This is a comprehensive "How To" for anyone looking to replace their propeller shaft, seal and cutlass bearings on a 2015 era Z3 but most operations listed here will apply to all shaft driven boats. It bears mentioning, this should be a relatively straightforward procedure and only requires a couple pieces of precision equipment to perform shaft checks and alignment to attain installation perfection. This repair can be done by anyone who has mechanical aptitude but requires caution and the knowledge it must be done correctly the first time or you could cause severe damage to the vessel and/or bodily harm to yourself and passengers. Do not attempt to perform this type of repair if you are going to half-*** it like we found someone else had done.
Anyone experiencing a constant vibration while running the boat needs to inspect both their propeller and shaft for straightness. Follow these guidelines to perform the inspection:
Step 1: inspect the propeller for visual differences in its blades. ANY ding, dent or deformation no matter how small, affects efficiency, balance and performance. If any problems are found, remove the prop and send it out for tuning or repair. I've seen some terrible examples of people running damaged propellers thinking it was no big deal.
Step 2: once the prop has been verified, check the prop shaft for straightness. This will require a dial indicator and a magnetic base stand. In the photo below, we set up the dial indicator and rolled the shaft until it showed its lowest point. We then zeroed the dial indicator and rolled the shaft again to find how far out it was.
We found the shaft was .012" out of round which is waaaaaaayyyy more than industry standard of .000-.004". Fortunately, Wilmington Iron Works said it would be no problem for them to straighten it. However, at this point we had yet to discover the travesty of someone else's previous poor repairs which required shaft replacement instead. NOTE: When rolling the shaft using the magnetic base dial indicator, be sure to turn the shaft in one direction only (i.e. clockwise or counterclockwise only) so the shaft settles in the same spot of the cutlass bearings each time you change your grip on the propeller. The dial indicator will move dramatically just from pushing on the prop so take your measurements when the shaft is not turning.
Further inspection of the shaft revealed the following:
Step 3: Check the distance between the prop hub and the strut. It should be no more than 1" and but large enough to remove the propeller using the correct tool, heat and your Tanya Harding as required (See the propeller lapping write up). This tolerance will also help determine if you will need a new shaft. Once recorded, remove the prop. Watch this video on how to correctly measure for a new propeller shaft: https://www.youtube.com/watch?v=X-FNPI9wQUQ
Step 4: Determine which direction the shaft can be removed. For v-drives there is sometimes the option to pull the whole assembly out over the fuel tank in the middle of the boat. For inboards, it's gotta go out the back. Remove the 4 coupler bolts from the coupler interface. We noted we had to use a socket wrench to back the bolts out of their respective holes and determined later this was from the perverse misalignment we discovered upon reassembly. Remove the shaft coupler as required using the correct coupler removal tool, not a hammer or torch or anything but the correct puller tool. Pay attention and look for set screws in the coupler end of the shaft to aid in removal of the coupler retaining nut as well.
Step 5: Remove the shaft.
Step 6: Replace the coupler bearings per this video: https://www.youtube.com/watch?v=KsqOac-52Rs
Step 7: I HIGHLY SUGGEST REPLACING YOUR SHAFT SEAL WITH A NEW UNIT FROM GLIDE AT THIS TIME!!!!!
Step 8: Install the propeller shaft, coupler, coupler nut and 4 coupler face bolts(with NEW!!! DO NOT REUSE COUPLER HARDWARE!!!).
Step 9: Check coupler alignment per this write up: https://www.tigeowners.com/forum/tec...haft-alignment
Step 10: Install your propeller after reading this write up: https://www.tigeowners.com/forum/gen...heck-your-prop
Notes from this repair:
We discovered polished areas approximately 3/8" fore and aft of the strut during inspection. Normally when I encounter a polished area of a propeller shaft fore and aft of the strut it's an indication the engine/transmission may have been moving during operation but the extra large gap between the prop and strut revealed the shaft was previously replaced with a used unit, GRRRRRRRRRRR. This meant we needed to order a new shaft so we decided to open up the boat and see what else lurked in the shadows...
Oh dear Flying Spaghetti Monster, the following list was everything incorrect we found...
