Caliper bleed nipple

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cliffa

cliffa

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Hi all,
I'm overhauling a standard Lockheed caliper, but this one has a larger bleed nipple fitted than the normal 1/4". The thread on it is not well formed so I thought I'd replace it. I measured the thread pitch (admittedly with a metric gauge ) and it's 1.25mm so a tad over 20TPI. and just under 9mm diameter on the major thread, so I took a guess that it's 3/8" BSF. New nipple arrived and guess what - it won't fit, it's about 0.5mm larger on the thread diameter. It looks as though it came from the factory with this nipple are there are no signs of any work being carried out. Has anybody else come across this, and if so what thread is it please?

Cheers,

cliffa.
 
Norton part number 06.1929
Google got me this.
www.baxtercycle.com

06-1929

Caliper Bleed Screw, 1/4" x 28
www.baxtercycle.com www.baxtercycle.com
 
It would need quite a few turns of thread tape.

3/8" is around 9.5 mm, could it be M9-1.25 ? but seems odd when there are common M7 and M8 nipples if it was some form of well done thread repair.
 
Wow, Baxter Cycle want US$8 for a stock nipple when it cost US$2.35 from AN.
 
Time Warp said:
It would need quite a few turns of thread tape.

3/8" is around 9.5 mm, could it be M9-1.25 ? but seems odd when there are common M7 and M8 nipples if it was some form of well done thread repair.
Click to expand...
I guess it could be an old repair that was well done. I wondered if it may be metric too, but I've never heard of M9 being used for anything. Mind you my Morini has some M7 bolts so who knows :rolleyes:
 
I went with a SS bleed nipple the last time. Worth the extra bucks.

Caliper bleed nipple
 
cliffa said:
I guess it could be an old repair that was well done. I wondered if it may be metric too, but I've never heard of M9 being used for anything. Mind you my Morini has some M7 bolts so who knows :rolleyes:
Click to expand...

My 1973 Moto Guzzi had M7-1 on the shift and brake link rods but oddly enough my ALDI tap and dye set had both (Those crafty Germans) so was able to extend the thread easily.
IIRC the Magura brake light switch had a M9.1 thread so there are a few oddities about.

A (large) thread around 9 mm would be hard to place on that small pad on the caliper with the stock 1/4" bleeder offset as is toward the mounting lug.
A picture perhaps ?

Edit.
I just noticed the pad for the bleeder is different (Dec 73 / Mk2a) to that in the Dave pic and not raised circular like that but flat and more integral to the main body.
The rivet counters will be excited ??

Caliper bleed nipple
 
Last edited:
Here's a couple of pics of it which is the same pattern as yours coincidentally. I think you'll agree no real signs of a previous repair.
 

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Time Warp said:
My 1973 Moto Guzzi had M7-1 on the shift and brake link rods but oddly enough my ALDI tap and dye set had both (Those crafty Germans) so was able to extend the thread easily.
IIRC the Magura brake light switch had a M9.1 thread so there are a few oddities about.

A (large) thread around 9 mm would be hard to place on that small pad on the caliper with the stock 1/4" bleeder offset as is toward the mounting lug.
A picture perhaps ?

Edit.
I just noticed the pad for the bleeder is different (Dec 73 / Mk2a) to that in the Dave pic and not raised circular like that but flat and more integral to the main body.
The rivet counters will be excited ??

View attachment 20273
Click to expand...
Oh, and one for the rivet counters. Ex naval folks will be enthralled ;)
 

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Time Warp said:
I just noticed the pad for the bleeder is different (Dec 73 / Mk2a) to that in the Dave pic and not raised circular like that but flat and more integral to the main body.
The rivet counters will be excited ??
Click to expand...

I think you must be looking at the brake pipe fitting?
 
L.A.B. said:
I think you must be looking at the brake pipe fitting?
Click to expand...

I withdraw my, was there two caliper castings. :D

Yes I was looking at the brake pipe fitting and fairly sure I had my glasses on. (and no different to my caliper)
 
Final update on this. I managed to get a good second hand 3/8" BSF second tap and ran it down. I was a bit worried it would cross over the existing thread, it seems to have followed it exactly and did take out quite a bit of material. No idea what the original was though. Anyway all good now...


Happy & Healthy Christmas and New Year to one and all.

Cheers,

cliffa.
 

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cliffa said:
Final update on this. I managed to get a good second hand 3/8" BSF second tap and ran it down. I was a bit worried it would cross over the existing thread, it seems to have followed it exactly and did take out quite a bit of material. No idea what the original was though. Anyway all good now...


Happy & Healthy Christmas and New Year to one and all.

Cheers,

cliffa.
Click to expand...
The new thread looks good
As long as the taper in the bottom of the bleed nipple bottoms out properly it's a good job
Cheers
 
baz said:
The new thread looks good
As long as the taper in the bottom of the bleed nipple bottoms out properly it's a good job
Cheers
Click to expand...
The new nipple wouldn’t seal initially so I popped one ( I bought 4 as they were cheaper like that) in the lathe and removed the thread so it would slide in, then serrated the tapered tip with some saw cuts, put it in my battery drill and span it. Nice clean taper now and seals well.
 
Hi , thank you , just want to know if it exist , as it could help somedays, I had used only 10x100, 10x125, 3/8 UNF and 1/4 UNF , allways to glad to learn something , have a nice day , Pierre
 
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