Compressor clunking / rattling while running: need diagnostic / repair help

[tmassey]

More updates. If nothing else, this is turning out to be a decent visual guide to the internals of a three stage compressor...

Last we left, the third stage 'valve puck' was off the machine, but the valves were still in the puck. I could not practically get gas to move through them, and I was unable to get them out with moderate force. Tracy stated that the exhaust valve (the one with the wrench flats) was held in only by an o-ring. So I clamped the puck to the vise and used a little bit more force to rotate it: It rotated in place, so I used pliers to easily pull it out.

I have not applied more force to the intake valve: it looks factory original, and there's a chance that it was held in by Loctite. I don't have the Bauer valve removal socket, so I'm reluctant to apply much force with just a pair of snap ring pliers (more because of the pliers than the valve). I have removed the electrical fitting and will bake the part later to get the valve out. For now, I'm assuming that this is not the source of my noise, but given how they look, they're getting replaced.

Next step: examine the second stage. This one's an odd-looking one.

My understanding is that the black/bronze fitting is an overpressure relief valve (it's got the safety wire and everything), and it seems the round finned part with the cap nut should be to remove the exhaust valve. Once again, six hex screws and remove the intake/exhaust tubes and off it comes:

Once again, rotate the flywheel and the cylinder moves very nicely: smoothly and quietly, with minimal resistance (because only the first stage is still sealed at this point). Here's the underside of the second stage head:

As a wild guess, this is the intake (suction) valve: Bauer Suction Valve Kit 013822 - August Industries Inc. If that's right (remember: it's a wild guess at this point), this is the discharge (exhaust) valve: Bauer Discharge Valve Kit 013823 - August Industries Inc. I'd definitely need further confirmation before I move forward with those -- or any of the items I've listed so far.

A quick blow/suck test of the valves worked better this time. I can get gas to move in the proper directions and not get it to move in the opposite directions. It takes quite a bit of lung force, but that's just a fraction of the force the compressor would be applying, of course. But it gives me confidence I actually know what I'm doing to test these valves. (Still don't know why the third stage valves aren't working, but I'm assuming they're just too clogged for lung pressure.)

I still have a nice, quiet, rattle-free compressor... So after Tracy said that it won't be any more difficult than what I've done, I went ahead and tackled the first stage.

Here's the first stage after I've loosened the screws and intake. I then had to take off the exhaust tube and the hose that leads to the first stage gauge on the front panel. (Yes, I ended up cutting the hose: it was seized and wouldn't rotate.)

Here's the top of the first stage cylinder. Once again, smooth and quiet movement, and seeing as all three stages are open, no real resistance...

Next up is the head of the first stage that I have removed. This part is the part that sits directly on the cylinder above. This is actually two pieces. The next photo is those two parts separated.

Bottom of cylinder head:

Cylinder head opened up like a book:

So... I've got all three stages off. All three pistons slide smoothly and quietly. I've checked each of them as they retract the piston: there is no play or slop in the piston in any dimension (up-and-down or side-to-side). I feel no roughness or catch while rotating the flywheel. And no sound, either.

As for identifying or checking the first stage valves: I don't see anything even close to what I would expect to see for a check valve. I also don't see an easy way to test it in pieces like this. I've been told that first stage valves should not wear out in the less than 500 hours on this compressor, so I'm not going to worry about this further at this time.


Unfortunately, I don't think I'm any closer to my issue than when I started. I know more about my compressor, but not this specific problem! There isn't much that I can check on the top end of the compressor. Next suggestion I've been given: drain the oil through a coffee filter and look for metal/glitter. I have to find a suitable container to move forward with this.

An aside: I haven't been able to understand the oil system on this compressor. I've always assumed it was splash-lubricated because there's no oil pressure gauge. But a Bauer-designed 6CFM compressor block is very unusual. But when I look for any oil pump hardware, I don't see any anywhere. If anyone has any thoughts or suggestions, I'd love to hear them as well...


ETA: @Wookie: if by floating piston you mean that the third stage piston is not attached to the crankshaft, I suspect I do have one. It is possible for the piston to be held at the top as the compressor flywheel is turned. Plus, there has always been a small rattle when the compressor first starts up for about 5 seconds, which I understood to be the floating piston knocking until there was a bit of pressure from the second stage. No, I won't run it without heads in place... And all check valves have strongly resisted flow in the direction that they should. It's just that some of them also resist flow in the direction they should allow!

