Mk5 rebuild quandry.

[Ghost95]

Morning all, hope your doing well.

I have a question for you about a rebuild I'm doing with a scubapro Mk5.

I have a really clean Mk5 and a rebuild kit from VDH. Now, after taking this reg apart I found that it doesn't look like it's been used since the last rebuild. It has a white, flat, seat with barely any wear in it (very light groove). Everything else is clean and in excellent condition. So, he's the questions... Should I...

A) Use the complete VDH rebuild kit including the new cone seat and save the old style for a backup?

B) Rebuild with the o-rings from the VDH kit but use the old seat same side up since it looks good and save the new cone seat for another rebuild later?

C) Flip the old seat and use all o-rings from VDH kit and save the cone seat for later?

What do you think?

Thanks. Have a good day.

 

[axxel57]

Morning all, hope your doing well.

I have a question for you about a rebuild I'm doing with a scubapro Mk5.

I have a really clean Mk5 and a rebuild kit from VDH. Now, after taking this reg apart I found that it doesn't look like it's been used since the last rebuild. It has a white, flat, seat with barely any wear in it (very light groove). Everything else is clean and in excellent condition. So, he's the questions... Should I...

A) Use the complete VDH rebuild kit including the new cone seat and save the old style for a backup?

B) Rebuild with the o-rings from the VDH kit but use the old seat same side up since it looks good and save the new cone seat for another rebuild later?
well
C) Flip the old seat and use all o-rings from VDH kit and save the cone seat for later?

What do you think?

Thanks. Have a good day.

Just check the o-rings if they still look good ( also under magnification if possible), if so, lube them well ( at least the dynamic o-rings), check the stability of the IP, check for bubbles.
If there are no leaks, a stable IP and only little creep, you should be good for a while.
If you want to be more sure that there will be no problems with this 1st, then change the three dynamic o-rings ( that's what most here would probably do).
In lots of my MK5s I could use the o-rings and HP seats again with no problems ( at least on the test bench).
So if your baby looks good and works good when tested, save your Service Kit.......

 

[halocline]

It's up to you. When I get a 'new' (used) reg and rebuild it for the first time, I change all the o-rings just so that I know exactly how old they are. I might not change them again for five years or more. They are very inexpensive, but if the existing ones look and feel good, they probably are. I would change the HP piston o-ring for sure because taking it out is likely to damage it.

Regarding the seat, if you put it back in the way it is now, It might creep because the groove cut by the piston edge will probably not line up exactly the same. So you could flip it. But......I think the conical seats overall perform better, they tend to be quieter and they have better aerodynamics. So if it were me I'd probably use that. Again, up to you.

I'm trying to figure out what the third dynamic o-ring is that Axxel mentioned. Both pistons, what else? Static o-rings that are subject to HP are the one that seals the seat (sometimes it's purple in the old kits) and the o-ring on the DIN or yoke retainer. I keep an eye on those. Oh, I guess it's the turret o-ring, but to me that one never causes any problems, it's only subject to IP and it doesn't move as much as the piston rings.

 

[Ghost95]

I just decided to do a full rebuild with the new seat. I figure the conical seat was designed to improve performance, regardless of whether i can feel it or not so I might as well use it.

I'll keep the old seat for a spare because it looks in really good shape and because apparently I need to store more junk I never use.