Welding for MOT - What's required?

  1. ZEDBED Member

    Messages:
    7
    Are there hard and fast rules governing the type of weld required by MOT inspection.

    For instance I've heard everything must be seam welded, but seam welding right across a flat panel (VW bus rear arch bottom half) is going to warp it a bit. Is it ok to sort of half weld in on with say 10mm welds with gaps between?

    What if it's a whole panel and was originally spot welded (outer sill)?

    I'm not going to do anything structural like the chassis as I'm just learning the black art and wouldn't want it snapping in half.

    I've googled but haven't had any luck finding the info - just loads of adverts for books.

    Thanks in anticipation
     
  2. migmag

    migmag Member

    Messages:
    700
    North east
    Treet all auto welding as structural and yes repair pannels and patches must be seem welded for MOT work.

    And dont cheet by welding the top and leaving the bottom.

    Try and weld both sides and not cover any part of the patch up with sikaflex or some other gear.


    To stop pannels warping you need to swap and change going from one part of the pannel to another welding an inch or so at a time this reduces heat build up.


    Do the job right first time cos the worst thing in the world is getting a nock back from your tester.
     
  3. Lippyp Member

    Messages:
    566
    Lancashire UK
    My first big structural job was sorting out the chassis on my Trooper, including making new bump stop mounts and a new body mount (theres a thread on it in the brew room) Just take it slow and steady.

    I've just replaced the inner and outer sills, bottom of the kick panel and door pillar on my Chevy and have seam welded where metal has been cut or it was originally seam welded and plug welded the sections that were spot welded on to replicate this finish without a spot welder. It'll be going in for an MoT soon and we'll see what happens. The trooper passed first time and the MoT man actually commented on the quality of the work.
     
  4. eternal optimist Member

    Messages:
    56
    West Berks
    Zedbed, I'd be amazed if an MoT inspector considered your wheel arch repair as structural - I don't think it matters a bit how you fix it. I think it's a question of any structural member or any point within 30cm of a suspension mounting/load bearing point must be seam welded. Might be worth having a chat with your garage to get their point of view. Oh, and it can help if you leave your welding bare (if it's structural) for the MoT man before you smother it in underseal.
     
  5. Devonian Member

    Messages:
    10
    My MOT man won't pass any repair if it's freshly gobbed up in underseal.
    I leave mine 'as is' other than a coat of red oxide paint to stop it rusting, which he is happy with.

    After the MOT I put a coat of underseal on to better protect the repair.

    Nigel.
     
  6. chap Member

    Messages:
    218
    Clanfield, uk
    For my motor, the MOT guy had a good prod around, leaving shiny metal visible through the under-seal :rolleyes:

    I was told by our friendly garage, that if the MOT man can get his pry-bar in where there is a welded patch, he'll rip it off and this will fail.
    I tend to seam weld everything, even wheel-archs :)

    To the best of my knowledge, a complete new pannel can be attached using spot/plug welds, so this should be fine if you atach the new sill in as secure a manner as the old one was.
     
  7. Justme

    Justme Member

    Messages:
    2,956
    Location:
    Pwllheli Wales
    Technicly a spot welded panel can only be replaced by spot welding for the mot as its a like for like they are looking for. I think the book says some thing like must be repaired to original specification. So a hole must be seamed to restore it to as new. If the tester wanted to be funny he could fail plug welds but I doubt any do as they all do welding repairs them self & will use that method. Skin sills are a sort of half panel so need spoting on the bottom & seaming along the top in most cases unless they are full sills that meet the original welded joint.

    Justme
    PS

    They cant insist on you not covering your weld with seam seler or underseal (but they can refuse to test). Also the MOT is a NON destructive test so they CANT rip patches off. They are allowed to tap & prod & scrape only.
     
  8. HughF

    HughF Member

    Messages:
    5,615
    Location:
    Work: Dorchester, Workshop: Corfe Castle, Wife's place: Frome
    Allowed to tap, and only with a specially Department of transport supplied tapping hammer! Basically, if it aint within 30cm's of a suspension or seatbelt mount, it's not classed as 'structural'. Plug welding is allowed, but stitch/seam is better if you can do it.

    personally I would favour us all being coded for car body repairs as I've seen some pidgeon sh**e that has passed MOT's that is damn right dangerous!

    H
     
  9. Masked Marauder

    Masked Marauder Member

    Messages:
    199
    Relevant stuff is all here:

    http://www.motuk.co.uk/manual/contents.htm

    Specifically
     
  10. migmag

    migmag Member

    Messages:
    700
    North east
    I have tested more cars than I care to remember and used to make good money at it.

    The truth is there aint that mutch more work involved in fully seeming (on patches) or stitch welding (top and bottom) repairs than spotting so why not do the job proppa in the first place??

    Then you can be confident its not gonna fail on your repairs.

    Use the same tester and he will get to know you as doin a good job so will not be as picky about your work..........


    Omly my two peneth you understand...........
     
  11. Masked Marauder

    Masked Marauder Member

    Messages:
    199
    Seam welding where spots are the original standard can cause crumple zones to work incorrectly by not allowing the correct deformation of the panels in an accident.

    A repair should be to the original standard.
     
  12. Lippyp Member

    Messages:
    566
    Lancashire UK
    I've just plug welded the new outer sill on my Chevy because it matches the original spot welds, mind you, its not really that structural anyway as the chassis and floor are so solid. I'll see soon if the MoT man passes it or fails it!
     
  13. Justme

    Justme Member

    Messages:
    2,956
    Location:
    Pwllheli Wales

    If it has a chassis it will only fail on body work if its within 30cm of a seat belt / seat / attachment to chassis / steering / breaking / suspension mounting point. Or if it poses a danger to pedestrians.

    Justme
     
  14. migmag

    migmag Member

    Messages:
    700
    North east
    Christ............

    As I said seem patches sticth top and bottom on pannels.............



    I give up Why dont people reed posts?:rolleyes:
     
  15. malcolm

    malcolm & Clementine the Cat

    Messages:
    9,073
    Location:
    Bedford UK
    Good point from the Masked Marauder though. The front chassis members in particular are designed to concertina in a very controlled manner to absorb energy in the event of a frontal collision, and they often have bend initiators pressed in to start off the deformation from the front rearwards.

    Although if the front chassis has rusted it is likely to be a small area so it's best to cut out and seam weld bits of rust.

    The MOT manual is good reading. I plug weld in place of spot welds, and seam weld when I'm cutting out and replacing a section of panel. MOT folk have always seemed happy with that approach.
     
  16. migmag

    migmag Member

    Messages:
    700
    North east
  17. mikeknowle mikeknowle

    Messages:
    8
    Thanks guys - brilliant thread. You've just removed another nagging doubt in my head about when to use differing types of welds.

    Seam welding, here I come. Yeeehaaaaaa :p
     
  18. mr_doggy Member

    Messages:
    7
    You may find this site useful for vw camper repairs.

    http://www.volkszone.com/VZi/

    You should be able to find pictures of details of the exact repair job you plan on undertaking.

    Good luck!
     
  19. Superbad Member

    Messages:
    280
    Where is this quote,I can't find it?
     
  20. Wozzaaah

    Wozzaaah The wizard of woz Staff Member

    Messages:
    14,745
    Wiltshire, UK
    TADA! ;)

    Oops, migmag has already posted the same link. :whistle:
     
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