Any experts on hydraulic union threads?
Discussion
I am confusing myself rotten here... hopefully someone who knows how to measure threads can confirm.
I am attempting to use a land rover clutch slave cylinder on the 400SX. If I can make it fit, it'll provide us all with an alternative part which is much cheaper and more readily available than the standard slave.
Where I am stuck is finding a union which will fit the thread on the slave.
This slave cylinder is supplied with a bleed nipple, and the nipple fits both ports on the cylinder - they seem equivalent.
The nipple measures 11.0mm across the thread ridges, and also has an 11mm AF hex drive. The thread pitch appears to be 1.25mm.
I have got an M10x1mm union which is far too small, and an M12x1mm union which is too big.
The "standard" union on the end of the wedge clutch pipe is also too big to go in, and I suspect it's an imperial size, maybe 9/16"?
Ideally I would like a female union to attach straight onto this, so I can make a short adapter pipe, but I can't find one that will fit either!
So it looks like I need an M11x1.25mm male union? Which seems impossible to find. Any pointers gratefully received.
I am attempting to use a land rover clutch slave cylinder on the 400SX. If I can make it fit, it'll provide us all with an alternative part which is much cheaper and more readily available than the standard slave.
Where I am stuck is finding a union which will fit the thread on the slave.
This slave cylinder is supplied with a bleed nipple, and the nipple fits both ports on the cylinder - they seem equivalent.
The nipple measures 11.0mm across the thread ridges, and also has an 11mm AF hex drive. The thread pitch appears to be 1.25mm.
I have got an M10x1mm union which is far too small, and an M12x1mm union which is too big.
The "standard" union on the end of the wedge clutch pipe is also too big to go in, and I suspect it's an imperial size, maybe 9/16"?
Ideally I would like a female union to attach straight onto this, so I can make a short adapter pipe, but I can't find one that will fit either!
So it looks like I need an M11x1.25mm male union? Which seems impossible to find. Any pointers gratefully received.
I was going to say something very similar....
The earlier brake and hydraulic fittings were nearly all UNF threads on British Leyland built vehicles, as far as I know. So try that first. The bleed nipples across the cars were indeed something like 3/8 UNF for the small ones (like brake calipers) through to 7/16 for clutch cylinders.
There are also British Standard Pipe (BSP) threads, which are quite close to UNF. BSP threads used to be around all the cast iron plumbing fittings, before they went metric - As far as I know some still use BSP (kitchen taps and so on). BSP don't appear in vehicle hydraulics, but still turn up on the odd temp sender and oil fittings.
I do know some of the older Vauxhall cars had UNC (coarse) threads in their hydraulics as well, so there is a big range to go at.
Hope that helps...
PS - Not entirely sure newer seat belts are still UNF - Wedge ones probably are, but yer average Ford and so on now use metric fine threads - yet another variation in the mix !!
The earlier brake and hydraulic fittings were nearly all UNF threads on British Leyland built vehicles, as far as I know. So try that first. The bleed nipples across the cars were indeed something like 3/8 UNF for the small ones (like brake calipers) through to 7/16 for clutch cylinders.
There are also British Standard Pipe (BSP) threads, which are quite close to UNF. BSP threads used to be around all the cast iron plumbing fittings, before they went metric - As far as I know some still use BSP (kitchen taps and so on). BSP don't appear in vehicle hydraulics, but still turn up on the odd temp sender and oil fittings.
I do know some of the older Vauxhall cars had UNC (coarse) threads in their hydraulics as well, so there is a big range to go at.
Hope that helps...
PS - Not entirely sure newer seat belts are still UNF - Wedge ones probably are, but yer average Ford and so on now use metric fine threads - yet another variation in the mix !!
adam quantrill said:
Anyone know what the original clutch one is? That's the one at the bottom of the clutch pipe with the standard slave as supplied by TVR.
It seems to measure 11.9mm across the thread crests.
This one doesn't for the new clutch cylinder either (of course!) as it's too big.
Almost sounds like an undersize 1/2" but surely more likely to be 7/16"? It equates to 15/32" which isn't any standard I can find. It seems to measure 11.9mm across the thread crests.
This one doesn't for the new clutch cylinder either (of course!) as it's too big.
How many threads per inch?
Could it be an M12 coarse/fine/extra-fine? That would have a major diameter in the region of 11.966 to 11.974.
