alternator light ?
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  1. #1
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    Default alternator light ?

    One of the 404's had the alternator light come on and stay on. (It's the modified 404 with the Bosch Alternator with an internal regulator)

    Understand this indicates there's no charge happening.

    What steps should follow to diagnose the problem ?

    All informed advice appreciated

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    John

  2. #2
    1000+ Posts robmac's Avatar
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    Quote Originally Posted by bahay View Post
    One of the 404's had the alternator light come on and stay on. (It's the modified 404 with the Bosch Alternator with an internal regulator)

    Understand this indicates there's no charge happening.

    What steps should follow to diagnose the problem ?

    All informed advice appreciated

    John
    With ignition on and engine stopped

    1) Disconnect the 'L" wire at the alternator and check the light goes out.

    2) Short the disconnected wire (from the lamp) to ground and check the lamp lights full brilliance.

    3) Measure voltage on "S" terminal on alternator with respect to ground
    Should battery voltage

    4) If all is well connect it up again and check brushes or replace regulator assy .

    I'm thinking it's a regulator faulty or a brush. Two screws removes the brush box and regulator to check brushes. Can do on the car if you have installed the reg at at 12:00.

    If it's not a worn out brush, just go to the wrecker find another alternator is my suggestion. For $30 you can get another alternator, less than spare parts.

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    Much appreciated Rob! (a job for the weekend)

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    Not wishing to lessen Robmac's advice in any way, but it crosses my mind that you may just have a 2 wire Bosch alternator which are a little less complicated than the 3 wire one he refers to. Either way you may find the following site a help.
    http://apps.bosch.com.au/AAExtranet_...n/altR11-0.pdf
    Whilst this applies to the 3 wire alternator the principle is the same for the 2 wire one.
    I would also suggest that you remove the alternator from the car as, whilst removing the cover, regulator/brush box assembly is easy, replacing the latter can be the cause of much swearing and blaspheming -- as well as broken slip ring brushes. With the machine on the work bench it is easy to utilise the 2 small holes on the sides allowing small probes to be inserted to keep the brushes in a retracted position which allows easy re-fitting.

    Pavel

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    Quote Originally Posted by Pavel Moore View Post
    Not wishing to lessen Robmac's advice in any way, but it crosses my mind that you may just have a 2 wire Bosch alternator which are a little less complicated than the 3 wire one he refers to. Either way you may find the following site a help.
    http://apps.bosch.com.au/AAExtranet_...n/altR11-0.pdf
    Whilst this applies to the 3 wire alternator the principle is the same for the 2 wire one.
    I would also suggest that you remove the alternator from the car as, whilst removing the cover, regulator/brush box assembly is easy, replacing the latter can be the cause of much swearing and blaspheming -- as well as broken slip ring brushes. With the machine on the work bench it is easy to utilise the 2 small holes on the sides allowing small probes to be inserted to keep the brushes in a retracted position which allows easy re-fitting.

    Pavel
    Pavel,

    It's the three terminal K1 *** Bosch off a Holden. It has both "S" and "L" , plus the main output.

    It has an integral regulator and brush box.

    The dead regs are a quite common failure mode on these machines.

    With the K1 models the brushes are a spring fit against the slip rings and part of the brush box assy. The entire brush box and reg comes off with 2 x m4 screws. Fitting the bb just needs gentle pressure to depress the brushes.

    If you have separated the two halves of the alternator you need to use a unbent paper clip to hold the brushes depressed.

    When I split the alternator , I always assemble the alternator with the brush box in the most accessible position. You get a couple of 120 degree choices.

    On a 404 the bb is easily accessible with the alternator on the car and you don't need to split the alternator nor stuff around with compressing brushes when you refit it.

    Although it's worth grabbing a copy of the pdf service manual you posted. It covers the K1 model alternator.
    Last edited by robmac; 27th March 2015 at 07:34 AM.

  6. #6
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    I stand corrected, Rob; obviously your have knowledge of Behay's car that I was not aware of. Since my car, a 505GTi with a 2 wire Bosch, is younger than his, I assumed that the up-date he referred too was the fitment of an internally regulated alternator, rather than an external one.
    Mind you; I would still prefer to bench check the machine. It seems a pity not to avail one's self of the opportunity to check the condition of the slip-rings; the continuity of the rotor windings: and, as well, the diode pack. Quite frequently, ad hoc checks, or replacements, consumes more time and money than it should: and adds to frustration.

    Pavel

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    Quote Originally Posted by Pavel Moore View Post
    I stand corrected, Rob; obviously your have knowledge of Behay's car that I was not aware of. Since my car, a 505GTi with a 2 wire Bosch, is younger than his, I assumed that the up-date he referred too was the fitment of an internally regulated alternator, rather than an external one.
    Mind you; I would still prefer to bench check the machine. It seems a pity not to avail one's self of the opportunity to check the condition of the slip-rings; the continuity of the rotor windings: and, as well, the diode pack. Quite frequently, ad hoc checks, or replacements, consumes more time and money than it should: and adds to frustration.

    Pavel
    I didn't intend to correct. I happen to know the alternator Bahay used.





    i

  8. #8
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    All's well with the 404 again.

    Followed your steps Rob and ended up swapping the regulator/ brushes from another Bosch alternator.

    The brushes that came out didn't look too short but the rearmost one had a weaker spring than it's mate. Is it worth replacing the brushes to have a good spare alternator on the shelf? Or would the regulator still be an unknown quantity in your opinion?

    Thank again for the advice!

    John

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    Quote Originally Posted by bahay View Post
    All's well with the 404 again.

    Followed your steps Rob and ended up swapping the regulator/ brushes from another Bosch alternator.

    The brushes than came out didn't look too short but the rearmost one had a weaker spring than it's mate. Is it worth replacing the brushes to have a good spare alternator on the shelf? Or would the regulator still be an unknown quantity in your opinion?

    Thank again for the advice!

    John
    I'd replace the brushes on the original provided they are very cheap and then refit the reg assy to car. That way you do a dynamic test.

    I'd carry the "spare" in the glovebox as belt and braces short term.

    When whole alternator has DIY wrecker value of $30 odd and are very plentiful you shouldn't feel too inclined to spend a lot of money on repairing one .

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