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MG Midget and Sprite Technical - Hydraulics fittings

Good morning Gentlemen
I'm looking for a solution regarding connecting the clutch feed pipe, which has 7/16" outer thread, to a braided hose which has a 3/8" outer thread. The braided hose came with the concentric slave I'm to fit. I haven't found anything so far. I have been loking for an adapter with 3/8 to 7/16 inner threads. The cobber feed pipe dimension is 1/4".
Would any of you have an idea to an easy solution?
Jan

Jan Kruber

Morning Jan.
The fitting on the end of your braided hose is a JIC. nipple. Are you sure you have your measurements the right way round?
The reason I ask is that JIC uses UNF threads (same as SAE), but 3/8" UNF goes with a #3 JIC fitting which is very rare. #4 is much more common, which has 7/16" UNF thread. #3 is unusual, but they do turn up now and then.
To confirm you can count the threads. 3/8" UNF has 24 tpi and 7/16 has 20 tpi.
I suspect the other fitting will be a BSPP.

You can see at the end of the JIC nipple an angled face. This is a standard 37 degrees angle face and the JIC fitting seals metal-to-metal on that face. Which means it requires a specific JIC adapter to seal effectively.

You are looking for a fairly unusual bit of hardware, but it's not impossible to get. Any specialist hydraulic spares company should have something to help, even if it means two or three fittings screwed together. Personally I find my local tractor garage very helpful as they are used to dealing with both European and American (NPT/SAE/JIC) hydraulic standards, often on the same machine.
Greybeard

Hmm
Best bet cut the end off the copper pipe, get yourself a 3/8 female flare nut,it will have a 3/16 hole- drill it out to 1/4 and slip it on the pipe and then reflare the end of the pipe, then your braided hose should screw straight in to it--------
William Revit

Jan, I had the same difficulty, only I wasn't using a flexible hose but the threaded connection onto the slave end was too small to take standard brake/ clutch pipe fittings. I took the pieces to a tractor workshop and he went through drawers of fittings and adapters that they use for diesel injector pumps and found some adapters. I think I sent you a photo of it - not pretty but it works.
GuyW

Guy - you're on the right track I reckon. I didn't think of injection pipe fittings but they are often small JICs.

Willie - no disrespect, but a standard brake flare will definitely not seal on JIC. It's possible to flare the pipe to match with the correct tool, but it's designed for stainless steel or Tungum and thin walled copper will almost certainly split with such a wide flare.

Possibly the easiest adaptor would have a JIC swivel nut (#3 or #4 as appropriate) at one end and a 1/4" Swagelok the other. Just cut the pipe, install the nut and the two ferrule rings, push the joint together and tighten with a spanner. No special tools required - the ferrules crimp onto the pipe and burnish the mating surface, forming a gas tight seal. But best to use a brass Swagelok; the more common stainless type would crush the pipe before deforming the ferrules properly.
Then the JIC nut can simply be screwed onto the nipple. No sealant required, but you can get tiny flared copper gaskets for them. They are a bit of a "belt-and-braces" measure though, they aren't normally needed.
Greybeard

Jan, as you bought this as a kit of parts with the concentric slave, what do the suppliers say about it? They must have an intention about what union that pipe would attach to.

You have got the Flexi the right way round? It was the attachment at the Ford slave that I found difficult to match on mine as the extension pipe needed to go where the long Ford bleed nipple usually sat, and that was the undersized fitting.

The ideal would be a Flexi pipe made up with a JIC fitting at one end and a 3/16 SAE at the other.
GuyW

Grey,
The thread on the braided hose is a common 3/8" thread like the other 3/8" fasteners on the vehicle, tested it with a nut.
I consider trying to find a 7/16" banjo and bolt for the braided hose and fit it directly into the master.
There is a tractor machine shop not far away, and I'm not in doubt, that they have something I can use. Only, if I do not have a spare part number or a vehicle identification, they can not help me. I have tried before in another matter.
Jan Kruber

I am facing exactly the same issue on my MGA. I am going to get a hose or pipe made up with a female fitting for the clutch pipe on one end and a female fitting for the concentric SS hose on the other.

This can be made by any shop than makes hydraulic lines and doesn't require a search for or the expense of a specialist part

Dominic Clancy

Jan, I will go to the hydraulic shop in the next few days and take a clutch pipe and the JIC flex pipe with me - If I can get a solution do you want me to get a second one for you?
Dominic Clancy

O/T sorry.

Dominic, I'm trying to email you again but now my BT email is playing up!
Nigel Atkins

Dominic
I dismantled the 1/4" pipe and realized that there was an 3/8 thread in the master with an adapter with a 7/16" thread.
So suddenly it became an easy task. I went to the local Brake /clutch shop and they made a short pipe to me with a male fitting in one end and a female in the other.......
Jan Kruber

That's my plan too....
Dominic Clancy

This thread was discussed between 03/03/2019 and 04/03/2019

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