Air Arms Sl400 rebuild

Pyramid is the AA place. They have o-ring kits. You can find them on Ebay also. https://www.pyramydair.com/s/a/Air_Arms_O_Ring_Seal_Kit_For_S400_410_And_S500_510_Caliber_Specific_Breech_O_Ring_Sold_Separate/7360

   Well worth trying the replacement yourself. For Scuba regs we use a tool that is essentially a tapered rod. A pin punch with a flat tip the same size as the the part upon which you are replacing the o-ring works well. Simply roll a lubed o-ring onto the tool; mate the tip with the tip of the part (in this case the bolt tip) and roll it on from the tool to the tip of the bolt; and, finish by hand.

   If the barrel has not been removed and you are limited to the confined space between the bolt and breech, you can make a cheap tool from a stripped Bic pen. Just melt the barrel of the pen about 1" from the tapered tip into an "L" shape that will fit the gap. Have also done it with a long handled torx wrench. Fiddly and doesn't always work, but is worth a try for almost no cost. 

   Enjoy that fine rifle

You can order the o'rings from McMaster Carr if you want specific ones. And you will have a lifetime supply for about the price of Pyramyds kit.

There are two places that can leak at the breech, the breech/probe seal or the power adjuster seals.

O-rings:
Inside barrel/thimble 
.177 EV2, MPR, S500,S400 4.5X1.5mm
.22 BS009 (009)
Barrel/shroud support (inside) 14X1.5mm
or BS112 (112)
Barrel shroud support (outside) 20X1.5mm
Gauge seal BS211 (0011)
Gauge block to air tube 6X1mm
Gauge block to mounting screw BS008 (008)
Air tube o-ring seals BS213
Male Fill Port (banjo) 12X2mm
Fill valve to air tube 12X1.5mm
Power adjust knob shaft 2.5X1.5mm

I actually have the breech oring, but I can't get it seated.  So I figured if that oring is bad, then the whole rifle should get new orings.  Since one oring beat me into submission, I wanted someone to do the whole rifle for me.  I'll call PA on Monday and get an estimate. 

I may even just sell it as is.  I have a SL500 in 22 so I really probably maybe almost don't need 2.  I also have a new TX200 I can't use because I tore up my rotor cuff.  So I was thinking of parting with those two AAs, and getting a HW100. 

You may not need to replace everything, the breech o ring is a common seal that needs to be replaced in many PCPs not necessarily needs a complete rebuild. Use silicone lube.

HA

I have an HW 100 for sale on the classifieds and I like to trade.  I just had PA reseal it and I think it was around $80 if I remember right,  PM me if you want to work out a trade.

Bob in WV