Grating noise when cocking my trail

[Windmill01]

A couple of weeks ago I sought advise on accuracy problems with one of my trails and got some help full replies. This particular air rifle has had over 15000 pellets through it and The only thing I have replaced is the piston seal.
it is now grating through the cocking process, and sometimes it jams half way through. I have stripped it down and there is shiny wear in the cocking slot a on the side of the foot itself. My question is has anyone had experience with this before and what did you do to fix it. I'm thinking I may have to weld some extra onto the cocking foot to build it up but I'm not sure.
Thanks

 

[Bobbed06]

Missing the plastic roller or plastic u guide on the linkage?

 

[Windmill01]

All still there

 

[Windmill01]

I have noticed though that the u piece plastic on the linkage has started to scrape the metal shinny on the bottom of the compression chamber and also wear to the round of the compression chamber. 

 

[Smaug]

These rifles have plastic washers in the pivot where they break open for cocking between the barrel and compression tube. After 15k shots, those plastic washers are likely done-for. The usual remedy is to go buy some brass washers with the right inside diameter, a bolt and a couple nuts. Put them on the bolt and jamb them between the nuts. Then, chuck the bolt in a drill and turn them down with a file, until they're the right outside diameter. Then, wet-sand them down to the right thickness with emery cloth, grease them, and replace the worn-out plastic washers with them. That will also remove the side-to-side slop and bring back your old accuracy.

 

[Windmill01]

Thanks for that but Bobbed06 had already put me on to that. I found the washers a week or so ago and fitted them. The rifle is now accurate but has started to grate. It was doing this before I replaced with brass washers. The barrel is snugg and there is no side to side movement only the grating when cocking. I really think it has something to do with the cocking foot as I can see major wear on the foot and the cocking slot. There must be some side ways movement in the linkage. If I could source a new linkage and pins I would give that a go first without altering the shape of the cocking foot. I would prefer to save this rifle as it has been extremely accurate an reliable.

 

[bhbeyes]

Its hard to tell what might be wrong? Misalignment between the leaver and the bear trap?
the sear out of place? Trigger pack in the wrong place thousands of an inch play It can really move around before it tightens down,
What model Trail do you have? The seal can make a squeaky sound when dry did you oil with silicone chamber lube?( you know not to use petroleum oils right?)
Maybe try taking the stock off and cock it holding the leaver up against the compression tube(ouch pinch points) visual inspect cocking process watching where the noise is coming from don't cock to the point that it catches or you'll have to pull the trigger.
My experience come for my crosman phantom which I installed a nitro piston kit into (same gamo B3 design I believe is what its called and they still used for the trail)

 

[Windmill01]

Morning, the model is a BW1K77NP. Yes I only use silicone chamber lube on the parts held within the stock. I have noticed that when I turn the rifle upside down and cock it the grating lesions considerably. I have tried to cock it without the stock but am unable to do so. I tested the ram at 55 kilos and my old hands are unable to hold it in place. I have a benjaman trail np in 22 cal as well. I have removed the stocks on both rifles and compaired them side by side and all looks ok. You may be right a couple of mills off and things start to go wrong. Thanks for your thoughts.

 

[outdoorman]

I had a similar issue with a Diana 34. Turns out, there was galling in the upper rear portion of the compression tube caused by friction from the piston. It took lots of sanding and polishing of that area of the tube and the rear part of the piston and then lubing with moly to solve the problem. There is a lot of upward pressure on the rear part of the piston when cocking.

 

[Windmill01]

Thanks for that, I'll take it apart and have a look.

 

[Windmill01]

Outdoorman, you are correct it is galling on the piston and tube that is grating. Can I ask what did you use to polish it off and how did you go about removing the galling from the compression tube. Thanks

 

[outdoorman]

I used sandpaper wrapped around a dowel rod to work on the compression chamber working my way up to 600 grit and then using a dremel with flex extension shaft and polishing bits to finish it off. Used files and then sandpaper again up to 600 grit on the back end of the piston and then polishing with dremel tool.

 

[Windmill01]

Outdoorman, thanks for that I had to go into Gympie to buy a dremel, handy little gadget. The piston was very galled and it took a bit of work but it's nearly smooth now. The compression tube on the other hand was very rough and after much sanding and polishing it's about 9 tenths of being smooth. It will be dark soon and I'll clean and molly it tomorrow. 
Its got to work better than before, I was nearly going to scrap it. I'll put it together tomorrow and see how it goes. I'll keep you posted, thanks again.