Bravo noise

[scottmech]

Got an 89 Mercruiser 7.4L/Bravo I. With the drive in the lowest position, in or out of gear, there is almost no noise from the drive. But as it is raised (again in or out of gear) there is a teeth grinding niose comming from what seems to be the upper part of the upper gearcase (not from the universal joint, behind it toward the back of the drive). The noise sounds like an Alpha drive that needs the shift cables adjusted. I have checked the shift cables and they are adjusted properly and the drive goes in and out of gear ok. Check the gear oil every time I launch and I never find any metal or water in the oil. Any ideas on what it could be? Any info appreciated.

 

[Wellcraft 89]

Re: Bravo noise

Gimble bearing!!!!! by raising or lowering the drive <br />causes a strain in this area .was the drive ever out or the engine removed after factory install.or it could have been misaligned from factory and now the gimble bearing has gone bad. <br /><br />or is the noise the trim pump <br />is the noise only there with engine running?<br /><br />oops I almost forgot there are shims which set the <br />the upper main gear depth into the counter gears at the top of the drive if the drive has been apart <br />for rebuild ,the spanner nut which holds this assm.could have not been tightened properly and now when raising the drive the gear is being pulled away. <br /><br />This condition needs to be looked at or your repair bill could be higher.<br />Rich

 

[Wellcraft 89]

Re: Bravo noise

Gimble bearing!!!!! by raising or lowering the drive <br />causes a strain in this area .was the drive ever out or the engine removed after factory install.or it could have been misaligned from factory and now the gimble bearing has gone bad. <br /><br />or is the noise the trim pump <br />is the noise only there with enginge running?<br /><br />Rich

 

[scottmech]

Re: Bravo noise

The noise happens when I'm in nutral or in gear, with the engine running, about 2000 rpm and up, with the drive in the up position (not the trailer position, the full up driving position), full right and full left. The only time it doesn't make the noise is in the down position pointing strait back. Don't know fore sure if the drive was ever removed post factory. Doubt it considering the low time of the boat. I know it's not the trim pump, because that's in the boat and the noise is in the drive. By placing a screwdriver on the gimble housing and the upper drive I'm about 80% sure the noise is aft of the gimble area. Wouldn't the most likely cause be the universal joint? Is there a test or a diagnostic technique I could used to narrow down the causes? If I removed the drive (I'm a competant mechanic so I can perform just about anything given the proper tools) will a bad universal or gimble bearing be obvious? What should I look for? Thanks. Any info appreciated.

 

[Wellcraft 89]

Re: Bravo noise

Do you do your own maitenance?<br />Do you have a manual for your drive?<br />The drive comes out like a alpha.<br />The universals will be obvious chk just like a car.<br />The gimbal bearing you reach your hand up into the anals of the bellows and spin it,if it feels rough or <br />marbley(is that a word).Its bad you need to change it.<br /><br />if you have a manual for your drive there are 2 cover plates for inspection of your top gears.<br />If you have changed your gear lube regularly I don't suspect your gears unless you hit something under water.<br />let us know what you find <br />I have the manual for your drive right here if you need some help.<br />Rich

 

[Wellcraft 89]

Re: Bravo noise

Do you do your own maitenance?<br />Do you have a manual for your drive?<br />The drive comes out like a alpha.<br />The universals will be obvious chk just like a car.<br />The gimbal bearing you reach your hand up into the anals of the bellows and spin it,if it feels rough or <br />marbley(is that a word).Its bad you need to change it.<br /><br />if you have a manual for your drive there are 2 cover plates for inspection of your top gears.<br />If you have changed your gear lube regularly I don't suspect your gears unless you hit something under water.<br />let us know what you find <br />I have the manual for your drive right here if you need some help.<br />Rich

 

[scottmech]

Re: Bravo noise

After reading what was posted here I decided to take it to a shop. The mechanic thought it might be the gimble bearing also. He removed the drive and found a bad universal........but thats not the only thing. The yoke seal went bad and the outdrive was leaking lube. He thinks the lube washed the grease out of the universals and thats why they went bad. The gimble bearing felt fine. No rough spots, very smooth operation. Took the cover plate off the top of the drive and the gears looked fine also. That was also the opinion of the mechanic. At this point I dont know weather to replace the gimble bearing or just grease it and drive on. His reccomedation is to replace it while the drive is off. The total price for the replacement of the yoke seal and gimble bearing is $700 labor and $500 parts(worst case scenario)....and that includes pressure testing the outdrive. I got a trip to Pensacola comming up and I'd hate to have something go bad in the middle of the bay with 6 people on board. Plan for the worst and hope for the best I guess..........

 

[denniz]

Re: Bravo noise

$1200. sounds awful high, reseal upper $280. labor, u-joint and gimbell brg.laboR $105.Shouldnt be more than 250.00 in parts.@$70.00 hr.

 

[scottmech]

Re: Bravo noise

Yea, tell me about it. Here's the breakdown:<br /><br />Parts:<br /><br />gimble bearing 62<br />u joints 96<br />sealing rings 50<br />yoke 165 <br />seal kit 80<br />washer 3<br />cap 2<br />gear lube 25<br /><br />Labor: (72/hr)<br /><br />diagnosis 1.0<br />R&R drive 1.5<br />check/adjust alignment .5-1.0<br />u joint/yoke 3.0<br />gimbil bearing 2.0<br />yoke seal 1.0<br /><br />He said he may not have to replace the yoke if no groove is worn in it from the seal. I almost wish he'd let me do the work using their tools.

