Thanks, Derek...i was days away from sending my VC to
Wheddle.  I will stand by until this develops a little
more.  Does your source do rebuilds???  I want my 4wd
back!
Yes, you get the VC award!
steve

Derek Drew wrote:
>
> I located this morning an expert who works at a manufacturer of viscous
> couplings. As part of a lengthy interview, he said these things:
>
> 1. The viscous coupling fluid goes bad over time when it acquires small
> metal particles from the surrounding metal and suspends these particles.
>
> 2. The process of having the fluid go bad is called "gellation" and was
> caused as a reaction causes a gas to be formed.
>
> 3. You can fix a VC by replacing the fluid with fresh fluid. You should
> also examine the condition of the plates.
>
> 4. The percentage of air in the viscous couling is critical, and the
> percentage is almost always a low of 80% and a high of 86%. He said that if
> you went above an 86% fill then you would have the VC activating on the
> highway during normal driving and a dangerous situation would exist. If you
> went below 80%, he said you might never achieve lockup, even when stuck. He
> said all these numbers are subject to investigation and confirmation, which
> he will try to give me in August after consulting with Europe to check on
> our exact unit. He said the probable range for our vehicles is 84% to 86%
> air--possibly closer to 86% for a vehicle intended to go off road as ours is.
>
> 5. He said a room temperature VC should *not* be under any internal
> pressure, and that it might be a simple fix to partly repair a VC to simply
> open up the bleeder holes and let the fluid under pressure in there out and
> then put the plugs back in and keep using the unit.
>
> 6. He said that he wanted to help us in order to keep VCs from getting a
> bad rap amoung OEM manufacturers. He said that even if his company did not
> make the SDP units themselves, his company would have an interest in
> helping us and making sure our VCs were not wearing out prematurely and
> that they were being rebuilt properly.
>
> 7. He said that if Wheedle and Oregon Transaxle were refilling the VCs
> without letting any air get into them (which both Wheedle and Oregon told
> me!!!) then the rebuilds from Wheedle and Oregon would be faulty. The
> symptoms would be early wear, intense heating of the VCs, and lots of
> premature lockup.
>
> 8. I observed that this might be the reason Wheedle and Oregon both told me
> they are moving to a lighter formula fluid--that they are mistakenly not
> adding the required 14% air and that they are not rebuilding the units
> correctly. The GKN official agreed that this is a logical possibility. He
> said the idea of a VC being 100% filled with fluid was something that would
> simply never be done under any circumstances. This statement tracks the
> statements of the engineer Wolfgang in Tim Smith's article from VW in 1979.
>
> 9.  I believe it is possible that after my guy checks with SDP that someone
> will shut him up and they won't talk to us any more.
>
> 10. He said the proper refilling procedure is to apply pressure at one
> little hole while applying a vacume at the other little hole .
>
> 11. He said the key to preventing the fluid going bad over time was
> additives in the fluid that his company routinely uses. He said it is
> possible that SDP does not use these additives.
>
> 12. He said the fluid gets hot and that this is what causes the lockup.
>
> 13. I asked him why the VC doesn't appear to have any air in it and asked
> him why it seemed to be 100% fluid. I asked if perhaps this was a special
> VC that required 100% fluid. He said that no, this would not be the case.
> He said that in manufacturing the air is added and then the air gets mixed
> up in the fluid and occupies the little holes between the plates of the VC
> and you cannot see the air any more.
>
> 14. He said not to quote him on any of this. I guess that means I should
> leave his name out. :-) I think what he really meant was that he wanted to
> investigate and confirm what he told me.
>
> CONCLUSIONS:
>
> a) Anyone with a bad VC should hault any work being done by Wheedle and/or
> Oregon until we resolve the issue of the % air.
>
> b) Anyone with a bad VC might want to simply vent it, reseal it, and reuse
> it, and see if that fixes the problem.
>
> c) Derek gets this week's "VC Award."
>
> At 11:13 PM 7/19/99 -0700, you wrote:
> >
> >Derek,
> >
> >at the risk of stating the "bleeding obvious", for the fluid to under
> >pressure there must be some "airspace" in the VC. Wasn't there some
> >discussion about whether the VC was completely filled with fluid or not?
> >
> >Alistair
> >
> >
>
> _______________________________________________
> Derek Drew                                            New York, NY
> CEO, ConsumerSearch
> drew@interport.net
>
> 212-580-6486
> 917-848-6425 (cell; this phone is a reliable way to reach me fast or to
> leave messages)
>
> Alternate numbers for the industrious phone caller that wants to try every
> avenue: 202-966-7907 (Work), 212-580-4459 (Home), 202-966-0938 (Home)