VW T25(T3)-Tech - User contributions [en]

Parts - Modifications - Oil cooling

2025-11-03T21:10:38Z

2025-11-03T14:27:50Z

HarryMann:

'''Wiki explained,'''
*[[80-90 wiki sandbox|If you want to have a test your wiki editing skills you can do that here]]

Wiki is the Hawian word for quick. Have you ever visited a website after reading what it had to say and thought "yes, but you should have mentioned this aswell", Well a WIKI page gives you an oportunity to do this. At the top of every page and section it says edit in blue, click this and you have the ability to add text sound and pictures to the page. Generally editing someone elses edit is not considered good Wiki manners, unless you see something obvious like grammer or spelling, but generally you want to add to rather than take away from the Wiki.
Formatting of webpages is done with HTML, basically this determines the size and position of text and images. with WIKI a dfferent method for formatting what follows are some of the more common ones.

----

'''Formatting Text'''

generally speaking after you click edit you can just type away, if you need to make something bold put three
<nowiki>'''single quotes around it like this'''</nowiki>

and to break up sections add four ---- minus signs on their own, if you dont put a line of space between text it will run on continuously.
So this sentance would follows directly after the full stop above even though I pressed return once.

But this wouldn't as I pressed return twice.

If you cant be arsed and just want something up there as a one off mail your contribution to me and I will put it up for you, Its best if you send it as plain text either in an email or as a text file. If you have photos to add reduce to 640X480 if you can and RENAME them to something more descriptive like Camper-interior-Westy-joker1.jpg dont use spaces or underscores, then just put the name of the file in the bit of the text file where you want the image to appear with a line of space above and below, preferably number the photos in the order you want them to appear.

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'''Inserting an image on the WIKI'''
[[Image:Camper-interior-Westy-joker1.jpg|thumb|left]]
picture on the left was added by typing <nowiki>[[Image:Camper-interior-Westy-joker1.jpg|thumb|left]]</nowiki>
I have uploaded a picture to the WIKI using the "upload file" link on the left hand side of every page (under the search box), given it a descriptive name i.e. Camper-interior-Westy-joker1.jpg (underscores and spaces dont work well) then referenced it in my wiki page. I have added the "|thumb|left" to position it on the page and make it a thumbnail, although this is optional. The vertical lines you see in this link are acheived by pressing SHIFT and \ (bottom left on your keyboard). The 2 square brackets are to show that you are referencing something on the WIKI itself rather than on the internet in general which is covered in the next section.
.

.

.

----

'''Making a link to another URL (webpage)'''

[http://www.vwpix.org/eng/ | http://vwpix.terlinden.com almost every brochure and manual]

has been created in edit mode as

<nowiki>[http://vwpix.terlinden.com/index_en.htm | http://vwpix.terlinden.com almost every brocher and manual] </nowiki>

It seems best to leave a space before and after the | for the links to work properly, although you will end up with a | at the bgining of your link it seems necessary for it to work.

Diesel Engines Inj. pumps - AAZ pump adjustments

2025-11-03T13:11:56Z

HarryMann:

'''HarryMann:''' Inj. pumps vary a lot, even on nominally the same engines

1.9TD AAZs (usually from Passats) are excellent substitutes for the 1.6 JX TD in many T25s. There are a few gotchas, but here is a picture of a manually adjustable pump, with some notes for increasing fuelling...

[[Image:AAZ_Injection_Pump_new.jpg]]

1) The slotted screw that seems to give it real go and a bit of smoke (but raises the idle) 1/4 to 1 turn in (locknut is 13mm)
Main fulelling screw

2) & 3) Don't touch, provides reference face for dial-gauge timing adjustments

4)Solenoid for cold start advance (pulls a cable along engine side of pump which works a lever same side, small travel with adj. stop)

5) Lever boost enrichment (used to have something like this active from cab, when intercooler fitted, for towing caravan, kick-down)

?) Cover for blamked LDA vent.

