Hill Pump Question

rick983 · Post by **rick983** » Thu Nov 25, 2004 8:17 pm

I just received my Steyr LP50 and purchased a Hill hand pump at the same time. I don't know if other people have the same problem as me, but I can only pump it to 150 bars. Now I weigh 290 pounds, and even putting my full weight on it doesn't help. Is this normal for these hand pumps and should I be happy with 150 bars? Thanks.

RobStubbs · Post by **RobStubbs** » Fri Nov 26, 2004 2:54 am

You should be able to pump up to 200 Bar (and beyond if the cylinder is rated above 200). I weigh a fair bit less than you and I don't have a problem with my pump (not a hill though).

Rob.

SteveT · Post by **SteveT** » Fri Nov 26, 2004 9:23 am

I have a Hill and weigh 170lbs and can pump up to 200 bar. I kind of have to lunge on it a little for the last few pumps, but it is not that hard. I Wither you are doing something wrong, or there is a problem.

Your bleed valve is not leaking is it? Can't think of anything else likely, but I've never dissassembled the pump, so I have no idea what could happen inside.

Steve

QUICKBRICK · Post by **QUICKBRICK** » Sun Nov 28, 2004 4:03 pm

rick983 wrote:I just received my Steyr LP50 and purchased a Hill hand pump at the same time. I don't know if other people have the same problem as me, but I can only pump it to 150 bars. Now I weigh 290 pounds, and even putting my full weight on it doesn't help. Is this normal for these hand pumps and should I be happy with 150 bars? Thanks.

I USE A HILL PUMP TO PUMP UP MY RIFLE. I FILL TO 200 BAR WITH-OUT TOO MUCH TROUBLE ALTHOUGH IT DOES GET HARDER TO PUMP FROM 180 BAR.I WOULD THINK YOU HAVE A VALVE NOT OPENING PROPERLY

F. Paul in Denver · Post by **F. Paul in Denver** » Tue Nov 30, 2004 2:33 pm

I use the same pump on an LP50 cylinder as well - it does get harder beyond 180 bar but it does sound like you may have problem with your pump.

DavidO. · Post by **DavidO.** » Wed Dec 01, 2004 6:52 am

Has anyone had any problems with air escaping when you unscrew the cylinder after filling it. The first two times I filled my cylinders LP10, it worked fine, but after that at least 10 percent of the air escapes (if I unscrew quickly) when I begin to unscrew the cylinders from the hill pump after filling it to 200 bar. The air escaping has torn up two of my green rings installed in the adapter valve that comes with the LP10. I will attempt to install the white ring and see if it works better than the green ring. The cylinders are working just fine in the LP10. Has anyone heard of this problem with the hill pump?

David Levene · Post by **David Levene** » Wed Dec 01, 2004 8:04 am

Air will always escape when you unscrew Steyr cylinders from the filling adaptor as it manually opens the cylinder valve.

The cylinder valve on the Morini cylinder is opened by air pressure.

dflast · Post by **dflast** » Wed Dec 01, 2004 1:02 pm

The Steyr cylinder does have a mechanical valve, but the o-ring is located to seal "outboard" of the valve: threading the cylinder on, the seal will be established before the valve opens & spinning it off, the cylinder valve should be closed before the seal is broken. The air released when the cylinder is removed from the pump should be only what's in the adaptor sections between the cylinder valve and the pump check-valve. If you're actually losing pressure from the cylinder in the process, this pretty much has to be on account of the o-ring failures.

The o-ring itself shouldn't give much trouble. A touch of silicone grease to lubricate, and DONT thread the cylinder partway off and then back on again under pressure. I'd guess that the recurrent o-ring failures will turn out to be because of a burr or a sharp edge on the adaptor cutting the ring, or (less-likely) the adaptor nose or ring groove out-of-spec dimensionally, causing the ring to extrude under pressure and rupture. If the issue was in the cylinder itself, you'd expect it to be killing the o-ring on the pistol too. Try replacing the adaptor.

DavidO. · Post by **DavidO.** » Wed Dec 01, 2004 1:07 pm

Thanks Dflast that was very informative.

David Levene · Post by **David Levene** » Wed Dec 01, 2004 1:37 pm

dflast wrote:The Steyr cylinder does have a mechanical valve, but the o-ring is located to seal "outboard" of the valve: threading the cylinder on, the seal will be established before the valve opens & spinning it off, the cylinder valve should be closed before the seal is broken.

You learn something new every day. Does that mean that I, like many others, have been doing the "panic cylinder twist" for nothing and that a slow leisurely removal would have been just as good.

dflast · Post by **dflast** » Wed Dec 01, 2004 2:31 pm

Think of it inside-out: do you need to hurry to thread the filled cylinder onto the pistol before all of the air escapes?

There is one apparent disadvantage to the Steyr mechanical valve using a hand pump: when the cylinder is spun all the way on, the bleed valve bleeds off the cylinder as well as the HP outlet of the pump. Warren's advice to me was to pump up to 220bar and bleed back down to 200 by way of expelling condensation from the pump. This seems to work perfectly well, still well short of the proof limits of pump and cylinder and come to think of it clears the cylinder valve too. Maybe not a disadvantage at all!

funtoz · Post by **funtoz** » Wed Dec 01, 2004 5:14 pm

David Levene wrote:You learn something new every day. Does that mean that I, like many others, have been doing the "panic cylinder twist" for nothing and that a slow leisurely removal would have been just as good.

I have a Gehmann pump for my Steyr, but understand that the hill is similar.

Backing off the cylinder 1 to ¾ of a turn should close the check valve without breaking the adapter seal. Release the bleed valve. No air should escape from the cylinder. No need for a panic un-screw if all the seals are working properly.

The cylinder should seal to the adapter before the check valve opens. So if the bleed valve is closed, no air should escape the pump.

Am I missing something?

Larry

DavidO. · Post by **DavidO.** » Fri Dec 03, 2004 1:24 pm

With the Steyr and hill pump, at least with mine, unless I unscrew the cylinder quick I loose pressure. A little bit of silicone grease around the rings helps a good deal. So far the rings have not torn.

funtoz · Post by **funtoz** » Fri Dec 03, 2004 2:52 pm

Because my experience is so much different than yours, and others on the list, I took a closer look at my setup. The brand of pump should not make a difference. The cylinder valve is depressed by the adapter. The adapter generally comes from Steyr, and should be pretty much the same for all of us. While the LP-1 adapter may have been different from the LP-10 one, I doubt it. The only other explanation for your setup to loose significant air is excessive wear. You might want to see about replacing your adapter with one that works better.

Please see the Air Guns Only tech tips for hand pumps.

http://www.airgunsonly.com/frames.html

Larry

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