viscous coupling testing best method?

Advise, whats the best method of viscous coupling?

& what should or shouldn't happen when I do it

thanks all!!!

that's what I mean, it drives pretty well except tight turns it drops the rpms like your in a gear too far up the gearbox, plus I found the tyres scrub on full lock so that will be adding to the issue & I will be sorting that issue pretty quick sticks!

but like i say in another thread my van don't seem to have a power steering pressure switch????





what I did today "wether" it was any sort of test was s follows

1. jacked the "back" of my van up on a flat-ish level-is surface

2. put two bricks in front of the front wheels

3. got in started the van, put it in gear & slowly let the clutch out

the result I got from doing the above was the clutch was nearly out all the way, probably an inch to an 1.5" away from fully released, then the van rpms dropped as it then wanted to drive/climb over the bricks in front of the front wheels

how does this sound to the more experienced with syncro's than myself???


my rear diff lock seems to work including the LED on the dash, although I'll probably change all the flexible tubing parts of the vacuum system, the operation is a little sticky but I'm going to take the diff lock switch out tomorrow & spray some wd-40 in there & also top it up with gear oil & see if that quickens the action - I'm rambling off topic again aint I,
I have niggling thing in my mid the front diff lock is not engaging, the LED stays flashing so I'll try to get my hands in to remove the front diff lock switch & get some gear oil in there also - fingers crossed eh!

so viscous coupling, keep me posted of methods of testing & if mine turns out to be foobared where can i get a new one??? recon??? who or what company is recommended???

thanks again!!!

Edited by covdubber - 10 Apr 14 at 22:42

It sounds about standard to me....they all scrub a little on tight turns and the locker will need a turn or differing wheel speeds to engage...the vw test method is...

Set the van in a brake roller ( or jack it off the floor using a central mounted trolley jack)

Engage g gear with engine at idle ( idle speed must be correct of course)

Van should sit in the rollers and not climb out untill a little more rpm is applied...if it comes straight out as soon as clutch is in then its a bit stiff...

Thing is with test it's not very calibrated...how much drag do the rollers have? How deep are they set and how far apart? but it gives an idea...I would say if you used a jack under the rear bash plate to get the wheels 1/2 " off the ground and but a brick under each front wheel it shoud sit at standard idle without being able to climb the bricks untill some revs are added...if it did it will fall off the jack of course...


So yours sounds almost ok....but what gear were you in? If you use first it will either stalk or climb out....G is much lower and therefore the output is a lot slower allowing the VC to cope with it...


Edited by max and caddy - 11 Apr 14 at 21:12

that makes perfect sense bud, if a bit nutty, definitely better than I could type it out!!!!!

when I tried it I was in 1st gear! also I had the jack at full height at the back if the van! & I'm unsure if my idle is correct as my van doesn't have a rpm counter, i'll hook one up & set it to factory! I have the front jacked up as I'm changing the front diff oil, well I was going to until I went to find the big hex to undo the drain plug, I can flippin find mine, in the minefield of crap in the garage

I'll redo the coupling test & video it & pop it up on here when I do it, should be able to do it next Friday or the weekend!

the front diff lock I will postpone checking/testing until I can drive the van on gravel or something, see if it engages/dis engages, in the meantime I'll get some gear oil where the diff lock switch is, get some lube in that hole

got my tax disk holder on it today & its insured so gagging to go for a spin to circulate the radflush trough the system ad the coolent ix in at present is ridiculously weak but the cooling system on the hole is in good order

thanks again max n caddy, quite enjoyed ya single cab syncro thread, quality panel work dude!