Gromit Posted February 11, 2008 Share Posted February 11, 2008 I had an old alternator sitting here, so I thought I've have a go at reconditioning it. My local auto electrical place wanted €80. I bought the parts for €20. This alternator is found in lots of LR vehicles, Ralph will tell you exactly which ones. It's pretty straightforward. You'll need a high wattage soldering iron and a selection of sockets to use as drifts for the front and rear bearings. To remove the front bearing, it needs to be supported by a piece of pipe, bigger than my largest 32mm socket. Here's what you get in the kit; Regulator/Brush box, rear bearing, slip ring, front bearing and rectifier. Using a hex drive in the centre of the shaft, remove the nut, pulley and fan Remove the 3 bolts securing the regulator. Remove the regulator and unplug the connector. Remove the single self tapping bolt located under the regulator. This holds the rectifier in position. Remove all bolts from the terminals. Mark the position of the front bracket, stator and rear bracket with tippex so that you out it back together the way you pulled it apart. Remove the 3 through-bolts holding the alternator together. These are splined and need to be gently tapped out. Then remove the rear of the alternator. Unsolder the 3 wires to the rectifier, noting their positions. These are reasonably large connections, so you'll need a good amount of heat. Remove the rectifier There are 2 wires that connect the slip ring. Open each crimp, and remove the wire. Remove the slip ring. This was easier said than done, and I ended up taking a cold chisel to it. There copper wires sit on an insulator under the slip ring - be careful not to crack or break it, if using excessive force to remove the slip ring. Drift the new slip ring into position ensuring it is lined up with the 2 wires. Check your drift bears on the plastic of the slip ring, not on the copper. Crimp the 2 wires to the slip ring. To change the front bearing, remove the stator and carefully tap the rotor out of the front bracket. Place a pipe of suitable diameter under the bracket and drift the bearing out. ** The bearing is very tight and the housing is brittle. Make sure your supports and drift are exactly the correct size. I didn't and cracked the front housing. Not a problem as I'll swap the housing when I swap it for the alternator in the truck, but you don't want to be doing that to your only alternator. To change the rear bearing, again make sure your drift is larger than the shaft diameter, and your support will allow the bearing to be drifted into it. Then drift in the new bearing. Refit the stator and rotor. Place the rectifier in position and clamp the wires. Solder the wires in position. Use lots of heat and allow the joint to sweat for a few seconds before removing the iron. Replace the insulators on the rectifier in the correct position. Refit the rear housing, feeding the regulator feed wire through the hole. Refit the terminal washers and nuts. Refit the self-tapper securing the rectifier to the rear housing. Refit the through-bolts and tighten. Check the alternator rotates freely. If not, loosen the through bolts and re-adjust. Refit the regulator/brush box. Refit the front bush then the fan and bush, then the pulley, split washer and nut. Thanks to Ates for the artistic photos Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted February 11, 2008 Share Posted February 11, 2008 great post! You forgot the paperclip from the brush pack - don't want to damage those nice new brushes. Where did you buy the kit from? Quote Link to comment Share on other sites More sharing options...
Gromit Posted February 11, 2008 Author Share Posted February 11, 2008 great post! You forgot the paperclip from the brush pack - don't want to damage those nice new brushes. Where did you buy the kit from? I was remembering white90s post about the paperclip but found that if you're careful, you can press the brushes into position without it. Otherwise, there's the paperclip method Got the kit on Ebay. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted February 11, 2008 Share Posted February 11, 2008 Good post Gromit, one for the tech archive methinks Mo Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted February 11, 2008 Share Posted February 11, 2008 I was remembering white90s post the paperclip method Who's post! Quote Link to comment Share on other sites More sharing options...
Gromit Posted February 11, 2008 Author Share Posted February 11, 2008 Who's post! Sorry Luke, saw his post in the tech archive on changing the regulator with the same method and assumed it was his Apologies for the mis-credit Quote Link to comment Share on other sites More sharing options...
Discovan300tdi Posted February 11, 2008 Share Posted February 11, 2008 thats rather well timed as my alternator decided to pack up last night, so ended up having to put my spare 65 amp on instead of the 100amp that the 300tdi runs looks like I'll be tracking the kit down off eblag and doing it myself Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted February 11, 2008 Share Posted February 11, 2008 Sorry Luke, saw his post in the tech archive on changing the regulator with the same method and assumed it was his Apologies for the mis-credit No worries, The tech archive posts are "copy & paste" versions of the originals, I though the orginal author was credited in the sub-title. Edit: A127 Alternator regulator replacement, By Luke I was Quote Link to comment Share on other sites More sharing options...
simonb Posted February 11, 2008 Share Posted February 11, 2008 If you are careful there is no need to unsolder the diode pack. Once you have removed the rear cap, gently insert some thin screw drivers between the iron ring of the stator and the top cap. You can gently then lever the front cap free from the stator and diode pack without unsoldering it. In fact when i rebuild these, i do this bit first after taking out the through bolts, lifting out the rotor and end cap complete from the stator and rear cap. I never bother changing the rectifier, they very rarely fail on the 65a unit (unlike those fitted to 1980s version of a series 3 alternator..) Sometimes the rotor shaft will be a very tight fit in the front bearing - its then 3 legged puller time to release the rotor... Quote Link to comment Share on other sites More sharing options...
western Posted February 11, 2008 Share Posted February 11, 2008 Nice Tekkie thread Gromit Quote Link to comment Share on other sites More sharing options...
