Silca Italia pressure gauge not detecting pressure



urge2kill

Member
Aug 13, 2013
448
10
0
It pumps air fine, but the pressure gauge falls down after every pump.

This person had the same problem, but they ultimately returned the pump rather than buy a replacement part.
http://www.bikeforums.net/showthread.php/539488-Floor-pump-gauge-problem

How much the gauge rises seems to depend on degree of obstruction. If chuck is empty, it reaches 0.5 bars (then falls back down). If a presta valve is screwed in, it reaches 20 psi (1.5 bar).
I suspect that air is escaping between the chuck and the valve. With my thumb plugging the empty chuck, the gauge will gradually rise as I force the handle down, and gradually fall as I let air seep out. I suspect that the pressure gauge only works when it is a closed system, but it is not a closed system because air is somehow escaping between the chuck and valve.

I took the pump apart and lubed or greased everything. No difference.
I even put some Pro-Line lube onto the gasket of the spring-loaded thingy beneath the gauge (video).

0.jpg
 

CAMPYBOB

Well-Known Member
Sep 12, 2005
11,945
1,043
113
Try pushing your chuck further onto the tire's valve stem.

Hmmm...my 1970's Silca plunger leather cup looks as worn as Steve's from Excel Sports and it still hits 120 PSI in 30 strokes.
 

urge2kill

Member
Aug 13, 2013
448
10
0
The chuck doesn't seem to go in any further.

I forgot to mention that it's a new pump.

This is the head it has.



 

Volnix

Well-Known Member
Feb 19, 2011
2,883
140
63
Quote:
Originally Posted by urge2kill .
I suspect that air is escaping between the chuck and the valve.


Yep, that's probably it. I was using these cheap tubes with a blackburn tower pump and the pressure gauge was working fine.

Then I found these "better" continental tubes for less in a LBS and switched to those, but they dont fit the pump very well and have the same problem.

Have you tried to use some other tubes? Or are you using tubulars?

If you somehow hold constantly the chuck on the valve it will probably work fine.
 

urge2kill

Member
Aug 13, 2013
448
10
0
I was testing it on a continental tube.

I just took out a SUNLITE 32mm Presta valve thorn resistant tube. It was showing a pressure reading, but the reading was very low. The tube popped while the gauge was reading 40 psi (3 bars). It turned out to be a defective tube with two over-inflated bubbles near the valve, but I still don't think it should have popped at 3 bars.
 

CAMPYBOB

Well-Known Member
Sep 12, 2005
11,945
1,043
113
You tested your pump on a tube? With no tire?

Of course it's going to blow.

I don't know what kind of air chuck you are showing, but this is what you need:



Dead.

Nut.

Simple.

You pusha da on. You pumpa da tire. You pulla da off.

And your grandchildren will still be using it as they glance at your urn on the fireplace mantle.
 

Volnix

Well-Known Member
Feb 19, 2011
2,883
140
63
Originally Posted by urge2kill
I was testing it on a continental tube.
Is it that tube?
big-smile.png
If it is, it's official, these tubes have thinner valves or somethng...



Best ones I found:

Talced, they look seemless, and the valves are very good...
smile.png
(5 euro, just like the conti ones)


 

urge2kill

Member
Aug 13, 2013
448
10
0
Originally Posted by Volnix

Is it that tube?
big-smile.png
If it is, it's official, these tubes have thinner valves or somethng...

Replace the word "Wide" with "Light" and give it a 80mm valve, and it's the same tube exactly.

Originally Posted by CAMPYBOB
You tested your pump on a tube? With no tire?
I tried to use it on a tire first, but it didn't seem to be filling the tube because the gauge wasn't rising. That's when I tested it on a free tube.

I will look into replacing the head.
 

Volnix

Well-Known Member
Feb 19, 2011
2,883
140
63
Originally Posted by urge2kill

Replace the word "Wide" with "Light" and give it a 80mm valve, and it's the same tube exactly.
Maybe a coincidence but I am getting those from one LBS and every 3 of them I tried so far, had the same problem of not fitting the pump that well.

Maybe try a different tube brand?
 

CAMPYBOB

Well-Known Member
Sep 12, 2005
11,945
1,043
113
Quote by U2K
"I will look into replacing the head."

I don't know when Silca introduced that reversible, thread-on chuck, but make certain you have it snugged up securely and inspect it for any missing gaskets or O-ring seals. It should not leak.

When inserting the reversible part into the quick change slip chuck, make sure you have it fully inserted and seated before releasing the spring-loaded collar. A little grease will not hurt.

Lastly, try threading on the Presta end of the reversible chuck onto your valve stem and then carefully connecting the quick change chuck. Be careful not to damage the valve stem.

The classic brass Silca air chuck has been THE Presta valve chuck of choice for decades. If you can't figure out your reversible Schrader-Presta chuck, order the Chuck shown above and a spare seal gasket at the same time.The brass chuck is adjustable for grip pressure on the valve stem.

Something simple that works well is preferable to something complicated that works poorly.
 

urge2kill

Member
Aug 13, 2013
448
10
0
I already lubed it. There is a seal near the end of the chuck, but it doesn't appear to be out of place. I don't know what its part # is, and I didn't find any info on how it's supposed to be configured.