On the top of the LDA diaphragm unit, selaed under a brass cover, is the boost enrichment spring pretension screw (setting the pressure at which boost enrichment starts?)

====

Main fuelling screw...

[[Image:Disel_Pump_Back_01.jpg]]

2025-11-03T12:39:43Z

HarryMann:

Syncro Speedo diff drive gear replacement

2025-11-03T12:39:18Z

HarryMann:

'''HarryMann/Ray:''' When your Syncro's speedo packs up, many look toward the cable breaking or the speedo head - which is rare.

I've known the speedo head to start clicking and the needle to jump around before packing in completely, but not the cable to break.
''But by far the most common cause seems to be the plastic drive gear within the front-diff, stripping a couple of teeth''
- easy to check... if you can get the large alloy nut undone that locates the cable into the diff. Don't crush this (its ally) unless you have a new cable anyway, so use plenty of brushing and plussing, and as thick a spanner as possible ( [[General Pipe spanners|a hydraulic split-ring spanner might be ideal]]) but I'm not sure of the size. As the front wheels won't turn together with propshaft on, then simply ensure top-end at speedo is NOT spinning when underway + PLUS + twiddling that end rotates the cable at the diff-end - bingo, say YES to both these and it's got to be the diff-drive thats broken.

The nylon gear inside the diff can be changed without removing or dis-assembling the diff. The plastic gear now only comes from VW as a complete assembly with the shaft, bush and bearings - ready to insert. A 5mm roll-pin, along the top of the cable attachment boss, aligned fore-aft, secures the gear/shaft/bush assembly into the diff housing. Remove roll-pin; remove old gear assembly (noting that couple of teeth at least are damaged, if not think hard!); replace gear assembly (in exact alignment for pin; replace roll-pin; replace cable (lube inner while have chance); connect back up at speedo, test drive!

There's two problems drifting the pin out. Access - to get a few good strong blows to get it moving; a drift 12~13" long allows a decent swing and strike. My parallel drift set had a 4.8mm drift that just didn't seem beefy enough to get it moving, and from what Ray says below, don't try anything much smaller than this else you could be swaging the hollow roll-pin out rather than drifting it out.

[[File:5mm_drift.jpeg]]

I found 15 minutes on a bench grinder was time well spent, whittling a suitably sized tapered punch down to just under 5mm over the first inch and being as careful as possible to keep it nicely round and concentric. Steel punches and drifts are often made from hex bar, so to get some extra length (bringing the striking face well aft of the diff support cradle), I had just to grind a shade off two opposite angles and then a bit of masking tape to pad it nicely in a 1/2 drive extension gave a tool that transferred the blow well enough to shift the pin on the second strike of a club-hammer. Must be held as near to dead-in-line as possible - some hoses neeed forcing back out of the way.
If someone offers to do this for you on a proper cylindrical grinder or in a lathe with a grinder attachment, specify 4.95mm +0.0/-0.05 as the finish size.

==Ray and Harry exchange some banter on doing this job==
Could be heaven (1 hour) or could be hell (a week or more?) - pick through this to make sure its somewhere in between.

'''Harry:''' Ray, I stripped two other diffs I have, both 5.43s and one was appalling, been right mullered around the boss and roll-pin area, so expected a stripped gear to come out... It did.

Second one, helluva job driving out roll-pin but gear assembly as good as perfict, so thats the one I put in today. Think they're about £80, and you can't buy just the gear anymore, whole assembly only. (over £100 now, check ETKA for the right one!!!, there are many and depends on both diff gearing and number of teeth on pinion).

'''Ray:''' I had a nightmare driving the pin out. I didn't realise it was a roll-pin and used a small drift which just drove the dirt out. The assembly would not come out so the bloke next door made up a puller for me which of course just broke the housing. I repaired that with araldite which is still OK after nearly a year and even after having a new VC fitted! The assembly cost £110 from Wayside Parts! Now I know what these roll-pins are like, todays one in the diff-lock came out easily with the correct size drift

'''Harry:''' Ah! Sorry to dredge up a troublesome saga then Ray.

