Lunched brake bleed screw thread

In article <zrHbg.4704$UR3.3688 (AT) newsfe7-win (DOT) ntli.net>,
MikeL <noone (AT) noone (DOT) com> wrote:

I'll have to become a bit more resourceful and find out. You're probably
right and it's not, although I'm loath to swap a known good caliper for a
few mm of thread unless I have to.

Well if it's shared with other cars get a seal kit and overhaul the 'new'
one. It's pretty simple to do.

--
*A bicycle can't stand alone because it's two tyred.*

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

In article <VyHbg.72515$wl.70342 (AT) text (DOT) news.blueyonder.co.uk>,
Steve Robinson <steve (AT) colevalleyinteriors (DOT) co.uk> wrote:

Make sure you use the correct type of tap pitch taper etc

I'd say it might be difficult to get the right tap? Looks a pretty fine
thread. Just a guess, though.

--
*A journey of a thousand sites begins with a single click *

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

In article <1148143843.313293.132800 (AT) u72g2000cwu (DOT) googlegroups.com>,
<dscharl (AT) supanet (DOT) com> wrote:

its only a hole for re leasing fluid when you want to, anything with a
sealing washer will do, no need to get too technical, had same thing on
sri for ten years with no problems, bleed screws on calipers are crap ,
good quality bolt and washer will last for years and years.

Seems the makers have got it wrong again, then. Given the vast pressures
involved I'd prefer a properly engineered seal to a 'bolt and washer'

--
*Dance like nobody's watching.

Dave Plowman dave (AT) davenoise (DOT) co.uk London SW
To e-mail, change noise into sound.

a bleed screw is only a modified bolt.

The message <1148147177.131443.133250 (AT) 38g2000cwa (DOT) googlegroups.com>
from dscharl (AT) supanet (DOT) com contains these words:

a bleed screw is only a modified bolt.

Yes, but modified in such a way that it, and the seat into which it
fits, make a seal capable of containing very high pressures reliably for
many years. Using the head of the bolt will mean, for a start, that
you're exerting many times the load on the threads because of the much
larger areas involved.

--
Skipweasel
Pay no attention to that man behind the curtain.

"MikeL" <noone (AT) noone (DOT) com> wrote

"Steve Robinson" <steve (AT) colevalleyinteriors (DOT) co.uk> wrote in message
news:MnFbg.72412$wl.14900 (AT) text (DOT) news.blueyonder.co.uk...



try re tapping it first with a tap the same size as the bleed screw


Oops...sorry for all these multiple posts.

Now I've managed to get a better look at it, I can see that the bottom on
the thread seems ok, about half way up it's been stripped. Makes me feel
slightly better that it looks like it's been done by a previous owner and
not me. Wondered why it suddenly refused to tighten - I must have
slackened
it a bit more than I ever had previously.

As Steve suggested, I'm going to try retaping it the same size and see how
I
get on.

I wouldn't bother. If the first half of the thread is stripped, that's about
as far as the bleed nipple screws in.
Safer to have a thread insert fitted and know that it wont suddenly fail.
Mike.

<dscharl (AT) supanet (DOT) com> wrote

a bleed screw is only a modified bolt.

Wrong.
About the only thing a bleed screw has in common with a bolt is the thread
and a hexagon to turn it. It is a valve. A crude one admitted, but a valve
nevertheless.
Mike.

"MikeL" <noone (AT) noone (DOT) com> wrote

"Dave Plowman (News)" <dave (AT) davenoise (DOT) co.uk> wrote in message
news:4e2a03e529dave (AT) davenoise (DOT) co.uk...


Forget it. Even if you could find a larger one, the taper seating at the
bottom of the hole would need re-machineing.

Agree totally. What I should've said is that I've seen oversize ones
mentioned for this very purpose, although where one can purchase them I
don't know.

Easy enough to have made if you know what you want.
Best bet though is to have a thread insert fitted, and use std nipples.
As for remachining the seat, see my earlier reply to Dave.
IMO it's easier to retap accurately, rather than worry about remachining the
seat.
Mike.

"Dave Plowman (News)" <dave (AT) davenoise (DOT) co.uk> wrote

In article <qfEbg.2469$Dd1.1652 (AT) newsfe1-win (DOT) ntli.net>,
MikeL <noone (AT) noone (DOT) com> wrote:
As the subject suggests, I've managed to lunch the thread in the caliper
what the bleed screw, screws into.

After doing it bit of googling, I'm thinking of attempting to tap out
the hole and use a larger screw, if I can actually find anywhere either
locally or online that stocks any suitable bleedscrews, so far I've
drawn a blank.

Forget it. Even if you could find a larger one, the taper seating at the
bottom of the hole would need re-machineing.

Not necessarily. Depends how carefully it's tapped. I've just fitted 2
thread inserts to a mates caliper. Screwing the new nipples in with
engineers blue, showed them seating perfectly on the original seats.
Mike.

"Dave Plowman (News)" <dave (AT) davenoise (DOT) co.uk> wrote

In article <VyHbg.72515$wl.70342 (AT) text (DOT) news.blueyonder.co.uk>,
Steve Robinson <steve (AT) colevalleyinteriors (DOT) co.uk> wrote:
Make sure you use the correct type of tap pitch taper etc

I'd say it might be difficult to get the right tap? Looks a pretty fine
thread. Just a guess, though

Shouldn't be a problem.
Being european the chances are that it's a 10mm x 1mm pitch.
Even if it's not, there are only about 5 different threads used for bleed
nipples. Taps easily obtained for all of them.
Not that I would advise using one anyway. The right way to repair it is by
fitting a thread insert.
Mike.