Bravo 3 Swivel Shaft repair instructions
craigswardmtb
Member Posts: 1,015 ✭✭✭
Well I finally did the swivel shaft repair and thought I would list some instructions for those that decide to tackle this repair themselves. Advance warning I was very thorough and wordy on the below install instructions so put your reading glasses on. I hope this is helpful to someone that has to tackle this fix...
Some may recall last season i posted about a leak that I thought to be coming from my driveshaft bellow. Well it turned out to be the infamous Swivel shaft seal leak. In Mercs brilliance they decided to use a steel swivel shaft, which bluntly put was incredibly stupid. The swivel shaft goes from the underside of the gimbal ring and then up into a hole in the lower side of the gimbal hosing, then into your steering arm inside the engine room. In that gimbal housing hole is a single lip seal and a bushing. Well the lower part of the steel swivel shaft is exposed and submerged in water in most scenarios all of the time. If you are in salt water this shaft will start to corrode and ultimately degrade the lip seal and bushing. Once that lip seal degrades the water has a clear path to the inside of your transom and your bilge. Not Good! If you are in salt water my best recommendation to at least prolong having to do this fix, is to install a grease zerk in the gimbal housing. From the outside of the boat you will notice there is a little dimple at the top of the gimbal housing, it may be underneath the Merc sticker if I recall. On Bravo 1's they actually had a zerk installed here so you could grease the swivel shaft. For some reason they got rid of it on Bravo 3's. The gimbal housing and ring are the same on all Bravo's so you can actually drill and tap this hole and install a zerk. This will help keep the swivel shaft lubed and hopefully prevent some corrosion. I think ultimately it is inevitable that the shaft will corrode from the outside in and the seal will fail, but perhaps this gives you a little extra time.
Now onto the fix. Last season my mechanic wanted to address the swivel shaft replacement by removing the engine and replacing the entire transom assembly. Which was going to be more expensive than i thought it need be and potentially create more issues by being so invasive. Merc obviously realized this to be a major hassle as well so they offer a repair kit that allows you to do this fix from the outside of the boat. This involves drilling two large holes in the side of the gimbal housing; using a punch to turn the nut on the top of the swivel shaft, barely fitting two wrenches in there for the steering arm, reinstalling plastic plugs, etc etc. Basically my mechanic said it is an absolute nightmare and he wouldn't do the "repair" method anymore. After some research I came across the JR Marine repair kit. This method differed in that instead of drilling holes in the gimbal housing it allowed you to cut a window in the front of the gimbal housing, thus giving you much better access to the swivel shaft nut and steering arm. You then patch the hole by installing a stainless plate/gasket/sealant. I opted for this method, which proved to be a reasonable diy fix if you are somewhat mechanical. To do the fix you will need a decent entourage of tools (JR Marine modified 5/8 wrenches, ratcheting wrenches, sockets/extensions/breaker bar, dremal w/ cutting wheel, metal punch, power drill, pry bar, lubricant, Merc greases, etc). More tools listed below in the steps.
Step 1 - Remove drive: Before doing so I built a drive stand seeing I was doing this solo and the Bravo 3 weighs 190 lbs. I had lumber laying around and four casters, so I put together a drive stand which will prove useful in the future I'm sure. I removed the props. If you have a big enough set of channel locks you really don't need that super expensive Mercury prop nut tool. First I clamped the oil line from inside the engine room to prevent oil loss and made sure the drive was in neutral. Second, I then removed the two trim rams from the drive. There are 4 plastic caps on the trim ram attachment points, and underneath each cap a 5/8 lock nut (two front, two back). Remove the most aft trim ram nuts first and pull out the shaft that the rams attach to. It should be greased and slide right out. Take note that there are two different sized washers on each side of the ram. The large ID washer goes on the inside and the small ID washer on the outside. Now slide the most forward rams off of the other shaft (this ram shaft does not need to be removed). The rams will now dangle by the hydraulic hoses and grounding cables. Third, remove the six 5/8 lock nuts/washers that secure the drive to the bell housing. Wiggle the drive and it will separate from the bell housing. Be careful not to pull the drive off of the studs just yet. Reach in with some long needle nose pliers or a screwdriver and push down on the clasp/clamp that secures the shifter cable. The cable should pop right out. Now you can pull the drive off. Again careful this thing is heavy. My stand definitely helped but a strong lad and a helper should be able to man handle the thing off if you don't have a stand.