I mole-gripped it, got a good purchase, made sure it would rotate both ways a bit, squirted a bit of plus-gas around and then used same grip to lever it outwards... mullered the thread though, but knew the unit was knackered and they come as whole these days.

Yes, 5mm for that one and 3mm for the difflocks. Too small and just tries to expand the roll-pin creating more bedlam. Even a genuine 4.8mm parallel drift wouldn't budge it, so made one up (above), and then I could finally get a good blow from a club hammer on it... moved immediately then.

Now that seems to be the trick... dead in line as poss (though not really possible on front diff) and a really hearty blow, anything less leaves it cold.

'''SyncroMonVie:''' I also unbolted and removed the mounting bar that supports the rear of the diff. This allowed me to get a better angle onto the roll pin.

'''NB.''' Might be worth changing diff oil afterwards, though the molten/sheared/ground up plastic teeth seem to disappear.

'''PS.''' As with all these jobs, good light and visual scrutiny of the point of impact (at the pin end) helps a lot. As does cleaning up the whole area beforehand... Strike that ally boss instead of the centre of the roll-pin one time too many and you may regret it. If the drift is bouncing around a lot upon impact -that's a warning sign - maybe not heavyweight enough blow or not directly in line. So a headlight is becoming an important part of the mechanics toolkit for working underneath. Vehicle needs just a gentle front lift for access to do this job, though get it on a lift and it'd transform the job completely!

File:Sudoku.png

2025-11-03T10:53:19Z

HarryMann:

2025-11-03T10:40:47Z

HarryMann:

Syncro Speedo diff drive gear replacement

2025-11-03T10:35:46Z

HarryMann:

Syncro Speedo diff drive gear replacement

2025-11-03T10:35:03Z

Syncro Speedo diff drive gear replacement

2025-11-03T09:44:03Z

HarryMann: Image not showing

'''HarryMann/Ray:''' When your Syncro's speedo packs up, many look toward the cable breaking or the speedo head - which is rare.

I've known the speedo head to start clicking and the needle to jump around before packing in completely, but not the cable to break.
''But by far the most common cause seems to be the plastic drive gear within the front-diff, stripping a couple of teeth''
- easy to check... if you can get the large alloy nut undone that locates the cable into the diff. Don't crush this (its ally) unless you have a new cable anyway, so use plenty of brushing and plussing, and as thick a spanner as possible ( [[General Pipe spanners|a hydraulic split-ring spanner might be ideal]]) but I'm not sure of the size. As the front wheels won't turn together with propshaft on, then simply ensure top-end at speedo is NOT spinning when underway + PLUS + twiddling that end rotates the cable at the diff-end - bingo, say YES to both these and it's got to be the diff-drive thats broken.

The nylon gear inside the diff can be changed without removing or dis-assembling the diff. The plastic gear now only comes from VW as a complete assembly with the shaft, bush and bearings - ready to insert. A 5mm roll-pin, along the top of the cable attachment boss, aligned fore-aft, secures the gear/shaft/bush assembly into the diff housing. Remove roll-pin; remove old gear assembly (noting that couple of teeth at least are damaged, if not think hard!); replace gear assembly (in exact alignment for pin; replace roll-pin; replace cable (lube inner while have chance); connect back up at speedo, test drive!

There's two problems drifting the pin out. Access - to get a few good strong blows to get it moving; a drift 12~13" long allows a decent swing and strike. My parallel drift set had a 4.8mm drift that just didn't seem beefy enough to get it moving, and from what Ray says below, don't try anything much smaller than this else you could be swaging the hollow roll-pin out rather than drifting it out.

[[File:5mm_drift.jpg]]

I found 15 minutes on a bench grinder was time well spent, whittling a suitably sized tapered punch down to just under 5mm over the first inch and being as careful as possible to keep it nicely round and concentric. Steel punches and drifts are often made from hex bar, so to get some extra length (bringing the striking face well aft of the diff support cradle), I had just to grind a shade off two opposite angles and then a bit of masking tape to pad it nicely in a 1/2 drive extension gave a tool that transferred the blow well enough to shift the pin on the second strike of a club-hammer. Must be held as near to dead-in-line as possible - some hoses neeed forcing back out of the way.
If someone offers to do this for you on a proper cylindrical grinder or in a lathe with a grinder attachment, specify 4.95mm +0.0/-0.05 as the finish size.