 

[Wookie]

ETA: @Wookie: if by floating piston you mean that the third stage piston is not attached to the crankshaft, I suspect I do have one. It is possible for the piston to be held at the top as the compressor flywheel is turned. Plus, there has always been a small rattle when the compressor first starts up for about 5 seconds, which I understood to be the floating piston knocking until there was a bit of pressure from the second stage. No, I won't run it without heads in place... And all check valves have strongly resisted flow in the direction that they should. It's just that some of them also resist flow in the direction they should allow!

You absolutely have a floating piston. No doubt in my mind at all.

I’m not surprised that you can’t overcome valve spring pressure with the force of your lungs. In fact, it’s what I would expect.

I would take this opportunity to clean your first and second stage valves, and replace the third stage valves.

 

[Gone for diving]

My little baur needed work when I got it,
3rd stage outlet check valve was sized open, (does not disassemble, it's all pressed together,,, ) I priced it from baur in Canada, it was something stupid like 400$+,
So I figured I had nothing to loose, I drop it into diluted muriatic acid, washed blew it out and repeat, it cleaned up so nice,
(I was worried about the spring inside)
Still working well,

 

[tmassey]

TL;DR: a long-winded description of what I learned about older Bauer compressors, and how the parts have changed over time. I have parts ordered and I'm waiting to get them. Do you have any suggestions for the best way to clean the valves, as well as the rest of the compressor parts before I put them back together?

Update since Thursday (post #11). At that point, I had the heads off of all three stages. The compressor turned by hand freely, smoothly and virtually noiselessly. And no visible issues with any of the stages, including any kind of debris.

This post is *long* and mostly about what I've learned researching parts. If you're not interested in Bauer part evolution over time, skim or even skip it -- but if you've got any suggestions about cleaning these parts, please let me know: details are at the end.


On Thursday, I had started the process of draining the compressor oil. The idea was to see if there were any metal debris in the oil. Compressor oil moves slowly under the best of circumstances, even when it's hot from running; doing it in 30 degree weather means that it makes honey look watery. So it literally took two days to complete this, between draining it from the machine and straining through a coffee filter. Nothing in the filter -- not just metal, there was almost no debris at all. Which is good, I guess. Still no smoking gun, but at least no damage.

During this time, I had spent a great deal of quality time with a variety of Bauer compressor diagrams, none of them for my compressor. I had pretty much pieced together everything that I needed, but as an amateur (and nervous) compressor technician, I was uncomfortable moving forward with my cobbled-together knowledge. Friday morning I e-mailed Bauer Austria (the people who handle Bauer Poseidon) at info@bauer-kompressoren.at and asked if they might have the proper diagram, and by Monday they sent me the diagram for my 1986-vintage machine! Yay!

The pre-early-2000's Poseidon compressors are odd. They are similar to the Mariner, but the castings do not always seem to be the same (including part numbers), and some items are clearly different, like the crankcase and third stage cylinder housing. The Poseidon are *splash* lubricated, and the third stage cylinder housing is one piece. These two items are unique in Bauer compressors of this size. However, the valve heads of the Poseidon and the Mariner are very similar, including "matching" valve part numbers. (The Poseidon part numbers often have a W instead of a 0.)

In my previous update I had stated I couldn't identify any kind of valves on the first stage. That's because they use a different kind of check valve: a reed valve. It's the item with the variety of oddly-shaped holes that you see with the green gasket in the last picture in #11. They are not user-serviceable or rebuildable, and a replacement is most of $200. The test to verify function is to put water on them: if it does not leak through for at least 10 minutes they are good.

However, even with the "correct" diagram, there was still an issue: the diagram doesn't exactly match my compressor. In this case, it's the first stage valve gasket. (That's the green gasket still on the reed valve.)

In my diagram, that gasket is shown as a round gasket with two smallish cutouts: one rectangular, one trapazoidal. Mine is different: a thin circle with a thin line through it. I don't want to simply order the one the diagram calls for if it doesn't look like the one that I'm replacing... In a video from Lawrence Factor I had found, they mentioned that there were two gaskets: an 'old style' and a 'new style', and sure enough, they show the two different gaskets, and identify the 'new style' as the one I have. So it seems that I have the 'new style' valve head, even though the diagram says I should have the 'old style'.

