JourneyMan Posted September 6, 2009 Share Posted September 6, 2009 Hi All, My Radiator started leaking shortly after I bought my LSE so I decided to change it and the water pump at the same time along with the top and bottom hose, all Genuine LR parts. I've had 2 attempts at fitting the water pump and it always end the same, me swearing a lot and sheared bolts. The first time I used all of the original bolts from the old pump, 2 of the 1/4 bolts sheared when being torqued up. The second time I used all new bolts ordered from LR, every single one is brand new including the long bolts (I read a story on another forum of someones shearing while they where driving and it trashed the pump) so didn't take any chances, you've guessed it, one of the brand new 1/4 bolts has sheared. What am I doing wrong? Am I using the wrong torque setting on these 1/4" UNC Bolts, I really need to get the car back on the road but don't want to take it to a Specialist for open wallet surgery I've ordered all new bolts from LR so they should be the real deal high tensile I've had my torque wrench calibrated I'm torquing them up to 28Nm which is what the Haynes and LR Workshop Manuals tell you to Anyone??? Please?? Cheers Quote Link to comment Share on other sites More sharing options...
GT6Steve Posted September 6, 2009 Share Posted September 6, 2009 I've had my torque wrench calibrated I'm torquing them up to 28Nm which is what the Haynes and LR Workshop Manuals tell you to Anyone??? Please?? Cheers Seems too high a torque value to me. And the evidence supports that. 1/4" fastener would get about 14 Ft/Lbs or 18 Nm (I think) to be reliable. I don't think in Nm so take this with a grain of salt but your values sound like a 5/16" bolt to me. Back it off to 18 Nm and see how it fares... The alloy castings don't need or expexct much, you just need to pull it up so as to not leak under pressure. Sneak up on it if you must... Quote Link to comment Share on other sites More sharing options...
Dengie Boy Posted September 6, 2009 Share Posted September 6, 2009 28Nm is the correct torque as stated by LR workshop manual. If you have sheared new LR bolts then I suggest the threads need cleaning. Can you screw the bolts in by hand or are you using a ratchet? If your using a ratchet more than a couple of turns then the threads might be tight or dirty. Get the correct tap for the bolt and clean the thread first. You should be able to tighten the bolts by hand then use your torque wrench just to torque them, which should turn the bolt no more than 2 turns. Good luck. Quote Link to comment Share on other sites More sharing options...
GT6Steve Posted September 6, 2009 Share Posted September 6, 2009 28Nm is the correct torque as stated by LR workshop manual. 28Nm may be what's in the book but that doesn't mean it's correct. Do a google for torque specs and you'll find that a grade 8 bolt doesn't go much beyond 12 Ft/Lbs in iron and even a Special alloy bolt is nowhere near the 28Nm quoted. That's twenty foot/Pounds! That said, cleaning the threads is sound advice as well as your statement about two turns max. Clearly he should not be breaking bolts, thankfully he hasn't pulled the threads... Quote Link to comment Share on other sites More sharing options...
JourneyMan Posted September 6, 2009 Author Share Posted September 6, 2009 Hi Guys, Thanks for the responses. They all screw in by hand with no excessive resistance required. 28Nm did seem very high for a piddling little 1/4" bolt, but I was following what those wonderful people at Solihull put in there wonderful book Lesson learned! I've done some digging on the web and found for a High Tensile 8.8 1/4" Diameter bolt a Max Torque value of 10Nm Fortunately I've got more bolts as my local LR Dealer doesn't stock them so had to order them from LR in packs of 10 (Good money making scheme) so I'll give it another go tomorrow night, hopefully no harm done. Pulling threads, sounds painful Cheers Mark Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 6, 2009 Share Posted September 6, 2009 Your Data is wrong : Large bolts - 20-25 Ft Lbs Thin bolts - 6-8 Ft Lbs Nige Quote Link to comment Share on other sites More sharing options...
Dengie Boy Posted September 6, 2009 Share Posted September 6, 2009 28Nm may be what's in the book but that doesn't mean it's correct. Lesson learned. I dont use Nm either, use threadlock on important stuff and then torque everything to FT Quote Link to comment Share on other sites More sharing options...
bluespanner Posted September 6, 2009 Share Posted September 6, 2009 I cant say i have ever torqued water pump bolts... or had one leak. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 7, 2009 Share Posted September 7, 2009 28Nm is around 21 Lb/ft, so about the same as HFH says for the large bolts. Same as bluespanner I've never torqued these bolts and never had a leak. As they are screwed into Ally I am generally more concerned with stripping threads if I over tightened them. Based on this I don't think the WSM is wrong. The first clip does spell out that it refers to the bolts that go through to the block (i.e. the large ones). Quote Link to comment Share on other sites More sharing options...
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