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Step 2 - Remove Bell Housing: First remove the mercathode grounding cables. There is one attached to the port side of the bell housing and one attached to the underside of the gimbal ring. They use T25 torx bits. One of mine sheered off and I had to drill a new hole and tap it, so be gentle. Second remove drive shaft bellow end from bell housing. There is a retainer ring that secures the bellow in place. There is a special tool to remove it but I just bought a new retainer ring and pried the old one out using some pliers and a screwdriver. Push the bellows inward away from the bell housing. If you need to replace your bellows now is the time. Mine were new mid season last year so i did not, and in turn I did not fully remove my drive shaft bellow. I left the glued side attached to the transom assembly. Third push the water intake hose inward away from the bell housing. There is a special insert inside the hose end which secures it in place and of course there is a special tool from Merc to install and remove. Again I just bought a new insert and pried the old one out. Upon reinstallation I used an appropriate sized washer (7/16 I believe) and vice grips as "my special tool" for installation. Fourth remove the nut that secures the shifter cable to the bell housing. The cable will likely be extended out too far for even a long socket, so advance the binnacle control forward to retract the cable into the housing. YOu will need to hold the back of the shifter cable with a 5/8 wrench so it does not twist the cable housing and ruin it when loosening the nut from the front. Its a bit tricky as the back of the cable housing hard to see seeing the bell housing is still in place. I was able to reach a wrench in from the underside of the bell housing. Once removed you can push the cable housing into and away from the bell housing. Fifth cut the drive oil line in half. You can see the drive oil line behind the bell housing and should be able to get some snips in there. Some oil will drain so have a container and rags handy. Remember you clamped the line from inside so not much should come out. The reason you cut this is to prevent breaking the plastic hose barb on the transom assembly (its a brass barb on the bell housing side, so no worries there). God knows why they used plastic but it is renown for breaking with the least bit of torque and replacing it is a major PIA. In turn you will need about 12 to 18 inches of replacement oil hose upon reassembly. Sixth, time to remove the two hinge pins that secure the bell housing to the gimbal ring. These are located under the trim senders fastened to the left and right sides of the gimbal ring. There are two Phillips screws that fasten each sender. Take pictures of the sender positions so you can reference upon reassembly. Remove these screws but be careful, they are renown for breaking. Hopefully someone used antiseize on them prior. Once removed you will see the hinge pins. The pins can be removed using Merc's hinge pin tool (its inexpensive and there is a Sierra version). These things a red locktite'd in place and torqued to 110 ft lbs. You need a big breaker bar. I read and heard stories of people stripping these out. If you decided to remove your drive shaft bellow you can always heat it up with a torch from the inside to loosen the locktite. If you left the bellow on, this is not an option. Mine came out pretty easily without heat. Once the pins are out the bell housing will now come away from the gimbal ring. There are two fiber washers between the bellhousing and the gimbal ring. You will want to replace these upon reassembly. Inspect, paint and do whatever you need to do to the bell housing while its off. Below is a picture of the trim senders and those breakable screws. On the starboard trim sender you can also see the drive oil hose which you cut in a prior step.
Second, you will now drill the four tap holes and all of the green and red holes using a 3/32 drill bit. I center punched each hole and then drilled. The tap holes you only drill 7/16 deep. I did this by putting tape around my bit indicating the 7/16 depth. The green and red holes you drill only far enough to where you feel the drill enters empty space. The red holes are over the steering arm and when you drill through you will feel the bit hit into the steering arm. Try not to drill into the steering arm. Drill the four tap holes with the provided #3 bit, again only 7/16 deep. Third you can now remove whats left of the template and its time to cut the rest of the access window out using a dremal. In the repair kit they provide dremal rotary cutting blades. I found my Dremal Multimax to work better than the rotary dremal. Cut carefully along the drilled holes. When done you will have a nice access window to the swivel shaft lock nut and steering arm. Use some compressed air to get rid of all of the metal shavings. Fourth you will tap the four #3 drilled holes using a 1/4" x 28 tap.
You will see in the picture below that my swivel shaft nut and steering arm nut/bolt are pretty rusted. You will want to replace these if yours looks like this. I was pleasantly surprised that the steering arm was in great condition, as were the gimbal housing and transom assembly. If you notice heavy rust/flaking/corrosion/etc on the gimbal housing below the steering arm, you will likely be looking at replacing the entire transom assembly at that point. Prior to starting this project I took a bunch of pictures of the steering arm area from inside the engine room and was able to hypothesize that my arm/transom assembly were still in good shape. Also note in the below picture the dimple in the gimbal housing that could house a grease zerk fitting.
