SP MK-20 - IP Creep

[rhwestfall]

Is it possible the SCW was thought to be necessary due to the "skirt" on the piston? Maybe it was thought to be necessary to prevent alignment/clearance issues early on, but then deemed unnecessary (and cost - save at every opportunity) thus eliminated?????.

 

[buddhasummer]

Is it possible the SCW was thought to be necessary due to the "skirt" on the piston? Maybe it was thought to be necessary to prevent alignment/clearance issues early on, but then deemed unnecessary (and cost - save at every opportunity) thus eliminated?????.

Who knows, it is listed as a required part on the latest schematic I have dated 2001 but at that date they decided it was no longer necessary to replace it annually. I've ordered some Christolube so will rebuild it when it arrives. Hooked it up one last time and ip is now dropping, guessing stem O ring is leaking very slightly. I'll leave the project for a few weeks until my frustration abates and lube arrives.

 

[snowdog61]

I'll leave the project for a few weeks until my frustration abates and lube arrives.

There's a lot of truth there!

 

[fmerkel]

SCW? Is that the large flat plastic washer with the ridge on it? Seen them in kits, had no idea what they were for. Never seen one used in a reg.
Suppose I could open up a reg and see if it fits but it's easier to ask you guys.

 

[buddhasummer]

SCW? Is that the large flat plastic washer with the ridge on it? Seen them in kits, had no idea what they were for. Never seen one used in a reg.
Suppose I could open up a reg and see if it fits but it's easier to ask you guys.

Maybe, it's a split washer, white plastic with a collar. It no longer comes in the service kits.

 

[halocline]

I think that washer is there because SP felt that piston alignment might be more crucial in a MK10+ than the original MK10, but I'm not really sure.

A leak in the piston stem o-ring would have no effect on IP. That o-ring deals HP air from ambient. A leaking piston head o-ring would cause an IP drop until the drop was enough to separate the piston/seat and re-pressurize the IP chamber.

I have also had regs where IP drops a little over several hours of sitting pressurized. It's usually a tiny 2nd stage leak, but sometimes there's no discernible leak and I don't know what causes it. It has to be a leak or simply inaccuracy in the gauge, which I would think is a decent possibility.

 

[Couv]

the spring centering washer 10-500-118 must be left in place? Or can it be removed along with the additional shim that sits above it against the body 01-060-101? Removing both would leave the spring "floating" and sitting against the body.

Again, I'm not very familiar with the Plus model, so I don't know if the spring centering washer is necessary. As you've mentioned, it's not a part that was in the original MK10 which shares the same body and spring with the Plus, so I cannot see how it would be required.

I'll order the recommended grease and then re do. Does this grease get used on everything or just the piston and piston stem O ring?

In this case, use the PTFE grease on at least on the piston stem, piston stem o-ring, and piston head o-ring. I would not go through the trouble of removing the other seals to clean and re-lube them. However, on a rebuild where you are removing, cleaning, etc. I would use the same lube on everything.

 

[buddhasummer]

I think that washer is there because SP felt that piston alignment might be more crucial in a MK10+ than the original MK10, but I'm not really sure.

A leak in the piston stem o-ring would have no effect on IP. That o-ring deals HP air from ambient. A leaking piston head o-ring would cause an IP drop until the drop was enough to separate the piston/seat and re-pressurize the IP chamber.

I have also had regs where IP drops a little over several hours of sitting pressurized. It's usually a tiny 2nd stage leak, but sometimes there's no discernible leak and I don't know what causes it. It has to be a leak or simply inaccuracy in the gauge, which I would think is a decent possibility.

Your were correct, I had a tiny leak out of my 70 degree adaptor. Glad I went slowly as was about to pull the reg apart. Tried with just the hose sans adapter and no leak. That then explains my drop in ip. Thanks Halocline, I've learnt something else. So much for leaving it a week or two.

 

[buddhasummer]

Tried to buy Christolube here, not at $280, my god...

But at least it's free shipping.

 

[Couv]

Perhaps the vendor thinks it's like a fine wine. I note the date and see that it has been aged.