MAC Valve Issues

[sqslabs]

Well, with all the talk of press issues lately, it looks like I'm the only one who forgot to knock on wood. 

The MAC valve that controls the flip cylinders on my Javelin seems to be getting stuck between the flood stroke and the print stroke.  Not every time, but here and there at an increasing frequency, and it seems more likely to happen while the machine is in production mode.  Of course, its the only valve that was not replaced on my recent restoration of the press so it figures it would give me issues eventually.  I do have an unused valve installed that I can swap it out with, but before I go about ripping the guts of the machine out, I figured I'd see if there were any tips or tricks to unsticking it without having to undergo a major operation.

Heading out to the shop now to make sure my chiller is working properly.  Fingers crossed.

Any help would be greatly appreciated, thanks!

[sqslabs]

Update:  There is no water in the air lines.  Whew!

[ebscreen]

If the valve has a manual or push button switch pressing that a bunch of times can help
clear any stickyness, and a drop of oil if your machine uses it can help as well. That said,
I've never seen a sticky valve that got better.

[jsheridan]

I've never seen a sticky valve that got better.

same here

just replace it

[ScreenFoo]

Had sticky valves on the old GT-8 I ran many years ago, pulled each hose, put a drop of oil in, cycled it.  Last time I visited that shop, they were getting worse again, they still hadn't replaced them.

You might get lucky.

[sqslabs]

Thanks for the input everyone! Now that I have the weekend ahead of me I'll just swap it out with a new one and oil/rebuild the bad one as a potential backup.  But I will try the oil trick first as an experiment to see if it gets moving again.

[sqslabs]

Alright one more question before I dig in..  Are the valves lined up in a certain way for a purpose, or is it just to keep things tidy?  For instance, I have two rows of valves.  The top row is:

Lift --> Unused --> Fork --> Dump (?)

and the bottom row is:

Flip --> Stroke 1-6 --> Dump (?)

I have the question marks there as I'm not 100% sure those are dump valves, but I believe they are.  In any case, I've swapped out stroke valves to different heads before just by switching the air lines, and it didn't affect the functionality of the machine.  But they were pretty much next to each other in the setup.  Now, I'd like to swap the unused valve on the top row with the flip valve on the bottom, by switching the air line going to the flip valve to the unused valve, and wiring the unused valve (currently unwired) to where the flip is wired to.  So they'd be changed out via air and electronics without moving the actual valves at all. 

I hope I've made myself clear with what I'm trying to do.  Will this work?  Or will moving the flip function to the top row affect the functionality of the machine?

[jvanick]

Moving the flip valve to the top row will affect your print on/off switch.  Basically the flip cylinders will always have air going to them.

Sent from my SAMSUNG-SM-G900A using Tapatalk

[sqslabs]

Moving the flip valve to the top row will affect your print on/off switch.  Basically the flip cylinders will always have air going to them.

Ah yeah, that would suck.  Was hoping for an easy workaround, but it looks like I'll be getting my hands dirty on this one.

Thanks much for the help.

[Binkspot]

Pull the cover off the valve being careful not to damage the gasket, pull the poppet clean the bore and poppet with a little diesel or light oil and a q-tip. At this point you have nothing to loose.

[jvanick]

I curious to why your press apparently has 'extra' mac valves on it tho...

never heard of Tuf/Workhorse doing that...

I wonder if somebody before you was trying to do some 'upgrades' or something.

[sqslabs]

Pull the cover off the valve being careful not to damage the gasket, pull the poppet clean the bore and poppet with a little diesel or light oil and a q-tip. At this point you have nothing to loose.

Thanks man, will give it a shot...

I curious to why your press apparently has 'extra' mac valves on it tho...

never heard of Tuf/Workhorse doing that...

I wonder if somebody before you was trying to do some 'upgrades' or something.

The press was rebuilt at some point while the previous owner had it, and somehow one of the valves is now bypassed completely.  The wires are not connected to anything, and there are no air lines going to it.  Not sure if it was just used as a spacer or if it had a function at some point, but its definitely just sitting there unused now.  When I had all the valves replaced recently, the tech I brought in put a new one in the unused space but didn't replace the flip, I'm guessing accidentally.  Fortunately I hung out with him while he was replacing them in order to learn how to swap them out myself moving forward.