E60 M5 alternator rebuild.
Discussion
My alternator appears to be playing up, so I have ordered parts to rebuild the slip rings and brushes.
This is a £25 and couple of hours work job, rather than the £600+ that BMW want for a replacement alternator..
Has anyone got an old alternator that I can rebuild and then just swap it in, rather than have the car off the road for a longer period (especially if I manage to mess it up)?
TIA - Simon
This is a £25 and couple of hours work job, rather than the £600+ that BMW want for a replacement alternator..
Has anyone got an old alternator that I can rebuild and then just swap it in, rather than have the car off the road for a longer period (especially if I manage to mess it up)?
TIA - Simon
Likewise would be interested in the symptoms.
Mine has the annoying battery discharge/ clock reset issue.
Stealer plus an independent have had various goes at fixing it replacing the battery strap and IBS but neither cured it and cant face the cost for them to tell me its my aftermarket amp again (it occurred before the amp was installed and also whilst the amp was fully disconnected so clearly not that!)
Other than the clock resetting or the occasional battery discharge warning whilst sitting with ignition on but engine not running no other symptoms.
Mine has the annoying battery discharge/ clock reset issue.
Stealer plus an independent have had various goes at fixing it replacing the battery strap and IBS but neither cured it and cant face the cost for them to tell me its my aftermarket amp again (it occurred before the amp was installed and also whilst the amp was fully disconnected so clearly not that!)
Other than the clock resetting or the occasional battery discharge warning whilst sitting with ignition on but engine not running no other symptoms.
Undercharging mainly.
The last battery was failing and I got a couple of low battery errors.
The new one has been fine, but it hovers between 11.5 and 12v when I switch the ignition on.
It can take 10-15 minutes from startup before the alternator decides it will kick in and go above 12v. Once it is charging, it shows 13-14v consistently.
I know about recoding when replacing a battery and still have to tell it the new type (but have updated the change date), but the alternator should start charging within a few seconds. The fact it can push out a stable 14.2v shows the alternator is capable of output.
Searching online, the main cause for failure of Valeo alternators is brushes.
Occasionally, the slip rings wear badly.
I found a great set of youtube videos by an alternator remanufacturer in Ireland. He said that Valeo alternators almost never fail as such, it is just the brushes wearing and they are an easy fix. He also goes through changing the slip rings, if they are significantly worn.
The brushes cost under a fiver and can be replaced simply once the regulator is removed. You can take the regulator off without removing the alternator.
Changing the slip rings is more involved and needs the alternator removing in order to partially disassemble it on the bench.
I have bought a rebuild set from him, which includes brushes, slip rings (just in case) and bearings. If I decide to do the slip ring, I'll swap the rear bearing as well, as you need to remove it to get at the rings. Came to about £20 for everything, including delivery.
The last battery was failing and I got a couple of low battery errors.
The new one has been fine, but it hovers between 11.5 and 12v when I switch the ignition on.
It can take 10-15 minutes from startup before the alternator decides it will kick in and go above 12v. Once it is charging, it shows 13-14v consistently.
I know about recoding when replacing a battery and still have to tell it the new type (but have updated the change date), but the alternator should start charging within a few seconds. The fact it can push out a stable 14.2v shows the alternator is capable of output.
Searching online, the main cause for failure of Valeo alternators is brushes.
Occasionally, the slip rings wear badly.
I found a great set of youtube videos by an alternator remanufacturer in Ireland. He said that Valeo alternators almost never fail as such, it is just the brushes wearing and they are an easy fix. He also goes through changing the slip rings, if they are significantly worn.
The brushes cost under a fiver and can be replaced simply once the regulator is removed. You can take the regulator off without removing the alternator.
Changing the slip rings is more involved and needs the alternator removing in order to partially disassemble it on the bench.
I have bought a rebuild set from him, which includes brushes, slip rings (just in case) and bearings. If I decide to do the slip ring, I'll swap the rear bearing as well, as you need to remove it to get at the rings. Came to about £20 for everything, including delivery.
The voltage regulators fail as well. They're connected to the ECU via the CAN bus - an ECU tells the alternator what to do rather than the alternator deciding for itself. They can be replaced for about £60 without pulling the alternator but they are a bit fiddly to get at.
