BSA Challenger - Advice please....

[SRV1]

Mmmm...failed this afternoon!!!

Please help - I want to service and lube my Challenger, but have the following situation that have failed me miserably:

Stock and barrel removed leaving the cylinder and trigger block.
Scribed across cylinder to trigger block marking original alignment.
Clamped breech jaws in soft jaw vice (in direction of pivot!).
With a solid, good fitting bar inserted into the trigger block hole, tried to unscrew it. Bloody tight, but, I thought yippee, it is starting to turn, but, the scribe marks are still in line. What the, who the, what the hell is going on?
The cylinder had started to turn around the breech jaws section!!!!
Turned it back into place.
Repeated same again after using a gas torch to heat up the cylinder near the trigger block to expand cylinder and soften any Loctite should it have been applied in its passed history.
Still no go, even with some sharp blows to the bar inserted in the trigger block.

Please;
How is the breech jaw section fitted to the cylinder tube? Is it brazed in? Pressed in? What to do now it had started to turn? Will it be safe?
How the hell can I unscrew the trigger block from the cylinder? I presume a right hand thread?
Talk about a Friday afternoon job...this is a Sunday afternoon job I wish I had not started.....
Any advice welcome!

All the best to all.

[Shed tuner]

are you sure the breach assy is unscrewing from the cylinder ????

also don't use the hole in the trigger block, it's not strong enough...

[SRV1]

Hi Jon thanks for your reply....

The breech jaw section appears not to be screwed into the end of the cylinder, but, possibly a brazed (can't see any fine braze marks) or, a very tight press fit. It is certainly turning as I had to re-align the jaw section in its correct axis relative to the cylinder/trigger block. It turned by about 5 degrees.....

[silva]

I do feel for you. I would leave it alone for a day or two for the trauma to subside.....then nightly apply heat and dunk into diesel or try to spray penetrating oil into back of breech area. Giving the cylinder in the thread area a few sharp taps with a clean rubber mallet helps too, wrap a bit of leather or similar around it first to protect finish.

[thisisdonald]

I use a bit of old roughed up conveyor belt rubber wrapped around the cylinder and clamped in the vice. that way you dont run the risk of squashing the cylinder or scoring it. I then clamp a couple of bits of hardwood onto the trigger block and rap it hard with the hammer.. sometimes you just need a sharp blow to loosen it... squirt some acetone up inside the trigger and try and clean out any visible gunk, then squirt in some light oil.. that way if the spring end is all gunked and stuck inside the block, it might get it moving.. it could be a bit of friction caused by that, as well as the block being stuck.

another good thing to use prior to whacking things is a penetrating oil.. ive had success with paraffin and 40w mixed, everyone has their own recipes for loosening oils.. might be worth giving the joint a wee soak and get some up inside the trigger

[SRV1]

Thank you silva and thisisdonald for your response....

Prior to attempting the job this afternoon, I had been soaking the area concerned with PlusGas for a few days anticipating it being tight. I have applied PlusGas again and will try your suggestions. I am worried about the situation of the cylinder starting to rotate from the breech jaw section regarding safety...

All the best

[thisisdonald]

if its rotating, I would try and remove it and see how its fixed. you might be able to clean it up and solder or simply loctite it back on. Ive never heard of one shifting. If you were using the U shape of the jaws to give you purchase to unscrew the trigger block - that trigger block is either REALLY on there or you had a bad breech block in the first place. in which case this is a bit of a silver lining and you can get it rectified.... another silver lining is any work you want to do on the transfer port will be very easy while its off

[joffy]

One word of warning.....when you do manage to release the trigger block make sure that you have something around it like an old towel (the bsa springs are usually under a fair bit of preload )

Good luck

[thisisdonald]

hang on a second.. scratch what I just said - removing the breech jaws could potentially be dangerous and might result in the piston becoming stuck in the void the jaws create once removed... youll need to get the trigger block off first before inspecting the breech end... doh.. what a wally I am...

[magnummike]

The trigger block was the same on a Mk2 I did a few months ago I got mine in a large Vise so the cocking slot was just above the top of the gaws , fit in the length of the slot something like a door handle square bar , turn the cylinder so that the bar is trapped between the top of the gaws and cocking slot , tighten the Vise then with a rubber mallet a couple of sharp whacks on the price of the end block with the hole in should do it . Mine came off a treat after struggling with other methods for days hope this helps Atb Mike

[QUIGLEY]

They can be tight.
The shock tactic with a nylon headed mallet is the one I employ.
Once you get it moving you have about 15mm or so of thread to unwind before it will release the spring which could be under a fair bit of tension from preload as already said.
If you are not confident put it in the hands of someone who is, as it would be a shame to damage the rifle or more importantly yourself.
Edd.

[fozzy45]

Just hold onto the cylinder and hit the trigger unit anticlockwise with a rubber mallet. I have taken dozens to bits like this before, also on the airsporter range with no problems. You shouldn't even be going anywhere near the breach end.

[deejayuu]

Good advice so far. I would just add that the trigger block is an alloy which expands faster than the steel tube when heated.
So try going deep freeze then as fozzy45 describes.
Just to muddy things a bit more if its been wet for a while the dissimilar metals will corrode and stick fast so after
degrease try vinegar soak. Good luck.

[QUIGLEY]

The alloy back block does not extend into the cylinder.
It has a steel cup thread fixed to it by a bolt which lives in the cup.
The thread on the cup is what actually screws into the cylinder.
The worst that can happen is that the bolt that holds the cup comes loose. Then you have got problems.
Edd.

[deejayuu]

Ah gotcha Quigley. Good shout.