12 replies to this topic

[Big_jim]

Hello, can anyone tell me the bolt thread sizes used on a mini?

Im looking to order an assortment of bolts to help with the re-build im doing but i dunno anything about bolts and threads and pitch etc etc....

If anyone can help that would be brilliant!!!

thanks
Jim

[Udo]

Firstly imperial not metric

Basically UNF (Fine thread) if going into steel/iron

and UNC (coarse thread) if going into alu ie gearbox /transfer casing

You may find the odd metric one on anything somebody has added non standard and some odd brake setups had a larger metric union on the master cylinder


Various sizes from 1/4unf/unc upto things like the front subframe tower bolts

Edited by Udo, 27 February 2007 - 07:52 PM.

[Guess-Works.com]

Udo pretty much has it... but what I would also say is, dont be tempted byt stainless steel... most mini bolts are HT Steel, and should be replaced with the same...

The majority of bolts are 5/16 and 3/8, with various sizes up and down.... it's also worth noting that a lot of bolts are shanked which holds items in place.

[Big_jim]

The main stuff i have to find bolts for is things like door handels, and rear numberplate light housing...

these would all surely be ok in stainless....

I wouldnt replace anything that would need its strength with anything other than high tensile....


Thanks for the replys...

Jim

[OllyD]

I think you can buy big assorted bags of bolts for minis on ebay. Keep meaning to order a bag myself.

[$way]

I think you can buy big assorted bags of bolts for minis on ebay.

you get raped on the price of these, and it might be 200 pieces but thatll be various nuts bolts and washers.

much better to go to a local tool shop/bearing place and buy the nuts and bolts in individual boxes of 200 or whatever. youll get many more for a LOT less.

they are cross head set screws for the door handles and number plate light arent they, probably 1/4 UNF or smaller.

J

[Big_jim]

Can anyone tell me the small sized bolts that hold things like the door handels and interior door components...

thanks
Jim

[Guess-Works.com]

you're probably down to the likes of 3/16" unf or even 1/8", these you'll not get in a mixed bag... best find a local engineering supplier...

[dklawson]

Some of the door lock components use a funky thread that is neither a machine screw... nor a wood screw. However, the machine screws on most the door lock parts (at least on Mk1/2 cars) are 10-32. That size is close to (but smaller than) M5x.8 You can thread a 10-32 directly into an M5 tapped hole... but not the other way around.

The balance of the other fasteners are typically UNF as mentioned, specifically 1/4-28, 5/16-24, 3/8-24 and 1/2-20 in a couple of places. Where fasteners go into castings it's more common to see coarse threads. Those would be 1/4-20, 5/16-18, 3/8-16. I don't think I've seen a 1/2" coarse thread bolt on a Mini.

[Dan]

There are lots of different threads used.
Some of the interior parts are BA, the small size version of Whitworth for sizes up to 1/4" and which is sort of metric and sort of not. This thread was declared obsolete by British Standards in the early 60's and therefore BMC / Leyland / Rover naturally carried on using it up to the late 80's.
Door catches are BS on later internally hinged doors.
There are many metric parts fitted to later Minis and all hydraulic brake parts have been metric on the Mini for ages.

There is no short answer to this question, you just need to get the right stuff for each part. A bulk order won't really help as there are so many different threads and parts used.

Get a parts manual, the Moss one is the most helpful in this respect as it has a table in the back giving the thread and size for each type of standard screw and bolt used by Rover, along with the dimensions of all other standard parts like washers. For example washer GW302 is very common in the Mini so you could look that up and buy some to the same spec. That way you'll know that things not appearing in the tables are unique and that a genuine part might be better.

[dklawson]

Dan, the only BA threads I can think of (apart from on some of the Smiths gauges) are the screws holding the center binnacle to the firewall. Where else have you found them? I'm just curious which ones I may have put the wrong fastener in!!

[Dan]

Holding the cable retaining brackets to the dash rail on padded dash rail cars and other similar small bits and pieces of interior trim like the early binnacle as you say. If a Mini has a ratchet choke cable then one end of the switch panel is held by a metric nut and the other end by a BA which is extremely annoying. I have discovered a couple of these BA threads by not being able to remove the metric or UNF nut that I have threaded onto them in the past sadly.

[dklawson]

Dan, that's bad news. Now I'll always be wondering if I'll be able to get things apart when I next disassemble the interior! Live and learn.