Cutless replacement (in a strut)
I wrote this up for a friend who is replacing his cutless on a Catalina 30. It includes some stuff that I've posted here not too long ago. hope this helps. -------------------------------------- To remove the bearing, remove the set screws in the bearing housing, remove the shaft, use a hacksaw/holder and make a cut all the way through the bearing (along the longitudinal axis), then use a drift pin through the set screw holes to crush the bearing. Pull the bearing out with a needle nosed pliers. You may have to use a gouge chisel to help loosen the bearing .... dont bugger the ID of the strut housing bore as its VERY important to the 'final' size of the bearing. The set screws are only a back-up to restrain the bearing in case it gets hot. What holds the bearing in place is a press fit - the bearing is 0,001" / inch of housing diameter *larger* than the bore of the hole in the strut. You force the larger OD bearing into the ID of the bore - ie.: a 1.500" OD bearing woud fit into a ~1.4985" hole. The *press fit* keeps the bearing in place. The set screws are there only for 'safety'. Dont even think of using a hammer to seat the bearing ... use a long heavy bolt and nut and apply the 'correct sized' ratchet wrench socket and heavy washers to the bolt, apply the bearing and 'screw' the bearing into the strut housing. For buggered set screws, run a tap into the bore to dress the threads, etc. Its good practice to clean/dress the shaft so that all the surface galling is removed and to produce a super-smooth bearing surface, then using a micrometer measure the shaft and measure the ID of the bore in the strut. Take the dimensions to the bearing dealer/manufacturer and let them calculate the dimensions AFTER you press fit the bearing into the strut --- which should after pressing it into the strut develop an operating clearance of about 0,003" for every 1" of shaft diameter. ..... then realign the engine for perfect/true running of the cutless bearing. Its IDIOTIC to NOT remove and inspect the shaft as any galling caused by the previous bearing will still be there if you press in a new bearing and not inspect the shaft. You can take the shaft to a machinist for dressing or use emery cloth followed by crocus cloth to repolish the shaft where the bearing runs. When reinstalling the new cutless (using a long bolt and nuts and a wrench to do the 'pressing' (intereference fit)) its best to heat the bearing housing with a torch and put the new bearing into either dry ice or water/ice ..... the ID of the housing will be LARGER and OD of the cutless bearing will be SMALLER. As soon as you get the bearing 'home' immediately (not two minutes later or after I go a 'pee') pour cold water to set the bearing and prevent melting of the polymer bearing material. Bearing sizing .... use a micrometer and measure the shaft (after dressing a new surface on it) to the closest 'thousandth', measure the ID of the bearing housing (COLD) ... then call a distributor of the cutless bearing and LET HIM calculate the proper installed operating clearance .... typically 0.003" per inch of shaft diameter. The distributor will include the 'intereference fit' when you PRESS the bearing ... the ID of the bearing gets SMALLER when you press it into the bore of the strut. ... Let the distributor do this, its their JOB. Then reinstall the shaft (with water soluble grease on the bearing, reattach the shaft flange .... let the shaft seek its OWN level (but in the CENTER of the stuffing box, THEN realign the engine to exactly meet the engine output flange with the UNDISTURBED prop shaft. MOVE the ENGINE mounts to meet the x,y,z requirements of the SHAFT. Use a feeler gauge between the faces of the coupler flanges to insure proper fit and PROPER ENGINE ALIGNMENT ... should be WITHIN 0,001" around the face of both flanges. If you dont do this the shaft will bend when turning, you will get a large 'kicking sound' as the shaft 'whips' ... and the bearing will soon be destroyed. Buy a 'stock' bearing from West marine or Catlina, etc.? ... not in this lifetime. If you want to do the job all over again in a few short years, dont dress the shaft and put in a stock bearing. Do the job RIGHT. A cutless is destroyed by two things - silt in the water and a galled shaft, you should dress the shaft and put in a 'properly sized' bearing. If you dont, the shaft will 'precess' (orbit) in the bearing (unless its always running a very high rpm) and will soon wear out, and you will do the job alll over again - sooner than later. Do the assembly and then consider to use "GFO" all teflon packing in the stuffing box instead of flax .... no drip/leakage and no friction and the stuff is 'permanent'. PTFE packing is air-permeable so you wont have as much galling on a stainless shaft because the little bit of water that gets into the packing will be 'oxygen-rich' and wont cause the stainless to become un-stainless because of the oxygen present in the water and (air permeable) packing. We use such PTFE for 'perfusion' of gases into liquids, etc. hope this helps.
