Daisy 753 Rebuild

[korny351]

Recently, I picked up a nice Daisy 753.  Reading up on it, I decided to upgrade the trigger to the adjustable 888 parts.  While I was ordering parts, I also ordered new O-rings and valve assembly.  While I have the rifle all torn down, I figured I would rebuild the pump assembly and bring everything up to spec.  My problem is that the two o-rings appear to be identical except one is orange and the other black.  The original o-rings are both black.  A call to Daisy CS confirmed that the o-rings are different, but the agent I spoke with did not know which one went where.  She said she would call back when she found that information.  I'm getting impatient and was wondering whether anyone on the forum knew specifically which one goes to the pump assembly and which one is for the valve assembly.  Thanks for any input.

John

[45Man]

753 parts list shows both o-rings the same.  All online docs show them the same.  Pics of replacement kits show 2 black for 853.  888 is different, probably because of CO2.  Orange is viton, black is nitrile.  I'll bet the orange goes on the piston.  It probably doesn't matter for the 753.

[korny351]

Thanks for the reply 45Man.  I just got a reply from Lori at Daisy CS.  The orange o-ring (Viton) is for the valve body, whereas the black one is for the piston.  Maybe a recent change to the 753 spec or maybe just an across the board change to simplify inventory?  Daisy stock # on bag and packing slip coincide with parts list sent by Daisy for 753.  Either way, I'm back in business and my wife will be happy once I've re-assembled and got everythong off the kitchen table.

[ac12]

Korny
Before you button up the rifle, check out this thread on the x53 trigger.
http://www.gatewaytoairguns.org/GTA/index.php?topic=39648.msg370084#msg370084
I used a finer 8-32 screw for the trigger adjustment on my 853.  The finer screw makes trigger adjustment easier.
Too bad I'm not going into Stockton in the near future, or I could tap the 8-32 hole for you.  I bought a 8-32 tap just for this trigger mod. 

[korny351]

Thanks for the offer AC but I purchased the 888 parts, which are set up for the pre-travel set screw.  A 6-32x3/8 stainless screw fit perfectly, no need for tapping.  At 32 tpi it has the same sensitivity for adjustment.

[45Man]

Thanks for the reply 45Man.  I just got a reply from Lori at Daisy CS.  The orange o-ring (Viton) is for the valve body, whereas the black one is for the piston.  Maybe a recent change to the 753 spec or maybe just an across the board change to simplify inventory?  Daisy stock # on bag and packing slip coincide with parts list sent by Daisy for 753.  Either way, I'm back in business and my wife will be happy once I've re-assembled and got everythong off the kitchen table.

I was going to do the upgrade on my new 953.  Decided to only disassemble for polishing & lubing.  It didn't make a huge difference but it was noticeable.  Helps to have genuine Arkansas gun honing stones, which now cost more than the 953.

Less expensive ones are now available.
----------------------------------------------------------------------------------------------
I assume these are the parts you ordered for the trigger upgrade?
888-3   Trigger Housing, already has the hole drilled for the adjustment screw
888-5   Trigger Assembly, already has the trigger parts shaped for you

In addition to these?
853-1 “O” Ring & Valve Group
or 753-1 “O” Ring & Valve Group

and/or

888-16 O-ring
888-19 O-ring valve group (includes o-ring, spring, valve)
888-18 Screw assortment (includes 2 receiver screws, 1 trigger housing screw, 1 trigger adjustment screw, 1 rear tie down valve body screw, 2 stock screws, 1 seat screw)
----------------------------------------------------------------------------------------------
953 Manual has no parts list or drawing.  Daisy has too many different part numbers for the same exact parts.  No reason why 953 can't have 888 part numbers.  They should just use the 888 trigger housing & assembly for all variations.  Then update all manuals & drawings.  We used to call it Configuration Management & they obviously have little or none, since the CS had to go ask.  They already have significant parts standardization across products, so it's mostly a matter of documentation.
----------------------------------------------------------------------------------------------
Saw that ac12 writeup said:

I recommend that you replace the Daisy trigger adjustment screw with a 8-32 screw as done in the slides.  However, I used a stainless steel headless hex allen screw (from Home Depot) instead of the socket cap screw in the slides.  The 8-32 screw provides a finer adjustment than the course screw of the stock Daisy setup, and the headless screw was easier to install than the cap screw in the slides.  And don't forget to get a matching allen key for the screw or you won't be able to install and adjust the screw.
BTW, "headless allen" is a called a set screw.  I have a disliking for those long set screws; most hex wrenches are either too long or too short in the small size needed.
Does this mean that the 888-3 now has 6-32 threads?  Or maybe ac12 just made it larger?  I can see how the 8-32 allen head is too big.  It's not a big problem in this application because it's behind the trigger guard, most have adjustment inside the trigger guard.

[ac12]

@45man

Maybe Daisy changed it. 
The one that I got was threaded for a coarse thread, like sheet metal screw, NOT a 32 tpi machine screw.
If it is already threaded for 6-32, that is one step already done for you.  Saving you from having to buy a tap and handle, like I had to buy.

I don't know about the sear in your 953, but mine was so rough it wasn't funny.  When I pulled the trigger on the stock sear and hammer, the sear hung up at a few point in the pull.  The burrs on the sear hung up on the ridge on the hammer.  I had to pull HARD to get past the hang-ups.  It was BAD.  I was fighting the trigger so much that I could not hold the target. 

- My first try was just to simply deburr the sear and hammer, and that was a HUGE difference.  I could actually concentrate on the hold and the target and not be distracted by a lousey trigger.  This was the simple easy fix, to see just how much better the trigger could be with minimal work.  As this was the easiest of the trigger mods to do.

- My second try was to install the adjustment screw and polish the sear for a smoother pull.   The 2nd try wasn't really necessary, but I'm spoiled by my target guns with GOOD triggers, so I figured I might as well try to smoothen out the pull as much as I could, and to shorten the travel, all within the limits of the Daisy.  While it is nowhere near my target guns, I think it is pretty good for a casual rifle.

Both trigger mods were an exercise in what can be done to make the trigger better.  And try #1 showed me that the old 80/20 rule was in operation here.  The easiest mod to do gave the biggest improvement.  And 80% of the shooters will be happy with that and that is enough.