- My model of MX-5 is: __1997 NA 1.6 90BHP
- I’m based near: __Glasgow
- I’m looking for technical help or recommendations on: __Greasing the suspension bolts when reinstalling them.
I’m thinking of replacing my coilovers and I’ve been watching numerous youtube videos on the subject.
What I wondered was why don’t they use grease on the bolt shafts when putting them back in the suspension arms along with copper grease on the threads to help with future removal?
Is it down to being messy or increasing install time?
Or simply because you shouldn’t do it?
I personally would apply some grease on the non threaded shoulder section where it goes through the bushing inserts, this could help prevent seizure long term. Very important not to get it on the threads though as it will be impossible to torque to spec, they will be overtightened if there is. Will also help a lot with adjustment of alignment settings as the bolt will rotate nicely in the insert. I will be doing all of mine before I get it aligned,for now it’s just been put back together dry.
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Cooper grease the shaft not the threads.
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Thanks
That makes sense about the torque setting being off if the threads are greased.
Don’t the torque settings assume some greasing of the threads?
If they (mazda) provide torque settings with greased fastenings, this I don’t know. In my experience torque values are for clean/dry threads unless otherwise specified.
Edit: I may be contradicting myself slightly here but whenever I strip down components (that have a hard life/under car/wheel arch etc) I have a small bowl of penetrating fluid I throw them all in. Just for ease of reinstalling. I do dry the bolts off with a quid rub of paper towel and give them a spin in a scotchpad before refitting but the real torque may be slightly over when using the manual values in doing this, but not so much that I think it will be a problem. Never had an issue.
Only adds minutes overall to a job, actually probably net saves time overall.
So basically here there’s the correct, best practice answer which as others say is “don’t grease them”, because the torque settings are dry and grease messes this up. The numbers you usually hear quoted are 20% for threadlock, 25% for grease or oil, 40% for antiseize
But there’s also the real world practical answer, which is that it’s probably not that big a deal. Frinstance, on the NC the big arm bolts have a spec of 75 to 102nm, the bottom arm eccentric is 117-137, that’s a wild variation. So if you go to the bottom of the range greased, that’s pretty equivalent to the top of the range dry, meaning that the bottom value is equally acceptable for greased and dry and threadlocked. And there’s always a good margin built into these in the first place.
Also bear in mind these are all the torque settings with a new nut and bolt, your old tired ones may have gummed up or damaged threads, or they may be a little fatigued, so there’s variables in there too that are also messing with your torques.
On the other other hand, the problem with removing these bolts is rarely the nut anyway, so I’m not sure there’s that much to greasing the thread.
TLDR it’s not really that big of a deal in the real world, so I do the “best practice” of dry whenever practical, and there’s little reason to grease the threads but if you do get grease on the threads I’d not worry about it, I’d just bear it in mind when tightening.
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Yes, apply grease every time, those that say no , do not work on them everyday and and fixed on figures on paper not the real world of repairing.
M-m
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Personally i would (and will be when i rebuild mine underneath) grease them where they pass through the bushes, basically the shaft of the bolt, and use a small amount of oil on the threads to make it a bit easier to refit them. Best bet after that is to coat them with some clear underseal such as lanoguard (as an example) just to minimise corrosion creep back into the threads.
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