By the way, those Lawrence Factor videos are a very nice resource: LAWRENCE FACTOR® | Videos I haven't finished all of them yet, but they give you a breakdown of tear-down, replacement and assembly of all of the valves in each stage of a Bauer compressor, including first stages with reed valves and those with concentric valves (like the Capitano). The Reed Valve on 1st Stage video has that comparison of gasket types at 4:00, if you're interested.

But here's where my inexperience and nervousness kick in. The only gasket I can find that's similar to mine is the gasket for the Mariner II, and it is *slightly* different than the one currently on my compressor -- and the one shown in the Lawrence Factor video. One of the edges is thicker with a flat inner edge instead of the uniformly thick and curved edges on mine. It's a pretty small difference. And that extra part is against a flat and solid metal part of the reed valve disc, so that extra gasket shouldn't cause any problems... But it's not the same. So I worry.

So I called Filter Techs. Their website was *very* useful through this entire process. I could see pictures of parts from all kinds of models and easily compare them. So I figured I would call and ask if they might know why the gasket was different and if it was the right one for me. The first time I spoke to Joe, he was able check the actual physical gasket and confirmed that it matched the photo, with the flat spot. We both thought the extra width there should not matter and that this was the correct gasket -- and that there wasn't anything else even *close*.

In doing more digging, though, I came across a photo that showed the *exact* gasket I needed -- without the flat spot! Now it was for a $1200 Mariner II valve head assembly, so I couldn't order that, but it *was* the correct gasket. It made it seem likely that I did indeed need the Mariner II valve gasket. So I called Filter Techs the next day and spoke to Joe again. He said he would look at what was actually included in that package and call me back. A few minutes later he called and told me that the gasket in that package looks exactly like the Mariner II gasket he had looked at yesterday, including the flat spot. So it seems that Bauer changed the shape of that gasket at some point, but it should still be the gasket I need.

No doubt you grizzled old compressor veterans are laughing at me. I get it: I've seen exactly this type of situation in my actual day job. I've had plenty of times when, say, Lenovo will send me a replacement part with the same FRU but looks slightly different than the one I pulled out: things changed over the four or five years since that server was built. But even then I'm always leery of what this might do to my now-mixed-up mission-critical server. (And yes, it's caused problems once or twice: BladeCenters are *really* sensitive! ) But when you have *zero* experience, the more differences you have, the more risk you take. If I can minimize the differences (and risk) I will. But it seems in this case I'm going to have to be happy with the slighly-different gasket. And I'm sure it'll be fine.

So, with that decided, time to to buy some parts. I ended up buying a set of third stage valves *and* a set of second stage valves, as well as the two first stage gaskets. The second stage valves should be fine, but for $74 total I'll replace them and clean up the originals as spares (as I will the third stage ones, too). It ended up being $256 after shipping. I wouldn't have minded replacing the first stage reed valve, but not at $200... I'll clean it up a bit and test it, and if it's fine, it's going back in.

Stupid 10k limit: continued.

 

[tmassey]

Continuation of above post. Good thing I don't get paid by the word... Again, if you can help me with cleaning, details are at the end of this post. I would be grateful for any cleaning suggestions you might have.

So, for those playing along at home, here's what I ended up ordering:


Final Stage Valve Kit, which includes the intake and discharge valves as well as the valve tool recommended for getting the second and third stage intake valves out.

Bauer Final Stage Valve Kit 007790, NP-2201-1042AK

This NP-2201-1042AK Final Stage Valve Kit fits Bauer Compressor part 007790

filtertechs.com

Second Stage Intake Valve Insert, as opposed to the entire valve assembly, which includes the cap and a couple of other easily-reusable items.

Poseidon 2nd Stage Suction Valve 012841, NP-2201-0007A

This NP-2201-0007A 2nd stage suction valve fits the Poseidon Compressor part 012841

filtertechs.com

Second Stage Discharge Valve. It's called "Third Stage" on the page, but I think that's the third stage of a four-stage machine. My part number is actually listed.