These links any help?
http://www.cotswoldengineeringsupplies.co.uk/Hydra...
http://www.customfittings.com/jic-hex-male-x-hydra...
http://www.parquip.co.uk/246715.html
It sounds like you need 7/16 20tpi.
http://www.cotswoldengineeringsupplies.co.uk/Hydra...
http://www.customfittings.com/jic-hex-male-x-hydra...
http://www.parquip.co.uk/246715.html
It sounds like you need 7/16 20tpi.
People are getting confused with nut size and thread size for example the original poster says the nut size is 11mm actually as already pointed out it is a 7/16 spanner but very close the poster who suggested trying the seat belt bolt to establish the size is correct they are 7/16 unf but that is the thread size way to big any way i have loads of them p.m. Me your addy i will send a couple over to you.
John
John
Yeah the nut sizes are almost no indicator of thread size with these things - I have some where the nut end is barely bigger than the thread diameter, and others where it is much bigger. In my posts I've been very careful to say which I'm measuring (I hope).
Thanks, I'll send you a mail,, if PH mail is working....
One mystery solved though - the standard one on our V8 wedges with the Girling slave is indeed an M12 x 1. I think this is what was putting me off as it's a bit unexpected.
Thanks, I'll send you a mail,, if PH mail is working....
One mystery solved though - the standard one on our V8 wedges with the Girling slave is indeed an M12 x 1. I think this is what was putting me off as it's a bit unexpected.
Edited by adam quantrill on Sunday 9th November 23:09
Sooo - just received a 7/16" x 20 tpi nut wot I bought off the flea.
It's very close - but no cigar! Still doesn't fit.
Here's a piccie of the fitting one (bottom - the bleed nipple) up against the non-fitting one.
The number of turns per inch/mm seem to be the same. However the thread angle appears to be different.
The overall thread crest diameter is the same to within 0.1mm. (11.9mm)
The other oddity is that I also acquired a female union which purports to be 7/16 x 20 tpi, the new 7/16 one doesn't fir that, but the bleed nipple in the picture does fit it. I wonder if this is the difference between 20tpi and 24tpi? But I can't see a difference in the picture (apart from the helix angle)
It's very close - but no cigar! Still doesn't fit.
Here's a piccie of the fitting one (bottom - the bleed nipple) up against the non-fitting one.
The number of turns per inch/mm seem to be the same. However the thread angle appears to be different.
The overall thread crest diameter is the same to within 0.1mm. (11.9mm)
The other oddity is that I also acquired a female union which purports to be 7/16 x 20 tpi, the new 7/16 one doesn't fir that, but the bleed nipple in the picture does fit it. I wonder if this is the difference between 20tpi and 24tpi? But I can't see a difference in the picture (apart from the helix angle)
What is the part number on the clutch slave that you recently bought or failing that what was it listed as fitting? I've done a bit of digging and it seems at some point Land Rover switched from imperial to metric threads (around the time of the early Discoverys). Given the part number we might be able to figure out what you've got and make sure it's the correct bore size too as this changed as well.
http://www.v8forum.co.uk/forum/viewtopic.php?p=810...
http://www.defendersource.com/forum/showthread.php...
http://www.v8forum.co.uk/forum/viewtopic.php?p=810...
http://www.defendersource.com/forum/showthread.php...
It's a Britpart FTC5071
The metric thread could explain a lot.... trouble is it might be M11 and I haven't found these anywhere, the nearest I can get is an M11 tap or die, then cut my own....
Looking at those threads they are not much help, I have M10x1 and M12x1 nuts which don't fit, and the 7/16" one is close but no cigar.
The metric thread could explain a lot.... trouble is it might be M11 and I haven't found these anywhere, the nearest I can get is an M11 tap or die, then cut my own....
Looking at those threads they are not much help, I have M10x1 and M12x1 nuts which don't fit, and the 7/16" one is close but no cigar.
Edited by adam quantrill on Thursday 13th November 08:51
I thought they would be helpful as it narrows your choice down to two thread types.
That male fitting you've bought is wrong, either the size or pitch.
You've even answered your own question with the female part you bought. You know it's 7/16 and your bleed screw fits into it as well as fitting the inlet on your new slave but still you think it might be metric.
That male fitting you've bought is wrong, either the size or pitch.
You've even answered your own question with the female part you bought. You know it's 7/16 and your bleed screw fits into it as well as fitting the inlet on your new slave but still you think it might be metric.
Edited by Russell Mc on Thursday 13th November 14:13
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