Step 4 - Time to remove the Gimbal Ring. The only thing that secures the gimbal ring to the gimbal housing is the upper swivel shaft and the swivel shaft. First, remove the lower swivel shaft. There is a cotter pin that holds the lower shaft in place. Use some needle nose pliers and pull that pin out. You may have to turn the steering left or right to get good access to the cotter pin. Make sure you have a replacement cotter pin for reassembly. Once the pin is out you can drive the lower swivel shaft out of the bottom of the gimbal. I used a socket extension and a screwdriver to get it out. It drove out pretty easily. The swivel shaft looked to be in good shape, but I replaced it anyways. Once the gimbal ring is entirely removed you will want to replace the lower swivel shaft bushing in the gimbal ring (mine was pretty beat up). I had to use a hack saw blade to cut it out. The bushing was really stuck in there and could not be driven out with an appropriately sized socket. When installing the new bushing I made a little press using a bolt/nut and large washers. Worked like a charm. Below is a picture of the lower swivel shaft (online picture). It shows the shaft half removed from the gimbal housing, but the gimbal ring is already removed. Take note there is a very thin washer that sits between the lower side of the upper "ear" of the gimbal housing and the actual gimbal ring. I replaced this washer. The lower swivel shaft goes through the lower ear, into the gimbal ring/bushing, through the washer, and through the upper ear.
Second is to now remove the Upper Swivel Shaft (the source of all your issues).... In order to do this I would recommend using JR Marine wrench kit. Its $75 and once done you can return it and get $55 back. It consists of two modified 5/8 wrenches and a thin 1-1/16 wrench. These wrenches are modified to make turning the steering arm bolt and nut, as well as the swivel shaft lock nut, much easier. I tried regular wrenches and it simply did not fit and allow you to turn the turn the nuts with the size of the access window being what it is. I first loosened the U-bolt (two 5/8 lock nuts). I then loosened the the steering arm bolt and nut using the two modified 5/8 wrenches (don't remove unless you are replacing them). Its takes some patience to loosen as you are turning the nut about an 1/8 of an inch every turn of the wrench. Next I removed the swivel shaft lock nut using the thin 1-1/16 wrench. You will have to manipulate the gimbal ring up and down and start to get the swivel shaft to slide out in order to fully remove the top nut. If corroded in there like mine, it can be a chore. I used lots of PB Blaster, a mallet, and some gorilla hands. Once the nut was off i used a screw driver and some brute force to get the swivel shaft to slide down a bit. Once the lower flange of the swivel shaft was exposed on the underside of the gimbal ring, i was able to get a pry bar in there and get the swivel shaft to come out. Be careful in there as you are working right by your drive shaft bellow. It would be a lot easier to remove the shaft if the bellow was not in your way, and i almost gave up and removed the bellow a couple times. I'm thankful i didn't because i did not want to mess with regluing the bellows (a messy pain in the ****, which of course requires a special merc tool). Now that the shaft is out you will be able to fully remove the gimbal ring from the gimbal housing. Now that its off inspect the swivel shaft hole in the gimbal ring and make sure it is not worn. If worn you will either need a new gimbal ring OR you can send yours to JR Marine and they will remanufacture/refurb the opening. If you have a lot of steering slop (left to right) it is very possible your gimbal ring swivel shaft hole is worn. Fortunately mine was in good shape. I then cleaned up and repainted my gimbal ring prior to reinstalling. Below is a picture of a worn out gimbal ring and a corroded shaft (not my picture). My swivel shaft looked worse than the below, but ring looked much better.
Step 5: While everything is off replace that drive oil hose you cut. I used an exacto knife and cut a slit down the hose where it attaches to that plastic barb. This made for easy removal without worry of snapping the barb. Install the new hose and clamp.