==Ray and Harry exchange some banter on doing this job==
Could be heaven (1 hour) or could be hell (a week or more?) - pick through this to make sure its somewhere in between.

'''Harry:''' Ray, I stripped two other diffs I have, both 5.43s and one was appalling, been right mullered around the boss and roll-pin area, so expected a stripped gear to come out... It did.

Second one, helluva job driving out roll-pin but gear assembly as good as perfict, so thats the one I put in today. Think they're about £80, and you can't buy just the gear anymore, whole assembly only. (over £100 now, check ETKA for the right one!!!, there are many and depends on both diff gearing and number of teeth on pinion).

'''Ray:''' I had a nightmare driving the pin out. I didn't realise it was a roll-pin and used a small drift which just drove the dirt out. The assembly would not come out so the bloke next door made up a puller for me which of course just broke the housing. I repaired that with araldite which is still OK after nearly a year and even after having a new VC fitted! The assembly cost £110 from Wayside Parts! Now I know what these roll-pins are like, todays one in the diff-lock came out easily with the correct size drift

'''Harry:''' Ah! Sorry to dredge up a troublesome saga then Ray.

I mole-gripped it, got a good purchase, made sure it would rotate both ways a bit, squirted a bit of plus-gas around and then used same grip to lever it outwards... mullered the thread though, but knew the unit was knackered and they come as whole these days.

Yes, 5mm for that one and 3mm for the difflocks. Too small and just tries to expand the roll-pin creating more bedlam. Even a genuine 4.8mm parallel drift wouldn't budge it, so made one up (above), and then I could finally get a good blow from a club hammer on it... moved immediately then.

Now that seems to be the trick... dead in line as poss (though not really possible on front diff) and a really hearty blow, anything less leaves it cold.

'''SyncroMonVie:''' I also unbolted and removed the mounting bar that supports the rear of the diff. This allowed me to get a better angle onto the roll pin.

'''NB.''' Might be worth changing diff oil afterwards, though the molten/sheared/ground up plastic teeth seem to disappear.

'''PS.''' As with all these jobs, good light and visual scrutiny of the point of impact (at the pin end) helps a lot. As does cleaning up the whole area beforehand... Strike that ally boss instead of the centre of the roll-pin one time too many and you may regret it. If the drift is bouncing around a lot upon impact -that's a warning sign - maybe not heavyweight enough blow or not directly in line. So a headlight is becoming an important part of the mechanics toolkit for working underneath. Vehicle needs just a gentle front lift for access to do this job, though get it on a lift and it'd transform the job completely!

File:15-syncro-prop-bush.jpg

2025-11-01T17:46:04Z

HarryMann: Picture 15

== Summary ==
Picture 15

Syncro prop shaft bush replacement

2025-11-01T17:45:27Z

HarryMann:

[http://www.syncro.org/DriveShaft.htm See this:]

Syncro Propshaft Poly Bush fitting
(to cure propshaft ringing at low speed/low revs clutch take up combination.)

'''Aidan Talbot:'''

September 2005

This is the new replacement Poly bush as supplied by Gordon Craig in South Africa.

[[image:1syncro-prop-bush.jpg]]

Note the flanged end on the left needs slightly profiling in order to fit the space vacated by the O ring - I lightly sanded the edges off to give a better profile and facilitate fitting.

[[image:2syncro-prop-bush.jpg]]

I found I needed to hold the whole donut in a vice in order to undo the four Allen headed bolts holding the UJ and donut to the propshaft.

Once the bolts are undone and removed recover the four washers from between the donut and the propshaft and gently withdraw the whole assembly to leave you looking at the o ring and the two bronze bushes inside the prop

[[image:3syncro-prop-bush.jpg]]

This is the UJ, donut and shaft assembly that you have withdrawn from the prop.

