CPS 4100 Mark 1 trigger snapped

[theTman1221]

on a separate note, my old CPS 4100 Mark 1 model just suffered a trigger snap. the little plastic trigger sheared off. I removed enough screws to manually reach the stump where the trigger was so I could discharge the bladder as it was fully pumped up when the trigger went. Tomorrow I plan on opening it up entirely and either using a guide I found online to make a replacement trigger, or possibly rebuild the internals completely with sturdier parts but keep the cool frame. I might also leave the pump intact if I went that route. The gun is 11 years old, and I bought it as a kid so it wasn't cared for so nicely. Lots of hard water and it didn't get flushed out usually. I can see through the clear side that the tubes either have a white hard water deposit buildup or some really old mold. The water flows through just fine so probably the former.

I stated it is a mark 1 as I hear there were 2 models, and the mark 2 was more prone to breakage. I identified it by the purple tank cap tether it has that I read is only on mark 1's.

I'll have to decide how I want to deal with the endcap at the front of the pump rail. From what I've read I might have to saw it off.

[soakinader]

Protip: Remove all the screws from the 4100, then gently pry the entire shell open, starting from the back where the reservoir is. If you work it back and forth you can usually remove one half of the shell from the cap, and then it's pretty easy from there to detach the cap from the half it's stuck to. Then you can press fit the cap when you are all done, no damage, plus you can always pop it back off easily.

[isoaker]

Note: posts split from other thread for clarity.

[theTman1221]

Yeah, I'll try what soakinader mentioned rather than saw it. After looking at some pictures of the internals of the gun it may be a bit much to replace the internals with stronger homemade parts. The most I could probably do is replace the water lines depending on how bad the buildup is inside them.

[theTman1221]

Update: I got all of the screws out, but I could not wiggle either half loose from the end cap. I tried manually finessing it for a half hour, then tried warming it with hot tap water and then wiggling and twisting it. After that I tried heating it with a hair drier and using an adjustable pliers (Not a vicegrips, some other thingy) to twist or pull it off to no avail. I'll have to keep trying tomorrow. Anyone else got some ideas on how to get the cap off?

[soakinader]

Get a good knife under the edge and pry on it. Try to get part of it loose, and then work from there. Most of the time the glue wasn't done very well, and there will be less glue on one side/part than the other. If it's glued really, really well, and you can't even get a little bit of the plastic to separate, than you'll either have to cut it or be less gentle and pry & pull until it breaks or pops off. Try and lift one half of the shell while pulling backwards and down nearest the cap. I will take some pictures of the process next time I take a gun apart, I have done it successfully a half dozen times, and broken or had to cut something a few times. I have seldom found heating to be an effective method; it only works on a few kinds of glue. Using pliers tends to hack up the plastic more than anything. One method that might work is using long, toothless needlenose pliers and pushing the prongs in from the bottom like a wedge, using mechanical advantage to separate the cap from the body. It just takes experience, good tools and luck.

[marauder]

For some reason I've always found that boiling water does a better job dissolving glue than the hair dryer method. I'd recommend both that and the knife method.

[theTman1221]

I GOT THE CAP OFF!!!!!!!! I used my big sharp and sturdy knife and worked on one side until it broke free of the glue and came off just one half of the casing. I then removed all the guts and disconnected the intake hose to clean out all the crud inside the tubing. After looking everything over it seems that the only thing I couldn't replace with homemade parts is the valve that fires the gun. I Imagine I could build a PVC pump to fit inside the spot for the old one if I ever need, the intake tube is just simple vinyl tubing I can buy at a local store, and I imagine I could replace the pressure chamber with some LRT if it broke for some weird reason.

Now I have to decide how I want to go about making a new trigger. It snapped off right at the narrow spot between the trigger and the guide that goes around the pump tube. I am trying to think of a way to replace both the broken trigger and the guide that goes on the tube as I do not relish the thought of trying to bolt or glue anything to the cheap plastic trigger guide. I'll have to fiddle around a bit, and I might ask my dad for ideas. He works at a tech college as a CNC machining professor's assistant and can make things on the machines from time to time. Maybe I could get him to make an aluminum copy of the old trigger and trigger guide combo piece lol! That would be epic.