Need size for RFD-27 pump seals

I started having problems with the pump on my rfd27, I have had the pump gall up on me a few times with my devol side and typically I just replace the pump and were back to running. This last time I replaced the seal and pump and now I’m having an issue with the pump immediately seizing within about a minute or two from starting up. Everything is lined up with the motor to the pump and nothing has changed except for the seal and I am now two pumps down since changing and wondering why this is happening. Seems as if the shaft is grinding against the bottom of the hopper so I am left thinking that the seal is not thick enough between the pump and the hopper. Does anyone know what size seal is needed here?

Oof. That sound made my butt pucker. What is the ticket on one of those? Seems like it should be rebuildable for how nice it looks.

Might I add that it might be possible to look in your area for a rubber and gasket co. We have one in my hometown that has been really helpful when trying to spec out different seals and stuff

the pump is like $3,000 the issue is the galling that’s happening (the screeching sound). I would order one from Delta but their customer support sucks now that Prospaint bought them, calling them is just sitting on a phone till you get tired and hang up. Also this is just an o-ring so I’m hoping someone here knows the size, it’s a lot cheaper to go grab from the hardware store than paying 100x from them.

The gear pumps? Aren’t those made by Beaker and Wrench? If not, maybe buy one of theirs.

No it’s made from Whitte pumps and the beaker won’t match up with this setup.

In that case, you might could get Witte on the horn and see if they can tell you the size. I had to get some viton orings a while back for my stainless QC fittings. I ordered a big box of assorted sizes from slamazon, and wouldn’t you know that none of em fit. So I took my fittings to the local rubber/gasket company, and dude at the counter grabbed a bunch of sizes and helped me narrow down which one it was.

I also saw an AvE video where he used bubbalicious bubble gum to make an oring that held to 3k psi Hydralics. It definitely works!

Just finally got a call back from Delta and they said it sounds I am doing everything right but they said the lubricant on the shaft might be evaporating as I heat up the hopper so they suggested that I soaked the pump holes in some MCT oil before attaching it to the bottom of the hopper and then pour a little bit in the hopper while it’s heating up so that the MCT oil has time to soak down the shaft. This will be my next hope to get the pump going. :pray:

I am no expert, but that solution sounds like dude on the phone is outta ideas. I’d love to be wrong and it fix your problem. I could understand needing to lube the seals but to prime it with a shit load of MCT first sounds kinda sloppy to me. Keep me updated as I am super interested in learning everything I can about these pumps. I just bought my first mag drive gear pump but haven’t had a chance to play with it.

Do you wait until you have a bit of residue collecting on the inlet to turn it on? I’d think that the residue should provide adequate lubrication

Yeah, that happened to me a couple months back. Eventually, it will lock the motor down and you’ll be spending 4500 on it to be rebuilt.

Take it to a machine shop and have it honed…shaft and hole. I’ll check and see if I can find the oring # you need. I think we bought a couple extra due to not being able to get a perfect match on it local.

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83% sure it’s this one……I’ll 100% it one way or another by COB

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Oof that sounds spendy as hell to maintain. Would love to get input from different operators as to what pumps they run and their associated operating costs and maintenance schedule. Is there a consensus on which pump is both affordable and cheap to maintain? Or is it better to buy “cheap” pumps and replace them regularly?

The pump is excellent but they operate metal on metal so with lack of lubricant they will “gall” up. What the Delta guy said has some merit to it, he said they only dust the shaft with lube and with it just sitting on a shelf for months it can essentially go dry. So pre-lubing with MCT oil allows to get the shaft lubed and viscous again. Seems legit but just in case I’m also pulling the hopper apart and making sure it can’t be anything else causing the problem.

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Is this the seal? Looks like I found it at grainger

Search that part number…it is the correct seal. I had to go back and look up on the maintenance schedule to confirm. My mind is slipping these days and I didn’t want to lead you astray.

Delta told me the same things. I burned up another pump in 5 minutes. Have it mic’d, honed and never look back. I didn’t and paid the price. Adding the MCT oil is a short term fix once it has heated up and started galling the walls/cylinder.

If you don’t hone it, please post up the results (only if they are positive) just to give the other side of the story. Everyone has different results and I’d be super excited to hear you didn’t do any machine work and it panned out.

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So Chun the original engineer on the RFD confirmed to make sure there’s plenty of lubricant on the shaft or galling can happen, he also informed me of the 3 adjustment screws on the back of the mount for the motor (had no clue they were even there). So I lubed up the pump with MCT and then attached the pump to the hopper and proceeded to add more MCT to the hopper while everything was getting hot. Once everything was hot I ran the MCT through the pump and then stopped the pump and added oil, then ran about 6 liters (45 minutes) through the system and it worked great! The pumps previously only lasted like a minute so this all has seemed to work…so far! I will report more tomorrow when I run a full days work through it.

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When you say “mic’d and honed” you’re referring to having it rebuilt? Or somehow made better? I was looking into possible other pumps but I think there would be a degree of remanufacturing to another hopper or something right?

I was talking about calipers to make sure the shaft was in fact true. If it is out of round in any way, it will continue to build heat.

Honing it would be the use of milling equipment. Setting up a new system to feed that joker would take some thought and R&D.

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