Tom17 Posted August 10, 2016 Share Posted August 10, 2016 I've fitted two alternators now and they've both snapped in the same place and I don't have a clue why. please help I'm not sure what I could be doing wrong Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 10, 2016 Share Posted August 10, 2016 Alternator snapping? Where? Quote Link to comment Share on other sites More sharing options...
Tom17 Posted August 10, 2016 Author Share Posted August 10, 2016 the alternator is mounted with two bolts one on the top and one on the bottom... the bottom mounting hole is snapping and I haven't got a clue how or why. Quote Link to comment Share on other sites More sharing options...
Tetsu0san Posted August 10, 2016 Share Posted August 10, 2016 Pictures? What engine? Quote Link to comment Share on other sites More sharing options...
Tom17 Posted August 10, 2016 Author Share Posted August 10, 2016 I'm struggling to upload a photo but it is a 200 tdi and it is the bottom mounting hole Quote Link to comment Share on other sites More sharing options...
Tom17 Posted August 10, 2016 Author Share Posted August 10, 2016 Quote Link to comment Share on other sites More sharing options...
Tetsu0san Posted August 10, 2016 Share Posted August 10, 2016 I would imagine that when you do the bolts up it is twisting the casing on the alternator. It's not easy to see from that picture but if that is a picture of it in place and it has just cracked then it looks like that bolt is not at right angles to the alternator. Quote Link to comment Share on other sites More sharing options...
Tom17 Posted August 10, 2016 Author Share Posted August 10, 2016 the belt is still under some tension that is why the body looks at a different angle to the snapped piece. I'm wondering if I've been putting too much tension on the belt? Quote Link to comment Share on other sites More sharing options...
Tetsu0san Posted August 10, 2016 Share Posted August 10, 2016 Unlikely, but could be. You only want just enough tension to stop it slipping, nothing more. Overtightening will cause the bearings in the alternator and the waterpump to fail. What brand alternators are you breaking? Quote Link to comment Share on other sites More sharing options...
Maverik Posted August 10, 2016 Share Posted August 10, 2016 The bolt that goes through the bottom from memory is the long one, and on the opposite alternator lug to the one that's broken (back of the alternator) there is a small sliding insert, this moves inward when you tighten the bolt up to act as a spacer so you don't "axially" load the aluminium lugs, that lug is sliding as it should i.e. you've not packed it out with washers instead at all have you? Do you have a picture of the nut side of the bolt? I'd be sceptical that you can snap the anchor arm like that just by loading up the belt. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted August 10, 2016 Share Posted August 10, 2016 Put your location in your Profile Tom? some one may be able to pop round and have a look with you. Chances are you have something not quite back in the same place i.e may have an arm or washer on the wrong side. Or could be your replacement alternator has a slightly different casing or is not to spec causing the cracking when you try and close the gap (there shouldn't be any gaps ideally). You should have a long bolt as the pivot through two points (this should be packed with spacers inside the flanges so not to cause squashing effect on tightening up). This shouldnt do anything else than location so shouldn't be mega tight at all. The other shorter bolt should only act to stop rotation or spacing via a distance strap, with a sliding link action. Quote Link to comment Share on other sites More sharing options...
Tom17 Posted August 10, 2016 Author Share Posted August 10, 2016 my location is wirral Merseyside and I will take a photo asap and get it up but from memory the bolt at the point of it snapping is going into a threaded hole not a nut. Quote Link to comment Share on other sites More sharing options...
Maverik Posted August 10, 2016 Share Posted August 10, 2016 Put your location in your Profile Tom? some one may be able to pop round and have a look with you. Chances are you have something not quite back in the same place i.e may have an arm or washer on the wrong side. Or could be your replacement alternator has a slightly different casing or is not to spec causing the cracking when you try and close the gap (there shouldn't be any gaps ideally). You should have a long bolt as the pivot through two points (this should be packed with spacers inside the flanges so not to cause squashing effect on tightening up). This shouldnt do anything else than location so shouldn't be mega tight at all. The other shorter bolt should only act to stop rotation or spacing via a distance strap, with a sliding link action. You shouldn't have to put any spacers in anywhere. You should just have to tighten up both bolts and the sleeve (on the back mount) - as seen in the photograph should take up the slack and stop any squeezing of the mounts... http://www.defendersource.com/forum/attachment.php?attachmentid=23358&d=1259860434 Quote Link to comment Share on other sites More sharing options...