1) Bronze shaft coupler
2) Stainless nyloc shaft coupler nut
3) Stainless coupler bolts
I spoke with Tim at Glide Systems and got a new seal kit ordered and installed. For those wondering, we have 1 3/4" stern tube and 1 1/8" propeller shaft. The Glide Systems video on how to install the new seal with its special tool is straightforward and easy to do. We found the previous water line feed to the old seal had a single oversized hose clamp incorrectly installed. We replaced it with double hose clamps of the correct size per ABYC standards requiring all raw water hoses below water line to be double clamped, reversed and opposed.
We also replaced the stainless coupler bolts with proper Grade 8 fine thread bolts, split washers and Grade 8 nyloc nuts.
So...in brief summary, do not use stainless nuts to hold torque on something such as a propeller shaft. I know, some manufacturers supply their equipment with stainless nuts but DO NOT INSTALL THEM, THEY WILL MOST LIKELY GALL. Order bronze shaft coupler nuts to replace them. A new stainless steel coupler and shaft nut come with new shaft purchases. Prop shafts get bronze woodruff keys and nuts or hardened steel as was supplied with our new stainless coupler and shaft combo from Elder's. On to the shaft seal replacement...
I spoke directly with Tim at Glide bearings and had a great conversation with him regarding their Glide shaft seal systems. As a result, I'll be using them on our big boat installations and hope to provide continued positive reviews of their products. Glide has a YouTube video as well showing proper installation of the propeller shaft with their special installation guide tool which is not shown in the photo below.
Now, before we passed the shaft into the face of the v-drive, we cleaned the coupler face with our carbide super scraper and then wiped it with 800 grit sand paper and brake cleaner. If you notice the unpolished look on the shaft of the coupler taper end it's because we lapped the shaft coupler to its taper prior to installation. For further instructions on the lapping process, see the thread "Propeller lapping" linked above. All the same applies to the coupler taper. After installation we checked alignment, also see the alignment thread I wrote, and found it was waaaaaayyyy off with a massive gap at the top of the couplers. This indicates the engine mounts had sagged but we raised the engine front mounts and got a perfect alignment at .000" all around. Side note, read the how to on alignment and check yours immediately, I doubt ANY of the dealerships do it at the 100 hour service (wink, wink).
Thats it for the shaft replacement. We lapped the new prop to the shaft and have about 5/8" clearance between the prop hub and strut so it all ended up perfect. I'll be changing out the steering cable and doing spark plugs and oil before we take her back out to storage next week.
Anyone experiencing a constant vibration while running the boat needs to inspect both their propeller and shaft for straightness. Follow these guidelines to perform the inspection:
Step 1: inspect the propeller for visual differences in its blades. ANY ding, dent or deformation no matter how small, affects efficiency, balance and performance. If any problems are found, remove the prop and send it out for tuning or repair. I've seen some terrible examples of people running damaged propellers thinking it was no big deal.
Step 2: once the prop has been verified, check the prop shaft for straightness. This will require a dial indicator and a magnetic base stand. In the photo below, we set up the dial indicator and rolled the shaft until it showed its lowest point. We then zeroed the dial indicator and rolled the shaft again to find how far out it was.
We found the shaft was .012" out of round which is waaaaaaayyyy more than industry standard of .000-.004". Fortunately, Wilmington Iron Works said it would be no problem for them to straighten it. However, at this point we had yet to discover the travesty of someone else's previous poor repairs which required shaft replacement instead. NOTE: When rolling the shaft using the magnetic base dial indicator, be sure to turn the shaft in one direction only (i.e. clockwise or counterclockwise only) so the shaft settles in the same spot of the cutlass bearings each time you change your grip on the propeller. The dial indicator will move dramatically just from pushing on the prop so take your measurements when the shaft is not turning.
Further inspection of the shaft revealed the following:
Step 3: Check the distance between the prop hub and the strut. It should be no more than 1" and but large enough to remove the propeller using the correct tool, heat and your Tanya Harding as required (See the propeller lapping write up). This tolerance will also help determine if you will need a new shaft. Once recorded, remove the prop. Watch this video on how to correctly measure for a new propeller shaft: https://www.youtube.com/watch?v=X-FNPI9wQUQ
Step 4: Determine which direction the shaft can be removed. For v-drives there is sometimes the option to pull the whole assembly out over the fuel tank in the middle of the boat. For inboards, it's gotta go out the back. Remove the 4 coupler bolts from the coupler interface. We noted we had to use a socket wrench to back the bolts out of their respective holes and determined later this was from the perverse misalignment we discovered upon reassembly. Remove the shaft coupler as required using the correct coupler removal tool, not a hammer or torch or anything but the correct puller tool. Pay attention and look for set screws in the coupler end of the shaft to aid in removal of the coupler retaining nut as well.
