robbh · Jan 10, 2015

Just a quick one.

Been having issues with my battery going flat.

Readings from multimeter suggest that my alternator is dud as I get the same reading of 12.2v with a charged battery whether the engine is running or not.

Given it gentle taps with a hammer, cleaned all connections and still no difference in voltage reading when the engine is running.

So before I shell out for a newun is my alternator definitely knackered?

Cheers.

listerdiesel · Jan 10, 2015

Might just need a set of brushes, once they get right down you don't get a good contact and no field excitation.

Worth checking, and while you're there, see what the bearings are like. You can change the brush pack without stripping the alternator on most models.

Peter

Iann · Jan 10, 2015

I watched a guide on you tube when i stripped mine

Could have done it any way but watching a vid always helps imop

Datatek · Jan 10, 2015

robbh said:
Just a quick one.

Been having issues with my battery going flat.

Readings from multimeter suggest that my alternator is dud as I get the same reading of 12.2v with a charged battery whether the engine is running or not.

Given it gentle taps with a hammer, cleaned all connections and still no difference in voltage reading when the engine is running.

So before I shell out for a newun is my alternator definitely knackered?

Cheers.

An overhaul kit can be found for £20/30. Make sure you get one with a regulator set point of at least 14.2 volts to suit modern sealed batteries.
Same if you replace the alternator, 13.8 volts is no longer enough to charge Lead Calcium automotive batteries.

trax · Jan 10, 2015

double check your wiring first.

do you have the dash light coming on, etc.

robbh · Jan 10, 2015

Thanks for the replies all.

Ended up forking out for a new alternator today at my local motor factors. Needed the disco on the road asap so I could collect welding gas so couldn't mess about replacing brushes and what not. Maybe next time I'll think about it.

Wiring is all good. Checked all that before replacing the alt.

Anyway fitted the new alternator (after swapping the pulleys between new and old) and now getting 14.6 volts with the engine running. So the old one was definitely dead.

It's what I get for playing in mud I guess. Especially when the engine bay ends up like this at the end of an outing.

easye1 · Jan 10, 2015

thought my alternator was not good as i was checking it with a years old multi meter.
bought a new multimeter from china, took a few weeks to get here but its a good one -
charging voltage now just fine.
in between buying and recieving the tester, i bought a new brushpack/ regulator, thats sits in my sock draw now / so i cant lose it in me shed..

Datatek · Jan 11, 2015

robbh said:
Thanks for the replies all.

Ended up forking out for a new alternator today at my local motor factors. Needed the disco on the road asap so I could collect welding gas so couldn't mess about replacing brushes and what not. Maybe next time I'll think about it.

Wiring is all good. Checked all that before replacing the alt.

Anyway fitted the new alternator (after swapping the pulleys between new and old) and now getting 14.6 volts with the engine running. So the old one was definitely dead.

It's what I get for playing in mud I guess. Especially when the engine bay ends up like this at the end of an outing.

That will feck any alternator

robbh

Crazier than a box of frogs on acid

listerdiesel

Well-Known Member

Iann

Active Member

Datatek

Well-Known Member

trax

.

robbh

Crazier than a box of frogs on acid

easye1

Banned

Datatek

Well-Known Member

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