Syncro Decoupler on the blink

[MTV1960]

The issue i had with the 3/4 clear tubing actuator plunger protector was that it seemed to hang up on the orange rubber boot because the shaft installs offset to the rod. so its not centering in the tube protector. May have to relook at that when i have it over the pit to pull the front axel and do the CV repack. Thanks
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86 Wolfsburg Weekender
87 Syncro Westy

[davevickery]

If you don't put something over the actuator shaft it can get crud all around it and stop working. At least some really thick grease would help. A pice of 3/4" pvc hose works and shouldn't affect movement.

The clanging might be normal depending what it sounds like. The inside of the shaft gets loose and "rings" a bit on some vans. Even aftermarket and donutness shafts do it. It does it more when you are lugging the engine. If that is what it is, no big deal. I once put a rubber donut over a shaft and it quieted it down a bit but it fell off eventually and I didn't worry about it again.

[MTV1960]

If any one is interested i fixed the issue with the front decoupler not engaging. No problem with any of the vacuum system not working. I removed the actuator and manually pushed in the shaft while slowly turning the front wheels until it locked and moved it back and forth a few times. Reassembled everything and got rid of the clear plastic tubing cover for the actuator shaft that also seemed to be part of the problem as the shaft was hanging up on it. Works awesome now. Now i have what sounds like a CV issue when the front is engaged and under load. clanking when gassed and nothing when coasting or not engaged. any advice here?
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86 Wolfsburg Weekender
87 Syncro Westy

[MTV1960]

Ok so I didn’t remove the actuator totally. I removed the mounting bolts that hold the actuator to the bracket then pulled the part off as far as it would allow and cleaned off the clear tube so I could see what was going on. Then sucked and blew through on of the hoses and the plunger moved in and out and moved the silver shaft part way in so I reconnected everything and drove it but no luck engaging unless the light is bad but I usually can tell if im locked in the front. Doesn’t feel like it. What do you think I should do at this point?
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86 Wolfsburg Weekender
87 Syncro Westy

[MTV1960]

Thanks for getting back so fast. Got the van up on a lift at the moment. I was taking it off to move it and check it out to why it’s not engaging the decoupler. All the hoses are in good shape so not sure what issue is. Was working perfect when parked 5 months ago. Rear works Fine.
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86 Wolfsburg Weekender
87 Syncro Westy

[davevickery]

[MTV1960]

I’ve got the actuator partly remove but it won’t coem all the way off. Is there a pin or screw in the shaft that needs to be removed so it will pull off? Thanks
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86 Wolfsburg Weekender
87 Syncro Westy

[Howesight]

I had a problem recently on my Syncro which has front diff lock, rear diff lock and a decoupler. All my actuators were replaced with new in 2012 and I added the dash vacuum switches for decoupler and front diff lock in 2012. This Van is garaged when not in use, so I did not really expect that the increasingly slow engagement of each of these three devices was due to the actuators. I suspected a vacuum leak and checked every hose and every actuator and the vacuum reservoir also. None were the problem.

It turned out to be two vacuum switches - - the ones installed new in 2012! The 30-year-old factory vacuum switch for the rear diff lock was fine.

The new vacuum switches now on the market seem less robust than the OEM ones. I broke open the worst leaker and examined it. There was no wear observable, so I suspect that the O-rings were of poor material.

Since we have no choice but to buy what is out there, I suggest that you remove the vacuum switch that is leaking (I tested mine with my gauged hand-operated vacuum pump) and try to soak your vacuum switch in ATF (auto trans fluid) overnight. You can use a small piece of vacuum hose to inject the ATF. The theory is that the ATF will expand the O-ring seals in the vacuum switch. I have used this trick in past to revive cruise control vacuum valves that were suffering vacuum leaks.
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'86 Syncro Westy SVX

[gears]

If you can suck air through the check valve in one direction only, it's OK (it's supposed to seem semi-restricted).

Leaky hose somewhere would be my next guess.
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aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[clift_d]

[MTV1960]

Any one headed to Costa Rica that can bring me a check valve and an actuator?
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86 Wolfsburg Weekender
87 Syncro Westy

[MTV1960]

Right, so your saying that you were engaged but the sensor was not sending so the light was not on?
Im pretty certain im not engaged at all. I dont here or feel any grinding on the gravel when making a turn. I have zero access to parts here in Costa rica. I know of a syncro club in Nicaragua that could have parts but its too far. Im going to drop the Rock guard and remove the actuator and see if i can clean it. All the tubing looks fine.

