TheSamba.com :: View topic - Chris' Syncro Project. A bit of progress, a lot more questions!

Tue Mar 25, 2025 1:20 pm

I thought I'd gather all of my questions, issues, confusions, more questions and occasional progress into one thread.

I've owned a handful of Bay Windows(camper and non campers), along with a mess of campers(2 diesel truck campers and one sprinter), but Ive never owned a Vanagon or Syncro or TDI diesel. We live up in the mountains of PNW and four wheel drive is frequently required to access our home, almost always December to March, and Ive always admired syncros from a far and casually browsed them. This past December that search began in earnest and we found a van we thought would work down in CA. So we made our way down there, drove it, crawled over and under it, and struck a deal. It's a 87 Syncro Westfalia with a 1.9 AHU swapped into it. Lots of suspension/brake upgrades.

Being middle of winter we were cautious about the 600'ish mile drive back north through the mountains, but the weather window was amazing so we decided to give it a try. However a few hundred miles up the road we stopped for diesel and found she was leaking oil.

I couldn't see an obvious source of the leak, but it was substantial. So onto a trailer she went and a combination of uhaul trucks, a stop at my folks(where my pickup was waiting) and we got her home.

First order of business was dealing with the oil leak. I was never able to replicate the leak in the driveway, but I believe the ccv puck was the culprit. So I replaced the breather tubes, ccv puck, valve cover gasket(it was leaking a smidge). Then it was time for some driving to test her out. She got several 40-60 mile trips and the oil leak seemed to be resolved.

Unfortunately less than 2 weeks after buying her and resolving the oil leak I tore my rotator cuff and shifting into reverse was absolute agony. I tried a few errands and was being very careful about where I parked hoping I could avoid reverse, but reverse was needed. So she sat for almost 2 months.... I was able to do small jobs like replace all of the rollers on the sliding door, deal with the gasket on the engine compartment lid, replace struts for rear hatch, applied sound deadening material to some areas of the body.

Once I was out of the arm sling, I jumped back into the project. I knew the CV boots were torn and they would need attention.

First up was the passenger front. I got lucky and the outer cv came off with very little effort to spread the retainer clip. I found some scoring on the races, nothing terrible.

They probably would have been fine, but I wanted a fresh start. So I cleaned the axle shaft, sprayed it with some paint I had, and ordered a bunch of goodies from T3Technique.

Reassembling my first ever front cv axle shaft was pretty straight forward and went together well.

Tue Mar 25, 2025 1:27 pm

Getting ready to reinstall I noticed one of the bolts that connects the Burly upper control arm to the upper ball joint was shorter than the other...

Too bad I didn't notice that upon disassembly. Nearest hardware store is about 25 miles away, nearest auto parts(not great) store is 30+.

I got lucky with a ez out, and found a suitable replacement at the hardware store.

Passenger side is all back together now onto drivers side. Having removed and installed one axle assembly made this side significantly faster. First thing I noticed upon removal was the spacer for the inner cv joint was missing.

Oh yeah, and one of the two bolts that connects this sides upper control arm to ball joint was broken also....

That brings me up to speed for now. I can't think about the entire project, it's too overwhelming. Im working on a front to back approach! Trying to keep the projects manageable and celebrating each success!

Current priorities:
-Front differential isn't unlocking!
-Ordered a spacer for my inner cv, and then reinstalling drivers side axle assembly.
-Washer fluid pours straight onto the ground when I try to fill her up.
-The brake lines that immediately leave from the front calipers up front are in rough shape, replace those and flush system.
-oh, and I was hoping I just kept stepping in greasy snow and it was melting on my floor mat. But no, master cylinder/reservoir is leaking.

Tue Mar 25, 2025 1:39 pm

Wow you're #notafraidofit.
Perfect Syncro owner.

Quote: First thing I noticed upon removal was the spacer for the inner cv joint was missing.

Sometimes it's buried in the grease (in the flange) on the differential.
If it's missing..... the bolts will be shorter too, so you will need a set of longer bolts for when you put a new spacer in.
T3 has spacers.

I do NOT like the 26ft-lb, 10.8 allen bolts that Syncros came with (on the front inners).
I like 12.8s and 36 ft-lbs torque.

I really like T3's 12-point CV bolts set, they're 12.8 and you can torque them to the full 36 ft-lbs but be sure they're the proper length..
You will need to get a 12-point 8mm socket (or 5/16) for these bolts.
I like the "deep socket" for its length.
See this link: https://www.thesamba.com/vw/forum/viewtopic.php?p=10181374#10181374
55mm bolts shortened to 54mm is perfect.

You can see here, 55mm bolts (with 5mm Syncro spacer not visible) plus an extra 1mm washer.

