When doing system overhauls, do you replace washers, nuts, and bolts?

[Musicisair]

A lot of "kits" (cooling system, suspension, brakes, belts, etc) sold by ECS and others include extras like new bolts, clamps, washers, and nuts.

Do you generally​ replace these misc parts when doing an overhaul or part replacement? For instance, when replacing a thermostat, do you get 4 brand-new tstat-housing bolts (https://www.ecstuning.com/b-genuine-...537511580kt/)? Why or why not? What misc parts do you generally replace?

[pbonsalb]

I don't unless the bolt or nut or washer is damaged or is a "stretch bolt" designed for one time use. I have boxes of salvaged bolts, nut, washers so I rarely buy them unless I need new ones for cosmetic reasons,

[Pyropete82]

This subject has been posted multiple times here. I believe the Bentley manual tells you exactly which are reuse and which are replace. Obviously anything that is altered after install requires replacement i.e. Crush washer, head bolts, exhaust nuts, nylock nuts. All non graded steel is one time use, same with aluminum. The graded steel bolts and nuts are all reusable, however if you've had to over torque or use heat to tighten/loosing its time to replace.

Do you replace your lug bolts each time for tire change?


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[AJLM34A]

I will replace some the of cooling system hose clamps & hoses if I they have not been replaced since I owned my car.

[TostitoBandito]

Doesn't hurt, as long as you make sure and get exactly the right OEM hardware. I usually do a cost/benefit on it. If it's a few bucks I usually get fresh hardware if I'm replacing something that's been on the car since it was built. That way I get fresh bolts/nuts without any grime or damage. I also have a drawer full of miscellaneous OEM fasteners that are handy for when crap falls or is torn off the bottom of my car. Just used a bunch replacing my mangled fuel filter cover and the two plastic aero pieces that sit in front of the rear wheels.

Obviously, as has been said, any consumable hardware like locking nuts or crush washers must be replaced every time you take them off.

[RRSperry]

An infamous example are the two bolts that attach the bottom of the strut to the upright. Bentley says to replace them, but I just clean the loctite off of them and reuse with new loctite. (yes, I also clean the holes, and have measured the length of those bolts to make sure they aren't torque to yeild. They aren't.)

So in most cases, I reuse bolts. (exhaust nuts, head bolts, damaged bolts and nuts are a no no.)

[RightYouAreKen]

Depends. I got in the habit of replacing little nuts and bolts when doing major jobs because of a friend of mine. There's something gratifying to installing new parts with new hardware, and generally it only costs a few extra % of the overall parts total to toss them in the cart. However, for some stuff that will get removed/reinstalled often or doesn't get very dirty/damaged during use, I don't.

[tjm3]

My philosophy on this is:

if it's recommended then replace it.
If the nut, bolt or washer is in a place I can't get to very easily at a later date then I replace it.
If it looks like it needs replacement then it gets replaced.
If it's right next to other stuff in the list I'm ordering then I order it and replace.
If there's any other doubt, replace it.
If it can be replaced with something better, better yet, replace it.

By the way, nuts lose about 30% of their clamping force by the third time they've been torqued.

[pbonsalb]

I have been reusing nuts and bolts for decades without issue.

[tjm3]

F$ck the factory R&D guys. We have a new standard.

[JitteryJoe]

My philosophy on this is:

if it's recommended then replace it.
If the nut, bolt or washer is in a place I can't get to very easily at a later date then I replace it.
If it looks like it needs replacement then it gets replaced.
If it's right next to other stuff in the list I'm ordering then I order it and replace.
If there's any other doubt, replace it.
If it can be replaced with something better, better yet, replace it.

By the way, nuts lose about 30% of their clamping force by the third time they've been torqued.

This. I usually end up replacing. There are exceptions but more often than not I replace.