Theoben Rapid Forum

Theoben General Chat Area => RAW, Impact, and All Rapid Derivatives => Topic started by: Stevep123 on August 09, 2022, 10:07:12 PM

Title: Probe adjustment
Post by: Stevep123 on August 09, 2022, 10:07:12 PM
How do I go about adjusting the pellet probe?
The grub screw that holds adjuster in place  must be loose as the probe seems to be moving further forward the more I use the rifle.it's out as far as couldn't get a magazine in
Can it be done with out stripping rifle?
thanks
Title: Re: Probe adjustment
Post by: nevadacowboy on August 09, 2022, 10:24:53 PM
Loosen the grub screw and insert a allan key into the back of the bolt and adjust as necessary, then tighten the grub screw. If the bolt will not lock down at the end of its forward travel you have gone too far.


Hope this helps.
Title: Re: Probe adjustment
Post by: angrybear on August 10, 2022, 11:49:53 AM
Is it the whole probe or just the inner that's that's sticking fwd ?

I had a sticking inner on a rifle because a previous owner had used oil rather than dry lube & it was full of gunk.
Title: Re: Probe adjustment
Post by: Kernal on August 10, 2022, 02:53:57 PM
I remember the very old probe`s not having any allen key to adjust on the back just food for thought,

;)
Title: Re: Probe adjustment
Post by: Stevep123 on August 10, 2022, 04:01:55 PM
Hi thanks got probe adjusted now getting blow back from barrel tried probe in different positions but still the same any ideas? Thanks
Title: Re: Probe adjustment
Post by: maxtich on August 10, 2022, 04:08:20 PM
May be worth trying to lap the probe with barrel using paste.
Title: Re: Probe adjustment
Post by: angrybear on August 10, 2022, 04:42:34 PM
Quote from: Stevep123 on August 10, 2022, 04:01:55 PM
Hi thanks got probe adjusted now getting blow back from barrel tried probe in different positions but still the same any ideas? Thanks

That's not right at all
  :o
The inner probe should retract under spring pressure & only push out with the last 8mm or so of the bolt being closed,
that spring pressure also seals the outer probe to the breech face.

Take out the probe by removing the circlip at the front strip clean & reassemble as per the service guides on here, but I suspect the inner is slightly bent.

Also in the lower photo your barrel is too far forward, which will cause sealing issues, undo the barrel clamp & grubscrew in the front scope mount,
fit a magazine with a slip of paper behind it as a spacer hold the rifle so the barrel is up vertical & let it rest on the mag, then do up the clamp,
without the slip of paper the mag should now be a perfect fit & the outer face of the barrel level with the block.
Title: Re: Probe adjustment
Post by: angrybear on August 10, 2022, 05:09:31 PM
Top pic bolt back,
mid pic going forward,
bottom pic it has reached here with no resistance at all, only now should you feel the probe spring as it pushes the inner probe fwd to seat the pellet.

With the bolt mid way fwd you should be able to hold the cocking lever with your thumb, & use a finger on each side of the outer probe, and just about be able to push it back against the spring to expose the inner probe
Title: Re: Probe adjustment
Post by: Ca_Varminter on August 10, 2022, 05:16:58 PM
Well, with what I have been reading in this thread...
If the probe adjustment had move out so far as to interfere with the Mag...
It would be a Extremely tight lock down of the bolt--If it would lock down at all!!
So it sounds like the barrel has back out also!!
When you insert a Mag, is it loose against the barrel??
Title: Re: Probe adjustment
Post by: Stevep123 on August 10, 2022, 06:13:46 PM
Hi thanks
No the inner probe doesn't retract,it looks as if previous owner has put quite a bit of grease in bolt housing.
Even when probe was right out  it locked down easily no force required I'll adjust barrel anyway
If it's damaged inner probe or spring where's best place for replacements.
Title: Re: Probe adjustment
Post by: angrybear on August 10, 2022, 07:36:24 PM
Dr Bob does good probes, I'd always get the pair rather than just buy an inner or outer,
but check the old one first it might be gunked or even hydraulic lock if there's loads of grease in there, only thing goes on my bolt is dri-slide.
Title: Re: Probe adjustment
Post by: Ca_Varminter on August 10, 2022, 08:07:33 PM
Just for reference, here is a parts contain in the bolt..
(https://photos.imageevent.com/scl_electronics/gun/air/websize/bolt%20parts.jpg)