==============

Save all those front outer CVs, kept organized with their original balls etc.
There's a LOT of miles left in them, especially if you renew the grease periodically.
You never know if the outer CVs will go NLA.
The list of NLA items waiting to brick your Syncro is growing.

You will torque the CV axle nuts to 258 ft lbs.
500 miles later the nuts will be loosened somewhat.
Probably not loose to the point where it damages your hub, but you don't want to get that loose (creaking).
OG hubs are NLA but you can get aftermarket hubs now.

So re-torque the nuts back to 258 and after retorque they'll probably stay at 258. You can try again 500 miles later just to be sure they didn't loosen.

If your wheels have a hole in the center it's much easier to check torque.

Also keep your long nuts. I read somewhere of someone stripping the short JP nuts.

Here's an image for your files, of the front hub construction.
I drew this in 2016 because I could not find an actual front hub diagram.

I was expecting someone, somewhere in the world, to post a "REAL diagram".

But its still.... AFAIK
(9 years later)
the ONLY cutaway diagram of the Syncro front hub that you can find.

Tue Mar 25, 2025 4:30 pm

Yeah what Sodo said.

Those CVs were just getting broken in. I’ll take them off your hands. 8)

Welcome to the club…

Tue Mar 25, 2025 4:39 pm

dobryan wrote: Yeah what Sodo said.

Those CVs were just getting broken in. I’ll take them off your hands. 8)

Welcome to the club…

They have been safely mothballed into my parts storage cabinet!

Tue Mar 25, 2025 4:59 pm

The passenger side came with this assortment of nut and washers. I opted for the new nut that came with the new outer cv and the thinner washer.

Regarding inner cv bolts, these are the bolts that came from t3. Standard hex, no prob torquing to the 33 ft lbs. Some of the bolts came out finger tight!!

Wed Mar 26, 2025 8:41 am

Subscribed 8)

Wed Mar 26, 2025 8:22 pm

Keep one of those outer Cvs with you. When the JP group units fail in Bumfuck somewhere you can slap it back in and keep going.

Like others here I would have put those back in use, I'd of swapped them side to side.

Looks like you've got your self a true project.

Stacy

Thu Mar 27, 2025 11:09 am

I had a little bit of time this morning to work on the van.

I got the new cv joints pressed onto the drivers side axle shaft and that is awaiting the new spacer from T3 for install.

My front differential is locked and won't unlock. I read somewhere about removing the actuator assembly and manually activating/freeing the rod on the drivers side of the case. I found the 10mm bolts that hold the assembly on but in my limited time I struggled to no success in removing them. There is a soft cylinder in between the two bolts that makes fitting a thin wall socket impossible and the small window I have for accessing with a combo wrench I can't get a grip on the bolt head.

Suggestions for removing those bolts, and Im hoping my thoughts of removing that assembly and freeing the actuator rod is correct.

While I contemplated the differential locking issue, I confirmed the fluid fill plug was capable of being loosened and then started draining the fluid. I will raise and lower the front end through out the day or so to try and get as much of the old fluid out as possible.

Final goal for today was to try and search out the brake fluid leak, I haven't had much time to search this out on the forums yet. The reservoir and master cylinder appeared dry. I couldn't get a good view of the brake booster. I have some aftermarket gauges mounted on top of the oem gauge cluster which complicates removing the gauge display for inspection.

I believe it's common for the master cylinder to leak into the brake booster, how can I diagnosis that?

Is going from the top the best way to access that area? Is it common for the brake boosters to leak fluid?

Thu Mar 27, 2025 11:27 am

Chris-a wrote:
I believe it's common for the master cylinder to leak into the brake booster, how can I diagnosis that?

Is going from the top the best way to access that area? Is it common for the brake boosters to leak fluid?

I started a thread asking about this a couple weeks ago and there might be some helpful replies in there.

https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

The booster will only leak fluid if the master is failing - the booster has no fluid in it during normal operation. BUT fluid can run down the outside and collect at the bottom of the booster making it look like its leaking. I found going in from the top after removing the air vent hose to be way easier than working from the bottom.

In my case, upon further examination, I'm hopeful it was just fluid leaking from old (but not THAT old) grommets that hold the reservior onto the master cylinder which then ran down the MC an onto the outside surface of the booster. I cleaned everything up good and am watching for more leaking.

Thu Mar 27, 2025 11:48 am

Project looks great!! Post a few pictures of the engine bay if you don't mind. I always like seeing how people get TDI's mounted and hooked up.

From that picture, your brake master looks good. But of course it is only one picture from one angle, so I may not be correct.

You also have a clutch master cylinder that could be leaking. Just look up underneath the clutch pedal and you will see it. From there you should be able to tell if it's leaking.

