Silca pump gauge repair how-to

On 9/8/2016 8:02 PM, John B. wrote:
On Thu, 08 Sep 2016 08:15:13 -0500, AMuzi wrote:

On 9/8/2016 3:14 AM, Gregory Sutter wrote:
On 2016-09-01, AMuzi wrote:
On 9/1/2016 12:08 AM, Tim McNamara wrote:
My 20+ year old Silca Super Pista pump has, for the first time,
malfunctioned and needs repair.

Unless it was badly smacked around, replace the screw,
tighten both of them (moderately, you're threading into a
brass block). If needed, lift the needle off and press it
back at the zero position. Try not to bend/move/alter the
bourdon tube[1] or its linkage in any way.

Now is a good time to check/tighten the two screws on the
very bottom as they work loose over years of use. You might
also remove the checkvalve and clear out any crud, a common
service issue on these.

[1] looks like a brass tortellini with soldered seams.

Thanks, Andy; yesterday I disassembled, cleaned andlubed my
Silca pump, which now works much better. Leather washer was
still well-lubed and supple, so the leakage was via the dry
gasket on the check valve.

Does anyone know where I can get a top spring for this pump,
shown here (second image)? Mine's missing.

http://www.terapeak.com/worth/vintag.../391375008872/


Hardware store? It's not clear to me what that spring does
and in fact my own (very old) Silca and the ones we sell
here don't have that.

I've seen a "top spring" on quite a number of hand pumps (some
predating the 10 Speed English Racer :-). I'd always assumed it was to
prevent an enthusiastic pumper from banging the pump plunger down on
the bottom of the pump cylinder.


?? That last small increment at the bottom is what gets your
tires inflated.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Thu, 08 Sep 2016 08:15:13 -0500, AMuzi wrote:

Hardware store? It's not clear to me what that spring does
and in fact my own (very old) Silca and the ones we sell
here don't have that.

My guess(tm) is that the spring is lawyer repellent. If your hand
comes to a sudden stop at the end of travel, you could injure yourself
from the impact. Someone may have complained or sued, resulting in
the added spring to slow down the plunger. The impact might also
break some internal plastic parts.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Fri, 09 Sep 2016 10:31:05 -0700, Jeff Liebermann
wrote:

On Thu, 08 Sep 2016 08:15:13 -0500, AMuzi wrote:

Hardware store? It's not clear to me what that spring does
and in fact my own (very old) Silca and the ones we sell
here don't have that.

My guess(tm) is that the spring is lawyer repellent. If your hand
comes to a sudden stop at the end of travel, you could injure yourself
from the impact. Someone may have complained or sued, resulting in
the added spring to slow down the plunger. The impact might also
break some internal plastic parts.

I saw the upper spring on hand pumps way back when I was a kid -
before the "sue you" mania began, way back when they were known as
"tire pumps" and people used them to up all kinds of tires, not just
bicycle tires.
--
cheers,

John B.

On Fri, 09 Sep 2016 07:28:32 -0500, AMuzi wrote:

On 9/8/2016 8:02 PM, John B. wrote:
On Thu, 08 Sep 2016 08:15:13 -0500, AMuzi wrote:

On 9/8/2016 3:14 AM, Gregory Sutter wrote:
On 2016-09-01, AMuzi wrote:
On 9/1/2016 12:08 AM, Tim McNamara wrote:
My 20+ year old Silca Super Pista pump has, for the first time,
malfunctioned and needs repair.

Unless it was badly smacked around, replace the screw,
tighten both of them (moderately, you're threading into a
brass block). If needed, lift the needle off and press it
back at the zero position. Try not to bend/move/alter the
bourdon tube[1] or its linkage in any way.

Now is a good time to check/tighten the two screws on the
very bottom as they work loose over years of use. You might
also remove the checkvalve and clear out any crud, a common
service issue on these.

[1] looks like a brass tortellini with soldered seams.

Thanks, Andy; yesterday I disassembled, cleaned andlubed my
Silca pump, which now works much better. Leather washer was
still well-lubed and supple, so the leakage was via the dry
gasket on the check valve.

Does anyone know where I can get a top spring for this pump,
shown here (second image)? Mine's missing.

http://www.terapeak.com/worth/vintag.../391375008872/


Hardware store? It's not clear to me what that spring does
and in fact my own (very old) Silca and the ones we sell
here don't have that.

I've seen a "top spring" on quite a number of hand pumps (some
predating the 10 Speed English Racer :-). I'd always assumed it was to
prevent an enthusiastic pumper from banging the pump plunger down on
the bottom of the pump cylinder.


?? That last small increment at the bottom is what gets your
tires inflated.

The spring doesn't prevent the pump plunger from reaching the bottom
of the cylinder, it simply slows the stroke down as it approaches the
bottom of the stroke.... so it doesn't bang against the bottom of the
cylinder. http://tinyurl.com/z7hxujg
--
cheers,

John B.

On 2016-09-10, John B wrote:
On Fri, 09 Sep 2016 07:28:32 -0500, AMuzi wrote:

?? That last small increment at the bottom is what gets your
tires inflated.

The spring doesn't prevent the pump plunger from reaching the bottom
of the cylinder, it simply slows the stroke down as it approaches the
bottom of the stroke.... so it doesn't bang against the bottom of the
cylinder. http://tinyurl.com/z7hxujg

You're both exactly right, which is why I want to put the spring on.

--
Gregory S. Sutter Mostly Harmless

http://zer0.org/~gsutter/

On Fri, 09 Sep 2016 10:31:05 -0700, Jeff Liebermann
wrote:

The impact might also break some internal plastic parts.

One of the reasons I have kept this pump for 25+ years is that there are
no internal plastic parts. Steel, brass, leather, n O-ring or two.
Hmm, though, now that I think about it vaguely remember a nylon washer
or something down there at the business end of the plunger... But
sturdy enough for decades of service- hopefully it will see me out, just
another 30 or so years probably. Seems like it should last, after this
bit of a scare.