ABS Bosch 5.3 Module

Discussion in 'General Technical Questions and Answers' started by N3IDT, Aug 4, 2008.

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  1. AUDI20V

    AUDI20V QRZ Member

    My email back from the Russian:

    Да, это алюминиевые провода и паять ихнадо с применением флюса для алюминия. Если такового нет, то алюминиевый провод надо как бы царапать медным жалом в канифоли. При этом температура дала не должна быть высокой, иначе сгорит весь флюс и эффекта не будет.

    Translated, he says that there exists special aluminum flux for soldering to copper. If you don't have it, he says that you can immerse the aluminum in flux, scratch it up, then solder to it. I tried the latter method with no success and will try the former next.
     
  2. N3IDT

    N3IDT Ham Member QRZ Page

    From a website on soldering. I have never tried this and I think it may cause long term damage to the board, but here it is:

    The rapid formation of an aluminum oxide layer and the difficulty in removing that oxide layer so the solder can wet the aluminum are the reasons for the use of flux. In “normal” soldering of copper, removal of the copper oxide is relatively easy with mild organic and inorganic fluxes. Aluminum oxide is not so easily removed and may require stronger fluxes such as an organic amine-based flux (up to 285°C), inorganic fluxes (chloride or fluoride up to 400°C), and complex fluoroaluminate salts (above 550°C).

    I have no clue what these are or where you can get them.
     
  3. AUDI20V

    AUDI20V QRZ Member

    The way I see it there are 3 methods to make the connection:

    #1. Use your silver epoxy. No idea how long this will hold. Very expensive.

    #2. Use special aluminum flux. No idea where to get this. Not tested.

    #3. Use regular flux and scratch up aluminum surface while covered in flux or oil so that it does not oxidize in air. Solder with regular solder in the air.

    I just acquired a bunch of these modules and I am going to try all three methods to determine which works best. Will report back.
     
  4. N3IDT

    N3IDT Ham Member QRZ Page

    Good Luck. It's been something like 3 weeks and my module is still functiong using the combination of standard rosin flux solder and the silver epoxy. I would not have used the epoxy if I hadn't broken two of the gold bonds. I can't see an easy way to solder those as they are so small. Repairing the pair of AL wires probably is best using a cleaning and soldering technique #3 that you are working on.
     
  5. AUDI20V

    AUDI20V QRZ Member

    In retrospect, none of these methods worked to any reliable degree. The silver epoxy failed to make a connection for VAG-COM to detect the module, the special aluminum flux was so corrosive that it ruined the substrate and destroyed the module, the traditional aluminum scratch method for pipe welding proved impossible on wires this small. Probably best left up to techs who have specialized repair methods (e.g., www.cheap-abs.com). For $99 they charge for the repair, hardly worth the hassle anymore.
     
  6. N3IDT

    N3IDT Ham Member QRZ Page

    I don't want to jinx anything, but my tin/lead solder and silver epoxy repair is still going since August 08. Hoping to dump the whole piece of junk before other expensive issues pop up.
     
  7. KI4KMP

    KI4KMP Ham Member QRZ Page

    May I suggest...

    A dab of silver conductive epoxy?
     
  8. N3IDT

    N3IDT Ham Member QRZ Page

    It has been 1 year and 1 week and my silver epoxy repair of the ABS is still holding. I have traded in my clunker astro van for a Nissan and now I get to drive my repair job with 86000 on the odo. If anything goes wrong with the repair and the car is wrecked, I will be first at the scene.
     
  9. WOLFSBURG

    WOLFSBURG QRZ Member

    Guys,

    Just wanted to thank you about the usefull info you posted about the module reparation.

    I got some more info there: http://forums.audiworld.com/showthread.php?t=1757414

    The guy there used silver epoxy as you did, and as I just did on my 2000 B5 Passat. Working fine so far, and is a very inexpensive alternative (30$CAD for the silver epoxy) compared to what I was asked for at the garage.

    I am leaving for V.A. Beach next week, driving all the way from Montreal. Will be a good test for the repair.

    I will post the result of my little trip when I come back.

    P.S.: If you attemp this repair, be VERY carefull not to break these little (microscopic) golden wires.
     
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