £0-35
Being very small the heads on these corrode and get rounded off.
* Diff-lock electric tell-tale switch 013 941 521 A £11-96 (compression washer for above not supplied/unknown part no (being light alloys, the above two parts corrode very badly))
* Diff-lock electric tell-tale switch rubber Cap 191 919 459 £1-55
* Spring-pin (roll-pin) (3dia. x 10mm) – (Vac Actuator pushrod securing) N 013 294 2 £0-23
* Circlip (Ring) – Pushrod Bush Retaining N 012 417 1 £0-26
* O-ring for diff-lock pushrod bush (seals bush in transaxle or front diff unit) 19.7mm x 1.7mm O-ring N 902 621 01 £0-26
O-ring can easily get damaged (split) when freeing up a seized pushrod; some don’t replace hoping a small oil weep will stop it seizing up again).
Freeing-up seized difflocks
Aidan: There’s an ‘O’ ring on the outside of the alloy sleeve that seals it against the case and there’s the most expensive oil seal in the world on the shaft itself. There’s usully electrolytic corrosion in front of and just behind the seal, also certain chemicals seem to affect the seal and cause it to swell and deform (it’s square section twin lipped thing) and become jammed.
I recommend using gear oil as the lubricant, in through the tell tale hole and repetative manipulation in and out, with an allen key through the roll pin hole on a late (mid 86 build on) one. Early’s with the short pin are a pain to free, they are like the front one, you were lucky with that, when the front is bad it’s a diff out job; if you can’t free the rear insitu then it’s box out time to take the bellhousing off and strip the whole thing and do it on the bench. I have had to ream some sleeves they were that corroded.
They are splash lubricated with gear oil through a little hole with no drain, as the oil becomes cruddier the crud builds up and the lube fails. Salt water seepage from without and it jams shocked solid.
Diff-lock actuator strip-down (photo-article)
Diamond Hell: I had one of these on the floor today that needed to be stripped off and I had the camera handy, so you get some of this. Apologies about the state of it – blame Concorde, it’s his.
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.