Old Schrader tire inflator

[65Val]

If you don't insert the gage part, does air come out the opening vacated by it when you hold it on the valve stem of an inflated tire?

Yes.

 

[The Cobbler]

with it all together, and applying air to a tire , is there a leak at the gauge ? that could indicate air pressure by passing the seal and not able to over come the spring tension

 

[65Val]

with it all together, and applying air to a tire , is there a leak at the gauge ? that could indicate air pressure by passing the seal and not able to over come the spring tension

No.

 

[whateg01]

I'm somewhat confused. If air is coming back out the supply hose, is that air coming from the tire somehow? If so, there may not be enough pressure on the gauge to extend it. Or is that air leaking from the supply itself. I still think you need to fix that before troubleshooting anything else

 

[RTM]

It should be feeding from the tire back to the gauge.

 

[hop up]

I haven’t worked on this model but looks like it operates similar. The spring has a specific load to push the indicator slide out. So when its 10 pounds air pressure the spring will have 10 pounds of load and same with 35 lb of air pushing the slide with 35 lb of load. Did you mess with the springs?
Also how are the O-rings as they seal the slide from air pushing thru

 

[65Val]

I haven’t worked on this model but looks like it operates similar. The spring has a specific load to push the indicator slide out. So when its 10 pounds air pressure the spring will have 10 pounds of load and same with 35 lb of air pushing the slide with 35 lb of load. Did you mess with the springs?
Also how are the O-rings as they seal the slide from air pushing thru

Have not messed with the springs…they do seem very “heavy”…takes pliers on the end of the slider to pull it out.

 

[65Val]

I'm somewhat confused. If air is coming back out the supply hose, is that air coming from the tire somehow? If so, there may not be enough pressure on the gauge to extend it. Or is that air leaking from the supply itself. I still think you need to fix that before troubleshooting anything else

There is no air leaking from anywhere when the supply air is hooked up to the quick disconnect, and the chuck is on the tire valve.

 

[Provincial]

I believe that the system works like this:
Handle released and inlet valve closed, connect to tire valve stem
Handle depressed, inlet valve open, air to tire, no gauge indication
Handle released, keep connected to tire valve stem, pressure in tire activates gauge

For this to work, there is a check (or shuttle) valve somewhere between the air supply and the gauge. It keeps the inlet air from reaching the gauge, and allows the tire pressure to reach the gauge when the inlet air is released. For this to work, there has to be a way to bleed off the air in the inlet side when the handle is released.

Look for parts that seem more complex than just turning the air on and off.

If there is a patent number on the tool, research it, since patents show how it should work.

 

[RTM]

Following Provincial's thoughts, I'm assuming there is a valve buried in the inlet bit, between the quick connect and the hole in the body below the o ring blue oval. The o ring on top, and the one on the floating trigger green oval, don't look like they can seal off the compressor supply, but might be enough to capture the air returning from the tire to the gauge.

When the trigger is pressed, air flows out the hole below the o ring, and up to the tire, thru the red path of the body. The red trigger pushes the floating piece down to open the valve in the blue oval. (Does air flow if you just plug the quick connect into a pressurized line. If not, confirms a valve)

When the trigger is released, the green oval seals the top, the valve in blue seals the bottom, and the air flows across the yellow part of the body, escaping thru the gauge.




¢¢

 

[65Val]

I believe that the system works like this:
Handle released and inlet valve closed, connect to tire valve stem
Handle depressed, inlet valve open, air to tire, no gauge indication
Handle released, keep connected to tire valve stem, pressure in tire activates gauge

For this to work, there is a check (or shuttle) valve somewhere between the air supply and the gauge. It keeps the inlet air from reaching the gauge, and allows the tire pressure to reach the gauge when the inlet air is released. For this to work, there has to be a way to bleed off the air in the inlet side when the handle is released.

Look for parts that seem more complex than just turning the air on and off.

If there is a patent number on the tool, research it, since patents show how it should work.

There are no numbers anywhere on the unit.

 

[65Val]

Following Provincial's thoughts, I'm assuming there is a valve buried in the inlet bit, between the quick connect and the hole in the body below the o ring blue oval. The o ring on top, and the one on the floating trigger green oval, don't look like they can seal off the compressor supply, but might be enough to capture the air returning from the tire to the gauge.