Quote:
Originally Posted by Volnix .

Maybe a coincidence but I am getting those from one LBS and every 3 of them I tried so far, had the same problem of not fitting the pump that well.

Maybe try a different tube brand?


I just found an XLC 700 X 23/25 R-Core (60mm valve), and the pump didn't work on that either. It has the same kind of valve as the Conti, the valve that only has a little threading near the tip.

It seemed to work on the valve that was completely threaded.

 

Volnix

Well-Known Member
Feb 19, 2011
2,883
140
63
Probably a tube issue... Can you return the tubes in the LBS?
 

urge2kill

Member
Aug 13, 2013
448
10
0
Originally Posted by Volnix
Probably a tube issue... Can you return the tubes in the LBS?
Yes, but it's not specific to the individual tubes or even a particular brand. It was the same problem an XLC and Conti tube that shared the same kind of valve stem.


I found the manual for Pista and Super Pista on their site. I don't know what happened to my Super Pista manual.
http://www.silcapompe.it/instruction-silca/AWVM0155.pdf

Under Failure Search, symptom 6 most closely matches my symptom of the pressure gauge underestimating pressure. It says one potential cause is that the non-return valve is dirty or has oil on it, or its washer (gasket) is damaged. Yeah, I oiled it up pretty good.
sour.png
The non-return valve is the small spring loaded piece inside the valve body, which is the metal encolsure that connects the tube to the gauge and the hose.

Manual section E2.2: "Make the screw-thread on the cap tight again using the PTFE tape for gas."
I didn't do this either. Where exactly does the PTFE tape go?
 

Volnix

Well-Known Member
Feb 19, 2011
2,883
140
63
You are more tedious them me cleaning the bike!
big-smile.png
(I totally did not mess up the spokes tension by scrubbing the spokes, totally...
big-smile.png
)

Bike tubes are not built with Swiss watch precision.
big-smile.png


I think that your pump is fine.

Have you tried another pump on those tubes?

Another idea (allthough kinda primitive) is to put a brick over the valve - pump chuck attachement when pumping the tire. That will put some pressure and the gauge will probably work. That's what I kinda do with the one Conti tube left in the wheel that is still refusing to leak so far so I can change it with the Vredestein one from the seat bag.

Btw... Can you find a Vredestein race one? Same price as the conti, talc'ed and it doesn't leak on the pump...
wink.png




 

CAMPYBOB

Well-Known Member
Sep 12, 2005
11,945
1,043
113
"Where exactly does the PTFE tape go?"

Between the male and female threads. It is used as a seal on fasteners that lack a precision machined mechanical seal. A couple turns tightly wrapped around the male thread (clockwise when facing the end that's threaded into the female thread) should be about right.

Why Silca would recommend the yellow colored "gas tape" (for use with natural gas), I have no idea. The white colored Teflon tape is fine for everything from bicycle pumps to air compressor fittings.
 

urge2kill

Member
Aug 13, 2013
448
10
0
Can you replace the "tube fixing screws", the plastic screws that connect the base, valve body, and tube?
 

Volnix

Well-Known Member
Feb 19, 2011
2,883
140
63
Originally Posted by urge2kill
..the plastic screws that..
Plastic screws, what can possibly go wrong?
big-smile.png


Can you replace them with metalic ones?

Silca pumps look like they are designed to be rebuild-able...
 

urge2kill

Member
Aug 13, 2013
448
10
0
Originally Posted by CAMPYBOB
You tested your pump on a tube? With no tire?

Of course it's going to blow.

I don't know what kind of air chuck you are showing, but this is what you need:



Dead.

Nut.

Simple.

You pusha da on. You pumpa da tire. You pulla da off.

And your grandchildren will still be using it as they glance at your urn on the fireplace mantle.
Can I order this online from a business that ordinarily ships to the states?
I placed an order on Amazon a month ago. They delayed shipment of all the items in the order until finally, a week ago, they decided to ship the order without the air chuck. A few days ago, they removed the air chuck from the order summary, which means they aren't shipping it. They didn't even charge me for the air chuck when they charged my bank account a month ago, as if they never intended to include the air chuck. Now I need to get the air chuck elsewhere.

I'll check my LBS since I'm going there anyway.
 

alfeng

Well-Known Member
Jul 23, 2005
6,723
126
63
Originally Posted by urge2kill

Can I order this online from a business that ordinarily ships to the states?
I placed an order on Amazon a month ago. They delayed shipment of all the items in the order until finally, a week ago, they decided to ship the order without the air chuck. A few days ago, they removed the air chuck from the order summary, which means they aren't shipping it. They didn't even charge me for the air chuck when they charged my bank account a month ago, as if they never intended to include the air chuck. Now I need to get the air chuck elsewhere.

I'll check my LBS since I'm going there anyway.
You should be able to order just the SILCA pump head from either COLORADO CYCLIST or EXCEL SPORTS.
 

urge2kill

Member
Aug 13, 2013
448
10
0
You have helped me much.

This time, I thank you before the thread sinks into the depths of Cycling Equipment.