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Author Topic: Benjamin 310 pump rod  (Read 212 times))

Offline Kasilofsteve

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Benjamin 310 pump rod
« on: June 19, 2022, 09:44:25 PM »
Need advice. I'm reassembling a Benjamin 310 and question. The pump rod, how far should it B2 the valve what's the proper length. I accidentally moved it around when I disassemble the gun going to put it back together with a new seal kit just not sure the length and how to figure that out thank you.
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #1 on: June 19, 2022, 11:32:00 PM »
Well I went for it reinstalled the pump rod with the new seal kit getting a farting sound when pumping trying to readjust now the pump rod
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline bantam5s

  • They might sound like a lot of work till you realize you only need 3-4 pumps for plinking.
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Re: Benjamin 310 pump rod
« Reply #2 on: June 20, 2022, 01:55:18 AM »
Sounds like it needs some oil.

You'll want to adjust it so the pump handle has to cam over a little before it's closed all the way.
  • USA CA Arbuckle
PCP? I never touched the stuff !
No, it's a type of airgun !
Oh!, no I don't have one of those.

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #3 on: June 20, 2022, 02:43:11 AM »
Okay I've been trying to adjust it a few mm now it's still farts but only hold air when I cock the bolt back it seems like I'm getting closer I've gone easy on the oil just a few drops
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline pgritty

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Re: Benjamin 310 pump rod
« Reply #4 on: June 20, 2022, 10:45:23 AM »
Did you replace any of the internal springs?
You will have a inlet spring, an exhaust spring and a hammer spring.
Pat
  • Houston Texas

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #5 on: June 21, 2022, 01:44:18 AM »
Sorry for the late response
 Well yes but the new seal kit outlet spring is a little bigger than original. I took it all back apart and gave it a super deep cleaning inside the main tube a lot of hidden grease down by the ports. I'm going to reassemble it tomorrow in the daytime and have another go at it
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #6 on: June 21, 2022, 08:23:18 PM »
I'm at a loss I replace the inlet Outlet Springs twice and using the original ones now, got LED washers,I think my problem is that the pump Rod seal. air is still escaping when I try to Pump It Up
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline bantam5s

  • They might sound like a lot of work till you realize you only need 3-4 pumps for plinking.
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Re: Benjamin 310 pump rod
« Reply #7 on: June 21, 2022, 08:28:51 PM »
I'm at a loss I replace the inlet Outlet Springs twice and using the original ones now, got LED washers,I think my problem is that the pump Rod seal. air is still escaping when I try to Pump It Up
Did you not replace the pump cup on the piston ?

Maybe try posting a picture or two of any concerns you may have.
  • USA CA Arbuckle
PCP? I never touched the stuff !
No, it's a type of airgun !
Oh!, no I don't have one of those.

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #8 on: June 21, 2022, 08:31:15 PM »
Yes I did replace the pump Rod cup with the new one that came with the kit that's on there now the old one wasn't supple.
I'm cleaning the felt pads with tissue paper to get old oil off. Also adjusting the length of the rod various positions trying to troubleshoot as we speak
« Last Edit: June 21, 2022, 08:33:35 PM by Kasilofsteve »
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline sicumj

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Re: Benjamin 310 pump rod
« Reply #9 on: June 22, 2022, 09:58:17 AM »
Do you have air coming out the barrel when you pump?  If you followed directions above on how to adjust handle until it just cams over your pump cup is set.  When set right the cup will be flush with the inlet valve hole.  Handle will be within one inch of closing.

 It is easy to have a leak in the valve assembly or the lead seals.  Pictures would help.  I like tapping my valves with a wooden dowel to help seat them.

Jim
  • NE Ohio

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #10 on: June 23, 2022, 12:04:40 AM »
Do you have air coming out the barrel when you pump?  If you followed directions above on how to adjust handle until it just cams over your pump cup is set.  When set right the cup will be flush with the inlet valve hole.  Handle will be within one inch of closing.

 It is easy to have a leak in the valve assembly or the lead seals.  Pictures would help.  I like tapping my valves with a wooden dowel to help seat them.

Jim
Thank you I will give that a try with the wooden dowel and try and seat the valve closer I will try and reset the bolt handle two and see what happens. Pictures don't like me here can't seem to upload even on Photobucket I'm picture challenged
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod

Offline DanD

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Re: Benjamin 310 pump rod
« Reply #11 on: June 23, 2022, 12:44:53 PM »
Just cock the gun before pumping. It's a non-issue. It's "farting" when uncocked because the exhaust valve spring is weaker than the hammer spring- which is a good thing because it ensures you'll dump more air at higher pump counts.
  • Binghamton, NY

Offline Kasilofsteve

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Re: Benjamin 310 pump rod
« Reply #12 on: June 24, 2022, 01:28:54 AM »
Good advice Dan at first you don't succeed try try again. Success😃 the larger exhaust valve spring did the trick I was able to sandwich it back into the tube and it worked first pump held air I'm in business thanks for all your help guys.
If I stare at something long enough I'll figure it out kind of weird
  • Kasilof, Alaska
Mountian airgun Custom crosman 1322
26" barrel/TKO
1987 and 1990 Sheridan 20 cal
Crosman Prowler 22 cal
1389 backpacker w/ flattop mod