I needed to come up with some house rules to run a test campaign, as there were a few issues in the RAW that I just couldn't vibe with. Here they are, in case you're curious. These first ones all relate to reliability checks and mishaps.
Weapons
On weapon mishap, roll a save with 2 dice against the weapon's current reliability. Failure means reliability decreases one step and a jam occurs. This roll cannot be pushed.
* Clearing a jam is a slow action, and requires a roll of the relevant WEAPON skill.
* If this roll fails, the jam is more severe, and future attempts require TECH rolls to clear.
Outside of combat, maintenance on non-broken weapons can be done without parts and using the relevant WEAPON skill, or TECH (whichever you prefer). Each SUCCESS rolled restores the item by one level, up to its max. A mishap reduces the reliability by one level.
Repairing a broken weapon requires a TECH roll and a Weapon Spare Part. On success, it returns to Reliability D. The part is not used up on a failure.
Body Armor
Every time armor is penetrated, automatically reduce its reliability by one step. If it goes below D, the armor is rendered useless until repaired.
Restoring armor reliability requires a TECH roll. Each success restores one level of reliability, up to its maximum. It also requires a General Spare Part, which is used up on any success, regardless of how many reliability steps are recovered. It is not used up on a failure.
(For vehicle armor I am using RAW)
Vehicles
For driving mishaps, the same rules apply as per weapons. Roll a save using 2 dice against the vehicle's current reliability. Failure means reliability decreases one step and the vehicle suffers a minor malfunction.
Fixing the malfunction is a slow action, and requires a DRIVING skill roll. If this roll fails, the vehicle breaks down (as per Driving Hazards, chapter 6 -- re-roll non-sensible options).
Travel Hazards:
At the start of each shift you drive, you must make a DRIVING roll, modified for terrain type, to avoid a hazard. If you drive off-road into a new terrain type during a shift, you need to make an additional roll. In heavy rain, you get a -2 modifier. At night you get a -1 modifier. (These modifiers are cumulative)
If you fail, you suffer a hazard – make a roll on the table on page xx. Mechanical hazard results are resolved as follows:
* Roll a save using 2 dice against the vehicle's current reliability. Failure means reliability decreases one step and the vehicle suffers the listed malfunction.
The Referee decides the exact hex in which the hazard occurs.