Today was the MoT on my 2020 Dacia Logan 1 litre petrol. I had checked the lights yesterday but on the test they found one dip headlamp bulb blown. The tester replaced it with a new one I had in the boot but it blew again 5 minutes later. When I got home I checked the battery voltage with the engine running and it was very erratic, sometimes hitting 17 volts. I see you can buy new voltage regulators for some alternators and I have seen a couple of YouTube videos on alternator repairs. One mentioned that you need silver solder to renew the connections. I have a soldering iron and a gun but have only used normal electronics type cored solder. will my tools get hot enough for silver solder (assuming I can buy some)?
Alternator Repair
- Thread starter fidom
- Start date
No, not hot enough.
Do not go there.
Before anything else, check all of the connections to the alternator and the battery and the ground lead(s) to the vehicle chassis.
Then if the alternator is indeed bust, buy a new alternator and a new battery to go with it.
Even if you could replace the regulator, that may not be the problem. The new one could be destroyed in seconds along with other electronics in the vehicle.
Normal electronic cored solder is fine but you'll need an iron of 125W or more if you have to get stuck in.
Personally I'd go for a guaranteed replacement unit, but do make sure that you can shift the pulley by yourself - particularly if it's a free wheeling one.
John
Personally I'd go for a guaranteed replacement unit, but do make sure that you can shift the pulley by yourself - particularly if it's a free wheeling one.
John
I don't think it is just the rating of the iron but also the size of the tip and the thing that you are trying to solder. If it applies the heat too locally (ie it's small ) and it quickly dissipates you will never get a good join that will stand the heat and vibration that an alternator might sublect it to. I rather think though that the terminals will be ready crimped or screwed rather than soldered.
Many replacement alternators don't come with a pulley fitted.......at least over here......hence my comment.
Are you going to give it a bash? At that sort of age, the rest of the alternator should be in good nick - unless it's been to the moon of course!
John
Are you going to give it a bash? At that sort of age, the rest of the alternator should be in good nick - unless it's been to the moon of course!
John
Are you sure the alternator has a built-in regulator? In many modern cars the voltage is controlled by the engine management computer (by varying the field current, same as with built-in)
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Alternators I used to work on years ago, the rectifier had soldered connections, but the regulator had screwed terminals. If yours is like that changing the regulator isn't a soldering job. I suppose these days it might have a combined rectifier/regulator, you can tell if you dismantle it.
I now have the alternator off and I'm completely confused! There is the usual thick, bolted wire and thin wire with a plug that plugs into the plastic outer alternator casing. I was expecting to see a male spade or something in the socket for that plug but could not see anything. I wondered if that had broken off and was thinking in terms of soldering a new wire inside. I took the cover off but that socket does not have any wiring, it just seems like a dummy socket. I watched a YouTube video about changing brushes on a BMW alternator. It had a similar looking brush holder / regulator but theirs had the socket for the thin wire on the regulator. I dug out my old scrap Daewoo alternator and that also has the socket on the regulator.
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So am I. In the photo is the bit on the right rotated relative to the other bit? And the brush holder turned over? If the rectifier goes where it seems to, have bolts been put back in?
The part with fins looks like a rectifier. The Valeo website refers to a regulator, but if it has one maybe it's built in to the rectifier or brush holder. Have you contacted parts suppliers? Can you buy a regulator (or rectifier/regulator)? Overcharging strongly suggests a faulty regulator.
And to go back to your question about silver solder, I can't see any soldered connections.
To my eye, it looks as if the pins have broken off, on the alternator, leaving just a rusty mark, where they were. That itself seems odd, usually the pins would be brass, rather than steel.
It suggests to me, that the regulator has been replaced in the past, and whoever fitted it, didn't manage to fit it fully, and water has got in.