Thu Mar 27, 2025 12:19 pm

First off nice project! Next, are you sure the front locker is engaged? Is the steering extremely stiff (as in not being able to turn)?
If this this is indeed the case then be very careful trying to remove the front locking actuator! It's easy to break off the tip. Have you first made sure you don't have any vacuum leaks?

A inexpensive hand vacuum pump is very handy tool to help test the system and activate the locker actuators.
https://www.amazon.com/Performance-Tool-W87030-Aut...amp;sr=8-5
By attaching the supplied tubing to either nipple on the actuator you can bypass the Syncro's vacuum system and check if the shaft moves.
(It also works for brake bleeding)
Helps to have one of the front wheels off the ground to allow movement inside the diff so locking fork does not bind.

Don't try removing the assembly by undoing the bolts holding the bracket to the front diff!
You cannot remove the actuator without first removing the roll pin holding the rod to the locking shaft!
If you just undo the two screws holding the actuator to the bracket and try pulling on the actuator body it may be possible to pull the shaft out, but most likely you will break off the tip. Then you are faced with trying to remove the broken tip and will most likely end up having to drop the front diff for access.

Thread about damage:
https://www.thesamba.com/vw/forum/viewtopic.php?t=646777&highlight=locker
And Syncrodoka's thread with more pictures of both the external pin and the internal parts of locker shaft/fork (the rear, but basically the same). The thread is about completely replacing the shaft so a bunch of extra stuff but a very good read to understand what's inside.
https://www.thesamba.com/vw/forum/viewtopic.php?t=591023&highlight=

Here are a some pictures of what's there.

(This is the rear but exactly the same) If yours is still original the cover over the shaft may be this black rubber/metal ring arrangement. If so it will be a bit of a pain to remove but it is doable. You need to pry the metal ring far enough aside to get a small punch onto the roll pin. It's two pieces of tubing with the metal ring in middle covering the gap. Do all this with both bracket and actuator bolts/screws secure, you don't want any movement or you'll break the tip (you can kinda see a theme here :wink: ).

Here's what's under that cover (clear nylon tube replacing stock black bits) so you can see what needs doing. There is a very small roll pin capturing the actuator rod; it's slightly offset from center. In the picture you can see a drop of sealant used to plug the hole through the clear tube. The roll pin needs to be driven out with a small punch. It's very important to get the roll pin out far enough to allow the rod to pull away easily. If you force it you WILL break off the small tip. It's fragile. Also, the small orange bellow covering the rod is NLA and is also fragile.

Here's side shot showing the offset hole in the locker shaft and the roll pin location. Roll pin is 3mmX10mm (available from BusLab)

Here's a shot of the various parts (this is for a decoupler, but again they are all the same)

After you get the actuator removed from shaft you can get a grip on the locker shaft and with some lube work it in and out until it moves freely.
Reassembly of the actuator requires starting the roll pin in it's hole just enough to stay while you insert the actuator rod, then drive home carefully. This is where having the clear tubing makes life easier. Drill a small hole through the tube for the punch before assembly. Make sure tube is big enough for the orange bellows. Seal the punch hole with a spot of sealant.

Thu Mar 27, 2025 4:56 pm

MsTaboo wrote: First off nice project! Next, are you sure the front locker is engaged? Is the steering extremely stiff (as in not being able to turn)?
If this this is indeed the case then be very careful trying to remove the front locking actuator! It's easy to break off the tip. Have you first made sure you don't have any vacuum leaks?

THANK YOU for saving me from my own ignorance of the locker system! Im sure the locker is engaged, and its engagement was sporadic when driving. I was under the thought that the system only relied on vacuum to engage the locker, then I thought it 'sprung' back unlocked once vacuum was removed. Upon educating myself some more Im understanding that it requires vacuum for both the locking and the unlocking operations. Tomorrow I will inspect for vacuum leaks, Im anticipating finding one or more. Im going to bring my vacuum pump under there to test the system more thoroughly.

My memory seems to be that only one of the vacuum lines was actually attached to the actuator!

I stumbled upon this schematic on GoWesty I found helpful.
https://gowesty.com/blogs/schematics/difflock-deco...MaMyuic8E7

Thu Mar 27, 2025 5:05 pm

SCM wrote:
In my case, upon further examination, I'm hopeful it was just fluid leaking from old (but not THAT old) grommets that hold the reservior onto the master cylinder which then ran down the MC an onto the outside surface of the booster. I cleaned everything up good and am watching for more leaking.

That's where your's was leaking from?

Thu Mar 27, 2025 11:35 pm

Please do also check the filler port of your clutch cylinder, that broke on my Vanagon also leaving such a puddle, it's connected via a line from the brake reservoir too...

Fri Mar 28, 2025 9:06 am

Chris-a wrote: SCM wrote:
In my case, upon further examination, I'm hopeful it was just fluid leaking from old (but not THAT old) grommets that hold the reservior onto the master cylinder which then ran down the MC an onto the outside surface of the booster. I cleaned everything up good and am watching for more leaking.

