Right, i'm currently constructing the brake system on my stm locost. In the front circuit there is an m10x1 4-way union (front wheels, master
cyl. and brake light pressure switch), the male fittings from the two front wheels and master cyl. will seal correctly in the 4-way because of the
convex/concave faces, the one that worries me is the brake light pressure switch as it is a male tapered thread (and no convex face) going into a
parrallel female thread in the 4-way union, surely this can't seal suffciently for a braking system, shouldn't the female thread in the
4-way be tapered as well...? What pressure switch/4-way union combination has everyone else used..?
Cheers.
It will be fine, The taper will seal the thread.
Steve.
i thought that my part was called
3way + brake switch.
sow it has a special hole (incl. thread) in the middle and 2 outlets on the sides and one entrance in the middle.
Tks
quote:
Originally posted by stevec
It will be fine, The taper will seal the thread.
Steve.
quote:
Originally posted by tks
i thought that my part was called
3way + brake switch.
sow it has a special hole (incl. thread) in the middle and 2 outlets on the sides and one entrance in the middle.
Tks
That is what I have - 4 way M10, and the sensor has a tapered thread. No leaks from that part so far (leaks most other places!). You can also get a compound to apply that helps the seal (I dont think PTFE is advisable). Try it and see, if it leaks, nip it up a bit tighter. If it still leaks, look for another solution.
Put a suitable no. of copper washers in to stop it bottoming out and provide another seal...
yeh i was going to try it but i'd prefer to get it right in the first place... Anyone used a pressure switch with a convex end fitting or 4-way
with a tapered thread for the switch...? or any other ideas...?
cheers
make a pic of yourse
/ look at suppliers sites wich you have and wich they also sell,
i'm quite sure there are wrong ones out there
Tks
We've done this one before re suitability of ptfe tape and bodged non-similar threads in the brake circuit. Whilst it's possible and can
work, the concern is re weeping brake fluid loss resulting in a distinct lack of breaking.... In fact, I recall it getting quite heated
okey i looked at merlin motorsport.
there are 2 types M10x1 or UNF
the switches exist also in 2 types sow make your own conclusion.
Tks
p.d. my switch was deliverd incl. a copper/blue grommet thing..
quote:
Originally posted by BenB
We've done this one before re suitability of ptfe tape and bodged non-similar threads in the brake circuit. Whilst it's possible and can work, the concern is re weeping brake fluid loss resulting in a distinct lack of breaking.... In fact, I recall it getting quite heated
quote:
Originally posted by jackal
quote:
Originally posted by BenB
We've done this one before re suitability of ptfe tape and bodged non-similar threads in the brake circuit. Whilst it's possible and can work, the concern is re weeping brake fluid loss resulting in a distinct lack of breaking.... In fact, I recall it getting quite heated
Well the way i look at it there should be no need for sealant/ ptfe tape as the fittings should make the seal, eg convex/concave face, tapered male/female, paralell thread with copper washer either side (as long as the faces are suitable), a mixing of any of these types of sealing won't seal in the way designed surely...? or am i just wrong/being too picky..?
So has anyone fitted a brake pressure switch without putting a tapered thread into a parallel one....?
cheers.
Its not unheard of in the steam-engine world to run tapored male bsp threads into parallel bsp female threads. Making the seal with the threads and a
turn of ptfe.
- Many parts are cut with a tapored thread and no facing flange, and a lot of boilers/manifolds are cut with parallel threads.
However at the same time, its obvously not recomended pratice. And certainly if your finding that the tapored is running out before it its tightening
up, that doesnt sound at all good to me!
Daniel
quote:
Originally posted by jackal
quote:
Originally posted by stevec
It will be fine, The taper will seal the thread.
Steve.
I would say it was a bit of a bodge really, tapered thread sealing relies on the two tapers tightening into each other across their length, where as if a male taper goes into a female parrallel then it will only seal right at the base of the male thread...? Also my pressure switch looks like it will bottom out if i tighten it properly....
cheers.
quote:
Originally posted by twybrow
...
You can also get a compound to apply that helps the seal (I dont think PTFE is advisable).
...
I always put a drop of Loctite Threadseal on anything with pressure behind it - never PTFE.