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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
Flakotter
Skin Diver
Posts: 25
Joined: Mon Nov 27, 2017 8:32 pm
First Name: Traner
Location: Lakeville MN

Mistral rebuild question

Fri Jan 19, 2018 2:40 pm

Happy Friday everyone, I’m in the process of rebuilding (very slowly) my first Mistral. I’m using the Aqua lung repair manual as a guide but I am not clear on one of the steps. Step three, removal of the yoke retainer, states “Secure two sides of body with an adjustable wrench. Invert regulator and insert handle of wrench in a vice.” That seems straight forward enough. My problem is the edges of my Lever Plate overhangs my body. I can’t seem to see a clear attachment point on my body for the wrench. I am assuming (maybe incorrectly) that the lever plate is not a sturdy enough attachment point for my wrench (plus the repair manual clearly states the wrench should attach to the body) Am I missing something here? Thanks in advance.

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ScubaLawyer
Master Diver
Posts: 865
Joined: Thu Apr 08, 2010 11:25 am
First Name: Mark
Location: Laguna Beach, CA

Re: Mistral rebuild question

Fri Jan 19, 2018 3:32 pm

Not sure what you mean by "the edges of my Lever Plate overhangs my body." May be post a picture? From my way of looking at it your wrench should be on the body of the regulator outside of the can, on the retainer, not inside. For what it's worth, unless the yoke retainer is really stuck hard, I just hold the can in one hand, place a large crescent wrench on the retainer itself (should fit around the yoke just fine as the yoke is thinner than the retainer), and twist counter-clockwise. Usually does the trick. On occasion I have held the can with the wrench attached to the yoke retainer and struck the garage floor with the end of the wrench to jar the retainer loose. Probably not the recommended way of doing it but I have had great success with that brute force procedure. :D Doing it per the manual, i.e., “Secure two sides of body with an adjustable wrench. Invert regulator and insert handle of wrench in a vice" to me means that the wrench, secured in the vice, is either on the yoke retainer and you are twisting the can to loosen it, or you have removed the lever plate, put a wrench on the body and a second wrench on the yoke retainer. Others probably have more experience doing it the right way than I do. I'm more intuitive than a ridged direction follower. :shock:
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

Flakotter
Skin Diver
Posts: 25
Joined: Mon Nov 27, 2017 8:32 pm
First Name: Traner
Location: Lakeville MN

Re: Mistral rebuild question

Fri Jan 19, 2018 7:44 pm

Scuba lawyer
Thanks for the reply. I tried the “hold the can in your hand and put the wrench on the retainer nut” method but the nut was stuck fast. That’s when I went to the repair manual. I will post a photo of my regulator lever plate tonight when I get home but for now, here is the photo in the manual that I was using as a reference. The red arrow points at the adjustable wrench clamped in the vice. The adjustable (from what I understand) is griping the body from the inside and the crescent wrench is applying torque on the retainer nut. I’m guessing this prevents too much stress being transferred to the can when the retainer nut is stuck but from the sounds of it, the can is stronger than I assumed. My issue is, which a photo with explain better than I can in words, my lever plate has a larger foot print than the body on which it is attached so there are no edges of the body exposed to grab with an adjustable wrench. This being my first rebuild, I’m not really sure of a roundabout way to disassemble the regulator other than what the manual says. For my second rebuild, I should (in theory) better understand what I’m working with so I can address the issue from a different angle. I will get that photo of the lever plate posted tonight and try the hand holding method with a little more force. Thanks for the advice. I will keep you guys posted.
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Flakotter
Skin Diver
Posts: 25
Joined: Mon Nov 27, 2017 8:32 pm
First Name: Traner
Location: Lakeville MN

Re: Mistral rebuild question

Fri Jan 19, 2018 8:45 pm

Here are photos of my lever plate. If I follow the repair manual, the adjustable wrench would not be able to connect with the body because the level plate would get in its way. I’m not worried about deveateing from the manual so much as I’m wondering if I am interpreting the manual wrong or, if I understand it correctly, why the manufacturers suggested method does not work on this particular regulator.
C4DEE44D-C7F8-4639-B8DD-477B312F4929.jpeg
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ScubaLawyer
Master Diver
Posts: 865
Joined: Thu Apr 08, 2010 11:25 am
First Name: Mark
Location: Laguna Beach, CA

Re: Mistral rebuild question

Fri Jan 19, 2018 9:09 pm

Just take the lever plate off. Two screws and a nut is all there is. You can then grip the body with a wrench if you need to. There is no guarantee the lever plate is adjusted correctly anyway. I always take it off, run the parts through an ultrasonic cleaner (although yours looks pretty pristine) and adjust the height of the lever to the optimum level on reassembly. Mistral's are very simple and a great performing regulator. Good luck on the rebuild. Keep asking questions. I still do on issues that come up on reg rebuilding from time to time. Mark
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

Flakotter
Skin Diver
Posts: 25
Joined: Mon Nov 27, 2017 8:32 pm
First Name: Traner
Location: Lakeville MN

Re: Mistral rebuild question

Fri Jan 19, 2018 9:35 pm

Mark, thanks for the help! I’m sure I will have plenty more questions in the future.

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Bronze06
Master Diver
Posts: 577
Joined: Tue Jul 01, 2014 5:33 am
First Name: Russell
Location: Tabuk, Saudi Arabia

Re: Mistral rebuild question

Sun Jan 28, 2018 7:17 am

ScubaLawyer wrote:
Fri Jan 19, 2018 9:09 pm
Just take the lever plate off. Two screws and a nut is all there is. You can then grip the body with a wrench if you need to. There is no guarantee the lever plate is adjusted correctly anyway. I always take it off, run the parts through an ultrasonic cleaner (although yours looks pretty pristine) and adjust the height of the lever to the optimum level on reassembly. Mistral's are very simple and a great performing regulator. Good luck on the rebuild. Keep asking questions. I still do on issues that come up on reg rebuilding from time to time. Mark
Ditto what ScubaLawyer said and I might add that you take off the venturi as well. It is just good practice to disassemble and clean all the parts down to the bone. Once you get the body free, ensure that you get the old micro-o-ring out of it and replace it with a new one. I like and use Bryan's technique to install it using a WD40 spray straw. Bryan has a good little video on Youtube showing this procedure. I would send you the link, but I am at the office and can't get on Youtube.
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

Flakotter
Skin Diver
Posts: 25
Joined: Mon Nov 27, 2017 8:32 pm
First Name: Traner
Location: Lakeville MN

Re: Mistral rebuild question

Tue Feb 06, 2018 2:53 pm

Bronze06,

Thanks for the reply, I have not seen the WD40 videos, I will go look that up right now.

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