owner assist annual , a few questions

[piperboy84]

I decided this year not to put the Maule into the shop but to do it at home with and A+P with FAA sign off authority supervising,

I am preparing the plane for his arrival by removing all cowlings, fairings,cuffs and inspections plates, lubricating all the hinges, chains,bellcranks etc, cleaning and checking all oil and other connections on the engine. I have the following questions:

I'm having a crack at doing a compression check before the A&P arrives next week, i remove the top plug in cylinder 1, ensure the key and fuel are off ( not sure how to ground the mag at the engine so i give the prop arc area great respect when cranking) turn the prop till the compression stroke screw in the gauge and crank the prop 4 full cycles , the gauge shows a reading of 50PSI which i know cant be right as it seems really low and the engine runs fine and its performance is pretty close to what it was new. The gauge is brand new, so am i missing something?

Secondly, the torque setting on the spark plugs, the plug manufacturer and i believe engine manual say the plugs should be torqued to 35 ft/lbs, this seems really really high to me, i set my wrench for this and tried it on a demo nut on the workbench and it seems incredible tight, am i missing something as there is no way i would put a plug in that tight, again my torrque wrench is new also.

Any ideas?

[pilot]

35 isn't a lot of torque...... and you have the wrong compression tester.

You are looking for a hot reading with a "leakdown" tester. All of the tests that you see people talking about with numbers like xx/80 are done with a leakdown tester hooked to an air source and set to 80 psi through an .040 orfice - so the number on the cylinder side always will be lower than 80. You set the cylinders at tdc to keep the prop from knocking you out when you apply air and so all of the valves will be closed.

I will say that if you have a good quality "pressure" type compression tester and are only coming up with 50 psi then you have problems, I would expect near 180 psi, more when hot - piston expands more than the cylinder so seals better when hot.

You would be welcome to use my tester if you want to swing by the farm.

[rjb]

I suggest you look through the EAA videos

This one on compression

http://www.eaavideo.org/video.aspx?v=2363274331001

This on on engine timing

http://www.eaavideo.org/video.aspx?v=2372015970001

Good luck

[piperboy84]

thanks for the vid links, i understand the differential test now, have another question though, i noticed my engine mounts have castle nuts but no cotter pins? seems kind of strange.

[Jon]

Are those castellated nuts (AN310) or all-steel lock nuts (AN363)? I'd guess the latter if there's no cotter pin (I use those on mine).

Other things you can do while waiting for the inspector: change air, oil, vacuum, and vacuum regulator filters; drain and clean gascolator; change oil (don't forget the oil sump screen!); service wheels and bearings; check aux pump sumps; and so on.

[Tomkatz]

Don't forget to check for cracks in the exhaust and airbox. Every year I find new ones. I've welded so much I have to do a new weight and balance.

Use of the 100 inspection list is a great guide.

[maules.com]

Piperboy, I suggest you get the help of the mechanic first time through. Doing the compression test wrong can easily hurt you and possibly kill you. 80psi cylinder pressure can whip the prop out of your hand very fast and whack you on the head very hard.
Remove all top plugs and all leads.
New gaskets on the plugs to replace if using 35 ft lbs torque.
Suggest test resistance on all spark plugs through centre electrode.
Easy to twist the brake torque plates if you havnt done brake caliper installation before.
Checking Top Oleo bolts is crucial and then must be retorqued, same with engine mount to airframe bolts.
Topping up brake master cylinders requires great care in getting the plugs back flush so its impossible for them to foul the brake lock levers.
Remove ALL floorboards and seats so all can be checked.
Download ALL SBs and SLs from Maule's website and comply with ALL required SBs and SLs marked "M".
Do a very careful oil filter examination, it can tell your mechanic a great deal.
If tailwheel has shimmied, strip down, clean reset shimmy damper and use correct grease that will not migrate down from bearing area to anti shimmy friction area. Shims are needed.
Remove wingroot fairings on top and reseal with masking tape when closing up later.

That should get you started.

[aero101]

Jeremy's advice on having mechanic help you through first time is very good advice. Even with over 25yrs experience, I tried to drive myself into ground while doing compressions here a couple of years ago. Speaking from experience, 80PSI drives that prop pretty good!! Ended up with split open head, saw stars for a period of time, and amazingly enough didn't knock myself out, but was not a pleasant experience. Lesson learned, no distractions while doing compressions in future

[Mountain Doctor]

I only do the compression checks with a helper, and then with great anxiety.