I marked the prop and the UJ with paint marks before disassembly so I could put it all back together in the same orientation.

I didn’t remove the donut from the UJ as no need - it only meant that I couldn’t take a close look at the wear marks on the shaft bearing surface at it’s outer end. But I could feel the play when the bolts were undone before withdrawing the shaft from the prop.

[[image:4syncro-prop-bush.jpg]]

[[image:5syncro-prop-bush.jpg]]

Close inspection shows the wear on the bronze bush - there’s a swarf edge on the lower edge and the top edge has taken the shape of the o ring , being removed below

[[image:6syncro-prop-bush.jpg]]

So you can see clearly the extent of the top bush which is to be removed.

I cleaned out most of the old grease then stuffed a clean tissue into the tube below the bush to catch the waste that will be created

Using an old chisel I cut two parallel score marks down the inside of the bush about 10 mm apart

[[image:7syncro-prop-bush.jpg]]

Then carefully tapped a small bradawl between the bush and the shaft between the scored marks and broke out this section of the bush in stages

[[image:8syncro-prop-bush.jpg]]

[[image:9syncro-prop-bush.jpg]]

Once the section was removed the remains of the bush were easily removed, a very little light filing required to remove the slight burr caused by the back of the bradawl. Turning the prop upside down and pulling out the tissue removed most of the waste, a blast from the airline and more careful cleaning ensured that the remaining lower bearing was free from debris and ready for some clean moly grease.

[[image:10syncro-prop-bush.jpg]]

[[image:11syncro-prop-bush.jpg]]

The remains of the old bush and the new one - I checked to see that it fitted over the shaft ok before I removed the old one..hence the spots of grease on it

With a little gentle persuasion the new bush is in.

[[image:12syncro-prop-bush.jpg]]

A bit more time spent profiling the top lipped edge would have resulted in a better fit on the left hand side but rather than damage the bush trying to remove it I applied a little more thumb pressure which evened it up to the point where I felt it was acceptable and I was able to ease the shaft in without deforming the edge.

[[image:13syncro-prop-bush.jpg]]
The wear pattern on the machined bearing surface of the shaft can be clearly seen....its very even and fairly minimal, hopefully the new top bush and some fresh lubrication will ensure that this contact point doesn’t become problematic. This shaft has about 112,000 miles on it and I expect that it’s the first time that it has seen daylight since 1989.

[[image:14syncro-prop-bush.jpg]]

I had no data for the torque setting for these bolts as this isn’t a normal procedure so I went with 33 ft/lbs which felt right and is the same as used for the drive shaft flange bolts which are a similar size and application. I didn’t use thread lock though there were clear signs that it was used originally. I’ll keep a close eye on the bolts tightness.

[https://club8090.co.uk/w/images/15syncro-prop-bush.jpg See this image:]

[[image:15-syncro-prop-bush.jpg]]

The Finished Prop ready for refitting
I didn’t have the prop rebalanced as the bushes weighed within a few grams of each other and are fitted close to the centre of the prop so I guessed the effect of the change to be negligible and I rebuilt the prop in exactly the same alignment as it was originally. I have marked it PB for poly bush. The red marks are the alignment marks I made at the beginning.

The newly bushed propshaft was carefully refitted to the van, checking the alignment of the gearbox, prop and front diff with a stringline...and the result is vibe free motoring and no more ringing prop at low speed/low revs clutch take up combination.

Syncro prop shaft bush replacement

2025-11-01T17:31:28Z

HarryMann:

[http://www.syncro.org/DriveShaft.htm See this:]

Syncro Propshaft Poly Bush fitting
(to cure propshaft ringing at low speed/low revs clutch take up combination.)

'''Aidan Talbot:'''

September 2005

This is the new replacement Poly bush as supplied by Gordon Craig in South Africa.

