Reply With QuoteI just hold the two halves of the exhaust valve in a couple of three jaw chucks then twist while pulling to get them apart.
When I've fitted a new seal I Loctite the exhaust valve back together.
All the best Mick
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My 1377 was holding air intermittently which I thought was possibly due to a defective pump seal. Lubricating it seemed to help but it was not a propper solution. So before Christmas I ordered up a seal kit. Never taken a pump up appart before so had a look at the parts diagram & got a pretty fair understanding of how they worked before getting down to actually taking it to bits.
All came apart pretty easily, trickiest bit was removing the circlip on the pump pivot so that the cylinder wasn't marked by something. Anyhow it came off without causing any damage. The pump slid out without a sound, no suction noises or pop as it came out, so fairly sure my suspicions were correct about the pump seal being the culprit. l cleaned things as they came off, popped them all in a clean plastic tray as I went. Took the old seals off the valve, seperated the two halves of the valve took off the washer/seal between them & shook, the bits out of the valve.. grungy, sticky horrible mess in there. Suppose all that pump lube had yo go somewhere!
Cleaned everything up rebuilt the valve, put it all back together, could feel compression ahead of the pump when sliding it in, so began to feel optimistic it was sorted. Popped the pump pivot circlip on, one pump ok, second pump hiss, whoosh, less confident...... tried it, no air stored. Ok cock it first, same result!
To bits again, nothing obviously wrong, back together, left the circlip off this time, still not holding air, pumped ok first held air,second fealt ok till the end of the stroke then hiss...
Appart again let's look at the valve stem seal, looked ok, thought about lapping it with some metal polish, seemed ok cleaning it up noticed a grain of something greenish, same colour as the seal on the valve stem. Closer look & yes the valve stem seal was disintegrating. Being soft it looked ok initially as it bedded to the mating face but it wasn't up to the job anymore. So I dug it out, no valve stems easily or quickly available or seals so it was either going to stay like that or I set about making a seal.
It seems the recommendation is that the brass cup be sweated off the steel valve stem first then a new seal fitted, guess the steel stem is then driven back in. But as I hadnt got a seal I didn't want to risk messing things up any more by doing this. Found some nice tough sheeting .06t thick, cut a disc out of it then took out the centre, pushed it down over the val e stem over the retaining flange & seated it down. Valve back in frame, all back together & hoorah!
No idea how long it will last but valve stem seals can be replaced fairly easily without having to part them.
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I just hold the two halves of the exhaust valve in a couple of three jaw chucks then twist while pulling to get them apart.
When I've fitted a new seal I Loctite the exhaust valve back together.
All the best Mick
Registered User
no need to Loctite them and that makes it a pain to align the port(some valves aren't drilled perfect and you find you have to adjust them so the port is central when the trigger frame screw is in the valve)
the early phase 1 and most 2nd phase ones have the steel and brass stem and I rebuild these quite often especially the similar ones fitted to 2100/2200 and 766 models but the later stem can be used on all models bar the 1322 medallist with the blow by stem
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Cough --- I was only talking about Loctiting the exhaust valve cap onto the stem.Originally Posted by --ped--
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that can help as they can be sloppy after being punched out I tend to just dot them with a centre punch
loctided valve bodies are a pet hate and I've seen many a valve bugger'd attempting to open them ,the 766 2100 type valves were often sealed at factory and need heat in most cases to separate them
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Seems theres more than one way to set about these but as an update the seal I made has held up so far after a fair few shots with no sign of any issues. Early days though but it's been tried with 3 pumps & seems very consistant & works fine on 8 or 9 pumps too.
Only issue now is the trigger...that really needs looking at, not just creep, it 'judders' as it creeps. Possibly the worst pistol trigger I've ever known.
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triggers are very basic seesaw type sears and are rough stampings coupled with overly strong sear springs
I prefer the one piece 1st variant trigger frame if removing the pins to polish sear be warned they're splined at one end to hold them in
last ones I did were installed from the right so tap out from the left but go steady and tap out a fraction to see if splines are visible if not knock out from other side
later frames are easier as they have a cover to access internals but to avoid losing safety ball and spring remove frame from tube before removing
swapping out the sear spring for a lighter one with a guide and adding an over travel screw to the frame really helps as does a wide blade trigger
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ped, thanks for the warning about splined pivots. Don't think I'd have considered that before punch met pin & hammer. While sorting the leak I'd looked briefly at the trigger components. It is certainly basic & asside from tweaking the spring & polishing the bearing surfaces there doesn't look like much else can be done without some serious thought. Still. I'll give it a go & see what it feels like step by step. Not even sure if anything in there is hardened yet, looks like unpolished stampings.
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sear is hardened to get the trigger out you have to twist it 90* and wiggle /rotate it bit like those bent metal puzzles you find in crackers
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Thanks ped, should have time to work on this over the next day or two. I hope the polishing results in an improvement, I'm finding the length of the pull is a bit of an issue, maybe it's something I can get used to but it feels very un natural compared to other pistols I've used. It's no breaking glass rod.
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not much you can do with length of pull unless you drill and tap frame for an adjuster
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Mmm, looking at the schematics I tend to agree, the geometry does not lend itself to shortening the length of pull. Ah well i'll give it a polish & see how it goes.
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Well I think I'm about done with the trigger now. After a bit of work polishing things up its definitely got a smoother pull. It's not juddering with a stop start feel to it anymore. Although the travel is still too long for my liking I don't think there is much I can do about that. There was virtually no over travel so I have not fitted a trigger stop & as the pull weight was ok I didnt try to alter the spring either by squashing it or swapping it with a lighter one.
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the phase 1 frame has a .250" longer sear and a lighter spring than the later phase 2 and 3 frames
you can take a fraction of the top to get travel down but I'd not recommend that method as it's too easy to take too much off and replacing the sear is a pain as no one in the UK stocks them so your either masking one or getting one from the US
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Didn't know that either. Learnt quite a bit about Crosman pumpers during this, think I will leave things as they are now. It dosent seem worth risking messing things up as the trigger feels better than it did. Its liveable with compared to what it was.
After fiddling around with this one I quite fancy having a bash at moderately customising one, I think I can see the attraction in these pistols.
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