 

[denniz]

Re: Bravo noise

He wont let you do the work but thats a 4hr. job max. I can do it in less, your not reshimming anything. Sorry your getting a bit hosed.

 

[scottmech]

Re: Bravo noise

Thanks for the info. I'll try to negotiate with him on the labor. Now there's a new development.......<br /><br />Told him order the parts and get it done so I could have the boat back and do a shakedown on it before my trip to Fla. He comes back and tells me the gimbil bearing was on backorder until Sept 26. Not good. Doesn't leave me enough time for the shakedown. He gave me a list of all the parts including the part numbers so I called around some other dealers to see if I could find a bearing. First of all, the part # he gave me wasn't a good #. So I searched for one by application (89 Bravo 1, 7.4L). Ended up finding one less than 5 miles from the shop where the boat is being fixed. Delivered the bearing to him. He tells me he had those bearings in stock but those didn't fit my application, that's why he had to order one. Told him to keep the bearing and compare it to the old one. When I went home I called 5 other dealers and they all verified I got the right part#, 30 60794A4. <br /><br />I was really hoping that this shop wasn't like your typical auto dealer service department.......incompetant and try to screw every chance they get. Next time I'm going to do more research on the shop I take it to. It's not like my combo is an odd ball set up. Sheeesh.<br /><br />What really gets my goat is if given the time, I could make (or have made for me)all of the tools needed to do this job myself for a lot less than the 740 labor. Live and learn I guess.

 

[denniz]

Re: Bravo noise

Youve got the right part # I dont know where he got his info.

 

[denniz]

Re: Bravo noise

I dont think theres much room for negotiation now though, youve already given him the OK, Dont wanna **** him off or you might not have your boat for the vacation...

 

[scottmech]

Re: Bravo noise

I gave him the OK, that part is right. But that was before he told me the bearing was back ordered, and he didn't even have the right part #. It's pretty bad when the customer can find the right part befoe the shop can. He knows I need the boat. If he really cared about the customer, he would have double checked his info. What are the odds 5 other dealers verified the right part (6 including Rod Knocking) the first time out? Seems to me he made an obvious mistake some where.<br /><br />And when I said negotiate, I didn't mean in a **** of the mechanic way. I'm a mechanic and know what it's like. Last time a pilot pissed me off (he deserved it, lied to me about a part installed on his plane) I wouldn't sign it off. I think it's fair to knock 2 hrs (at least) off the estimate. Thats about how long it took me to find and deliver the part. That's what I'm supposed to be paying him for.<br /><br />He supposed to get to it tomorrow. We'll see what happens. <br /><br />Thanks for the advice.

 

[flashback]

Re: Bravo noise

sounds like the u joints to me..........good luck

 

[scottmech]

Re: Bravo noise

Flasback,<br /><br />No doubt one of the U-joints was bad and the gimbil was good. But there's also no doubt about the yoke seal (amount of lube in the drive shaft bellows and the fact it was using some lube as indicated by regular checks of the lube moniter) I was replacing the gimbil as insurance. <br /><br />I do have some questions that may help me save some money:<br /><br />1. Does the alignment need checked after bearing replacement? The only thing I can find in my manual that needs it is engine/transome ring removal.<br /><br />2. Should I even bother having the drive pressure tested? Can it be pressure tested off the boat? I never found water in the oil when checked (7 times this season). The mechanic wanted to do it on the boat. If he can do it off, I'll replace the u-joints and install the drive myself. <br /><br />Thanks for the info.

 

[flashback]

Re: Bravo noise

I would check the alignment if you have the tool, just for saftey sake. but I don,t think the bearing replacement will change alignment. Don,t know anything about pressure testing the drive, what do they do, pump it full of compressed air? I think I would just go ahead and put it in the water. if it leaks then get it fixed. wait a minute... do you have a trailer for your boat? if your boat has to be taken in and out of the water with a lift, i can see the advantage of knowing ahead of time whether the drive leaks or not. those lifts are expensive...

 

[scottmech]

Re: Bravo noise

Rod Knocking,<br /><br />Any input on my previous questions?<br /><br />Thanks.

 

[denniz]

Re: Bravo noise

Its important to use the alignment tool to align the bearing once installed, or you may not get the drive back on. Pressure test any drive youve been into to double check your work, you can cut a seal on installation or have a grooved yoke. If you have a drive oil monitor, its best to pressure test the drive off.

 

[denniz]

Re: Bravo noise

Guess I should elaborate, the bearing is one unit with two parts, bearing and race, when installed the are driven in with a installation tool and more than likely the bearing wont be aligned. The alignment of the engine will not be changed, just the bearing. A pressure test is done in 2 steps low pressure 3-5 psi and high pressure 13-15 psi with a guage installed to verify it holds pressure, if the guage shows a drop in pressure it means you have a leaking seal.There is also a vaccumm test done for the seals that fit on the inside of the back to back seals. Normally if it doent leak on pressure it wont leak on vacumm(NORMALLY).