Morris Minor Owners Club

Can anyone please tell me what size the brake pipe and fittings are please

A mix of threads, it seems! 3/8 UNF and 3/8 BSF, the BSF being a bit coarser than the UNF

you can buy ready made complete brake pipe kits

I know I can buy a kit ,but I have fitted a marina pedal box so need to make all lines. Anyone knowes of a kit for this also with ford front brakes its a bit of a mix and match. What is the pipe size?? I dont at the moment have any to measure.
Cheers

pipe outside diameter 3/16", pretty much universal stuff hangs in reels from the wall in many a garage! Marina almost certainly 3/8 UNF. Ford...

beware - Marina is very likely to be M10 x1 thread. It's very like the 3/8 UNF thread - and they can sometimes be 'forced' into one another - but that is very dangerous! The front end of a Minor is 3/8" UNF as standard - the rear axle ONLY is 3/8" BSF (slightly coarser thread). Although some on here have reported anomolies - so do check very carefully.
If making up your own lines - then yes 3/16" pipe - and best to use Kunifer pipe.

With the different threads there is also a difference in the shape of the flare. 3/8 UNF fitting has the inside half of the double flare folded tight onto itself. Whereas the 3/8 BSF double flare is only partially folded in. The female fitting will have a matching surface inside. Convex for UNF and concave for BSF. Also a good idea to run a known 3/8 bolt in first to confirm the thread. The bolt needs to turn freely. Don't know about the metric one except 10mm is slightly larger than 3/8. I do think the flare is the same as UNF. If the 3/8 test bolt is real loose, might be 10mm.

The flares can be either way in each/any thread - there is no set rule for this - it depends entirely what the pipe is connecting to. You should always inspect the mating part - and then make a flare to suit.

Good point, but it seems in some kits the pipes all have female flares, which if used, need quite a bit of tightening to effect a seal, as some of the ends are trying to seal against the wrong profile in some unions.

Hmmm - good reason to NOT buy the kit!

les wrote:Good point, but it seems in some kits the pipes all have female flares, which if used, need quite a bit of tightening to effect a seal, as some of the ends are trying to seal against the wrong profile in some unions.

Yes, I've seen that- can't be good or safe practise to use a female(op 2) where a male (op 1) should go as you are working with almost a point contact!!
Definitely check your particular unions before getting pipes made as I for one have one of the "anomoly" Minors (and a set of wrong pipes!)

I thought MM and series II minors are BSF all round and minor 1,000s are UNF front with BSF at the rear.

Maybe! I don't know about early cars - hence always check.

I'm sure this is right, as the front brake design was updated so were the threads, but the rear stayed the same. My series II has BSF all round.

minor_hickup wrote:I'm sure this is right, as the front brake design was updated so were the threads, but the rear stayed the same. My series II has BSF all round.

My 62 traveller has a mix of BSF and UNF at the front, I'm not the only one either, but in 40 odd years anything could have happened, hence check what you actually have rather than what you should have!!

I thought I was clear on the brake union threads used but now Im confused!

The front brake threads on my 63 traveller are 3/8" UNF (this is a standard 24 TPI thread)

I thought all the rear ones were 3/8" BSF but looking on the Brake pipe co uk web site - They list morris minor ones as 3/8" UNF with 20TPI threads? is this a non standard UNF thread form or do you think there confusing with BSF which is 20 TPI? but has a different thread angle. The flats are 'nicked' as you would expect with a UNF fitting???

http://www.brake-pipe.co.uk/unions.html

The rear axle is 3/8" BSF - 20 TPI.

Top tip.If you want very nice bends in your brake pipes, form them around a large socket (35mm or similar) that way the pipes have a more professional finish.

PAULJ wrote:I know I can buy a kit ,but I have fitted a marina pedal box so need to make all lines. Anyone knowes of a kit for this also with ford front brakes its a bit of a mix and match. What is the pipe size?? I dont at the moment have any to measure.
Cheers

I'd strongly recommend making up your own lines as there won't be a kit off the shelf that will fit anyway. If you have the old male and female fittings and can note where they came from, you can repace old with new by comparing at a local motor factors.

The pipe diameter I'm fairly sure is always the same size. So if you ask for brake line it will fit Marina, Minor and Ford. Kunifer pipes won't rust and are easier to bend than steel. Copper pipes will work-harden so steer clear.

If you don't have the old unions, see if you can borrow one of each type for a deposit and go round documenting what fits where. Then you can go back and order the right ones and return the spares. Bit of a pain initially but will save time in the long run.

Ford are likely to be m10x1 thread - if reasonably recent vintage?