One time use bolts .
- Thread starter wpod
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- Jul 11, 2014
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I hope so.
My VW is full of them, so was the kids Regal.
Torqued and stretch bolt to angle/yield... but shops and DIY'ers tend to reuse everything and hope nothing happens.
en.wikipedia.org
rts.i-car.com
My VW is full of them, so was the kids Regal.
Torqued and stretch bolt to angle/yield... but shops and DIY'ers tend to reuse everything and hope nothing happens.
Torque-to-yield fastener - Wikipedia
Back-To-Basics: Torque-To-Yield Bolts
Sometimes going back-to-basics can make the difference between a quality repair and a failed repair. Let’s take a look at torque-to-yield bolts. What is a torque-to-yield bolt? It is a one-time-use fastener that is designed to stretch during the torquing process (installation). Because of this...
I replace them.
Keep in mind that many "one-time-use" bolts are in fact reusable, but require measurement to verify they are still within working length.
This requires that a) the spec be published and b) it be followed.
Usually the spec is unpublished because it wouldn't be followed anyway. But it does explain why so many DIYers and "professionals" get away with it.
This requires that a) the spec be published and b) it be followed.
Usually the spec is unpublished because it wouldn't be followed anyway. But it does explain why so many DIYers and "professionals" get away with it.
Wow, you da man! I learned something today. Cool...
It is just strange because lots of the bolts weren't torque to yield over the years or certain applications weren't one time use bolts. For example the drive line flange to differential bolts on my 2015 Ford P/U are 12.9, 12mm bolts torqued to 76 lb ft. it seems strange as the torque numbers seem low for the 12.9 bolts so I am guessing the differential flange is the torque basis and the 12,9 12mm bolts are for the twisting loads. Pondering while eating breakfast leads to strange thoughts.
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VW uses stretch bolts on suspension and subframes a lot also.
People tend to cheap out and reuse them because they don’t want to feel nickeled and dimed on parts
Other bolts marked as "one time use" come new with Loctite on the threads.
BMW oil spray bar banjo bolts come to mind.
Instead of trusting someone (wisely) to read the published note or catching the number in the diagram indicating that the fastener needs a certain spec threadlocker, it's marked for replacement.
I bill them out and hand them out on every repair, warranty or customer pay. Ford has a rule that a repair done without using the required OTU hardware will not have a warranty, even if done by an outside repair shop. Its not just hardware, but seals, turbo lines and filters, some hoses. I have to go through the repair procedures for each repair so verify all the parts and quantities.
Awesome parts guys are a blessing to the techs . The parts guys know what they are selling and what a proper job needs to be done properly , so with certain issues they know by sales what parts go bad for the issues. The parts guys at the main branch were such an asset to me. [ when I was gainfully employed]
I don’t know about other people and shops, I can only answer for myself, that answer is yes.
Had to look up a rear drive unit fluid pump for a Mach E yesteryday. It was a pain becuase in the workshop manual step 1 for the pump was "remove rear drive unit." Step 1 of that one was "remove halfshafts." Step 1 of that section was remove IIRC the LH knuckle. Step 1 of the knuckle section was "remove the hub" which you had to do on both sides. Then I had to check the brake section because the caliper bracket bolts are OTU. All the suspension bolts are OTU, and I had to order 3 p/n's through not normal channels because they are used on a recall on another car so they are restricted. Each of those sections I had to read through line by line because the OTU hardware lists are not complete, even on 2022MY vehicles.
I have found that if you are reusing one-time use fasteners, it is best to NOT follow the published torque specs. 
With the poor quality of most fasteners these days its probably a good idea to replace when possible. Exhaust manifold screws are a good example. Good fasteners arent cheap and cheap fasteners arent good. The OEM's know exactly what they are doing when they spec low quality undersized screws.
Yes and many wonder why techs have soooo many extra bolts laying around. Because we are getting a pile of new bolts on every job now a days
Some of these jobs give you a bag full of stuff and you may only really need 4 of them
Some of these jobs give you a bag full of stuff and you may only really need 4 of them
My Buick(17 Lacrosse) and Caddy(19 CT6) has them(tty) on the calipers and I reused mine because when I changed out the rotors I went to 3 different dealers and no one had them in stock, when queried they say they reuse them. I figured a one time use should be ok and no problems so far.
There are some double headed fasteners under the dash on Toyotas and Hondas (maybe others) that you torque until the head snaps off. Typically, they hold the lock cylinder to the steering column. Obviously, more of a security than a reuse thing.
I wish Ford would either just packs of 1, or quantities needed for a repair. Or even just include them with the parts.