Step 6: Time to reinstall the new upper and lower swivel shafts. I bought my upper STAINLESS swivel shaft from NuWave marine for around $100 and it fit perfect and will never rust out again. Merc also offers a stainless swivel shaft now, however it is around $300 if i recall correctly. The lower swivel shaft i replaced with factory and it was more affordable ($30 or so). First thing you will need to do is remove the old upper swivel shaft bushing and lip seal. My lip seal came out with the swivel shaft and was totally degraded and destroyed. No wonder why i had a leak. Next remove the bushing. I used a 24mm socket and drove it from bottom to top up into the swivel shaft gimbal housing cavity. I had to push the steering arm to the side to allow room for the bushing to exit. Take note that there are two washers in the gimbal cavity, the large diameter one goes below the steering arm and the smaller one goes above the steering arm. I replaced both of these. Second, I then reinstalled a new bushing and lip seal. The new bushing can be driven in with a 24mm socket from the bottom of the gimbal housing. You should drive it until it is flush with the top of the gimbal housing underneath the steering arm. Also note there is a seam in the bushing, position this seam to the left or right when installing in the cavity. Next put some red loctite on the new seal and in the cavity. Use a 25mm socket to drive the seal into place underneath the new bushing. With the bellow in place it makes it difficult to get any oomph behind your hammer, but the seal should eventually go into place. You will notice the seal has a bit larger diameter than the bushing and in turn the cavity in the gimbal housing also has different diameters for the bushing and seal. Be careful not to gouge the surfaces inside the gimbal housing seal and bushing cavity. Third is to install the new lower swivel shaft bushing in the gimbal ring if not already done (previously discussed in another step). Fourth is to install a new U-bolt in the gimbal ring. Interestingly the new Ubolt from Merc is a larger diameter than the old one (2005 bravo 3 drive), so i had to drill out the gimbal ring to get the new u bolt to fit. Fifth install the new lower swivel shaft and upper thin washer. Position the gimbal ring back into place in the gimbal housing. Use 2-4C grease on the lower swivel shaft and slide it up into the gimbal housing, through the ring, and install the new cotter pin. Sixth, install the new Stainless upper swivel shaft (use 2-4C grease on the shaft). Again the bellows are in your way but you should be able to slide the shaft through the gimbal ring and up into the gimbal housing and steering arm. I lined the steering arm, washers and new swivel shaft lock nut up prior to inserting the new swivel shaft and everything slid right into place. Next tight the swivel shaft lock nut. It will pull the gimbal ring up. You are supposed to tighten until the measurement between the upper ear of the gimbal housing and the gimbal ring is .02" (you will need a feeler gauge). Remember the ears are what the lower swivel shaft is installed into, and ultimately where that very thin washer is installed. Once that measurement is correct tighten the steering shaft arm, torqueing to spec. Once that is done you pretty much reference the above steps in reverse to reassemble. Just remember to use grease and torque everything to spec. U-bolt torque is 52 ft lbs, hinge pins 110 ft lbs, drive bolts 45 ft lbs.
Below is a picture of installing the new stainless shaft (not mine). Notice this person also has the Merc plug repair kit (perhaps a failed attempt).
Finished repair below. The stainless plate comes with a gasket but you should also apply a thin film of sealant on the gimbal housing.
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The system seems pretty robust to me if they used the right materials. It was simply an oversight, intentional or not, to use a swivel pin that is not stainless. It seems to me the rust is the catalyst for the seal failure, swivel shaft and ultimate gimbal wear. I had the port side on my fix list this offseason but I'm debating on letting ride another season.. Too many other things on the list and no time.
The U bolt goes through your gimbal ring and keeps the gimbal ring snug to your swivel shaft. The two shiny nuts on the top most section of your Bravo 3 drive. You just have to torque those to spec each season as preventative maintenance. If they loosen up you will get slop and ultimately the gimbal will start to round out.
You can't really grease a Bravo3 swivel shaft unless you install a zerk. These are standard on Alpha drives. And there is actually a dimple on the upper most section of the gimbal housing (in one of my picts), as its the same as an Alpha. You would just need to drill it out and thread it for a zerk. Not sure why they stopped installing them in Bravo's. It would essentially pack that whole area with grease and minimize the corrosion that occurs. Its really only a bandaid though and doesn't solve the underlying issue.
If you are really flexible and have a long grease gun flexible nozzle you could probably pack that area with grease from inside the engine bay.
I had started a post on greasing that and never really got an answer I was satisfied with as I'm guessing you could over pump grease in there and cause a problem- no one could really tell me how to know it was properly greased, just give it a couple of shots and your done. In my case, I would guess it had never been greased and while I "gave it a couple of shots" which is better than nothing, I would like to know that I did it and have sufficient grease in there to both lubricate and protect from corrosion...
Dream 'Inn III -- 2008 400 Express
Dream 'Inn III -- 2008 400 Express