help locating replacement part for Mitre-Mite VN2+1 underpinner

[Norton's]

Hello all-

I'm pretty sure I know what part needs replacement, but I can't locate it on the Fletcher website. I've attached the schematics and circled the problematic part which constantly leaks air. It seems to be labeled as No. 4 (7323900001 exhaust valve 1/8"), but when I look that item up on the Fletcher parts website the part doesn't look like it does in the schematic or my machine. I've attached a pic of the part they have listed as that part number.

The issue isn't the little blue filter. I switched that one out with two of the other blue filters in the machine and have the same problem.

I've been through many of the parts on the website and can't find anything that really looks like what I need. If it's discontinued, could I get it somewhere else?

The underpinner works but the leak sounds like it's getting worse and I'm afraid it's going to go out anytime now.
Thanks for your help,
Ty

 

[Underpinner Spares]

Quick exhaust valves are only a diverter for the used air during the clamping cycle and may not be the source of the problem as they are only active when the moulding is being clamped, if yours is leaking permanently then the fault could be down to worn clamp cylinder seals which are sending air to the exhaust valve.

If you want to test it then just disconnect the pipe that is attached at a right angle to the blue silencer - if air is coming from the disconnected pipe then its the cylinder seals at fault.

Mark

 

[Norton's]

Mark-

Okay, I unplugged the 90 degree pipe that goes into the part with the blue silencer (circled in photo No. 20251023_103931 above). Once that was unplugged the blue silencer wasn't leaking air when I put pressure on the peddle and no air was coming out of the pipe I just unplugged.

Normally, when I put a little pressure on the peddle (enough to bring down the stopper at the top, but not enough to shoot a v-nail), the blue silencer begins leaking air. The air leak continues when I take my foot off the peddle.

Did I do it correctly? Does that tell you anything?
Thanks for your help with this. It's an old underpinner, but I'm hoping to keep it going.
Ty

 

[Underpinner Spares]

Ty

Just to clarify, does the blue silencer only leak air when the pedal is depressed or does it leak all of the time?

Mark

 

[Norton's]

Mark-

When I first plug in the air hose and flip the airflow switch there is no leak. When I push the peddle down halfway the leak starts and continues constantly until I unplug the main air hose. The leak continues even when I turn off the air flow switch and won't stop until I unplug the main air hose.

Thanks,
Ty

 

[Underpinner Spares]

In that case when the vertical clamp is activated a seal must be flipping over (so to speak) allowing air to bypass.

I would suggest both vertical clamp pistons have their seals replaced and a new exhaust valve fitted, contact Fletcher but if they have no stock then i have them available:

This is for the vertical clamps with a 22mm diameter vertical chrome shaft: Clamp Piston Seal Kits
Quick Exhaust Valve

Mark

 

[David Hewitt]

 

[Norton's]

Mark-

I just noticed that the air leak stops at the moment I fully press in the peddle to shoot the v-nail. Aside from that, the air leak is going pretty much constantly from the first press half-press of the peddle.

Sorry I didn't notice it earlier, I don't know if that changes anything.

You've been very helpful with this, so I'm happy to buy my replacement parts from you. Looks like shipping rates from the UK aren't bad.

Thanks,
Ty

 

[Underpinner Spares]

Ty

The full press of the pedal shouldn’t change the leak unless you have more than one issue, the half press to clamp works on a preset 2 bar pressure and when the pedal is fully depressed the clamp pressure then increases to 8 bar and fires the v-nail.

Are you positive that the blue silencer is the only source of the leak?
Could I suggest you spray a small amount of soapy water / penetrating oil around the valves/fittings to see if there are any other leaks that may have gone unnoticed as your fault seems to be on two different sections of the pneumatic circuit.

Mark

 

[Norton's]

Mark-

Okay, groovy. It's crunch time for me here in The States with everyone wanting their pieces complete for Thanksgiving family dinners. I'll get in there with some soapy water and look for other leaks after Thanksgiving.

I appreciate your time on this and didn't want you to think I'd bailed on you.
Thanks,
Ty

 

[Norton's]

I just wanted to let anyone who stumbles across this post that Mark with Underpinner Spares was very helpful in getting my underpinner back up and running. We continued our conversation via email and he walked me through a few troubleshooting techniques until we identified the problem, which I was able to buy replacement parts for through his online store.

If you need help with your underpinner, I'd recommend contacting him. He went above and beyond.

 

[Underpinner Spares]

Ty,
Glad I could help, if you need anything in the future let me know.
Take care.

Mark