When the trigger is pressed, air flows out the hole below the o ring, and up to the tire, thru the red path of the body. The red trigger pushes the floating piece down to open the valve in the blue oval. (Does air flow if you just plug the quick connect into a pressurized line. If not, confirms a valve)

When the trigger is released, the green oval seals the top, the valve in blue seals the bottom, and the air flows across the yellow part of the body, escaping thru the gauge.




¢¢

“(Does air flow if you just plug the quick connect into a pressurized line. If not, confirms a valve)”

No. Air flows only flows when red button pushed.

 

[RTM]

“(Does air flow if you just plug the quick connect into a pressurized line. If not, confirms a valve)”

No. Air flows only flows when red button pushed.

Did you test that with just the quick connect, without all the other stuff assembled around it?

 

[65Val]

Did you test that with just the quick connect, without all the other stuff assembled around it?

You mean completely disassembled?…just supply air hooked up??

 

[RTM]

Just the piece with circle in blue from post #50. Yes, bare quick connect and the supposed valve piece.

 

[65Val]

Just the piece with circle in blue from post #50. Yes, bare quick connect and the supposed valve piece.

No air flows in that configuration.

 

[RTM]

He

No air flows in that configuration.

Ok, that confirms a valve in there, which makes me think what I wrote in #50 is where you should be attempting to find your problem. If you assemble it without the gauge, you should hear air blow out that port when you release the trigger. If it does that, maybe the spring is too big.

If no air blowing out that port, your seal provided by the o rings may not be sealing.

 

[65Val]

Ok, that confirms a valve in there, which makes me think what I wrote in #50 is where you should be attempting to find your problem. If you assemble it without the gauge, you should hear air blow out that port when you release the trigger. If it does that, maybe the spring is too big.

If no air blowing out that port, your seal provided by the o rings may not be sealing.

If I hook it up to a tire valve and supply air, with no gauge assembly installed, air from the tire comes out the gauge area, so air is getting to the gauge assembly area. I have seen the gauge function properly in the past, and I don’t think my Father-in-Law would replace the spring if it was working correctly. If it is the seal at the top of the gauge(black piece), I have no idea where to get a replacement…I can’t even find any mention of this thing on the ‘net anywhere! I have emailed the Schrader company for info, but haven’t heard back as yet.

 

[RTM]

If the black piece, red circle in my first picture back in post #23, is bad you would fail the finger tests I described in that same post. (This may be a piece available for some other thing, like a Bimba air cylinder seal, once you know diameter)

Alternatively, I'm trying to figure out the spring strength. You seem to be able to install the gauge without its base anchoring screws, (everything above the red circle), how easily does the gauge push up against its spring?

I have no idea how in a home shop you can dummy up 10 to 110 PSI against that tiny disk. I'm guessing set your compressor regulator to a known PSI, and block off all the other ports on your handle, it should climb up to that level with a blow gun on the end. (Need others' thoughts here)

 

[65Val]

If the black piece, red circle in my first picture back in post #23, is bad you would fail the finger tests I described in that same post. (This may be a piece available for some other thing, like a Bimba air cylinder seal, once you know diameter)

Alternatively, I'm trying to figure out the spring strength. You seem to be able to install the gauge without its base anchoring screws, (everything above the red circle), how easily does the gauge push up against its spring?

I have no idea how in a home shop you can dummy up 10 to 110 PSI against that tiny disk. I'm guessing set your compressor regulator to a known PSI, and block off all the other ports on your handle, it should climb up to that level with a blow gun on the end. (Need others' thoughts here)

I have the unit hooked to my 3/4 ton pickup with 65 lbs in the tires, so I think should read something, even if not correct.

 

[RTM]

Not if the springs are more than 10x too strong. Or no air is blowing up there for other reasons.

 

[65Val]

Not if the springs are more than 10x too strong. Or no air is blowing up there for other reasons.

Again, I can’t see my FIL changing out the springs if he didnt have to…and there is air getting into the gauge section… I have checked that.

 

[RTM]

Well, since I can't see it, I'm punting then. Good luck

 

[65Val]

Well, since I can't see it, I'm punting then. Good luck

Ok. Thanks for your efforts!