Step 5: Remove the shaft.
Step 6: Replace the coupler bearings per this video: https://www.youtube.com/watch?v=KsqOac-52Rs
Step 7: I HIGHLY SUGGEST REPLACING YOUR SHAFT SEAL WITH A NEW UNIT FROM GLIDE AT THIS TIME!!!!!
Step 8: Install the propeller shaft, coupler, coupler nut and 4 coupler face bolts(with NEW!!! DO NOT REUSE COUPLER HARDWARE!!!).
Step 9: Check coupler alignment per this write up: https://www.tigeowners.com/forum/tec...haft-alignment
Step 10: Install your propeller after reading this write up: https://www.tigeowners.com/forum/gen...heck-your-prop
Notes from this repair:
We discovered polished areas approximately 3/8" fore and aft of the strut during inspection. Normally when I encounter a polished area of a propeller shaft fore and aft of the strut it's an indication the engine/transmission may have been moving during operation but the extra large gap between the prop and strut revealed the shaft was previously replaced with a used unit, GRRRRRRRRRRR. This meant we needed to order a new shaft so we decided to open up the boat and see what else lurked in the shadows...
Oh dear Flying Spaghetti Monster, the following list was everything incorrect we found...
1) Bronze shaft coupler
2) Stainless nyloc shaft coupler nut
3) Stainless coupler bolts
I spoke with Tim at Glide Systems and got a new seal kit ordered and installed. For those wondering, we have 1 3/4" stern tube and 1 1/8" propeller shaft. The Glide Systems video on how to install the new seal with its special tool is straightforward and easy to do. We found the previous water line feed to the old seal had a single oversized hose clamp incorrectly installed. We replaced it with double hose clamps of the correct size per ABYC standards requiring all raw water hoses below water line to be double clamped, reversed and opposed.
We also replaced the stainless coupler bolts with proper Grade 8 fine thread bolts, split washers and Grade 8 nyloc nuts.
So...in brief summary, do not use stainless nuts to hold torque on something such as a propeller shaft. I know, some manufacturers supply their equipment with stainless nuts but DO NOT INSTALL THEM, THEY WILL MOST LIKELY GALL. Order bronze shaft coupler nuts to replace them. A new stainless steel coupler and shaft nut come with new shaft purchases. Prop shafts get bronze woodruff keys and nuts or hardened steel as was supplied with our new stainless coupler and shaft combo from Elder's. On to the shaft seal replacement...
I spoke directly with Tim at Glide bearings and had a great conversation with him regarding their Glide shaft seal systems. As a result, I'll be using them on our big boat installations and hope to provide continued positive reviews of their products. Glide has a YouTube video as well showing proper installation of the propeller shaft with their special installation guide tool which is not shown in the photo below. Now, before we passed the shaft into the face of the v-drive, we cleaned the coupler face with our carbide super scraper and then wiped it with 800 grit sand paper and brake cleaner. If you notice the unpolished look on the shaft of the coupler taper end it's because we lapped the shaft coupler to its taper prior to installation. For further instructions on the lapping process, see the thread "Propeller lapping" linked above. All the same applies to the coupler taper. After installation we checked alignment, also see the alignment thread I wrote, and found it was waaaaaayyyy off with a massive gap at the top of the couplers. This indicates the engine mounts had sagged but we raised the engine front mounts and got a perfect alignment at .000" all around. Side note, read the how to on alignment and check yours immediately, I doubt ANY of the dealerships do it at the 100 hour service (wink, wink).
Thats it for the shaft replacement. We lapped the new prop to the shaft and have about 5/8" clearance between the prop hub and strut so it all ended up perfect. I'll be changing out the steering cable and doing spark plugs and oil before we take her back out to storage next week.
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