Poseidon 3rd Stage Discharge Valve W1-2835, NP-2201-0004A

This NP-2201-0004A 3rd stage discharge valve fits the Poseidon Compressor part W1-2835.

filtertechs.com

First Stage Cylinder Gasket, for below the reed valve.

Poseidon 1st Stage Gasket for Cylinder Head NP-2202-0037A

This NP-2202-0037A 1st stage gasket for cylinder head fits the Poseidon Compressor part W5-8262.

filtertechs.com

First Stage Valve Gasket, for above the reed valve. This photo shows the bump mine does not have.

Bauer Mariner II 1st Stage Gasket 063340, NP-2202-0073A

This NP-2202-0073A 1st stage gasket for cylinder head fits the Bauer Mariner II Compressor part 063340

filtertechs.com

(In case you want to compare, this is the gasket for the 'old style' Mariner first stage valve head: Bauer Mariner 1st Stage Gasket for Cylinder Head NP-2202-0038A and this is the photo that contains the gasket that looks exactly like mine: Bauer Mariner II Gasket & Seal Kit NP-2202-0474AK )

I recommend Filter Techs. I've bought filters from them before, and now compressor parts. They had all of my parts in inventory (and some I only asked about to compare!), they shipped them the same day and they answered my anxious nonsense questions quickly and professionally. And their prices were about 25% lower than others I had found.


I touched base with @Tracy when all of this was done. My main question was: Bauer states that I should use 'a very thin layer of gasket sealant' when assembling them. What should I use for the gasket sealant? When I hear 'gasket sealant' I think RTV, but my context is automotive, not compressors. He suggested Permatex High Tack, so that's what I bought: At $7.50 delivered, it's cheap enough.

So now I wait for parts to arrive. In the meantime, I'm now thinking about how to clean up the existing parts.


Does anyone have any suggestions as to how I can best clean up the parts I've got? I've got an ultrasonic cleaner, but it's too small for the castings. For regulators and other such parts I use the ultrasonic with Crystal Simple Green diluted 10:1 with hot water, and 50/50 distilled white vinegar and hot water if there is corrosion I need to remove. However, that's usually plastic or (chromed) brass; I've found that Simple Green can attack anodized aluminum, and I don't want to do that here. But these things are fairly covered inside and out with compressor oil, carbonized to various degrees. It's going to need some good degreasing power, but I don't want to strip the anodizing. Any thoughts or suggestions?

I'm still pretty annoyed that I haven't found anything out of the ordinary. Assuming I can get it back together, I've wanted to understand compressor maintenance more fully, and I'm getting that opportunity here. I just hope when I'm done it still works...

Thanks for your interest. I appreciate any suggestions you might have!

 

[happy-diver]

Dress your surfaces

Change your Orings

Ulrasonic your valves





That permatex muck is for cars and aeroplanes not for the top end of your compressor
When it comes to quickly inspecting your first stage valves and or reusing your gaskets
your gaskets will be destroyed and you will have to clean up all the unnecessary muck!

Or any other metal to metal cylinder inspections

Do you see any stinking brown permatex muck on any of your sealing surfaces.
or any other thick sticky muck.
No!

read this

https://www.jordair.ca/pdf/BAUER-WORKSHOP-MANUAL.pdf

look here

https://www.bauer-kompressoren.de/fileadmin/documents/products/spare-part-list/mariner/1980-01-01_t138-9_1.pdf

I'll read your thread tomorrow Mr tmassey and see what I can see, good job.

 

[Wookie]

Agree with Mr. Happy. If you’re going to work on small, tight tolerance critical parts like regulators and compressors, an ultrasonic cleaner is a must-have.

Be very careful dressing or refacing metal. If you want to test the face, blue check them on a flat table. If you have a warp, lap the head on a lapping table. You can YouTube videos of both processes.

When assembling, a torque wrench is a critical tool.

 

[tmassey]

Agree with Mr. Happy. If you’re going to work on small, tight tolerance critical parts like regulators and compressors, an ultrasonic cleaner is a must-have.

Be very careful dressing or refacing metal. If you want to test the face, blue check them on a flat table. If you have a warp, lap the head on a lapping table. You can YouTube videos of both processes.

When assembling, a torque wrench is a critical tool.

