Inspired by recent/archive posts I found a Lisle seal puller (58430) for $10 and change on one of the online sites. I had a flywheel side seal to replace on a Stihl 034AV. I had tried the punch and drywall nail technique but the hole was a little off center and the screw pulled out at the edge. It was really in there. There is only about 1.5mm between the crankshaft and the metal rim of the seal. When I got the puller, I could see that the small horizontal part of the “L” shaped puller would have to be ground a bit. No problem – it still held and by making it shorter, put less torque on the bend. I also beveled the edges at the width of the puller to give it a more rounded shape. By taking the puller off the lever, I was able to lay it flat with the “L” extending down between the crank and the seal with the puller extending radially out perpendicular to the crankshaft. I then brought it back to vertical with the “L” hooked under the seal rim, reattached the lever, and found a good spot for the fulcrum. With one finger holding the puller against the rim, I put steady pressure on the handle and the seal slid right out of its seat.
If you’re reading this, you don’t have the Stihl sleeve and arbor press tools for replacing the seal, so I’ll continue with the excruciating detail. If you’ve never done this before I think you’ll appreciate it. Before you remove the old seal, measure the depth below flush. This can be done with an inexpensive caliper. Set the zero, then set the far end of the caliper (opposite the measuring end) on the edge of the seal seat. Extend the center slide of the caliper down to touch the metal rim of the seal. The reading on the caliper is the depth of the seal. After the old seal is removed, select a tall socket slightly smaller than the diameter of the seal. The service manuals tell you to grease the rim of the seal, but I don’t find that necessary. After cleaning the seal seat and the rim of the seal, I put a thin film of Dirko on both, to act as both lubricant and seal (Dirko takes a while to dry and gives you working time, which you will need.) Now grease the inside lip of the seal and slide it over the crankshaft. Slide the socket over the crankshaft and center it on the seal. Tap gently with a hammer to get it started. Lift the socket and see if it looks like it’s going in evenly. If one side looks a bit higher, tilt the socket and tap the high side. Check after every series of taps. TAKE YOUR TIME. When you get below flush, it’s time to start using your caliper to check depth. Measure all around to keep even. When done, I put a little Yamabond 4 at the outer edge of the seal (think of caulking a bathtub). It dries quickly and is tough. You’re done. Don’t forget the crankcase vacuum and pressure test.
If you’re reading this, you don’t have the Stihl sleeve and arbor press tools for replacing the seal, so I’ll continue with the excruciating detail. If you’ve never done this before I think you’ll appreciate it. Before you remove the old seal, measure the depth below flush. This can be done with an inexpensive caliper. Set the zero, then set the far end of the caliper (opposite the measuring end) on the edge of the seal seat. Extend the center slide of the caliper down to touch the metal rim of the seal. The reading on the caliper is the depth of the seal. After the old seal is removed, select a tall socket slightly smaller than the diameter of the seal. The service manuals tell you to grease the rim of the seal, but I don’t find that necessary. After cleaning the seal seat and the rim of the seal, I put a thin film of Dirko on both, to act as both lubricant and seal (Dirko takes a while to dry and gives you working time, which you will need.) Now grease the inside lip of the seal and slide it over the crankshaft. Slide the socket over the crankshaft and center it on the seal. Tap gently with a hammer to get it started. Lift the socket and see if it looks like it’s going in evenly. If one side looks a bit higher, tilt the socket and tap the high side. Check after every series of taps. TAKE YOUR TIME. When you get below flush, it’s time to start using your caliper to check depth. Measure all around to keep even. When done, I put a little Yamabond 4 at the outer edge of the seal (think of caulking a bathtub). It dries quickly and is tough. You’re done. Don’t forget the crankcase vacuum and pressure test.
