Bravo 3 U Joint Installation Advice

[pyrotek]

Hi All, I have been having a terrible time with a 2008 Bravo 3 u joints. I decided to replace my u-joints as they were a bit stiff from some water intrusion last year. After wasting a lot of time and money, I now understand the recommended way to do this is to buy the entire u joint assembly and install into outdrive. However this requires opening the top of the outdrive, pulling some of the gears out, opening the spanner nut with special tool. My question is, is this a job I can do myself? I am fairly handy and careful, but I see almost no one attempt this job. However I'm in a bind, since all the marinas I've called so far are booked for a month out. Not sure if I should attempt to do this myself.

Longer story: I originally purchased the Sierra 18-6406 u-joints for about $100 each instead of the $240 OEM ones. Because the old ones were rusted in it took enormous force with a u-joint ball press tool to get them out. By doing so, we bent the driveshaft yoke about 0.075" which was enough to not be able to get the outer clips installed. After attempting to bend it back it fractured the end. So instead of purchasing just the driveshaft, I purchased the entire assembly. I debated going with Sierra or OEM, and decided to go with OEM. So now with the complete assembly, I removed the last u-joint to the short driveshaft that goes into the outdrive and so I could instead attach it to the one already in the outdrive. As we installed it, one of the bearing pins dropped out and we crushed the cap against it, bulging and ruining the cap. And now I have a bunch of parts from the Sierra u-joints, but the caps, seals aren't interchangebale with the OEM ones from GKN. So now I have to purchase a $240 u-joint for a replacement cap. We may try to bend the outdrive yoke back ~0.040" that it needs to go to get the clip to fit in straight. And simply re-installing it may again bend it enough to not get the clips in. What I really want to do is just get the whole new assembly back together with new u-joint and install it like it intended to be installed, but I'm not sure if that's going to be another headache.

 

[tpenfield]

I've done u-joints on 3 Bravo outdrives . . . I think they were about $25 each, maybe a bit more, and did 1 or 2 of them with hand tools . . . used a press on the other one, because I had the drive shaft out of the upper gear housing to replace the seal.

I don't like to do u-joints, because they are a PITA, but it sounds like u-joints are just not your thing . . . :noidea:

As far as advice . . . heat the outer ring of the yoke to expand the metal a wee bit, which will make the u-joint cup easier to press out of the yoke.

 

[metsfan3197843]

I've done u-joints on 3 Bravo outdrives . . . I think they were about $25 each, maybe a bit more.

Maybe on the older Bravo 3’s but I’ve yet to find the newer style with the external clips for under 90 bucks a piece. They are awfully proud of them.....

 

[Rick Stephens]

Maybe on the older Bravo 3’s but I’ve yet to find the newer style with the external clips for under 90 bucks a piece. They are awfully proud of them.....

That is one part I would never ever consider getting with a Mercruiser stamp on it. Moog, NAPA anything but Merc.

 

[metsfan3197843]

Well in 2 years of asking on this forum I’ve yet to hear of anyone finding a non marine replacement/equivalent
I live on an island and our local NAPA parts people couldn’t even order me oil pan fasteners so no help there....

 

[metsfan3197843]

Forgot to mention achris has videos in his signature that cover changing the unis and setting the rolling torque if you haven’t already watched them

 

[pyrotek]

I've only found one video on ebay that describes it. That is what has me concerned - there is so little information online about it. But I did find an x-marine mechanic who sounds like he is well versed in this. He knew exactly what to do, what parts were needed. So for $200-$300 he's going to do it. I can't keep going down this rat hole. I am over $1000 in parts so far just to replace what should be 2 $50 u-joints.

Yes the 2006+ Bravo's have the exterior clips with 18 mm trunnions. Merc part number originally was 865496A01 which had a massive cross. The newer 865496A02 version has a much smaller cross similiar to Sierras. Both Merc and Sierra trunnions are 18mm, but the caps and grease seals cannot be interchanged as they are physically different. The only difference is Merc GKN's have a nicer grease seal which is slightly less diameter than the cap. Sierras's is same diameter of cap. So when sliding this back and forth Sierra's grease seals take a beating when sliding into the yoke. We completely damaged one because the yoke wasn't straight and the grease seal got hung up.

So today we tried to bend the yoke back sticking out of the outdrive. Really nothing to lose at this point. We had no way to pry this with any type of control so we just went guerilla style on it. It needed to go maybe 0.050" to get the clips to seat all the way around. We tried a pipe wrench with some metal plates. We tried half a dozen times and barely moved it any measurable distance. Finally the last time with more force we moved it, but it moved a little too much past where I needed to go. And of course, same thing, another hair line crack right at the end. They grind down the end of the yoke for clearance and there just isn't enough material. It seems to be very weak at the ends.

When originally removing the gear end yoke from a brand new out of the box u-joint assembly, it was still very difficult to remove the caps. I think it was from the factory paint that are on the cap ends and on the end of the yokes. After pushing it back and forth a number of times it finally became loose enough. I just can't imagine how you can get these out after being in the water for a year with the slightest bit of corrosion. We could barely get them out being brand new. If anyone tries this in the future do yourself a favor and do not even try to press. Just cut the crosses off with a grinder like I did originally on some of them. Then you can push the caps through with a press while grabbing on to the ear of the yoke which won't risk bending anything.

