Metadyne Thumper - Issues and remedies

[Chrisrook1]

Good to know! Sounds a lot like what I’m going through, so I’ll have to take the reg out tonight and give it a look.

[RuleOfSines]

There is a weird scenario Thumpers can run into, where the reg actually locks up, without ever actually opening and letting air in. I only realized it by accident on one of mine when I aired it up with the side plug removed, air never even reached the internals. I made a tiny shim that went around the reg so it would not go quite as far forward to prevent it.

[Chrisrook1]

Thanks for that! Hopefully it’s just a valve, but the regulator is gonna get a rebuild anyway. It’s weird, when you air it up, air goes into the marker, but it doesn’t fire. Seeing as how it was working when it stopped, my first thought is a blown valve. But, for all I know, there could be a blockage or something up with the regulator.

[RuleOfSines]

I think the detent is just a Tippmann 98 detent cut and glued into place. Valve is Clippard MAV-3C

[Chrisrook1]

So, long time no post and reviving an old thread all in one. But, things are finally settling down for me after the world went crazy, and I’m hoping to revive some dead markers for play. My Thumper just up and quit in the middle of a game one day years ago. Played a few games on 12ie, was in the middle of another, had just fired 2 shots, pumped for the third, and the trigger pull did nothing. I let it warm up for a while thinking maybe the reg froze, but it has never worked since. So, now I’m going through a full rebuild on it, but for the life of me, I can’t remember what the Clippard part number is for the valve. So, that’s where I’m hoping the smart minds here can help out. Also, seems my detent rotted away and split in half at some point, so was hoping maybe someone knew a source, or had a schematic/drawing of one so that I could cut a new one. I’m hoping I can get this thing back in running order and on a field soon, it’s always been one of my favorite markers, so it’s a shame to see it sit in a box.

[Siress]

Typical method of preventing air transfer holes from shredding o-rings is to burr hone the primary bore. Further, do that before sending it out for electropolishing. This is all prior to anodizing. Hard to correct that if it wasn't done.

[Bow]

I have a custom piston in mine as well. Works fine. I'm always a bit hesitant to run it on any kind of HP though. I'm just worries about blowing the clippers valve. I think I've had it for 7-8 years now.

My new piston still shreds that first oring on the Pistons stem.

From what I understand the original pistons were made on a machine that was very slightly mis leveled. That's where the bending comes from.

There is no real remedy for that except for replacing it with an aftermarket custom one, maybe make it slightly beefier.

There's no really good remedy for fixing that oring either since the Oring is pushed into the body of the marker and catches that air transfer hole and shreds. My only thought would be using one of those expanding internal chamfering tools to try and smooth the hole out a bit, but that could mess with the position of the Oring an make a brick out of the body. Let alone I don't know how big the hole is and if they make one of those that small.

I'm happy to see some other people interested in the thumper though!

[Jonnydread]

Jonny, what were the changes that you needed to make to the piston? Who machined it for you?

I am not the one to ask, it has something to do with making it more robust at a failing point but I do not really have any details beyond that.

[Rainmaker]

capitalpaintball had a new piston machined that I believe fixed most of the issues associated with the original one

Jonny, what were the changes that you needed to make to the piston? Who machined it for you?

[SomeGuyFromPitt]

I loved mine for the year I played it. I traded it for a Phantom because of the concern for critical failure.

it was a smooth pump stroke, however the pin that caught the hammer is based on gravity so if it's not vertically held, the marker would not properly cock.

I do miss mine It was a fun period where I had two and played Castle Nights double thumper shooting at ION in 2013. Now I just keep the reliable markers for the four times I've played in 2021.

If you can find one and your comfortable working and maintaining a marker, this one is for you.

[Chrisrook1]

Can agree that when they function, they’re fun, great shooters. Bought one used and working a few years back, a lot of fun on the field until the Clippers valve went out, now finally taking the time to put her back together and out there!

[XEMON]

You can try ...
The best case scenario: it shoot
The worse case scenario: the piston get screwy and need to remove o-ring and add a reg

Likely scenario: something gonna leak, something gonna bind, kinda shoot ... Sometimes and leak other ...

When they shoot they are great little shooters 👍

[Rainmaker]

So I have a question... I've got one of these bad girls now. If I just put a 12ie in the bucket changer and dry fire it, am I going to damage something? Do I need to put an inline reg on it? I'm really psyched about this thing, but I'm timid about shooting it, at least until I learn more, and feel confident in not going to break something. Sorry for the noob questions 😅

[RuleOfSines]

Quick question...
The end of this instructional video, the guy says the best way to lube it is to cram some Vaseline in the ASA hole, and you're good to go...? Is that true?

https://youtu.be/dxORumSkHGU

Well, kinda..

The itty bitty clippard valve inside there is not suitable for liquid lubricants, so the 'couple drops of oil' method is not recommended. However, the vaseline can also gunk up the inside, and the main piston can benefit greatly from lubrication.

Whenever I think mine needs lube, I take it all apart and lubricate that main piston directly. If you have no leaks, but you do have low velocity or a noticeable delay between when you pull the trigger and when it actually fires, you may need to do the same.

If on the other it is working fine and you're just looking to maintain it for now then I'd say yeah go for the dab of vaseline.

Fun note: I think I may actually now own the Thumper used in that video.

[Rainmaker]

Quick question...
The end of this instructional video, the guy says the best way to lube it is to cram some Vaseline in the ASA hole, and you're good to go...? Is that true?

https://youtu.be/dxORumSkHGU