[[image:1syncro-prop-bush.jpg]]

Note the flanged end on the left needs slightly profiling in order to fit the space vacated by the O ring - I lightly sanded the edges off to give a better profile and facilitate fitting.

[[image:2syncro-prop-bush.jpg]]

I found I needed to hold the whole donut in a vice in order to undo the four Allen headed bolts holding the UJ and donut to the propshaft.

Once the bolts are undone and removed recover the four washers from between the donut and the propshaft and gently withdraw the whole assembly to leave you looking at the o ring and the two bronze bushes inside the prop

[[image:3syncro-prop-bush.jpg]]

This is the UJ, donut and shaft assembly that you have withdrawn from the prop.

I marked the prop and the UJ with paint marks before disassembly so I could put it all back together in the same orientation.

I didn’t remove the donut from the UJ as no need - it only meant that I couldn’t take a close look at the wear marks on the shaft bearing surface at it’s outer end. But I could feel the play when the bolts were undone before withdrawing the shaft from the prop.

[[image:4syncro-prop-bush.jpg]]

[[image:5syncro-prop-bush.jpg]]

Close inspection shows the wear on the bronze bush - there’s a swarf edge on the lower edge and the top edge has taken the shape of the o ring , being removed below

[[image:6syncro-prop-bush.jpg]]

So you can see clearly the extent of the top bush which is to be removed.

I cleaned out most of the old grease then stuffed a clean tissue into the tube below the bush to catch the waste that will be created

Using an old chisel I cut two parallel score marks down the inside of the bush about 10 mm apart

[[image:7syncro-prop-bush.jpg]]

Then carefully tapped a small bradawl between the bush and the shaft between the scored marks and broke out this section of the bush in stages

[[image:8syncro-prop-bush.jpg]]

[[image:9syncro-prop-bush.jpg]]

Once the section was removed the remains of the bush were easily removed, a very little light filing required to remove the slight burr caused by the back of the bradawl. Turning the prop upside down and pulling out the tissue removed most of the waste, a blast from the airline and more careful cleaning ensured that the remaining lower bearing was free from debris and ready for some clean moly grease.

[[image:10syncro-prop-bush.jpg]]

[[image:11syncro-prop-bush.jpg]]

The remains of the old bush and the new one - I checked to see that it fitted over the shaft ok before I removed the old one..hence the spots of grease on it

With a little gentle persuasion the new bush is in.

[[image:12syncro-prop-bush.jpg]]

A bit more time spent profiling the top lipped edge would have resulted in a better fit on the left hand side but rather than damage the bush trying to remove it I applied a little more thumb pressure which evened it up to the point where I felt it was acceptable and I was able to ease the shaft in without deforming the edge.

[[image:13syncro-prop-bush.jpg]]
The wear pattern on the machined bearing surface of the shaft can be clearly seen....its very even and fairly minimal, hopefully the new top bush and some fresh lubrication will ensure that this contact point doesn’t become problematic. This shaft has about 112,000 miles on it and I expect that it’s the first time that it has seen daylight since 1989.

[[image:14syncro-prop-bush.jpg]]

I had no data for the torque setting for these bolts as this isn’t a normal procedure so I went with 33 ft/lbs which felt right and is the same as used for the drive shaft flange bolts which are a similar size and application. I didn’t use thread lock though there were clear signs that it was used originally. I’ll keep a close eye on the bolts tightness.

[https://club8090.co.uk/w/images/15syncro-prop-bush.jpg See this image:]

[[image:15syncro-prop-bush.jpg]]

The Finished Prop ready for refitting
I didn’t have the prop rebalanced as the bushes weighed within a few grams of each other and are fitted close to the centre of the prop so I guessed the effect of the change to be negligible and I rebuilt the prop in exactly the same alignment as it was originally. I have marked it PB for poly bush. The red marks are the alignment marks I made at the beginning.

The newly bushed propshaft was carefully refitted to the van, checking the alignment of the gearbox, prop and front diff with a stringline...and the result is vibe free motoring and no more ringing prop at low speed/low revs clutch take up combination.