That's where your's was leaking from?

It was definately leaking from there about 8 years ago when I last changed the grommets. It was a little difficult to tell this time as it appears the fluid dried up and it was difficult to track where it had dripped/ran. But there were traces.

Time will tell. The brakes felt great on the drive today.

Fri Mar 28, 2025 10:14 am

Chris-a wrote: Im sure the locker is engaged, and its engagement was sporadic when driving.

If it engaged while driving, that would be very scary as you wouldn't be able to steer. Are you sure it's not a bad spot in the steering rack, pump, or maybe the control arm ball joints?

If you remove the vacuum lines to test, realize that you now have a vacuum leak and your motor will die at idle. I swapped a whole motor for that lack of knowledge. :oops:

Fri Mar 28, 2025 1:05 pm

4Gears4Tires wrote: Chris-a wrote: Im sure the locker is engaged, and its engagement was sporadic when driving.
If it engaged while driving, that would be very scary as you wouldn't be able to steer. Are you sure it's not a bad spot in the steering rack, pump, or maybe the control arm ball joints?
If you remove the vacuum lines to test, realize that you now have a vacuum leak and your motor will die at idle. I swapped a whole motor for that lack of knowledge. :oops:

Yep, I'm still questioning the locker being stuck engaged. When the front locker is on the vehicle can only go in a straight line with very little turning available. You cannot drive a locked front diff on the road. It is meant only for getting unstuck in snow or mud/sand.
Is this how it acts?
If not it's something else. Are you trying to drive it without the front inner CV spacer? Maybe the CVs are binding?

I'm wondering if this may be a VC (viscus coupling) that is starting to fail in hump mode. A good VC should only impede steering a little bit (like turning in tight spaces) but a VC can fail two ways - open, which means it never engages - or closed, which means the VC has gone into hump mode and won't release.
The steering will feel very stiff but you can still turn.

If you have a VC that is failing closed it may not be completely locked up yet and might explain the on/off feeling you're getting.
Best way to tell is to drop the driveline and see if it still acts the same.
VCs can be rebuilt (it requires an expert to refill the special silicon fluid) and can be tuned to "stock", or "sport". Sport being a more aggressive VC that will engage quicker.

On the front locker:
Did the Syncro come from the factory with the front locker (Euro import) or did a PO install?
If it's an upgraded Syncro to front locker then careful attention needs to be taken about how the PO did the work. Factory front lockers came with a flashing warning light and a special lock-out knob. While you don't really need the flashing light a good upgrade should include the lock-out knob.
It requires the knob be pulled out and twisted a quarter turn to hold engaged. This prevents accidental engagement of the front locker while driving due to the total loss of steering while locked.

Here is the factory service manual from 1986. Disregard the middle bowden cable shown (also in that GoWesty diagram above) that system was never offered for sale to public. It was part of a "selectable" 4X4 system (solid shaft) that they dropped. But the rest of the manual will help. Aftermarket vacuum decouplers now sometimes occupy that middle position.
https://www.thesamba.com/vw/archives/manuals/1986_vw_syncro_service_manual.php

Another thought is this is a solid shaft equipped Syncro and it's engaged. This would give the same feel as a failed closed VC. In this case the decoupler would be at fault (if so equipped) for the intermittent action. Do you have three knobs? What did the seller have to say? If it has three knobs it could have either a VC or solid shaft depending how the Syncro was setup.
Maybe post a photo of the 4x4 control panel and the whole drivetrain.
Unfortunately there's no way to tell if it has a VC or solid shaft without looking inside the housing. Any receipts on work done or parts bought?

Fri Mar 28, 2025 1:35 pm

4Gears4Tires wrote: Chris-a wrote: Im sure the locker is engaged, and its engagement was sporadic when driving.

If it engaged while driving, that would be very scary as you wouldn't be able to steer.

I don’t think it would be going in and out. If its not working well the mechanism will be stuck one way or the other.
You would be physically unable to steer, to “park” on asphalt for example.
There is no question.

Feeling a drivetrain change could be “sport VC” that is engaging while hot, then disengaging. So in some conditions (like coming off the freeway) the VC is hot & aggressive. That could be the variance you noticed. It becomes difficult to steer and difficult to shift (or impossible). Then its less when cool.

If this is what you’re feeling, the effects will disappear entirely when decoupled (2wd).

Wed Apr 02, 2025 9:38 am

Quote:
Current priorities:
Washer fluid pours straight onto the ground when I try to fill her up.

Check out this thread for some ideas to repair and reinforce the windshield washer bottle.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

If your bottle has broken tabs this is a superb solution:
https://www.thesamba.com/vw/classifieds/detail.php?id=2311818