Lakeside53
Stihl Wrenching
From time to time I see questions on how to take off a clutch, get to an oil pump etc, so here an example using the Stihl 066 that I upgraded last weekend to put out more oil.
If you don't have an 066, with minor variations this is pretty much same process for getting into the clutch side of 024, 026, 029/31/39, 034/036, 044/046 and 066, and the MS updates.
- Dump any remaining oil out the oil tank.
- Take off the top handle so you have better access.
- Remove the spark plug and make sure you have on hand either the recommended piston stop or a short length of rope.
This is what it will look like, a familiar picture to many of you... The red color is just resin from the alder I was milling. The blue color of the clutch drum was from the prior owner bogging the saw.... it will be inspected..
Remove the cir-clip on the end of the crankshaft, unscrew the thin metal bar shield, remove the screws holding the plastic side cover in place. Pull off the plate, cover and the clutch drum. It may stick because of crud inside the drum, but it will come off.
Rotate the clutch until the piston is near the top of the cylinder (to be sure the ports are covered), make sure the decompression valve is UP (or removed), insert about 6 inches of rope into cylinder though the plug hole. Rotate the clutch CLOCKWISE (left hand thread) until the piston stops by compressing the rope. Use a breaker bar with care.... the 066 has a TIGHTENING torque of 51.5 ft/lbs, and a breakaway torque typically around 75, but can be higher... On smaller saws, use a conventional ratchet. Unscrew the clutch clockwise and remove it. There is a washer beneath the pump - make sure you note the orientation for reassembly. Pull out the break band. PULL OUT THE ROPE - don't leave it in expecting to use it when you put the clutch back on - it will be the opposite rotation and your rope can fall into the transfer ports etc...
Missing picture - camera operator error; just your typical filthy packed oily gritty resinous mess...
Pull out the oil pump drive arm and worm, remove the oil pump screws (probe around in the muck..) and lift off the pump.
Here's what came out from around the pump:
And then with the wave of my magic wand - actually a squirt of diluted Castrol super clean, and the garden hose, it's all clean. Some of you might consider the cleanup optional, but I don't. You can't see problems unless clean, and it's the last time you going back in for a few years, so just do it... It took me less then 10 minutes to clean and inspect all the parts.
Also, remove the tank oil hose (pulls out though the side), flush out the tank, pull the end off the hose and clean it all out.
Check the brake-band for wear. If there is any question, replace it. Inspect the drum for wear inside and side and flare. Bigger saws that have had a lot of break-band closing with overheated drums tend to flare the drum sides which causes uneven wear on the clutch shoes and tends to push the brake band out wards when it operates. A blue clutch drum will often have overhead clutch shoes and weak springs. Dead easy to replace the springs (a buck or so each) with the clutch in a vice. Check the keepers and other clutch parts for wear or cracks. Mine : Clutch is in great condition. Drum is "blue" but not flared and only slightly worn on the inside. The bearing and drum fitted well, so it will be put back on.
Check the operation of the brake system, lube it (moly grease on the actuator, oil the other contact points liberally. If the springs are rusting due to salt or whatever, replace them.
Look around at everything else. Check the oil seal - it should LOOK good (no peeled up edges, dents etc.. Tighten the crankcase screws (dig deep).
Hmmm.... where is that top pump seal? damn! the small bright hole at the 2 o'clock piston from the crank is where THE B4X2 SEAL GOES, and now it's somewhere out on my driveway - garden hose does a great job, but collect all the small parts first...
There will be a 90 minute delay while I drive back to work, grab a new 80 cent seal, BS with the Saturday shift, and get back..grrr...
Continued in part 2... http://www.arboristsite.com/showthread.php?p=409998#post409998
If you don't have an 066, with minor variations this is pretty much same process for getting into the clutch side of 024, 026, 029/31/39, 034/036, 044/046 and 066, and the MS updates.
- Dump any remaining oil out the oil tank.
- Take off the top handle so you have better access.
- Remove the spark plug and make sure you have on hand either the recommended piston stop or a short length of rope.
This is what it will look like, a familiar picture to many of you... The red color is just resin from the alder I was milling. The blue color of the clutch drum was from the prior owner bogging the saw.... it will be inspected..
Remove the cir-clip on the end of the crankshaft, unscrew the thin metal bar shield, remove the screws holding the plastic side cover in place. Pull off the plate, cover and the clutch drum. It may stick because of crud inside the drum, but it will come off.
Rotate the clutch until the piston is near the top of the cylinder (to be sure the ports are covered), make sure the decompression valve is UP (or removed), insert about 6 inches of rope into cylinder though the plug hole. Rotate the clutch CLOCKWISE (left hand thread) until the piston stops by compressing the rope. Use a breaker bar with care.... the 066 has a TIGHTENING torque of 51.5 ft/lbs, and a breakaway torque typically around 75, but can be higher... On smaller saws, use a conventional ratchet. Unscrew the clutch clockwise and remove it. There is a washer beneath the pump - make sure you note the orientation for reassembly. Pull out the break band. PULL OUT THE ROPE - don't leave it in expecting to use it when you put the clutch back on - it will be the opposite rotation and your rope can fall into the transfer ports etc...
Missing picture - camera operator error; just your typical filthy packed oily gritty resinous mess...
Pull out the oil pump drive arm and worm, remove the oil pump screws (probe around in the muck..) and lift off the pump.
Here's what came out from around the pump:
And then with the wave of my magic wand - actually a squirt of diluted Castrol super clean, and the garden hose, it's all clean. Some of you might consider the cleanup optional, but I don't. You can't see problems unless clean, and it's the last time you going back in for a few years, so just do it... It took me less then 10 minutes to clean and inspect all the parts.
Also, remove the tank oil hose (pulls out though the side), flush out the tank, pull the end off the hose and clean it all out.
Check the brake-band for wear. If there is any question, replace it. Inspect the drum for wear inside and side and flare. Bigger saws that have had a lot of break-band closing with overheated drums tend to flare the drum sides which causes uneven wear on the clutch shoes and tends to push the brake band out wards when it operates. A blue clutch drum will often have overhead clutch shoes and weak springs. Dead easy to replace the springs (a buck or so each) with the clutch in a vice. Check the keepers and other clutch parts for wear or cracks. Mine : Clutch is in great condition. Drum is "blue" but not flared and only slightly worn on the inside. The bearing and drum fitted well, so it will be put back on.
Check the operation of the brake system, lube it (moly grease on the actuator, oil the other contact points liberally. If the springs are rusting due to salt or whatever, replace them.
Look around at everything else. Check the oil seal - it should LOOK good (no peeled up edges, dents etc.. Tighten the crankcase screws (dig deep).
Hmmm.... where is that top pump seal? damn! the small bright hole at the 2 o'clock piston from the crank is where THE B4X2 SEAL GOES, and now it's somewhere out on my driveway - garden hose does a great job, but collect all the small parts first...
There will be a 90 minute delay while I drive back to work, grab a new 80 cent seal, BS with the Saturday shift, and get back..grrr...
Continued in part 2... http://www.arboristsite.com/showthread.php?p=409998#post409998
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