Question Skipping 1st stage Maintenance?

[Pearlman]

Now I opened the MK25Evo and I found only a single silicone sleeve on the piston! Did I forget to put it back in during the classroom session? What happens if I don’t use the missing piece and rebuild it?

Doh! The sleeve is part of the periodic replacement items - should have read the chart more closely, and there is a replacement sleeve in the kit!

 

[Mobulai]

Scary! The piston base already has a bump by design, I wonder what it does exactly since it’s a flow through piston…

I wonder what that bump does anyway (on mk2s as well)
All I saw it do is cause a deep vertical scratch on an mk2 ambient chamber

Luckily with the help of a polishing dremel head got that fixed/IP holds overnight (besides exposed brass.. let’s see how corrosion develops)

Probably something is shooting over my head, but my only guess has to do with pushing (with pressure) excess lube from orings (doesn't make much sense as well)

 

[BoltSnap]

I don't know if it's just me, but seems you would be better off letting someone else servicing your regs.
You managed to make 3 potentially costly mistakes already.

Well, how is he going to learn? Better off asking here for everyone's to learn and avoid making his mistakes at same time. I believe that he should be commended for having the balls to come here and ask in public.

 

[Mobulai]

Well, how is he going to learn? Better off asking here for everyone's to learn and avoid making his mistakes and same time. I believe that he should be commended for having the balls to come here and ask in public.

I agree, but… buying a beater/older reg to practice on is also a good middle ground IMHO, at least not the „main“ regs

Still nothing fatal so far to the regs in thread, and cosmetic battle scars are also Ok in my book

 

[BoltSnap]

I agree, but… buying a beater/older reg to practice on is also a good middle ground IMHO, at least not the „main“ regs

The mistakes would be different and inapplicable to his diving regulators.

Regardless, I don't think that he should be chastised in public.

 

[Geo7]

Anyone servicing regs has made mistakes, and I think there is value in reporting not only "how-to", but also "how-not-to". This could actually be worth a new thread where we all admit our most embarrassing mistakes.

If anything, it'll help others avoid the same mistake, and demonstrate that reg servicing is not rocket science, but there definetely is a learning curve.

 

[Mobulai]

Anyone servicing regs has made mistakes, and I think there is value in reporting not only "how-to", but also "how-not-to". This could actually be worth a new thread where we all admit our most embarrassing mistakes.

If anything, it'll help others avoid the same mistake, and demonstrate that reg servicing is not rocket science, but there definetely is a learning curve.

+100

I like that thread idea a lot, we can call it „ask me how I know that“
I’ll start: don’t think „oh this spg neck is caked in corrosion, I’ll microwave 1:1 vinegar water, and suspend the spg in it“ only to walk out of the room and go play with your kid… you remember it an hour later and it’s bare brass

 

[Geo7]

+100

I like that thread idea a lot, we can call it „ask me how I know that“
I’ll start: don’t think „oh this spg neck is caked in corrosion, I’ll microwave 1:1 vinegar water, and suspend the spg in it“ only to walk out of the room and go play with your kid… you remember it an hour later and it’s bare brass

Ok, let's create a new thread then

 

[Pearlman]

Ok finally made time to rebuild the Mk25evo - I needed to double check if I had used the correct o-ring after installation and so scratched out the new super-glide ring (23) that I had just installed so bad in trying to push it out of the 1st stage body with the brass pick that I had to reuse the old one that was also scratched during disassembly but to a much lesser extent. (This is one area never to make mistakes as it is a pain to remove). Took me more than 5 mins of trying each time while the sandwiched o-ring (22) and ring (21) always came out in a split second on the first attempt. Now the minimum swing IP I get with the spring pad adjusted all the way in is 9.8 bar which is out of spec. Is the washer (17) absolutely required to be installed in the bushing or can I remove it to lower the IP? And what’s the effect of a scratched out super-glide ring with a higher friction against the piston stem? Will it create scratches on the piston stem and should I just get a new service kit and redo instead? Just noticed there is IP creep to 10bar so looks like the seating is not right?

Edit : During the rebuild, I pushed the new seat down over the spring using a hex socket - could that have been an improper seating? It didn’t fall out after that but maybe that’s causing the creep? The reason for a high swing IP lockup is a mystery though… maybe the washer in the bush is not required?

 

[Mobulai]

Ok, had to get to a computer to view schematics

To answer your 1st q, no
The washer can be dropped out for the sale of IP

But the 2nd q is the critical one:
That stem oring is a HP interface, so, if it has a scratch I would expect IP to creep drag (if not now, soon); and maybe eventually a big leak, or worst case, tearing
It might drag with higher friction (causing a slow IP response— the mk20/25 are known to have rather quick recovery otoh), or maybe even catch a grit of sand and scratch the piston (but maybe very far fetched/impossible)

Better get another unscratched oring (the 01-050-138 is a 2-011 duro85), or if you can’t source it on its own then another service kit and use that

I saw you have the bushing tool in an earlier post, that combined with a piston bullet will help you seat it without scratching the oring

[shamless plug] Here’s my best try (not good )at documenting it (I’m sure there are other better versions out there)

HP75/SP Mk25 = @mobul.ai

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