Newbie repairing a Scubapro Mk11, R395, R295 regulator set. Progress report and questions

[stepfen]

I'm pretty sure that item 39 is the metal part surrounding the seat and is still installed.

I had another look at it and indeed part #39 is the thin metal cylinder surrounding the plastic seat. I pushed it a bit and it came apart.

That's great info @rhwestfall. Apart from the hp port it seems that the service kit also includes two diaphragm washers that I can't find in my unit.
I guess/hope that all these "upgrades" are compatible with my reg's body. Is there any chance them not to be compatible?

Finally as a progress report, today I disassembled both second stages with no problems whatsoever this time. Cleaning will follow once I have the repair kits and the new o-rings so that assembling can start soon afterwards.
Thanks a lot

 

[rhwestfall]

while not missing both, one of my used market sourced MK-17's came with only one of the clear washers. When I serviced it, the earlier version of the kits did not include them, so it is running (well) with a single. These newly sourced kits now appear to come with the two translucent washers....

 

[stepfen]

My reg has one too. I need to see what kind of kit I will get. If it doesn't have washers I'll use the old one (single) with the diaphragm from the kit. If the kit comes with washers I'll use them instead.

 

[Couv]

Again, the MK11 takes one washer, the MK17 takes two. I think because the MK17 has an enviro kit installed it uses a thinner diaphragm.

 

[stepfen]

Again, the MK11 takes one washer, the MK17 take two. I think because the MK17 has an enviro kit installed it uses a thinner diaphragm.

I'm not sure couv. The service manual of Mk11 mentions 2 washers too!

 

[Couv]

The manual, yes, the diagram no. So what to do?
Generally speaking, when a product manufacturer supplies documents that contradict each other, the document with the latest revision date is the one to follow unless there is a set priority. In this case, I do not know if SP has a pecking order for their documents, but it's pretty safe to say either way will work.

 

[rsingler]

@couv is correct.
Different diaphragm for the two regs.
The latest troubleshooting guide for the Mk11 confirms only one friction washer.
While two washers for the Mk11 might work, as the torque (310 in-lb) will determine how well the diaphragm is held in place, the reverse is not true for the Mk17. Leaving out a washer may leave the diaphragm inadequately secured, because reaching 310 in-lb may be metal to metal as you screw the chamber onto the body.

 

[stepfen]

Hello.
I'd like to give you an update of my progress and ask a couple of questions.

I have completed servicing both second stages without any major issues. Actually on Sunday I used/dived one of them with a rental 1st stage and octo (as a precaution I didn't try both of my 2nd stages simultaneously). I don't have an in-line adjusting tool yet and the 1st stage was rented so I didn't spend too much time to get a precise adjustment and as a result it was breathing a bit heavy but not too much. That didn't bother me much. What I fount a bit bothering was that the reg was not breathing "smoothly". I.e. once the flow of air was started, the flow was not nice and smooth. I don't know how to explain it better. Can that be attributed too to high cracking pressure or maybe because it is freshly serviced?
I did follow the maintenance procedure where nothing is mentioned about lubricating any of the parts of the poppet/level assembly, which seems a bit strange to me because all of these are moving parts. Hence I didn't lubricate any of those (poppet with washers, spring, housing, level with washers and nut). The only things lubricated were the orifice and few other o-rings (plugs, lp hoses etc). Is that correct?

Proper precise adjustment of the second stages will be done after I have the 1st stage done.

Now about the 1st stage. First concerning the diaphragm washer(s) that we discussed above the service kit came with just 1 washer. The thickness of the new diaphragm and the washer match the thickness of the old ones hence I will go ahead and replace both of them with the new ones.
The DIN knob assembly hasn't arrived yet so I can't complete the service but I did assemble the balance chamber.
When I screwed (just snug - not too tight) the balance chamber to the body I noticed there is a small gap between the chamber head and the body as seen below:

It feels like the chamber has no more space to move further in. I don't remember how the reg looked before I disassembled it. Can somebody confirm that this is how it is supposed to be? When I assembled the balance chamber I was careful to push the bushing and the small o-ring in the hole of the balance chamber followed by the centering washer.

Next steps (leak test) require connection to a tank so I have to wait for the DIN assembly.

Just to sum up the questions:
A) Any ideas why the second stage doesn't breath smoothly?
B) Did I correctly NOT apply any lubrication to the parts of the poppet/level assembly of the second stages? and
C) Is the gap between the balance chamber and the body of the first stage shown in the picture above normal or does that mean that something inside the balance chamber hasn't been done properly?

Thanks a lot in advance!

 

[Couv]

B) Did I correctly NOT apply any lubrication to the parts of the poppet/level assembly of the second stages?

You correctly did not apply lubrication to the poppet & lever.

C) Is the gap between the balance chamber and the body of the first stage shown in the picture above normal

The balance chamber bottoms out and leaves that space. There is a trim boot (protective bumper) that should fit snugly over the protuberance.

A) Any ideas why the second stage doesn't breath smoothly?

Classic downstream second stages have a few details about them that can cause erratic operation.
The most likely cause is the plastic insert; Item 30 in the drawing below. If it's worn from use, you should replace it-if you don't have one, you might be able to sand it down until no ridges are present-do this only if the indentations are very light. Next, but easier to check and correct, could be the washer (Item 32) that goes between the lever and lock nut. Ensure the smooth side of the washer interfaces with the lever. Finally, make sure the orifice is free of any nicks or scratches. Clean it with a pencil eraser and feel the knife edge with a fingernail or Q-tip (yeah, right. A knife edge on a plastic orifice-thanks for the "upgrade SP)

 

[stepfen]

WOW @couv !
Thanks a million!