Folks,
Simple answer, really, use approved and calibrated instruments (have the calibration certificate available) and in accordance with airframe manufactures CASA approved data.
And, don't forget, when you replace the approved valve cap, ensure that IT IS TORQUED TO THE MANUFACTURER'S INSTRUCTIONS WITH A TORQUE WRENCH WITH A CURRENT CASA APPROVED TORQUE CALIBRATION CERTIFICATE ISSUED BY A CASA APPROVED TORQUE CALIBRATION SERVICE.
I kid you not, a mate of mine was "done over" for the most serious crime of not doing the above.
It's AIR SAFETY, after all, and we can all read S3A and S9A of the Act, no matter is too too "trivial" for the bloodhounds of the Airstapo, in protecting the innocent public from the ravages of pilots and LAMEs of a criminal bent.
Tootle pip!!
Yes, such services exist, and the typical figure is 10 inch/pounds. For you decimal kiddies this will be a real challenge.
And do not neglect the relevant entries in the MR. as mentioned in the last post.
A daily will only take an hour or so on a C-172, five minutes to do the inspection, and 55 minutes the complete the certification.