Tim2809 Posted August 10, 2016 Share Posted August 10, 2016 Looks like the sleve is not sliding so is bending the front lug and snapping off. I always oil the sliding tube and then tap it both ways to ensure its free before fitting. It is a tight fit and most alternators are painted causing the tube to become stuck Quote Link to comment Share on other sites More sharing options...
pete3000 Posted August 10, 2016 Share Posted August 10, 2016 Is it a defender or disco engine 200tdi? Part showing as RTC5682N 45A for std, or could use STC234 or RTC5680 65A units, for defender 11L. or if it's a disco engine RTC5681N for 12L. Not sure of differences maybe worth looking into Quote Link to comment Share on other sites More sharing options...
Ex Member Posted August 10, 2016 Share Posted August 10, 2016 the alternator is mounted with two bolts one on the top and one on the bottom... the bottom mounting hole is snapping and I haven't got a clue how or why. Are you even using the second bolt on the bottom? Your description above does not sound like it. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 10, 2016 Share Posted August 10, 2016 There shouldn't be a second bottom bolt, just one long one which runs through the front lug, the mounting bracket on the engine and out through the steel tube on the alternator rear lug. It is important that the steel tube can slide in the lug. Tap it aft before fitting the alternator, and the nut will tighten it up against the mounting. Make sure the mountring bracket is secure on the block - if that is moving, then it could cause the problems you're having. Quote Link to comment Share on other sites More sharing options...
western Posted August 10, 2016 Share Posted August 10, 2016 my Defender 200tdi engine has 2 bolts for bottom of alternator mounting, one faces forward the other faces rearward & the adjuster link at the top front, Quote Link to comment Share on other sites More sharing options...
steve b Posted August 10, 2016 Share Posted August 10, 2016 Early and later mounting brackets I think , the alt. should have 3 fixing points , 2 lower - the rear has the sliding collar , and one upper for the adjuster strap . The rear lug has snapped because the sliding collar is either not sliding or not present cheers Steveb Quote Link to comment Share on other sites More sharing options...
western Posted August 10, 2016 Share Posted August 10, 2016 it's the front lower lug that's snapped off, not the rear one, the alternator cooling fan is above the broken lug in the photo/ Quote Link to comment Share on other sites More sharing options...
DC_ Posted August 10, 2016 Share Posted August 10, 2016 Not sure if it's the same as this one of mine Tom? As you can see the bottom left bolt secures to the block, there's a spacer in that bolt though, it's not on the wrong side of the bolt is it? That would cause your alt to be at an angle. The top bolt in the pick as you probably know is the tension adjuster. There's a third bolt bottom right. It goes right through the alt to a threaded "sleeve" which doesn't me to be anything more than 30Nm I would say. Hope this helps. Quote Link to comment Share on other sites More sharing options...
steve b Posted August 10, 2016 Share Posted August 10, 2016 Oh yeah wrong end , but the same reasons I'd say ? cheers Steveb 1 Quote Link to comment Share on other sites More sharing options...
DC_ Posted August 10, 2016 Share Posted August 10, 2016 Hard to say as we can't see the whole thing, C'mon Tom get those pictures up. Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted August 11, 2016 Share Posted August 11, 2016 Tom I am on the Wirral. PM me if you want me to take a look Mike 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 12, 2016 Share Posted August 12, 2016 it's the front lower lug that's snapped off, not the rear one, the alternator cooling fan is above the broken lug in the photo/ Yes, but if the sliding tube is missing from the rear lug, the bolt won't be centred correctly in that lug, twisting the alternator case out of parallel to the crank axis and shearing the front lug. I'd put money on that or a mounting bracket alignment fault being the correct diagnosis for the failures. Quote Link to comment Share on other sites More sharing options...
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