Scubapro MK25 rebuild/service "squeeking"

[jhelmuth]

I have a problem that I've not encountered before and do not have the knoweldge to address myself.

I recently had my Scubapro MK25/S600 reg serviced (annual) in November and took it out on it's first dive trip in Jannuary. Every breath and every push of the inflator button causes the thing to "squeek" rather loudly. It seems to breath fine, and by the end of the trip (15 dives) it did reduce the noise to an almost un-noticeable level to not at all. I did check it out at the time that the rebuild was done, and I did notice it when I breathed hard - but not when it was breathed normally (for me anyway). I probably should have said something, but I didn't think it was a big deal. Maybe it isn't, but I plan to take it back and talk to the service tech (an older gentelman who I've know for years and have a reasonable level of trust in and definately a good relationship with) about it.
It would be really great if I knew in advance what some of you "experts" thought was the reason for this. Any experienced thoughts would be greatly appreciated.
Genesis and DA - if you see this I'd really like to hear from you since I have come to trust and respect your opinons and knowledge on the Scubapro prducts from your prior posts.

Thanks in advance for any replies

Jim

 

[ZoCrowes255]

Sounds like it could be a deformed seat in the first stage or it was put in wrong (upside down maybe.) Take it back to wherever you had it serviced and ask them to have a look at it. They should be able to fix it free of charge. It usually doesn't bother the performance of the reg but it can be very annoying.

 

[Lane Zimmer]

Sounds to me like either the piston shims are not sitting flat and vibrating, or the main spring needs to be flipped. Simple fix.

 

[jhelmuth]

Zo... no doubt that I'll be able to get Ray (reg tech @ my LDS) to "look at it" or "re-do it". Would a deformed seat make sense if the rebuild parts kit was new? I can partly understand a mistake, and I'm certain they'll make it right with no charge. I'm just wanting to better understand what may be wrong.


Lane... does this make sense considering that the problem noise is nearly non-existant at this point? Do you think that I should be supicious of any permanent damage?

 

[LUBOLD8431]

I am more inclined to think that its the spring producing harmonics thats causing the trouble. Simply flipping it may rectify the problem like was already mentioned...

 

[jhelmuth]

I am more inclined to think that its the spring producing harmonics thats causing the trouble. Simply flipping it may rectify the problem like was already mentioned...

So that seems to be 2 votes for the spring (and I trust your opinion based on my perception that you are very knowleddgeable and trustworthy). So is that so easy that it's a "no brainer" to change out (at least to see if it is the cause)? Would you expect it to be a new spring in a rebuild? If not, then why would it make the squeeking after a rebuild?

How practicle would it be for me to do my own repairs/service on this reg. I own 3 (mine, my wife's and my son's). All bought at the same time and all identical. I'm very adept with mechancial things and technical information, etc. So I'm not scared of DIY. I also know enough about servicing mechanical assemblies (like bicycle assemblies, small engines, and some tools) that I know what value experience has in performing service and maintenance tasks. So I don't take for granted that I can or should service my own regs.

 

[TTSkipper]

Not sure if your are experiencing the same thing, but I bought my regs 1 day before a trip so I dove with them for over 1 hour in the pool at my lds. I had the same squeeking which seemed to sometime come and go, the shop took the reg apart ( I have taken classes with the tech and from conversations with other people trust his skills) and could find nothing that looked like it was wrong, the relubed some o-rings (not sure which ones) and back in the pool I went, the squeek was almost gone. 2 days later I was diving in FL and I did not hear the reg squeek once and the reg breathed very easily down to about 80fsw. I remember the tech say to the instructor who was watching me in the pool that he had seen similar problems from o-rings that did not have enough lube in the past.

Just thought I would chime in with my 2 pesos, but obviously they should be looked at by a tech.

TTSkipper

 

[LUBOLD8431]

How practicle would it be for me to do my own repairs/service on this reg. I own 3 (mine, my wife's and my son's). All bought at the same time and all identical. I'm very adept with mechancial things and technical information, etc. So I'm not scared of DIY. I also know enough about servicing mechanical assemblies (like bicycle assemblies, small engines, and some tools) that I know what value experience has in performing service and maintenance tasks. So I don't take for granted that I can or should service my own regs.

Well, its always good to take your reg apart with someone who knows what they are doing the first time. Its also a good idea to have a diagram to make sure you put it back together right.
What TTSkipper said about the oring is true as well. It could be the piston oring didnt get lubed enough on assembly. So, when you bring it back into the service tech, he can troubleshoot a couple things, and will know better what it is when he looks at it. THis time, I would recommend bringing it back to the service tech.

 

[DA Aquamaster]

A squeak on inhalation in a MK 25 is almost always caused by one of two problems.

1) The upper bushing in the stack is installed upside down. There are four mold marks on one side of this bushing, and they must face AWAY from the high pressure o-ring or else it will squeak. Or,

2) the HP o-ring is not adequately lubricated. A fairly liberal amount of cristo-lube on the HP o-ring will solve the problem. Inadequate lubnrication is more common now I think as people are more concerned with O2 cleaning and tend too view too much lube as a bad thing. It really is not an issue if it is O2 compatible and the HP o-ring/bushing area is one part I always want to make sure is adequately lubricated. (not dripping in christo-lube, but at elast adequately lubed.)

You need to disassemble the reg to check for the first problem, and while you are there, just lubricate the o-ring to address the second problem. It is often hard to get the upper bushing to come straight out so it is not always posible to tell if it was installed correctly or not.

You really need the Mk 25 assembly tool to stack and insert the bushings and o-ring to ensure the lower bushing, o-ring and upper bushing all get there in the proper order and orientation every time and stay there while the piston is inserted.

The main spring is flat on each side so its orientation really makes no difference. Flipping the spring often seems to help but my opinion is that this occurs as the piston has to be removed and reinstalled to flip the spring and in the process more lube gets delivered to/scraped off on the HP o-ring and inadvertantly solves problem # 2.

 

[ninja]

Yes again the piston orings should be heavily lubricated at the scubapro swminars they alway's tell you not to be cheap here.