Mac Valve Replacement

[Prosperi-Tees]

Does the whole block of valves need to come out to replace one?

[sqslabs]

Depends how far into the block the one you have to replace is.  But for the most part, yes.  The valves are held together on rods, so to get to one on the inside, you have to remove all the valves outside of it.  Keep an eye on the seals during the process, and make sure they stay in place or you'll have to do the whole process all over again.  And again.  And again.   

[Prosperi-Tees]

Im replacing #1 so I should be able to just take out the one to the right of it then. Wish me luck, I didn't want to pay $160 to have it replaced so hopefully this goes smoothly.

[sqslabs]

It's really not as hard as it seems once you see how it all goes together. The seals are the only tricky part at times. Good luck man!

[Binkspot]

If not too much trouble pull the whole assembly and stand it up on end, let gravity work for you. You do not want the rest to start sliding around and the seals leaking. To hold the seals a little grease or vasiline.

[Prosperi-Tees]

My luck, the little allen screws holding them... I dont have that size in the shop lol. Oh well I will get to it tomorrow. Kind of a slow week so trying to get all this done.

[jsheridan]

You only have to replace the bad one.

The little pins screw into each other and hold the entire block together.

Just be sure to put the seal that goes between them back in it's channel or you'll have leak issues.

[JBLUE]

Why are you replacing the whole valve? You should just have to replace the spool on those and they will work as good as new.

[CGS]

Those screws that hold the bank together are metric 3 mm. 

[Prosperi-Tees]

Why are you replacing the whole valve? You should just have to replace the spool on those and they will work as good as new.

Ok school me on the spool?

[Admiral]

On our challenger III I believe we have issues with the mac valves.

Are the screens / squeegees not coming down right away due to bad mac valves?  Sometimes we will have to keep hitting the print button / reset on the head to get the screen to finally drop then it works fine for the run...

Only an issue on a couple heads but it would be nice to fix it.

[Gilligan]

Admiral, how old is this press?

[244]

On our challenger III I believe we have issues with the mac valves.

Are the screens / squeegees not coming down right away due to bad mac valves?  Sometimes we will have to keep hitting the print button / reset on the head to get the screen to finally drop then it works fine for the run...

Only an issue on a couple heads but it would be nice to fix it.

A Challanger III does not have Mac valves. The valves are SMC valves. The valves if sticking may of been exposed to air with burnt oil from a compressor. Solution is to change valve on head but find reason for burned oil first. Probably worn compressor seals.

[Binkspot]

Change the whole thing, you paid for the complete valve use it. It's like buying oil and a filter for you car but only changing the oil. Can you just change the spool, is it easier, sure. More then likely the spool and body are worn or scored, you may not be able to see it, it works on tight tolerances. You could go through all this trouble, just change the spool and still have the problem, worse yet you could damage the spool in the old body and have to buy another valve assembly.

Keep everything clean when working on the valve body, make sure no dirt or lint gets in there.

[Prosperi-Tees]

Thanks Brian, SQS and John for your help, much appreciated, I will let you know how it goes.