Preventative Maintenance

This category will include information for the preventative
 maintenance for the older Bonanza's.

Engine area

1.) Ignition System

Spark Plugs

Nothing better than a new or fresh set of spark plugs. Yes they are expensive at around $15 to $20 each x 12 but worth it.

Spark Plugs

Champion PDF guide

Each annual remove plugs.

Inspect each plug noting any lead deposits. Look for oil saturation in bottom plugs. Bottom plugs full of oil can indicate problems such as worn rings or valve guides.
Look at center conductor for smooth round cylindrical surface. Look for wear, if center conductor shaped like oval football then consider replacing with new or serviceable plug.
Check gap. 
Have plugs tested with a spark plug test machine. Champion makes one and uses compressed air to test spark with pressure applied. 
Prepare to install. Use small amount of anti-seize on threads (not to much though).


Wiring Harness

The Wiring Harness is also something that is important to keep in good shape. You can test each individual lead or look for the obvious indications of worn or frayed wires or missing pieces, springs or caps.

Wiring Harness

Several wiring harness manufactures exist.

Slick (Unison) Wiring Harness
These are very nice and have very flexible leads. I prefer these and are available for either type magneto Bendix or Slick. Also come in natural or a variety of colors.
Champion Wiring Harness
Available for Bendix or Slick comes in Red



Either Bendix (original equipment) or Slick magnetos are used on the Continental engines. You'll want to keep up with AD's and Service Bulletins for compliance. 


If it is time for service you will need to select a repair overhaul shop. Some owners will decide to purchase new Slick magnetos to replace the Bendix. This will also require a new wiring harness since the do not interchange. 

It is a debate on which magneto is better than the other, Slick vs. Bendix. I prefer the Bendix. 
Timing needs to be check and set according to engine specs. The magneto has it own internal timing setting needs to be verified before installation on engine


(coming soon)

A.) From the Beechcraft Maintenance Manual.

B.) From the various equipment manufacturers.

C.) From various owners, mechanics and pilots.

D.) Breakdown by component

AN-15-G is AeroShell Grease 6

Grease fitting information

Here is one tip that will help protect your airplane from rodents. If you don't have a set of these around your landing gear, get or make some. It's a must have item. Go to Home Depot or any home repair center and get some metal flashing material to make yourself a set.

1949 A35 Bonanza