Any experts on hydraulic union threads?

[ElvisWedgely]

If my memory serves me right, a few years back I was offerd a Land Rover clutch slave on the bay to fit the Wedge, as they are the same, and the guy offered me an adapter union to join the old pipe to the Landy slave. I never took the offer as the car was sold before I got round to do the job but I believe such an adaptor union exists.

Tony. TCB.

[adam quantrill]

At last - some progress. I have purr-chased an M12 x 1mm female union, that fits the original TVR one perfectly, so I can begin to make a short adapter pipe.

I also got some 7/16" x 24tpi nuts, which start to screw into the slave cylinder, but then the thread gets tight after a few turns, so maybe not exactly correct.

I'll compare them with the other 7/16" one next (which was billed as 20tpi). Almost there - but no cigar....

Well the 24tpi ones are obviously too-fine thread.

The 20 tpi one looks much closer to the bleed nipple to the naked eye, but still it doesn't go in.

The bleed nipple does 5 exact turns in 6.2mm which is 1 turn = 1.24mm so 20.5 tpi.

I think the bleed nipple is looking more like 1.25mm pitch - which is metric, for sure. It's under 1% difference which is within my measurement accuracy.

So that's it - I have exhausted all possibilities, except M11 x 1.25mm. Time to order a die, then, as I don't think I have that in my metric set. £7 on the flea...

Latest update:

Hhmm well this is a turn-up! While the britpart slave has two of these "unknown" possibly M11 threads, the other one I bought before only has one M11, and one slightly smaller one ostensibly for the bleed screw. So... nick the bleed screw from the Britpart one, into the M11 hole, that fits, and a smaller union I had hanging about into the smaller hole - that fits.

So now I can make up the adapter pipe and it should all hang together...

That will give me a less leaky clutch until I can get to the bottom of the M11 (or is it?) malarky.

Edited by adam quantrill on Wednesday 26th November 23:03

[adam quantrill]

Well I bit the bullet - made up the adapter pipe:



(sorry about the focus but you get the idea)

whipped out the old clutch slave, whacked in the Landrover one, connected the pipe, job's a good 'un!

So I am now Landrover master and slave - and they are cheap as chips! And a nice firm clutch. Happy days.

I'll still order that M11 die to cut some threads just out of curiosity...

[Wedg1e]

adam quantrill said:

fk me, no wonder you can't work out what size things are if that's the sum total of your precision measuring equipment

[adam quantrill]

Yeah one day I'll invest in a digital one ;^) It's actually quite accurate - or at least easily accurate enough to tell the difference between 9, 10, 11 and 12 mm....

I've been using it to measure up bike parts for the son's carbon frame and I haven't ordered anything the wrong size... yet.

I also have my grandad's old Starret micrometer as backup - just have to convert from inches back to mm....

[adam quantrill]

Bump for rockettvr.

Also I now have digital calipers at last - £7 from chinese ebay.

Also note that this mod has been on the car now for 5 years. I was going to support it with a small bracket off a sump bolt, but never got around to it. The pipe is obviously man enough to support the extra weight of the union.

Edited by adam quantrill on Monday 13th May 10:59

[Rockettvr]

Raising up this again
Last year I gave up trying to find out what size the LR slave thread was - I’m guessing you never found out either Adam ??
The nearest I can find to 11 mm would be a 7/16 unf ??
I repaired my slave with a seal kit last year but it’s leaking again and the bore looks none too clever so need to replace entirely
I’ve still got the landy one but no idea of the thread ???
Anyone cast any light ??
Metric/ imperial/ bsp/unf
ffs why so many variables ??

[adam quantrill]

Yeah I think my advice is to buy a few LR ones and hope you get enough bits to make it work, as they are around 7 or 8 quid from 4x4 specialists.

[Rockettvr]

Just bringing this up to date
The thread in the clutch slave was indeed 10mm
After a bit of research I found a part number (FTC 5202) that seemed to correspond with the 10mm pipe union size - ordered one and its identical to the original- inc bore size etc
Seems to be common on the later land rovers - mine was marked for a td5
So if you need a clutch slave that’s the part no to look out for - £10 from a 4x4 specialist on eBay

[BoltonTVR]

Rockettvr said:

Just bringing this up to date
The thread in the clutch slave was indeed 10mm
After a bit of research I found a part number (FTC 5202) that seemed to correspond with the 10mm pipe union size - ordered one and its identical to the original- inc bore size etc
Seems to be common on the later land rovers - mine was marked for a td5
So if you need a clutch slave that’s the part no to look out for - £10 from a 4x4 specialist on eBay

Great work! I need to replace mine so will get one ordered.

[adam quantrill]

What's the thread pitch 1.25mm or 1mm on that 10mm union?

[Rockettvr]

Hi all
Bit of a brain fart in my previous post - the part no. Is correct but the Union thread size I quote is incorrect- it is in fact M12 x 1
HTH