This country is harsh on everything made by man. Syncro is headed back north for a refit in April. FYI think twice about bringing down your Vans to this part of the world unless you have at least one spare part of every part on the van, and every tool you can think of. List of parts replaced since 2014:
-2 wheel bearings
-2-rear CV's
-Power steering rack
-front claiper
-multiple bulbs
-Shure flow faucet
-Aux battery
-Subi oil pressure switches
-Subi SS header
-head light adjusters
-fuel filter
-prop shaft yokes
-wiper arms
-Front control arm bushings
-Coolant expansion tank

Pura Vida! Good surf though!
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86 Wolfsburg Weekender
87 Syncro Westy

[MsTaboo]

Van-Cafe:
http://www.van-cafe.com/diff-lock-actuator-check-valve

And lots of other goodies:
http://www.van-cafe.com/diff-lock-actuator
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Currently:
'90 Syncro Westy 3 knob w/Zetec

The information age has morphed into the age of disinformation and willful ignorance. Agnotology!
When you stir up shit you're bound to get some on yourself.
Resist Kleptocratic Oligarchy (and Idiocracy)!

[clift_d]

Check it's not the decoupler indicator sensor before you go much further. This is similar to the reverse gear indicator sensor in that it is switched by a groove on the actuating shaft moving past the sensor. You should have the access to pull this sensor from the nose of the gearbox without too much difficulty which will then allow you to see whether the actuator shaft is actually moving or not. We had a similar issue a couple of years back when we were in Iceland, in that we thought our decoupler was sticking but it turned out that the indicator sensor was failing.
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1988 LHD T25 1.6TD Westfalia Club Joker syncro

[davevickery]

You should be able to suck and blow through just one but take both hoses off the actuator then it doesn't matter the position of the dash button. The "suck to engage" is the inner blue nipple on the spare I just checked.

Gears may be right about the check valve. You could remove it and see if it is working. I don't think you even need the check valve, there is always suction in the cannister so it doesn't ever get pressurized. But you could remove it at least temporarily.

[MTV1960]

Regards to the ck valve. i can move air one direction only but it not super open feeling. not sure if thats normal. Requires a bit to pressure to blow air past the valve. could that be restricting that system? I Do have a working rear locker and i think they share the check valve right?
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86 Wolfsburg Weekender
87 Syncro Westy

[MTV1960]

Ill give it a try. What would be the procedure for that? Suck on the top or the bottom? guess i need a length of hose thats long enough to work the front wheel at the same time. Would the knob need to be open of closed at the same time ?
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86 Wolfsburg Weekender
87 Syncro Westy

[gears]

For me, it's always been the check valve ..
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[davevickery]

They do get stubborn from lack of use. Maybe you can try working the actuator back and forth multiple times with a couple pieces of spare hose. Jack up a front tire and turn it slowly while sucking on the tube. You will know as soon as it engages as it won't turn any more. It does not take a lot of mouth pressure to activate them so if it does you know it is probably gummed up and you might have to take some of it apart to grease it up.

Every time my locker or decoupler started to give me trouble it was a crusty hose with cracks right at the nipple on the actuator. I cut off a bit of the end and back to normal. In one case I replaced a small section with some silicone hose. But mine are well greased underneath and I exercise them regularly.

[MTV1960]

Hi there, hope you can help trouble shooting an issue with my decoupler as it is not engaging. was working fine when parked 5 months ago. van is located in costa rica and was parked during the rainy season. rear locker works fine! a bit slow bit comes on in a min or so when pulled. What ive done so far.: Pulled off the check valve and sprayed it with WD40 and blew it out with compressed air. Has flow one direction. I can hear pressure at the dash switch when depressed. Then i pulled off the tubes at the actuator and sucked on both. one was holding and the other one was not until i pulled the knob then is was holding a seal one direction. could it be the actuator is bad by just sitting for 5 months? was going to remove it to inspect and clean it but thought i would ask a pro if that is possible to clean and reinstall or a waste of time. I dont have a backup part here in Costa Rica and would have to wait for some one bring one from the states. What do you suspect the problem is and if there is suggestion to try something now? pain to take down the rock guard if i dont have a new part or if that is that is te actual problem at all.
Thanks Michael V
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86 Wolfsburg Weekender
87 Syncro Westy