It seems like the gasket is dry so I oiled it hoping it would solve the problem, but it hasn't. Does anyone know what to do?
Take a look on amazon Amazon com Crosman Powermaster 760 pump and take a look for replacement. have a nice day
If the rubber piston on the end of the piston assembly is missing, try this:
http://www.usacarry.com/forums/general-firearm-discussion/6931-crossman-66-powermaster-fix.html
If the piston is still there, it may just have shrunk a little due to age or lack of oil. Drive out the roll pin at the top end of the pump tube, then remove the square-drive screw holding the end cap to the barrel sleeve. Be careful not to strip the threads here, since the barrel sleeve is just thin metal.
Remove the end cap and extract the fore-grip and piston assembly. Pull the rubber piston off the assembly and place the cupped end against a golf ball, then compress in a clamp or vise for 15 minutes or so to flare out the cupped end a little.
Check the fit, and if it pumps, reassemble. Worked for me.
Tom
The dismantle instructions worked great. I did take a different approach to expand the rubber piston and clean it and the tube. Once I pulled the piston assembly out of the tube my inspection of the rubber piston at the end revealed the rubber to be an open cup at the end. I cut a slim 1/8" strip of pricing tag (you know, the plastic bar code tags stapled on the end of lumber) and slid it in between the rubber cup and metal piston (this expanded the rubber piston a few microns providing a better seal). I then lightly sprayed the rubber piston with carb cleaner. And, sprayed generous amounts of carb cleaner down the piston tube (up ended to pour out excess. Clean as a whistle! Re-assembled and worked the pump action / press trigger. Also held trigger down while pumping a few times. Back-n-forth until pumping up 3 times fire, then pump 5 times and fire, and then pump 8 times and fire (no bbs, just work it and notice the increased firing sound with more pumps). No more air blow-by hissing. All fixed! Happy shooting! Jeffro.
The roll pin at the top of the pump tube won't come out. Is there a special way to get it out?
I can't get the roll pin at the top of the pump tube out, is there a special way to do it or is my gun just messed up? Any ideas?
Perhaps you may have all ready managed to repair your gun if not , try this. First the proper terminology is not a role pin , it in fact is a spring pin. Reason being the material its made from is not only durable , its intelligent. Spring steel has properties that able it to return back to its original state , just as efficient as a spring. The hole your pin is in will be somewhat smaller than its dia. ,since it is not completely cylindrical but rather rolled its entire length the pin has give. This means the right sized hole will except the pin with some force . Once hammered in ,not beaten the pin tries to expand allowing it to remain tight. To remove it , its almost opposite. Never hold the cylinder in a vice the slightest damage to its factory machining will destroy it. Best lay it flat on a heavy bench , many work shops will have holes drilled thru benches for project's such as this. Place your workpiece over top the hole so that when it punches thru it will land on the floor. Now you'll need to find a punch , sizing is important to small it will get knocked it to the pin center expanding it and making it more difficult to remove. To large it will ride on the o.d of the drilled hole. line your punch up over the pin and tap with a hammer , some force may be needed. If you are able to fit the punch into your hole with out force , your on your way. Before you put the pin back in clean the pin up with fine sand paper round both end's as a lead in , just in case they were mushroomed when being removed. Good luck.
Do you know how to take apart the piston?
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Never use oil on the gun it will destroy the seals use automatic transmission fluid.If you go to Colemans web site and look up service centers you can call and get a seal kit for the gun for less than $20 and rebuild the whole thing.
I think it might just need oil . just get a fine air rifle or gun oil and put 4 or 5 drops in the plunger, and 2 or 3 in the place the trigger locks it back ,
By the way, I just took apart my 760 (2nd variant) and looked for a seal kit to replace everything. Kinda overpriced almost everywhere. I called the Crosman co. They patched me through to their customer service...I got the following parts for around 14.50 (that's with shipping). 130-034, 130-035, 140-058, 130-057, 1400a029, 1322D020 (used to be C, but they changed the part # to D) the following part were obsolete - 760-050 (brass nut goes on the bolt action), 760-037, 111a026 (standard spring). Hope this helps.
Power master 760 won't pump at all. Is there a repairman in my area of 45385
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The problem is the same with mine. i pop a bb down the tube. and i pump air, but no air is being charged. its just the handle moving up and down
i have the same problem also.
gun wont hold air charge
will not pump
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