[urq] Locking diff actuators - some history of options

[qshipq at aol.com]

 Hmm... I've seen stripped gears because the dog clutch backed off due to a weak 'hold'.  IIRC, the locking ring is only about an inch thick if that, and partial engagement is a strain on all three gearsets.  They are beefy, but they do fail, btst.  A 100% locking solenoid can work, but I see the advantage going to the vacuum 'full hold' system here.  Or, take a design like a locker electric motor from any 90's toyota truck, as it's a worm gear actuator, which ring and pinion locks the hold position by definition, until you physically unlock it.

I give Audi a lot of credit for the vacuum actuators, especially when they added the electric controller box.  Quiet, simple, and strong as an ox.

Cheers

Scott J

 

-----Original Message-----
From: bob <bob at maxboostracing.com>
To: qshipq at aol.com
Cc: cody at 5000tq.com; larichard at plguide.com; laraa at sympatico.ca; vittorio at mybares.com; urq at audifans.com; quattro at audifans.com
Sent: Fri, Feb 12, 2010 5:00 pm
Subject: Re: [urq] Locking diff actuators - some history of options


  No, its not that critical at all. Theres plenty of leeway. Besides, ifthats a concern you can just power the solenoid for 100% duty cycle(with the right solenoid) and alleviate that problem.
Bob

qshipq at aol.com wrote:
  
 
  
  
 Theproblem I see with solenoids is that without constant tension on thatdog clutch, the timer circuit could be too late.  The locking gear isvery narrow, and very little 'relaxed' movement from fully locked onthe dog fork, could prove catastrophic.  Exploring a lot of optionsback in the day, I see no reason not to use the vacuum actuators withthe 'smart-box' found under the rear seat of any 91-94 rear quattro. It defaults to off when the car is shut off, has the 'smart light'system built into the switch and graphic panel, and has been in my 83urq without a single repair for almost 10 years now.  
  
BTW, I also looked at having the manual locking levers built, whichused spring tension and locking notches to keep the levers in theirlocked position.  At the end of all the research and futzing around, Idecided that Audi chose the right hardware for the job.  IME, the bestway to keep a vacuum actuator living a long life, is to replace it'smounting screws with stainless.  The biggest failure with the actuators(other than overconfident mechanics thinking they won't break off thevacuum nipples with a clutch change), is the rusy screws eventuallycause a crack in the housing, and it then fails.  I have severalactuators on cars over 10 years old, working just fine with SS mountingscrews.
  
More actualatorizing nerding
  
Scott J
  
  
 
  
  
 
  
  
-----OriginalMessage-----
From: bob <bob at maxboostracing.com>
To: qshipq at aol.com
Cc: cody at 5000tq.com; larichard at plguide.com; laraa at sympatico.ca;vittorio at mybares.com; urq at audifans.com; quattro at audifans.com
Sent: Fri, Feb 12, 2010 4:46 pm
Subject: Re: [urq] Locking diff actuators - some history of options
  
  
 Thatsexactly right... in version 1.0, when you hit the diff lockbutton the solenoid engaged, but I found that with an adequate floggingthey would eventually come undone.  Version 2.0 had a timer circuit init, that kept pulsing the solenoid a few times a second to keep itengaged, and it worked perfectly.
Bob