For spares, check with Dr Bob or KevG...
If the adjustment rod was hydro-locked by Grease.
You will need to fully disassemble and DeGrease all parts...
Check by Tech post, if you instructions on how take the bolt apart.

Good Luck,
Stuart
Title: Re: Probe adjustment
Post by: Stevep123 on August 10, 2022, 08:57:28 PM
Thanks very much for all you're help,wish I'd realised when it was down Kev's last week
Title: Re: Probe adjustment
Post by: KevG on August 10, 2022, 09:24:47 PM
sounds like the inner probed as seized for some reason, how far are you from me steve  can have aook for you
KevG
Title: Re: Probe adjustment
Post by: KevG on August 10, 2022, 09:35:46 PM
is that the one were I dod a new reg body for to fit the banjo from that dodgy huma reg,plus we had problems with air tube
KevG
Title: Re: Probe adjustment
Post by: Stevep123 on August 13, 2022, 10:10:05 AM
Hi Kev
Yes that's the one.I've had a look today the inner  probe had unscrewed from the base at the back,back together all sorted.
It's shooting spot on with your reg in now
Title: Re: Probe adjustment
Post by: KevG on August 13, 2022, 06:37:45 PM
yes seen this happen before did it with one of mine,worth putting a bit of thread lock on the thread,glad it ok for m8.
KevG
Title: Re: Probe adjustment
Post by: angrybear on August 13, 2022, 07:07:49 PM
Quote from: Stevep123 on August 13, 2022, 10:10:05 AM
Hi Kev
Yes that's the one.I've had a look today the inner  probe had unscrewed from the base at the back,back together all sorted.
It's shooting spot on with your reg in now

Not sure I get you, but do you mean the inner probe shaft had come away from it's base ??
Title: Re: Probe adjustment
Post by: Ca_Varminter on August 13, 2022, 08:21:49 PM
Quote from: angrybear on August 13, 2022, 07:07:49 PM
Not sure I get you, but do you mean the inner probe shaft had come away from it's base ??
The inner probe is a 2-piece design...
So the base is used in all Rapids...
On the probe is different for .177, .20-.22, and .25 cals
So the base has a concentric nub that is threaded.
And the end of the inner probe shaft is threaded..
(https://photos.imageevent.com/scl_electronics/gun/air/websize/bolt%20parts.jpg)

Stuart
Title: Re: Probe adjustment
Post by: Stevep123 on August 13, 2022, 08:46:48 PM
Yes exactly as Stuart said,it had somehow unscrewed from its hub/base.I Kev I did put a bit loctite on it so should be fine now also cleaned all the grease out
Title: Re: Probe adjustment
Post by: Ca_Varminter on August 13, 2022, 10:21:19 PM
All you need was a couple of strands of fur from the Rabid Fox.
That would Lock-up anything!!!
;D ;D ;D ;D ;D

Stuart
Title: Re: Probe adjustment
Post by: angrybear on August 14, 2022, 12:43:54 PM
Cheers for that, I hadn't noticed, but of course makes complete sense.
Title: Re: Probe adjustment
Post by: KCE on August 16, 2022, 10:23:24 PM
I set you off with that rabbid fox stuart glad to see it ongoing still.
I paid it a visit few weeks ago it has not lost any more teeth yet.

Regards kev
Title: Re: Probe adjustment
Post by: Ca_Varminter on August 16, 2022, 10:38:40 PM
But has it gain more spider webs??
Just makes it look more Rabid!!

Stuart