mk10 VDH aftermarket kit and the pink urinal mint hp seat

[Candiru]

I started with a mk10 non-spec type off ebay. The ip was measuring 135 with no creep prior to rebuild (zero shims). The internal orings were scubapro urethane and some other colors. The hp seat was pink like a urinal mint. I did the rebuild with the aftermarket mk5 kit from Vintage Scuba - Vintage Scuba Gear at Vintage Double Hose . I had to purchase some 017 (2 needed) orings from McMaster Carr also. I took a guess and added one of the stainless steel shims suggested on this board (purchased from McMaster Carr) as this kit uses the infamous trident A242 seat I figured that this would lower my ip from 135. My findings were that the ip now reads 140 at 1500 psi. So the trident A242 is essentially equal to the old pink hp seat.
My first question is if I should take the shim out or leave it?

Second issue: prior to dissasebly the swivel turret had some free play (in the axis it shouldn't) as if the bolt was not tightened properly. At dissasembly the bolt looked fine. I tightend the bolt to 35 inch pounds and assembled. The turrent still has the free play in it. My mk10 spec booted first does not have this free play.
My second question is if this is normal or acceptable?

 

[redacted]

I like to set IP in the 125 to 130 range when I rebuild. !40 is in spec but I would probably remove 2 washers and bring it down.

A little play in the turret seems to be normal. If it were tight, it might restrict turret movement and allow the retainer to loosen.

 

[Candiru]

There is only one shim in. Is it bad to remove the piston after it has set on the hp seat?

 

[redacted]

I would remove that one shim which should get it down to 135. The critical thing is to not disturb the seat in the seat retainer. Some mark the piston so it can be reinstalled in the same orientation but I have never bothered and never had any problem.

 

[halocline]

I agree with awap, take the shim out. You might get a bit of creep when you first re-install it, but leave it pressurized for a couple of hours and tap the purge several times, it'll probably seat pretty well. Your play in the turret is probably normal, but you might look to see what kind of shape the plastic washer is in. That's part # 01-060-500. Try a new one of those and see if that gets rid of your play.

 

[Zung]

+1: remove the shim and don't worry too much about the play. If you look at the cutaway below, you'll see it's by design, even though years of wear may make it a bit worse. It should go away under pressure.



The plastic washer, part # 01-060-500 in red above may help a bit, but it's not easy to find.

 

[Candiru]

I pressurized the reg, then checked the free play and its gone! I never thought of doing that. I am probably going to take the shim out today. Thank you everybody for the input! This completes my first mk10 rebuild then. It didn't feel than much more complicated that the mk2. I'm excited to see how the trident hp seat holds up.

 

[Couv]

Well done,

If the swivel retainer is brass, don't torque it any further, if it's stainless you can tighten it more (I'll have to check the specs to be sure) up to about 70 in lbs if I remember correctly. That may take some of the unpressurized freeplay out of it. In addition to removing the shims, index the seat retainer and body so when it's reinstalled it, you don't change the ip by having it further in/out of the body.


Edit: I just checked the chart. 70 in lbs for stainless steel (which seems high) and 35 in lbs for brass.

 

[Candiru]

I removed the shim (no shims in now). The ip now reads between 125 and 130 at 1200 PSI with a 5 sec creep to 130. Before I removed the shim I had zero creep. Is this IP too low now?

 

[Zung]

130 PSI is good, I try to get all my regs in that area, +/- 5 PSI.
The small amount of creep is not uncommon, hopefully it's just the piston stem finding its way to its new home. Have you cycled the reg? If not, leave it under pressure over night and maybe te creep will go away.