Opening a Mk5

[aquaregia]

I'm trying to get this SP MkV open, but I can't twist off either the body or the end cap. I soaked the sorry thing in vinegar hoping to dissolve any corrosion without any success. I have managed to scratch up the end cap and ding up the ambient ports, however.

Any suggestions?

 

[redacted]

It will take the right pin spanner if it is particularly tight or there is much corrosion. If it has the large ambient holes, I suppose it is possible to insert a metal bar (nail) through two of the holes for leverage and have a go at it just to get it started. If you believe your tool is good enough, then go with more soaking along with hot and cold to get things loose. I'd soak the whole reg in ice water and then dip the turret end into hot water up to the ambient holes for about 1 minute. That should produce some separation between the body and the ambient chamber. Then dip it on down so the hot water can penetrate the threaded area. Repeats as necessary until it disassembles or you run out of patience. Running out of patience causes unnecessary damage.

 

[Zung]

Yep, get the right pin spanner. Actually, I use a hook spanner I got from an auto repair/part shop: the "tip" is a squarish hook instead of a cylindrical pin: it bites better and doesn't slip. Take your reg along to the shop to try for size; best match is when the spanner is a tiny bit smaller than the reg, so there's 2 points of contact.

awap, you should be diving instead of doing technical support.

 

[aquaregia]

If it has the large ambient holes, I suppose it is possible to insert a metal bar (nail) through two of the holes for leverage and have a go at it just to get it started.

Nope, bent up the brass using my Jameco pen-driver. This regulator stuff is way different to my car where I just toss flammable oils on everything and start hitting successively longer levers with successively larger mallets.

I'll try the hot-cold trick. If that fails, I'll head to the LDS to see if they'll lend me the pin spanner. I might buy a second MkV this weekend, so I'll wait until Monday in case I need the spanner for the other one as well.

And yeah, thanks for all the help guys. Next time I'm in your area(s) I'll make sure to bring a bottle of beer/whiskey/air.

 

[Zung]

Don't mess it up anymore, go buy a hook spanner NOW: it's only 10 bucks & it's one of my best investments.

I take you up on the air, but you've got to find a guy willing to fill a tank that's 2 years overdue for hydro.

 

[aquaregia]

I think that might be less problematic than finding a way to Switzerland.

For some reason I thought they were special SP tools. I'll check the hardware store and the mechanic tonight. Is there a cheap alternative to the valve tool too? I had planned to take a grinder to a screwdriver, but the grinder's owner (nominally the State of California) wasn't too keen on it.

 

[redacted]

You need one that will work in the 1.25 to 1.5 inch diameter range. Although a SP Mk5 with enviro cap runs close to 1.75 inch diameter. Hard to find in USA tool stores. Ebay tends to have a good offering including this one that looks good: Williams O-471 3/4" to 2" Adjustable Pin Spanner Wrench - eBay (item 280503516396 end time Jun-06-10 07:47:33 PDT)

 

[Zung]

You mean the screw driver with a slot for the tank? Sorry, I'm not there yet, I'm just starting to think about it. Maybe saw a slit and finish it off with a dremel. Or I may never do it: the hydro guys here don't care about the valve, they just want the empty tank and 80 bucks, thank you.

Edit:
Agreed, you won't find them in hardware stores. Go straight to where they sell tools and parts for cars; hook spanners are pretty common to deal with the knurled nuts as in the pic above. And yes, the adjustable ones could be cool.

 

[halocline]

Once you get the MK5 body apart, you're going to need another type of spanner to get the HP seat retainer out and a bullet to get the piston back in. The bullet is really cheap at scubatools. You can get both spanners in one plus the 2nd stage wrench by getting the scubapro tool.

Scubapro Multi-Tool, Brass Chrome

The bullet:
Scubapro Piston Bullet, Brass

And, an excellent o-ring pick:
O'ring Pick, Double Hook, Plastic Handle

If you're planning on doing your own service on your MK5, those tools are a good investment IMO. You can forgo the multi-tool and get separate spanners, but to me it's worth it to get the tool.

 

[aquaregia]

When I started working on my car a guy told me that I could choose whether I was going to spend money on tools or broken parts, but I wasn't going to save money by skimping on tools. For some reason, I'm always reluctant to spend money on custom tools. I'll probably get that multi-tool though just because it's brass, and I'm definitely seeing the problems with using steel tools on brass equipment. Speaking of which, I notice you linked me a metal o-ring pick, but I had someone tell me I should use a plastic pick with o-rings rather than my metal dentist picks. True/false/not a big deal?