[urq] Locking diff actuators - some history of options

[Cody Forbes]

Yeah, on the particular car of which I speak I can zig zag and do  
large figure eights all day long, but it still takes a good long time  
to unlock the rear.

-Cody (mobile)

On Feb 14, 2010, at 11:15 AM, "Louis-Alain Richard"  
<laraa at sympatico.ca> wrote:

> I'm sure you know it, but unlock can be slow if you have a tire of a
> different diameter on the car (wear, underinflation, etc) so even in a
> straight line, there is some rotational differentiation in the  
> driveline. On
> my urQ, unlock of center is instantaneous (thanks to the spring  
> Scott spoke
> of) but the rear usually needs to be helped by a little zig-zag.
>
> Louis-Alain
>
>
>
> -----Message d'origine-----
> De : quattro-bounces at audifans.com [mailto:quattro- 
> bounces at audifans.com] De
> la part de Cody Forbes
> Envoyé : 14 février 2010 10:17
> À : Tony Hoffman
> Cc : urq at audifans.com; bob at maxboostracing.com; quattro at audifans.com;
> qshipq at aol.com
> Objet : Re: [urq] Locking diff actuators - some history of options
>
> 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)
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