[urq] Locking diff actuators - some history of options

[Cody Forbes]

I'll hook mine up to the smoke machine next time I get a chance. I  
just figured that was the norm because all of the 6 5ktq's I've owned  
acted the same way.

-Cody (mobile)

On Feb 14, 2010, at 9:15 AM, Tony Hoffman <auditony at gmail.com> wrote:

> Cody, and all,
>
> I've owned over 10 Quattro's over the years, all the old two locker
> setup, with the exception of the V8. It has Torsen rear and an
> exectronic locker in the center.
>
> I'll have to 100% agree with Scott on this one. If your vacuum lockers
> aren't working properly, it's a vacuum issue. You have a leak
> somewhere, either the actuator on the locker, a line going to it, or
> something in the feed of the switch (including the check valve). Check
> the front actuator closely, I've seen them have a hole worn in them
> (don't recall from what) and slightly leak. That's on the disengage
> side of the center actuator on an 85-87 4000Q, BTW.
>
> Two of the ones I've owned had slow unlocking, and they both turned
> out to be a slight vac leak. One of them was the check valve. That one
> took half the trip back from WI to OK to unlock. If they are
> functioning properly, they are almost instant in their action. And, as
> Scott said, they are constantly held in place. That's a pretty big
> deal when you tear into one and see what the design is. I'd sure hate
> to have one slightly engaged on wet/gravel and hit the power hard. I
> can just imagine what it would do to the locking mechanism. The
> Germans tend to overbuild things, but even the strongest design is no
> good when abused.
>
> Tony
>
> On Sat, Feb 13, 2010 at 10:02 AM,  <qshipq at aol.com> wrote:
>>
>>  Cody, a properly working vacuum actuator is instant, with enough  
>> vacuum, btmt.  A second or so to turn on is normal, as the 2  
>> gearsets have to be traveling the same speed for engagement.   A  
>> mile to turn off, you have another problem, likely due to low  
>> vacuum.  First, make sure your ck valve is working properly.  I  
>> just replace them (Napa/autozone sells generics cheap).  Second,  
>> make sure you have no leaks in the vacuum system.  Old connecting  
>> rubber hose is the biggest culprit.  Then ck the actuator itself,  
>> it should hold vacuum on both nipples.  A strategically cracked  
>> housing can cause one side of the actuator to be good, the other  
>> not.  Lastly,  if running a lot of boost environments (track or  
>> mountains) find an old vacuum resevoir from any car (I like the egg  
>> crate style vw ones) and T it into the system.
>>
>  That actuator circuit is simple, bulletproof, and requires very
> little maintenance to function in a full race abuse environment.  btdt
>>
>> HTH and my .02
>>
>> Scott J
>>
>>
>> -----Original Message-----
>> Subject: Re: [urq] Locking diff actuators - some history of options
>>
>>
>> The only thing I see wrong with the vacuum actuators is that they  
>> are slooooowwww. My 5ktq takes a second or so to turn on, and  
>> sometimes takes a mile of driving to turn off. That doesn't do the  
>> job when you need it to turn off on corner entry then on again  
>> within a few tenths of a second.
>>
>>
>> -Cody (mobile)