It was Annual time again in February so I finally got around to doing several jobs I'd been putting off.
I noticed when I last changed the main wheel tyres that the wheel bearings were not running smoothly. This is after 500 hrs with most of that from grass runways which get very muddy here in the UK during the winter.
So I changed these bearings for new. I did not recognise the Italian brand of bearings that were in there from new so changed these ones for SKF which is a brand I trust. Hopefully they will last longer this time. I will make a note to check the wheel bearings every 200 hrs from now on.
The bearing part number is: 6004-2RSH SKF Sealed Ball Bearing 20mm x 42mm 12mm (BB-1853). You will need 4 in total, 2 per wheel.
Getting the old wheel bearings out was a real pain as the hub is a single piece of Ali which is not able to be split in half. There is also a spacer inside of the bearings which prevents a bearing puller being used to pull them outwards. The bearings sit on a shoulder on the inside so there was no way to push them out either.
I ended up having to dismantle one of the bearings from one side to then remove the balls and centre race, this then allowed me to remove the spacer and push out the other bearing (using a deep reach socket, a vice and the boiling water to expand the Ali hub technique). Finally I had to rework the remaining outer race of the dismantled bearing as it has a smooth concave shape which a chisel or screwdriver tip just slides off. A little Dremel work made this into a squared off shape so I was able to drive out the outer race too.
Onto the tailwheel.
This I found several months ago, the bearing had actually seized on one side.
So again these were changed for new.
That part number is: 6300-2RSH SKF Sealed Ball Bearing 10mm x 35mm x 11mm (BB-1919). You'll need 2 of these for the tailwheel.
I also discovered that the bolt which is used as the axle for the tailwheel was slightly too short in its shank. This meant that the thread was working against the hole in the tailwheel fork rather than against the smooth shank as it should be. See the pic below.
I sourced a correct sized bolt (M10 with 120mm length) and cut it down to the required total length. This still leaves enough thread for a washer and thin Nyloc.
I'm happy to have found these faults and fixed them.
While I was working on the main wheels I decided to change the brake pads for new too. They didn't really need changing as they had only worn about 30% but as I was in there disassembling everything then it was prudent to do so.
The engine has really settled down with its tappet clearances. Cylinders, 1, 2 and 4 didn't need adjusting at all this time. Cylinder 3 needed a small tweak - but this Cylinder head is only 100 hours old as it was replaced at 400 hours due to the leaking exhaust valve.
I replaced the engine mount rubbers at the front too. You have to take the whole engine forward to get to the rear rubbers so I've left those for the time being as I don't have an engine hoist anymore.
Finally, I decided it would be a good idea to have a backup to the Dynon EFIS - in case it ever went down for any reason (even though it has a back up battery, if you were IFR and it went down you would be screwed). So at AERO Friedrichshafen last year I bought a Kanardia Horis EFIS. I got it for a special show price which made it about £300 cheaper than buying here in the UK.
To make room for it in the panel I got rid of the mag compass and moved the old 'steam' altimeter into its place.
This left the altimeter hole free for the Horis.
It's a pretty straight forward install, just connect up Pitot and Static and then power and ground. The only other two things that need sorting are the outside air temp probe, which I've located on the underside near the main gear leg and the GPS antenna which I've located in the space above the safety cell at the front.
The EFIS is fully featured and even has a dedicated G-meter screen which will come in very handy for Aeros as the one on the Dynon is not easy to read in flight as it just displays as small numbers.
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Main wheel bearing hub, which is one piece and makes removing the bearings a real pain!
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| Destroyed wheel bearing to get it out of the hub |
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| Old and new brake pads - not too much wear after 500 hrs |
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| Old Tailwheel axle bolt to the left, note worn shank from seized bearing and damaged thread. New bolt cut down to same length but with correct shank length on the right. |
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| Still room for a thin Nyloc and washer |
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| Engine mount rubber - showing some wear and elongation of the hole |
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| New panel with Kanardia EFIS |
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| Features a dedicated G-Meter screen |
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| How the panel used to look with mag compass at right |
