TheBeastie Posted November 6, 2010 Share Posted November 6, 2010 Noticed very low volts and on investigation found (to cut a long story short) that the casing of the alternator has sheered just above the front securing bolt. It is a clean break through the casting. There is no sign of a bolt securing the rear which makes me a bit suspicious since I had the steering pump looked at and I know they took pump out so am guessing he took alternator off to get at it and perhaps forgot to put back the rear securing bolt on the alternator - Can see how it could be quite easy to forget, but may be doing him an injustice! I have checked the hole at the back of the bracket which would take the rear bolt and I can put a cable tie in for 40mm from the face. I do not know however if this means a bolt has sheered off or if it is completely clear for new bolt to go in??? My main question however is the alternator is the original 1991 A127-45. It would seem to me to be worth upgrading to a more powerful alternator given I have to get a new one and wonder if others agree. I run a double battery setup with split charge and use aux battery quite a lot for radio work. The current alternator seems to (be meant to) have three fixing points - bottom front and rear plus top front on the sliding bracket. Presumably much easier to get another alternator with same fixing points. What would I be best getting? Will also have hopefully constructive discussion with guy on Monday - grrr! Any thoughts most appreciated Malc Quote Link to comment Share on other sites More sharing options...
western Posted November 6, 2010 Share Posted November 6, 2010 the larger 65amp will fit straight on or go for a 100amp & uprate the large current carrying cables to suit. the bolt that fits from the rear should be a M8 x 40mm FB108081L front bolt should be a M8 x 45mm BH108091L my 100amp is a marrelli unit from a 300tdi Discovery, the multigroove pulley was just swapped with the original alt's vee pulley [fan is inside the alt body] Quote Link to comment Share on other sites More sharing options...
TheBeastie Posted November 7, 2010 Author Share Posted November 7, 2010 Thanks western. Presumably if going for the 65 amp upgrade still worth upgrading the cabling? Quote Link to comment Share on other sites More sharing options...
western Posted November 7, 2010 Share Posted November 7, 2010 Yes, another cable of the same size alongside the existing cable would be sufficient for a 65amp alternator. Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted November 7, 2010 Share Posted November 7, 2010 A cautionary tail. If you run another cable make sure its contined in conduit like the origional. My second cable happend to rub through on the back of the block and caused a lot of damage to wiring in the same conduits. All melted. So although a second cable is a good idea. Installing it in a quality way, something it didn't do, is also a good idea. Quote Link to comment Share on other sites More sharing options...
pete300tdi90 Posted November 8, 2010 Share Posted November 8, 2010 Hey, my alternator has gone on my Td5... What is the most powerful one you can get to fit stright on without modifications? (dont have time to play about, but like Malc I run a split charge twin battery system) Also, do Td5 alternators differ much from other models? Thanks Pete Quote Link to comment Share on other sites More sharing options...
nino Posted November 8, 2010 Share Posted November 8, 2010 western the 100a 300tdi altrnator, is it physicaly larger aswell as when i went to my local auto electrical place they didnt have any in stock and when looking in the book he said that the mounting lugs were the oppisit side of the alternator and they noramlly are bigger, did you need to undo it and spin it round at all or was it a bolt straight on? the 70a one on my 200tdi went half way through the playday at broxhead yesterday i have here another brand new 70a one but the original had the plug with wires and this other one has terminal nut and bolts Quote Link to comment Share on other sites More sharing options...
western Posted November 8, 2010 Share Posted November 8, 2010 western the 100a 300tdi altrnator, is it physicaly larger aswell as when i went to my local auto electrical place they didnt have any in stock and when looking in the book he said that the mounting lugs were the oppisit side of the alternator and they noramlly are bigger, did you need to undo it and spin it round at all or was it a bolt straight on? the 70a one on my 200tdi went half way through the playday at broxhead yesterday i have here another brand new 70a one but the original had the plug with wires and this other one has terminal nut and bolts it was fitted well over 10years ago, can't remenber if we rotated the body housings, not much help sorry, my memory isn't that good. Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted November 8, 2010 Share Posted November 8, 2010 My 100A switched directly for my standard. All i did was change the belt length as i didn't swap the pully over. I figured the new alternator was designed to run with the smaller pully so i changed the belt to the shorter version. Not had any issues at all. You could change the pully over but then it won't spin at its designed rpm. mechanically the fixings were identical and i'm running a 300TDI. I still have the old one if you want me to check the part number. I think its the same as yours. I'm also handy with a camera. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted November 8, 2010 Share Posted November 8, 2010 Sorry to hijack a thread again, but Neill, which alternator did you get? Disco 300tdi? Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted November 8, 2010 Share Posted November 8, 2010 Sorry to hijack a thread again, but Neill, which alternator did you get? Disco 300tdi? 1 x Alternator (High Output) 300 Tdi 100 amp AMR5425 G (AMR5425 G) From Island 4x4 Quote Link to comment Share on other sites More sharing options...