So tomorrow I'll get my new $250 Merc U-Joints. I'll take one cap off it and install the gear end yoke that I had removed just days ago. We will be clamping cap to cap so no pressure is exerted on the yoke. I don't know how to completely ensure that one of the bearings doesn't drop like last time. Eventually I expect we will have to push against the new yoke to seat the clips. Hopefully it does not bend.

I'll put the rest of the caps and parts on ebay in case anyone is in the same situation and needs to replace just a cap and seal.

 

[pyrotek]

So we were successful in getting the gear end yoke back in the rest of the assembly. Received the new ujoint and took the caps off to put them back on the existing assembly. It also came with instructions which include a number of specific tools. Unfortunately I have yet to see these instructions online. This tends to be a problem as the standard manual is not helpful for all these newer Merc parts. Manual attached for reference.

So lessons learned in case this helps anyone attempting to replace ujoints on external clip style Bravos. Some repeatss.

- Don't replace the ujoints. Buy the entire ujoint assembly preassembled and bring it to someone who can install it.
- Buy Sierra ujoint assy. That way you can at least service the ujoints for $100 each instead of $250 each.
- If you insist to replace ujoints anyways...
- Cut the crosses off with a cut off wheel in grinder. Don't even try to press them out. I guarantee you'll bend the yoke. This allows you to press against each ear and push the remaining cap out
- Ensure no paint or burrs on the yoke
- Learn how the cap seats against the yoke. Now, intentionally push a pin down against a cap. Now learn how far the cross can go into the cap. You'll see a gap. Note that gap, since once you start clamping, you need to make sure that a pin did not dislodge and get pushed against the cap.
- Press the caps and a single ear of the yoke in a vice, just to get started. Here you aren't yet pushing on the ears of the yoke. Don't go to far since you'll need to slip the cross in
- If you use Sierra 18-6406 ujoints, slip the seal on the cross so you don't have to push it through the yoke possibly damaging it. If Merc ujoints, this doesn't matter since they are smaller diameter.
- Now with both caps partially in, you can now use the u-joint press to press the caps together. This is again better, since the yoke doesn't want to bend as much with the tight fitting caps partially installed.
- Last tip: Did I mention don't do this. Buy the whole assembly. For the cost of two OEM ujoints vs the entire assemblyl it's a no brainer. Problem is the SIerra $100 ujoints make you consider replacing just the joints.

Hopefully my mechanic has no other issues installing in the drive. I'd love to learn how to do this, but too far into the season at this point.

 

[pyrotek]

Forgot instructions

 

[pyrotek]

I watched achris videos. Not sure how I missed that, excellent video. I'm starting to convince myself I can do this, as I learn more about it. But again, it's too close to the season so I'm trying to resist!

There are a few good videos of setting the rolling torque. But what's missing is a good video of removing and installing the entire driveshaft assembly and setting timing. Can someone clarify if the back cover, top cover or neither need to come off? I need to buy a new o-ring for whatever cover the tech takes off, but I think I may have understood which one he wants to take off.

 

[tpenfield]

I have taken out the drive shaft without taking the cover off. IIRC, the large castle nut holds the whole thing in the front face of the upper gear housing.

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Rolling torque . . .
.

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Aligning the gears for '+' and '-' before reinstalling the driveshaft . . .
.

I took it all apart to replace the oil seal, which was leaking and failed the pressure test.

 

[pyrotek]

Thanks for all the information. I was able to find an x-marine mechanic that did it in under an hour. And the local marinas told me they couldn't even look at it for at least a month!

I learned some info from watching a pro who's done this many times that I would share. He advised to get a new nut, o-ring and carrier with seal. You can buy the seal alone, but he didn't want to bother with that. Instead get the seal pre-installed in the carrier. The nut was suprising to me since I didn't see anyone else recommend that, but now I see why since that nyloc nut sets the rolling tension.

The spanner nut came off easily with some taps of a hammer. I was a bit scarred how much force that was going to take since it's supposed to be torqued to 200 ft lbs. He then easily yanked the entire assembly out. Set it all in the spanner wrench in a vice and took it all apart. He then took a hose clamp and put it around two of the pieces (I forget which two). This was to keep them concentric, especially when starting to torque up the nut and to get the pieces to tighten evenly without cocking to one side or another. He also said that it's difficult to get the assembly back into the drive. Ideally he would lie the drive down with the driveshaft sticking upwards. That way he would take the u-joint assembly and just kind of flop it around attempting to get the best alignment as it goes into the drive. I was not there to watch this part. In this case, he didn't want to bother leaning the drive over and holding it, so he was able to do it horizontally.

He confirmed very clearly that you cannot screw up the timing of the gears by only removing the u-joint assembly. So no need to verify timing.

This sounds like something I would attempt to do next time, except for the fact the tool was equal to what I paid him! But hope I never have to do this again!

 

[harringtondav]

Many U joints will fit the yokes, but pull a cap and check the needle bearing journal size compared to
the marine original. Same size, use it. Smaller, return it and get OEM or Sierra. Marine unis are larger for higher torque and working angles.