Practically Classics Forum

One of mine fell out somewhere on the B4029! They're no longer available at any of the usual suppliers so what size bolt do I need?

I do remember that the thread felt a bit dodgy the last time i did it up being the heavy handed montser that I am. So will I need to tap the hole in the carb body? if so what size tap? will I need to drill it out and tap a larger thread?

Can you get self tappers that big? (Joking...honest! unless you can...)

Is drilling and tapping something that a bumbling incompetent fool like me can do without special equipment? (apart from a drill and a tap obviously!)

I haven't asked any stupid questions lately so about time i did. Any and all help greatly appreciated.

Thanks Chaps

Fatbloke wrote:Can you get self tappers that big? (Joking...honest! unless you can...)

Sure can: http://www.screwfix.com/p/coach-screws- ... f-10/12307

(Also Joking.....)

Mike, I believe that these have a 3/16" unf thread so just measure the length that you need and order some from, for example, THESE.

Other suppliers are of course available but Namrick has Government approval as a supplier to educational establishments so once you confirm that size I'll purloin one from just such a place and send it your way.

Thanks Both. I'll think I'll go with John's advice though!

Namrick are great, but I have found them to be rather expensive (especially as I have needed a lot of bolts for the Landy recently!). I've been using eBay for most of my fixings - it's OK if you know what size you need and you will find uses for the extra nine bolts you buy. To be more exact, you'll find uses for the extra four or five bolts you have left after you've lost a few!

I don't know the size, but if John says 3/16, I would suggest you measure how long the bolt needs to be and go for the next longer (possibly a machine screw rather than a bolt) as you can always ruin one by cutting it down a little (you then use the four that you can find to make one good one).

JPB wrote:Mike, I believe that these have a 3/16" unf thread so just measure the length that you need and order some from, for example, THESE.

Other suppliers are of course available but Namrick has Government approval as a supplier to educational establishments so once you confirm that size I'll purloin one from just such a place and send it your way.

Hi John, Are you sure about the 3/16"? I only ask because that doesn't seem to be a size available when I followed the clicky thing. or am I being exceptionally dense even for me?

3/16" is a very common imperial thread size, you're not confusing it with the hex-head (probably "A/F") size are you? That would probably be something like 7/16" A/F.

Says this on the Page Luxo.

- All bolts and nuts are displayed by thread size, not AF/Spanner size

If only one bolt fell out why don't you take out the other one and use it as a pattern for the replacement? Are you sure that the bolt fell out and is not lodged somewhere in the air filter housing. Could get expensive if it finds it's way into the engine.

These can't get into the inlet manifold unless someone turns them down along their length and cuts them into three pieces, so no worries on that score. The sleeve is in fact the original diameter of the bolt beneath the head, rather than a separate piece, and the threaded end is a spigot that can go through the backplate of the filter box but must lift away with it, so can't fall inwards, only outwards as the cover of the box is removed. As the mating flange at the throttle body is nigh on vertical, the bolt will tend to end up falling straight down if it's loosened fully before the cover is pulled out.

That doesn't mean that the miscellaneous fastener faeries won't have twoced it though. These charming wee souls are the older generations of tooth faery families, in case anyone wondered what they do for a living after the kids have all of their adult teeth.