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injector retaining yokes bent on MD5A - why?

danielbeek

New member
Hi,

the three shims (EDIT: yokes) on my MD5A are bending when I tighten down the two nuts that push down the injector. I am using the recommended torque setting (10NM/7LBft) which is fairly low. I have flattened them out before, but this didn't last - first refitting bent them.
Why do they bend. Can I have them welded together to make them stiffer? Why are these not a single piece?

Also, in the process of tightening, one of the studs broke - I'll attribute this to the fact that the bent shims were applying load unevenly, and that the studs used to be a little rusty, hence weakened. Should I replace these with high tensile items? what's the original stud likely to be made of? If not high tensile, any reason for not using threaded rod (or a cut down bolt)? the current studs have a blank section in the middle, and are about 43mm x 6mm overall.

Thanks for any informed advice!
 
Last edited:
Thanks for the reply. Having talked to a couple of engineers, I've ended up making new studs from 304 stainless steel bolts - cut the head off, and tapped part of the smooth shank end. Yet to fit. I managed to buy some replacement yokes from Volvo at a reasonable price (normally unheard of!) as the distributor had them on the shelf for something like ten years or more! The injector hole through the yokes is shaped like a keyhole - narrow slot in centre of yoke (slides on to keyway halfway down injector), and round hole off-centre. I now wonder if the idea is that you drop each yoke over the injector in alternating direction, so that the weaker ends with the large round hole are not all on the same side? I'm sure a single piece thicker yoke would have been plenty strong enough... Maybe it was just cheaper to cut the yokes out of flat bar than to make a machined/cast part?
 
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