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Silca Impero Problem

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Silca Impero Problem

Old 01-15-20, 05:29 AM
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xetaprime
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Silca Impero Pump Problem



I have a Silca Impero dilemma. It should be easy with the simplicity of this pump but, here goes. And I google searched this to death. Old pump, new oiled softened leather piston. It pumps/pushes air out, but when connected to tire valve, on the reverse stroke, no air pulls in, and suction is created so the handle wants to spring back down. How does air flow into the chamber? Is it supposed to flow around the piston when pulled back? Ideas welcome. D'Ohhh!!!

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Old 01-15-20, 07:11 AM
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xetaprime I would make sure the leather is oriented correctly. I have had them fold part way around making them useless. Cup should be pointed toward the head. The pressure seals the leather against the cylinder to pump the tire. On the return stroke, the leather should let the air go by it and the cylinder. Oh and it should be lubed with appropriate grease for leather.
Take it apart and show us the assembly of the leather.
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Old 01-15-20, 09:44 AM
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Originally Posted by SJX426 View Post
xetaprime I would make sure the leather is oriented correctly. I have had them fold part way around making them useless. Cup should be pointed toward the head. The pressure seals the leather against the cylinder to pump the tire. On the return stroke, the leather should let the air go by it and the cylinder. Oh and it should be lubed with appropriate grease for leather.
Take it apart and show us the assembly of the leather.
Thanks. The leather is oriented correctly, but it is a tight fit. Sigh, I googled the lube and made my own :0 So, air is supposed to squeeze through on the return stroke... maybe I relaxed the leather too much. Their video shows them massaging and turning it inside out which I did. Works great when not connected to the valve... I'll post a picture later. Hmmm How can I DIY an air flow membrane
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Old 01-15-20, 10:09 AM
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too good a seal.
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Old 01-15-20, 11:05 AM
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Pushing the head too far onto the value and it's holding the valve open?
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Old 01-15-20, 11:19 AM
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Originally Posted by gearbasher View Post
Pushing the head too far onto the value and it's holding the valve open?
I tried that, not pushing it too far on. I tried it without, just finger over hole... I'll put the original back on and see. The one I used was NOS from ebay.
UPDATE: Old leather piston works fine.

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Old 01-15-20, 11:29 AM
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The problem lies in the leather seal. Its too tight of a fit.They come in 2 different sizes. Or you put a floor pump seal in it.

Last edited by Manny66; 01-15-20 at 11:33 AM.
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Old 01-15-20, 11:32 AM
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Originally Posted by Manny66 View Post
The problem lies in the leather seal. Its too tight of a fit.They come in 2 different sizes.
Now you tell me I thought I got the right ones. May try again with new ones at some point and double check size. Thanks all.
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Old 01-15-20, 11:55 AM
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On Silca website they have 741 - 30mm inside diameter, and 721 - 28mm. I guess those are floor pumps. My caliper is showing 20mm at the threads... why is it never simple?
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Old 01-15-20, 12:23 PM
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Originally Posted by xetaprime View Post
On Silca website they have 741 - 30mm inside diameter, and 721 - 28mm. I guess those are floor pumps. My caliper is showing 20mm at the threads... why is it never simple?
A couple of other things that may or not go without saying.

I always clean the inside of the body, they get pretty nasty. Then relube it separately, sparingly and thoroughly working the lube in before installing the handle and plunger.

I have always used mineral oil which I have seen indicated many times, sparingly on the leather.
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