dubwarrior2
Part of things
"Open up, its the filth"
Posts: 576
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Aug 22, 2019 17:46:46 GMT
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Ive just removed the rear suspension arms on my VW T4. They pivot on m14x1.5 and m16x 1.5mm bolts which I'm going to replace. Ive priced them up on the brickwerks site and they are pricey. I can get them cheaper on ebay. The question is, in the description, it says to use fine thread bolts not normal pitch because "VW used fine thread for a reason"..... Really? What reason? Id have thought normal thread would be ok. They both have the same diameter. And surely part threads would be better too. Any ideas?
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Aug 22, 2019 20:20:22 GMT
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There would be 2 main reasons,
- you get more clamp load for a given torque with a fine pitch bolt.(it would have to be a high grade bolt as well) - too make sure the wrong part can't be used in production, typically a manufacturer will use a fine pitch for all its 10.9 grade fastners to make sure they can't get mixed up with the 8.8.
Of more importance then the thread pitch is the getting right grade of bolt.
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dubwarrior2
Part of things
"Open up, its the filth"
Posts: 576
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Aug 22, 2019 20:38:29 GMT
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Yeah I appreciate the importance of the tensile grade. They are torqued to 160nm.....so I'm sure a wider pitch could handle it. Either way I'll replace like for like
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As kevins said, you get a lot more clamping load from the same torque, more precise clamping force too and less tendency to loosen.
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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VW T4, why fine thread bolts?slater
@slater
Club Retro Rides Member 78
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Aug 23, 2019 14:21:18 GMT
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A finer thread is stronger. Think about it. The minimum diameter of a m16x2 is smaller than and M16x1.5
I'm not sure that really matters in this case tho!
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Aug 23, 2019 17:19:32 GMT
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luckyseven
Posted a lot
Owning sneering dismissive pedantry since 1970
Posts: 3,839
Club RR Member Number: 45
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VW T4, why fine thread bolts?luckyseven
@luckyseven
Club Retro Rides Member 45
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Aug 23, 2019 19:14:37 GMT
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Seems a bit overkill... you ought to be able to hang a decent-sized boat from the ceiling using even a "normal" M16 bolt and expect it to hold
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Aug 23, 2019 19:25:03 GMT
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well its a rear suspension arm on a 2.8 ton van, so the loads are not insignificant.
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dubwarrior2
Part of things
"Open up, its the filth"
Posts: 576
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Aug 24, 2019 23:56:35 GMT
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Thanks all. On anything else I probably wouldnt be overly fussed, but on the suspension I'll copy the originals. I'll also use nylocs, which VW didnt
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