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LandyManLuke

A127 Alternator Regulator Replacement

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If you've got the A127 type alternator, and are experiencing an over or under-voltage fault, it's possible to change the regulator and brush pack relatively quickly and cheaply.

This type of alternator is easily identified by the curved regulator and stud terminals

Some poetic license is taken with the photos, as they were taken in the wrong order.

reg1.jpg

- Remove the battery +ve lead for safety, even though you don't need to remove the alternator wiring.

- To create room to work, remove the air filter and intercooler pipes.

- Slacken off the alternator belt tensioner, and remove the bolt and/nut on the alternator end.

- Remove the belt from the pulley

- Undo the two bolts holding the bottom of the alternator, 10mm socket required, IIRC

- You can now lift and rotate the alternator, to get to the back.

- The regulator is secured by three bolts, which have really small heads. I can't remember the size :ph34r::angry:

reg2.jpg

- You need to disconnect the regulator supply wire (pictured), which is a spade connector.

- the regulator/brush pack can be removed by rotating it slighlty and withdrawing it from the housing.

- It's worth checking for excessive wear where the brushes make contact with the rings on the shaft.

reg3.jpg

- Insert a straightened paperclip through the brush housing to hold the brushes in. this prevents damage to them on fitting.

- Connect the feed wire.

- bolt the regulator pack on.

- re-mount the alternator, remount the belt and tension etc.

- re plumb the air pipes.

- connect the +ve battery lead.

Hope that helps.

Luke

- Insert the pack into the alternator housing

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Sorry if this sounds wrong but I've done that a few times (last time at Minstead in the car park) and I just left everything in situ, undid the 3 bolts and unplugged the pack and replaced it. In this case it was because the brushes had got muddy and stuck in the housing (a regular occurrence with father's hands-off maintenance schedule :rolleyes: ) never gone as hi-tech as paper clips ;)

BTW the Bosch ones are even easier - undo two philips screws, remove regulator, replace.

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Agreed, FF, you can do it in situ, but you run the risk of snapping the brushes. Given the choice of working where i can't see with limited access, or 3 minutes with the air ratchet, well, y'know. ;)

Tony,

Please can you add a comment to remove the paperclip, after bolting the regulator down. :rolleyes::ph34r: oops.

Durite Part number is 0-831-55

Ta

Luke

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Cheers Luke thats the same as the one I took off the other day with the over voltage problem!

Will get a new regulator/brush pack & swap it when I get the chance :)

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I just did mine last week , But it was an A133 , Just as easy but replacing the slip rings was a bit of a fiddle. Parts are as cheap as chips and readily avalible , Got mine from LSUK , 2x bearings , 2x sliprings and brush pack for under £15 .

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Will I find an A127 on my 300 Tdi ? If not, what sort and would it have a different regulator ?

Mo

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- The regulator is secured by three bolts, which have really small heads. I can't remember the size :ph34r::angry:

Luke

The bolt heads are 5.5mm

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Will I find an A127 on my 300 Tdi ? If not, what sort and would it have a different regulator ?

Mo

I originally had an A127 65amp alternator in my 1996 300Tdi Defender if that's any help.

Colin

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Just looked at the pics again and the regulator brush pack dosnt appear to be sealed , On the A133 Ive just done the slip ring and brushes were sealed by rubber gaskets , So may come as an advantage especialy with some of JST`s boggy events :o

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Thanks Colin, mine looks the same and is 65 amp so I'll assume I have an A127.

Mo

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Just looked at the pics again and the regulator brush pack dosnt appear to be sealed , On the A133 Ive just done the slip ring and brushes were sealed by rubber gaskets , So may come as an advantage especialy with some of JST`s boggy events :o

nope, there aren't any gaskets or any sealant, but the alternator's open at the front anyway....

The regulator itself is sealed inside the housing, but i took my old one apart to have a look, it was full of a lot of carp :huh:

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Thanks for this @LandyManLuke and @FridgeFreezer  I’ve just done mine on a campsite with the alternator on the vehicle as per FF (300TDi). Not difficult and a whole lot easier with the confidence provided by reading this thread.

In my case the symptoms have been sudden over voltage, not all the time but intermittent up to 18V.  

Can’t really test until we get on the road again. It’s an “Eco” site and I doubt high revs and idling would go down very well. 

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