Gromit Posted February 11, 2008 Author Share Posted February 11, 2008 looks like I'll be tracking the kit down off eblag and doing it myself This is the guy I bought from: Kit on Ebay Quote Link to comment Share on other sites More sharing options...
idrisboyo Posted February 11, 2008 Share Posted February 11, 2008 Good repair instructions, if i may add a small bit to it and that is sometimes you might have to turn the two slip rings on a lathe as they are not usually true and you might experience brush bounce sometimes you can use the old comm end bearing in the lathe as a guide Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 11, 2008 Share Posted February 11, 2008 Cracking post gromit One thing maybe wrong though Showing yourself wearing those latex gloves may arouse an 'unwanted interest' from Mr Moglite Damned fine tech post Nige Quote Link to comment Share on other sites More sharing options...
sjane Posted June 26, 2010 Share Posted June 26, 2010 Just reco'd the A127 from my Discovery, this guide made it easy! Thanks! Almost came unstuck with the front bearing, didn't have any pipe the right size. A bit of stainless bent into a tube did the trick! $30 for parts is a lot better than $320 for a new alternator. Cheers, Scott. Quote Link to comment Share on other sites More sharing options...
Gromit Posted June 28, 2010 Author Share Posted June 28, 2010 Good to hear Scott; glad the post was helpful. Welcome to the forum Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 28, 2010 Share Posted June 28, 2010 I did this to an old transit alternator (same A127 model), and it didn't work. Turned out the insulation had broken down on the big coil (Stator?) meaning it was shorting out. Something to bear in mind before spending out on the rebuild kit. Only problem being you need to take the thing to pieces to find out whats actaully wrong with it. Given the time involved and the fact the repair kit was £20 and a recon alternator was £50, i would just be buying a new one after my experiences with the transit one Quote Link to comment Share on other sites More sharing options...
TDI300 Posted October 23, 2015 Share Posted October 23, 2015 New to this Forum. Would any member have the original post showing the pics, as these are not showing in this topic. Also, would anyone have a manual for the Magneti Marelli A127i -100A AMR AMR4278 ? Quote Link to comment Share on other sites More sharing options...
simonb Posted October 23, 2015 Share Posted October 23, 2015 Pics are showing - it maybe your browser settings... 100A version is similar but the rectifier and regulator are different and the bearings a different size - the basic principles are however much the same. Quote Link to comment Share on other sites More sharing options...
Sheffield Posted October 24, 2015 Share Posted October 24, 2015 I have a spare nearly new alternator taken from a RRC V8. Can I use it on a 300TDI Discovery by rotating the front plate to suit the mountings or will the rev counter output be different, please? Quote Link to comment Share on other sites More sharing options...
simonb Posted October 24, 2015 Share Posted October 24, 2015 Nope, V8 100A versions don't fit on Tdis. The spacing of the 2 lugs (which are in a line) at the front and back is too small to fit over the mount on the Tdi. Rotating the front cover won't change this. Quote Link to comment Share on other sites More sharing options...
Sheffield Posted October 25, 2015 Share Posted October 25, 2015 Thanks for that. Disappointing, but thanks for saving me an unnecessary job finding out. Quote Link to comment Share on other sites More sharing options...
dailysleaze Posted December 20, 2017 Share Posted December 20, 2017 Came across this really good video for reference Quote Link to comment Share on other sites More sharing options...
ludovic Posted January 21, 2018 Share Posted January 21, 2018 Hello Guys, Excellent topic, but the question now is where did you get the slipring? I have found the regulator but no way to find the slipring. Mine is also dead 65Amp, The slipring is not very good so I'm gona change it following this instruction. Let me know. Thanks Quote Link to comment Share on other sites More sharing options...
Yerik Posted July 28, 2023 Share Posted July 28, 2023 Guys, from which car this alternator? Quote Link to comment Share on other sites More sharing options...
pete3000 Posted July 29, 2023 Share Posted July 29, 2023 Many cars, search A127 alternator. Made under several brands Lucas, Magnetti Marelli, Denso etc etc. Guessing as it's on a Land Rover forum it's also found in several LR applications i.e Defender/Discovery/series. Quote Link to comment Share on other sites More sharing options...
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