Umm, I *said* I have a US Cleaner. And I use it for regulators and such. But the castings don’t exactly fit. Any suggestions for cleaning chemicals and techniques that I could use on them? (No, I’m not buying a huge US cleaner for this... )

Don’t plan on dressing or refacing anything. Just cleaning. That part was not broke: I ain’t gonna fix it at this time.

I have a torque wrench — a couple of them. I will use them.

Do you see any stinking brown permatex muck on any of your sealing surfaces.
or any other thick sticky muck.
No!

read this

https://www.jordair.ca/pdf/BAUER-WORKSHOP-MANUAL.pdf

look here

https://www.bauer-kompressoren.de/fileadmin/documents/products/spare-part-list/mariner/1980-01-01_t138-9_1.pdf

Got a suggestion for gasket sealant? Everything I read states it should be used.

The Workshop Manual was handy. Thank you for linking to it! Seems the bolts should be torqued (with that torque wrench @Wookie mentioned) to 15 ft-lbs max. My understanding was 10, so that is a change. (I’m always worried about stripping Aluminum.) None of the instructions for removal/assembly seemed unique, but they are nice to have.

It also calls out Loctite FAG2 (now 5922). Which seems to be black thick sticky muck. Not sure how that works in @happy-diver ’s personal reality... And it seems difficult to come by. But it‘s hard to argue with the manual.

Was there something specific you wanted me to glean from the Mariner manual? I have examined extensively the diagrams for a *bunch* of comparable Bauer compressors and different versions over time (including the Mariner) as well as the diagrams for my specific model and age unit from Bauer Austria, Of course, I‘m certain I don’t know what I’m looking for: I’m happy to be informed...

Any suggestions for cleaning these parts, beyond ‘ultrasonic clean them’? I mean, I have *some* concept of how to clean grease from metal, but nothing specific in this context. And the last time I tried heavy-duty cleaning really dirty anodized aluminum is how I found out that Crystal Simple Green will take anodizing off... I’m hoping to avoid such an experience this time, so if anyone has a description of what worked successfully for them, I would appreciate hearing about it.

 

[Wookie]

Umm, I *said* I have a US Cleaner. And I use it for regulators and such. But the castings don’t exactly fit. Any suggestions for cleaning chemicals and techniques that I could use on them? (No, I’m not buying a huge US cleaner for this... )

Sorry, I’ve never heard, in 35 years of rebuilding United States Navy HPAC and LPAC air compressors a ultrasonic cleaner referred to as a US cleaner. Apologies. I didn’t mean to sound condescending if I did.

It’s what I did for a number of years. Now I just buy rebuilt ends and have other people install them.

I have never in my life used a sealant to seal a head. Nothing but an o-ring and proper metal to metal contact and proper torque. I have used loctite on the head bolts, but only if they have backed out on the 50 hour check.

I am not a fan of chemicals in my breathing air.

 

[tmassey]

No worries. I wrote ”ultrasonic” in my original message, but I’m on my ipad now, and typing sucks here. But what would you suggest I use *in* that cleaner? Or outside of it for the objects too big to fit?

As for gasket sealant: *I* don’t want it. Bauer wants it. It is specifically mentioned in the workshop manual (page 19 of the doc happy diver linked), as well as in just about every other reference I’ve seen that has any kind of detail, including the Lawrence Factor videos I linked. I’m not about adding things unnecessarily. I *am* about doing things properly, and for me with no experience, “properly“ means “by the book” where possible. Which is why I’m poring over as many documents as I can. But that doesn’t mean it’s the only (or even best) way.

These heads don’t use o-rings. (The cylinder housings do, but I’m not touching those!) 2nd and 3rd valve heads are metal to metal (and I would use no sealant), but the first stage uses a ‘paper‘ gasket. And Bauer calls out gasket sealant. So, I ask.

I do not envision using Loctite thread lock/adhesive anywhere. I will be using a torque wrench, and I even will have the proper Bauer valve tool...

I’ve said from the beginning that I don’t know anything. I’ve also said that I’m nervous about this, And I’m not coming up with these ideas on my own — and I even try to identify *where* my ideas are coming from. I’m sure people are missing it in the wall of text — but that’s why that wall is there!

In any case, I do appreciate your suggestions. It worth way more than I’m paying for it! The hard part is meshing the variety of conflicting information, all presented with extreme confidence, and much of which conflicts with Bauer.