Failure mode I saw was voltage spikes to 17-18 V causing systems to momentarily shut down and reboot.
That your car eventually charges fine but takes some time to do so makes me wonder more about the voltage regulator rather than the slip rings?
Failure mode I saw was voltage spikes to 17-18 V causing systems to momentarily shut down and reboot.
That your car eventually charges fine but takes some time to do so makes me wonder more about the voltage regulator rather than the slip rings?
AW10 said:
The voltage regulators fail as well. They're connected to the ECU via the CAN bus - an ECU tells the alternator what to do rather than the alternator deciding for itself. They can be replaced for about £60 without pulling the alternator but they are a bit fiddly to get at.
Failure mode I saw was voltage spikes to 17-18 V causing systems to momentarily shut down and reboot.
That your car eventually charges fine but takes some time to do so makes me wonder more about the voltage regulator rather than the slip rings?
One slight correction, the alternator communicates with the DME over the Bit Serial Data (BSD) interface along with the Intelligent Battery Sensor (IBS), the oil quality/level sensor, and the A/C compressor. But completely accurate in that the DME controls the alternator's output voltage based on algorithms with input from the IBS on the battery's history. The entire purpose of the IBS and variable alternator is to improve efficiency by reducing the countertorque felt by the engine which is produced by an alternator under load. By lowering the output voltage of the alternator when the battery is believed to be fully charged, the voltage delta between the battery and alternator is lowered, therefore the charge current is lowered, thus the alternator countertorque is lowered.Failure mode I saw was voltage spikes to 17-18 V causing systems to momentarily shut down and reboot.
That your car eventually charges fine but takes some time to do so makes me wonder more about the voltage regulator rather than the slip rings?
All great in theory, but leads to a far more complicated variable voltage regulator more prone to failure than a fixed voltage regulator. Gotta drive parts revenue somehow...
jcolley said:
One slight correction, the alternator communicates with the DME over the Bit Serial Data (BSD) interface along with the Intelligent Battery Sensor (IBS), the oil quality/level sensor, and the A/C compressor. But completely accurate in that the DME controls the alternator's output voltage based on algorithms with input from the IBS on the battery's history. The entire purpose of the IBS and variable alternator is to improve efficiency by reducing the countertorque felt by the engine which is produced by an alternator under load. By lowering the output voltage of the alternator when the battery is believed to be fully charged, the voltage delta between the battery and alternator is lowered, therefore the charge current is lowered, thus the alternator countertorque is lowered.
All great in theory, but leads to a far more complicated variable voltage regulator more prone to failure than a fixed voltage regulator. Gotta drive parts revenue somehow...
Cool; thanks for clarifying.All great in theory, but leads to a far more complicated variable voltage regulator more prone to failure than a fixed voltage regulator. Gotta drive parts revenue somehow...
OK - so I took the regulator off over the weekend and the brushes were pretty worn.
The sliprings were near-perfect, so I just spun them against some P600 emery to clean them.
Once the regulator was off, it too about 10 minutes to change the brushes.
I found the mounting bolts on the alternator were loose (the alternator was changed a few years ago by a BMW main dealer - tw@ts), so I was glad I looked at it sooner rather than later.
Whoever changed the alternator also managed to strip the outer sleeving from the regulator wire - there was just 1 blue wire to the regulator, is this correct??
The charging seems to come on a bit sooner, but still takes a few minutes to kick in - I assume this is because the DME has to monitor the battery/systems and then decide to call the regulator for more power?
Cheers - Simon
The sliprings were near-perfect, so I just spun them against some P600 emery to clean them.
Once the regulator was off, it too about 10 minutes to change the brushes.
I found the mounting bolts on the alternator were loose (the alternator was changed a few years ago by a BMW main dealer - tw@ts), so I was glad I looked at it sooner rather than later.
Whoever changed the alternator also managed to strip the outer sleeving from the regulator wire - there was just 1 blue wire to the regulator, is this correct??
The charging seems to come on a bit sooner, but still takes a few minutes to kick in - I assume this is because the DME has to monitor the battery/systems and then decide to call the regulator for more power?
Cheers - Simon
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