cackshifter Posted November 9, 2010 Share Posted November 9, 2010 1 x Alternator (High Output) 300 Tdi 100 amp AMR5425 G (AMR5425 G) From Island 4x4 Neill thanks. Nigel Quote Link to comment Share on other sites More sharing options...
jcwcooper Posted November 9, 2010 Share Posted November 9, 2010 Certain ford Mondeo ones fit, I have a 90 amp unit on mine just swapped the multigroove belt pulley for one off my original alternator, mounting lugs are in the same position too. Cost about 20 quid from a car breaker. Dave Quote Link to comment Share on other sites More sharing options...
ajh Posted July 17, 2011 Share Posted July 17, 2011 Having searched for a few hours I'm still unsure which one will fit a LHD 200TDI Defender, lots of numbers are mentioned but then people say they won't work.... Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted July 17, 2011 Share Posted July 17, 2011 put a request in the part numbers section although its normally Western that responds and he will see this if its subscribed. Quote Link to comment Share on other sites More sharing options...
western Posted July 17, 2011 Share Posted July 17, 2011 Having searched for a few hours I'm still unsure which one will fit a LHD 200TDI Defender, lots of numbers are mentioned but then people say they won't work.... same as a RHD vehicle, there is NO left hand drive variant in the parts book. Quote Link to comment Share on other sites More sharing options...
ajh Posted July 22, 2011 Share Posted July 22, 2011 So several hundred dollars and a week later I have a AMR5425 G but now to rotate the housing it seems like the external electronics now need to be cut off? Is this accurate or is there some way to free up the housing to rotate? Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 22, 2011 Share Posted July 22, 2011 If you need to clock the housing, undo and withdraw the long bolts and rotate, replace bolts, it's that easy ! What external electronics are there on it ? Mo Quote Link to comment Share on other sites More sharing options...
ajh Posted July 23, 2011 Share Posted July 23, 2011 So I can confirm they changed the design to one with external brushes but a 4-bolt body. I have a line on a Bosch unit that will fit but I believe I have this one working anyway. What I did was mount it with the tab backwards and modified a RRC tensioner to pull instead of push and mounted it between the power steering pump pivot bolt and the alternator. The only possible issue is the lower rear tab and the steering pump output are tight, but I think I got enough clearance to make it work. I put a photo on my Facebook account if anyone wants to see the modifications. Quote Link to comment Share on other sites More sharing options...
ajh Posted July 23, 2011 Share Posted July 23, 2011 Here's a photo of my solution to mount wrong-sided tabbed alternator to a 200TDI. It also makes adjustment a lot easier. My only worry is the rear tab may be too close to the PS pump output but I think it's good. Quote Link to comment Share on other sites More sharing options...
western Posted July 23, 2011 Share Posted July 23, 2011 the rear attachment tab should be in--line with [it's bolt head facing rearwards] the forward attachment tab [new bolt head lower centre] so it shouldn't cause any problem with the PAS hose ends, if the hoses lie just above the chassis rail, the PAS connections should be below the alternator & clear of it. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 23, 2011 Share Posted July 23, 2011 Well, it looks like it works and like you say, it'll make tensioning the belt easy Mo Quote Link to comment Share on other sites More sharing options...
ajh Posted July 25, 2011 Share Posted July 25, 2011 After a day all seems to be fine, and yes not needing a prybar to set tension is nice. Quote Link to comment Share on other sites More sharing options...
markyboy Posted July 27, 2011 Share Posted July 27, 2011 Here's a photo of my solution to mount wrong-sided tabbed alternator to a 200TDI. It also makes adjustment a lot easier. My only worry is the rear tab may be too close to the PS pump output but I think it's good. I'd be concerned about the lack of contact between the belt and pulley with that set up. You may find under heavy load, eg winter with the a lot of electrical draw from lights, heater etc, you could have belt slip. Add a damp climate into the mix and it can only be worse! I hope I'm completely wrong and you don't get any issues with it. Regards, Mark. Quote Link to comment Share on other sites More sharing options...
ajh Posted July 27, 2011 Share Posted July 27, 2011 How do you see the amount of contact changed from the stock setup? In general this is allowing me to set the tension far more reliably and it never slips back like the stock setup can, and the bolts don't need to be overtightened to prevent the slippage so I'm thinking it'll be more reliable, not less. For the next one I'm going to build a similar tensioner but put it in the stock position if the tab is correctly located. Quote Link to comment Share on other sites More sharing options...
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