rust and torque values

[enotslim]

I'm looking for a simple way to remove rust from bolts, nuts and fittings and to prepare the "cleaned" parts for reassembly. This seems necessary because significant rust will alter the effect of torquing to specified values. Purchasing new is always an option for bolts and nuts, but rust on any female threaded fittings (or unthreaded tunnels) will remain.

In general, an acid (vinegar) bath seems simple for rust removal. Wire brush, wheels, etc. seem time-consuming and at least minimally destructive. What treatments will then prevent rusting after reassembly?

Bluing looks interesting if it really works (and doesn't burn the house down):
(
referenced here
viewtopic.php?p=580446&hilit=vinegar#p580446)
and


But what about the female fittings for bolts or even just non-threaded tunnels?

Or are there better ways (and does it really matter)?

[scot850]

I like the rock tumbler idea. Those bolts come out really nice. I use a rust remover fluid but it is more work intensive as I still have to help agitate any thicker rust using a wire wheel on a 6" bench grinder before re-dipping a 2nd time. There is also a 2nd solution that then coats the bolts similar to the oil treatment.

https://www.princessauto.com/en/super-s ... 0008606360

I will have to find the product I had for putting a rust resistor layer on the bolts.

Neil.

[abscate]

Nothing too exotic. Wire brush bolts, use thread chasers on nuts. I nickel lube everything in the rust belt and derate torque by 30% from spec value

[enotslim]

Thanks. Practically speaking, what is the difference between Permatex anti-seize #80078 (al/cu/graphite) and #77124 (nickel)? Which applications benefit from which compound?

[abscate]

Nickel is more Nobel and less prone to corrosion but there isn’t a big difference. Using either one will get you the 5-10 year improvement that is needed for these cars.

There is a lot of blind faith in torque values for parts, when Un calibrated and proofed torque wrenches, technique, and 25% variation nominal in these tools exist. If you aren’t using new hardware and new parts, the worn threads don’t support new torque specs anyway


. Hardware does four things…

1. Stops stuff falling off…non critical torque, tight enough to stay on

B Hold stuff in position…wheels, brake rotors….hold them on and make them flat without distorting, cylinder head covers

(iii) Seal critical stuff …cylinder heads, gaskets

SQRT (16) Preload and bearing presets in transmissions….Uber-critical

I routinely do the first two and sometimes three without torque wrenches.

Upshot? Torque isn’t that critical on most things

[volvolugnut]

I would add the thought that many inexperienced people are worried:

A. They leave the fastener too loose and it falls off.
B. They get the fastener too tight and it shears off.

These people need the torque spec and torque wrench to gain confidence.

volvolugnut

[enotslim]

Nothing too exotic. Wire brush bolts, use thread chasers on nuts. I nickel lube everything in the rust belt and derate torque by 30% from spec value

Well, I discovered strong opinions on line about torque values for dry (torque to spec) vs "greased" (usually 70-80% of spec) fittings. And then Permatex says torque to spec when using their antiseize. Seems like antiseize is essentially grease plus particulates. The particulates likely alter the relationship between torque and clamping force compared to "grease" without particulates.

I also understand the advice that reducing torque values isn't critical for certain types of fittings. I'm just trying to understand the basic physics of these fittings and any lubricants, antiseize, threadlocker, etc. that might be applied.

[volvolugnut]

The subject of threaded joints and fasteners becomes very technical. There are many thick books on the subject.
volvolugnut

[wittyquiz]

Thank you for your responsecoreball
What you're saying makes sense to me.

[454cid]

Nothing too exotic. Wire brush bolts, use thread chasers on nuts. I nickel lube everything in the rust belt and derate torque by 30% from spec value

30% seems like a lot to me. Is that number specific to the nickel lube that you're using? When I use anti seize I've only derated the torque from 15% to 20%.