Help, Odd vibration on inhale

[tanslacks]

Hello, My wife is getting back into diving after twenty five years. She wanted to use her same old gear, so I brought in her old regulator to be serviced. The LDS services Scubapro and the tech loved her gear and commented in what great shape it was in. He serviced the regs and said there was years left. I can't tell you the model but it is a Scubapro from 1985. At the time, it was top of the line.

Anyway today we went to a friend with a pool to test things out. The reg worked well, no leaks, and it is the easiest breathing reg I have ever used. So here is the question...

When she inhales, more at the end of the inhale stage, you can feel a bubble feeling/ gurggle feeling if you grap the hose. I can feel this bubbly vibration on the primary hose and the BC hose. The if she swaps and uses the octo, i feel it on the octo hose. This only happens on her inhale. I see no leaks at the bottle or anywhere. I am clueless what is causing this. Tomorrow we are going to try a diiferent tank, I am not sure how that will help, but I am trying to rule everything out.

Does anyone have any ideas, or what I might try.

Thank you so much

 

[mikediveguy]

if it is more of a 'shudder' then the first stage piston is grabbing,,,have tech relube or check for wear on inside surface piston travels on.

 

[DA Aquamaster]

If it was made in 1985 and was the top of the line it is probably a Mk 10 with either a D400 or Balanced Adjustable second stage. I think the G250 came out a year or so later

With the Mk 10, a shudder or whistle in on inhalation is almost always due to inadequate lubrication of the high pressure piston stem o-ring. For a variety of reasons techs may end up not lubricating it and the piston stem enough, causing friction that causes the piston to vibrate as it moves back and forth and this resonates through the hoses.

It is a 5 minute fix to remove the piston, apply a bit of lube to the o-ring and piston stem and re-insert the piston, but you'll have to take it back to the tech.

 

[tanslacks]

Thank you so much for these replies. I will go back to the tech on Tuesday and see what he finds. Thanks again

 

[halocline]

When she inhales, more at the end of the inhale stage, you can feel a bubble feeling/ gurggle feeling if you grap the hose. I can feel this bubbly vibration on the primary hose and the BC hose. The if she swaps and uses the octo, i feel it on the octo hose. This only happens on her inhale.....

Does anyone have any ideas, or what I might try.

Thank you so much

The piston vibration that DA is talking about is usually kind of a whistle or honk, not a gurgle. A gurgle to me sounds like a 2nd stage issue. If it's a D400 (great reg, funny looking 2nd stage that kind of hangs under your chin) and it's been sitting around a while I'd suspect that there might be a leak between the diaphragm and the coaxial exhaust valve. If you turn upside down, do you get a mouthful of water? Try that in a pool.

You might have both the 1st stage lack-of-lube issue on the HP piston and the leaky exhaust valve. If it were mine, I'd consider sending the whole set to DA aquamaster for a rebuild, as he's an expert with older SP regs, and your local tech might not be. The D series 2nd stages are quite a bit different to work on than contemporary SP 2nds. I've had two different SP dealers tell me they hated the D series regs, I suspect because they didn't understand them very well.

 

[tanslacks]

The piston vibration that DA is talking about is usually kind of a whistle or honk, not a gurgle. A gurgle to me sounds like a 2nd stage issue. If it's a D400 (great reg, funny looking 2nd stage that kind of hangs under your chin) and it's been sitting around a while I'd suspect that there might be a leak between the diaphragm and the coaxial exhaust valve. If you turn upside down, do you get a mouthful of water? Try that in a pool.

You might have both the 1st stage lack-of-lube issue on the HP piston and the leaky exhaust valve. If it were mine, I'd consider sending the whole set to DA aquamaster for a rebuild, as he's an expert with older SP regs, and your local tech might not be. The D series 2nd stages are quite a bit different to work on than contemporary SP 2nds. I've had two different SP dealers tell me they hated the D series regs, I suspect because they didn't understand them very well.

Hi Mattboy,

You are right about the second stage design. However, We get the same "rumble" in the line when we are using the modern Scubapro Octo. Plus I feel the vobration in all the hoses, even the BC inflator. I will copy everyones ideas and see what the tech says. I will have time to try the upside down experiment today.

Thank you again

 

[halocline]

Hi Mattboy,

You are right about the second stage design. However, We get the same "rumble" in the line when we are using the modern Scubapro Octo. Plus I feel the vobration in all the hoses, even the BC inflator. I will copy everyones ideas and see what the tech says. I will have time to try the upside down experiment today.

Thank you again

Right, the vibration would be coming from the first stage. If there's also a gurgling, like air bubbling through water, then I would suspect the problem I mentioned in the 2nd stage as well. If you weren't using the word "gurgling" that way, then I wouldn't worry about it.

Of course you could save yourself all sorts of potential trouble and just sell me the reg.

 

[requiembell]

I have been diving a D400 since about 1987 and it is still my primary today. I have tried to go with the "new and improved" and without a doubt there are some great breathing regs out there today but I don't know if I will ever replace it. I bought my wife an Atomic set-up last year and dove it once to compare it to my old Scubapro and still wouldn't retire the old system ... although I did add one of Atomic's swivel hose set-ups to my second stage. Jaw fatigue is never a problem. Great reg and timeless design, I love it when I get my moneys worth out of a product.

The D400 can be a little finiky to get set-up and if your LDS is not used to them I can recommend one that is and has been servicing mine since I got it. The guy that does my service holds several patents with Scubapro and has been published multiple times ... he has been around so long I think his PADI cert is only a two digit number but when my D400 comes out of his shop it is perfect. PM me if you need some assistance with your set-up and I will put you in touch with him. Its a fantastic reg when its set-up correctly and he is definately the guy that can do it.