Aren't lock nuts supposed to be crimped or deform or somehow lock?

  1. Welcome to VW Passat Forums : Volkswagen Passat Forum – General discussion forum for Volkswagen Passat

    Welcome to VW Passat Forums : Volkswagen Passat Forum - a website dedicated to all things Volkswagen Passat.

    You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, Join VW Passat Forums : Volkswagen Passat Forum today!
     
Results 1 to 6 of 6
  1. #1
    1st Gear
    Join Date
    Dec 2008
    Location
    Westchester, N.Y.
    Posts
    171

    Aren't lock nuts supposed to be crimped or deform or somehow lock?

    I ordered some 8mm OEM lock nuts from Europa Parts (N90894601) for a downpipe replacement. The nuts are copper (or copper coated) and easily go on and off the OEM 8mm bolt which appears to be 10.9 zinc. Even when I tightened to 30ft-lbs as a test once I loosened the nuts they were loose, the threads did not deform.

    I am concerned when I use the nuts to replace the cat-downpipe connection that they will vibrate loose. I asked EuropaParts and they said nobody has reported a problem and to e-mail a picture to their support line. My question is aren't the threads of a lock nut supposed to be deformed or deform when tightened? Otherwise how the hell are they locking?

    Last edited by passat03wagon; 06-05-2019 at 03:47 PM. Reason: added inline image

  2. Remove Advertisements
    VW Passat Forum
    Advertisements
     

  3. #2
    5th Gear
    Join Date
    Sep 2002
    Location
    Fallbrook CA USA
    Posts
    5,130
    Can't say, but if they are copper, you should be able to deform them enough with Vicegrips to increase the thread friction.

  4. #3
    4th Gear
    Join Date
    Jul 2006
    Location
    Phoenix, AZ
    Age
    52
    Posts
    3,999
    Normally they are crimped on the end or deformed right at the thread entry / exit of the hole.

    If there is no visual of that, the threads might be manufactured to an imperfect thread, which when mated to the bolt, will cause a locking effect due to the slight mismatch in thread pitch.
    If the nut feels like it gets tight right away when turning it onto the bolt, then it's an interference thread fit.

    We do that kind of stuff all the time where I'm at.

  5. Remove Advertisements
    VW Passat Forum
    Advertisements
     

  6. #4
    1st Gear
    Join Date
    Dec 2008
    Location
    Westchester, N.Y.
    Posts
    171
    Quote Originally Posted by AndreasPassat View Post
    Normally they are crimped on the end or deformed right at the thread entry / exit of the hole.
    These aren't they roll loose. I wonder if they sent me "Genuine OEM". Have you ever done an exhaust flange install, do you recall the nuts being lock nuts?

  7. #5
    Neutral
    Join Date
    Feb 2019
    Location
    Vermont
    Posts
    118
    All the new flange nuts I used when putting my exhaust manifolds back on my truck were all tight at the end to the point that you could only turn it about 4 threads by hand then it would require a tool.

    The nuts that came with the various other exhaust components were the same way.

  8. #6
    4th Gear
    Join Date
    Jul 2006
    Location
    Phoenix, AZ
    Age
    52
    Posts
    3,999
    Quote Originally Posted by passat03wagon View Post
    These aren't they roll loose. I wonder if they sent me "Genuine OEM". Have you ever done an exhaust flange install, do you recall the nuts being lock nuts?
    All of the exhaust work that I have done on Passat's, the copper nuts on the exhaust manifold and down pipe connector on the manifold have been some type of crushed nut that you'll get maybe couple of turns by hand and then after that a wrench is required.

    These here from ECS Tuning are actually crushed from the outside at 120 degrees apart (3 places equally) and the thread is undersized at the 3 points. When turned onto the stud they are pretty tight.

    Now there is a chance you might have a bad run of exhaust nuts. The manufacturer of those things chunk them out by thousands per shift. It's pretty easy to have a few non-conforming ones slip through. I'm in manufacturing so I know these things.


  9. Remove Advertisements
    VW Passat Forum
    Advertisements
     

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Where do you live?

Year of model

car model

Please select your insurance company (Optional)

Log-in

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

    Tags for this Thread

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •  
    Powered by vBadvanced CMPS v4.1.2