[piperboy84]

Making good headway here, and many thanks for the help and advice (believe me its needed) and I will wait for the inspector to get here to do the compression and timing checks, the proccess i am using is methodically going thru the Maule 100hr inspection list from the service manual and refering to the lycoming manual when the Maule document points that way. Today I done the oil change and filter, air filter, I have installed new plugs leaving the top ones finger tight for the compression check, removed all inspection plates fairings, panels and rear seat and floor boards ,inspected and applied a little 3 in 1 oil to all chains, cranks, hinges etc i even borrowed the better halves vaccum cleaner and cleaned out the floor round the insulation its amazing how much crap and soil, straw etc has gathered in there, i just installed new brake pads a few months ago so know they are good but will pull the main wheels off and repack the bearing, the taiwheel is new so its good to go, the small oil intake hoses on the engine where weeping oil and needed the clamp tightened. as expected i have some questions if I may they are
1.I stupidly had 10 gallons each in the aux tanks , I assume i will have to drain this before removing and cleaning the pump screen?
2. Rigging, cable tensions are part of the inspection, however i have lubricated and checked the cable conditions do i really need to do much more if the plane flies/handles correctly
3.I undid the laces and peeled back the boot on the top of the oelo strut i noticed a very slight dampness which was oil on one side the other side was dry, there are no noticeable runs or stains futher down the strut and the planes camber and level are correct, so i assume the leak is slight or perhaps someone spilt or overfilled it when last serviced, should i remove this strut for service or just keep and eye on it
Now for the funny thing, when I removed the panel surrounding the fuel selector valve a large piece of metal fell out, it was an aluminium drift, I assume from the factory installer, but it did make me wonder about how thorough the maintenance shop was with last years inspection, some interior panels appeared to have never been removed .

[pilot]

I only do the compression checks with a helper, and then with great anxiety.

You should be able to write yourself a prescription for that

should i remove this strut for service or just keep and eye on it

Did you check the oil level in the oleos?

[maules.com]

You can remove and clean the aux pump sumps with fuel in tanks.
Remove all gas caps and blow (with plastic tube and mouth not compressor) through the air vents to ensure clear.
Remove front seats also to remove floor pieces to access cables, pulleys, bellcranks, fuel line junctions, debris, flap mechanism, turnbuckles of trim, SB/AD re elevator cable paint, SB re elevator top cable shackle attach fouling of cable, nuts of upper oleo attach.
Top up both oleos (it takes time because air has to escape) (a syringe helps). Then watch for oil leaks running down oleo legs in next 20 landings. O rings could be cut or worn, or maybe someone did not have patience to fill properly.
Check for fuel stain at ALL fuel line fittings.
Check cable condition at rudder cable exit from fuselage and aileron top cable from wing as the phenalic is often not positioned correctly and contact is made with aluminium skin.
Check cable re SB 12 very carefully with Bright flashlight and positive eye contact of both cables.
Check ALL door bolts for wear of shank, its a mess when a bolt parts.
Check lower bolts of horizontal tail struts for corrosion and/or loss of cadplateing.
Check Rudder cable to rudder horn attach bolts.
Remove tailpipe location clamps and inspect re SB or SL and remove tailpipe so as to see inside mufflers for existence of flame traps. Remove heat muffs to inspect for swelling of muffler and leaks. Pressure the mufflers with 'blow' side of a vacuum cleaner while painting bubbly soapy water on all joints.
When re attaching tailpipes, they must be loose enough at the slip joint to move a couple inches in all directions when rubber hangars and crosstie are disconnected.
There's more as shown on SB SLs etc.

[rjb]

There is a modification to make the front seats easily removable. Now would be a good time to get the drawing and parts from Maule and look up in this forum how Jeremy suggests to do the modification.

[a64pilot]

There is a modification to make the front seats easily removable. Now would be a good time to get the drawing and parts from Maule and look up in this forum how Jeremy suggests to do the modification.

Please post info on this, I hate that **** spring.

[rjb]

http://maulepilots.org/forums/viewtopic ... dification