Bravo 1 removal and pressure testing
 

Is it normal for gear lube to come out from around where the cable enters the upper gear housing? I am getting crappy looking light green oil coming out at that location with the drive removed and still full of oil. I'm draining it down now and the lube that came out the normal drain hole initially looked normal, than started looking somewhat emulsified like the oil coming out the shift cable area. I think I must have a bad seal, or maybe just condesation. How does one check for bad seals in an outdrive. There has never been any indication when the boat is in the water of oil leaking out. I have changed this lube several times since July and never liked the look of the oil. On every other outdrive I've owned the old gear oil always came out looking pretty much like when I put it in. Any advise would be greatly appreciated!

BT

sounds Like a seal... The good news is. You found it Before blowing the drive. When testing they do a pressure, as well as a vacuum test. Good luck ;)

I also had a quarter inch of funny looking oil in the bottom of my reservour bottle this fall. Drive oil looked Ok. Question, It almost has to be the propshaft seals right? If the covers and screws are all tight and sealed, water cant get in through the drive shaft area if the bellows is ok, and the shift cable area is also dry too if the bellows is OK, right? I hate changing propshaft seals but all the other possible areas of entry checked out ok. Anybody know if there is a kit/tool to do vacuum and pressure checks on a bravo 1?

That always happens when you pull the drive.

What's that Badcat... oil comes out the shift cable area every time the drive is removed? Curious to see the answers to formula31's questions.

BT

A little oil always comes out the reservoir check valve if you have a 91 and up drive. But not from the shift cable.

Mines a 1988 bravo one. I don't have the remote reservoir or valve assemble. The oil comes out around what is actually the cable clamp/shifter link. There is an o ring that seals this opening from sea water and it looks good.

BT

Anyone able to tell me how to pressure test this outdrive, or how to find a bad seal?

BT

Same year as mine. Remove the rear cover. The O-ring must have failed between the gear section and the shift linkage, or the shifter shaft lower seal could have failed. If so, make sure to check the shaft and bushings. Look at the pictures in mercruiserparts.com if you dont have a manual. Youll see what I mean. But, thats not where the water came from unless the rear cover o-ring is so bad it let it in there. If so, be happy. Thats the easiest to fix.

Bt;

No oil is supposed to leak from the drive when it is removed, except for a little drop or 2 from where the gear lube monitor check ball is. In your case, you don't have that so it should be 100% dry.
I rigged up my car radiator pressurizer to do a pressure check. Then I rigged up a vacuum pump to do a vacuum test. To run a pressure check, it is easier to do when the drive is full of oil. For vacuum test the drive must be empty. You must do both tests to be sure the drive will hold oil in and also to hold water out.

Checkmate. How much pressure in psi and how much vacuum did you pull in inches of mercury. Thanks Tom

Formula31... are the shifter seal servicable through the rear cover or do I need to disassemble the upper gear case?

Anyone know the proper pressure/vacuum to use for testing outdrive seals... anyone?

BT

Ive never done it by itself, but I dont see why it couldnt be changed just through the back cover. How did the back cover o-ring look? Ive had those leak before. Theres only those 3 bolts holding the whole thing. Make sure the groove is good and clean and the cover is flat. If you need the instructions on getting the shifter stuff apart and back together, I could scan them and email them to you next week when I get home.

I have the same leak in the same area. Around the shift cable hook up. Same milky green oil when I removed the drive this fall. I have not yet drained the drive. Is it a tough job to replace this seal???

Formula31... I haven't taken the back plate off yet, but would be suprised if that was the water leaker. I believe that is probably the propshaft seal like you mentioned earlier. I'll check the seal closely none the less and let you know if I need more help on replacing the shifter seal.

Thanks,

BT

HI Mike, no replacing the shift shaft seal is easy, but (theres always a but) the seal might have gone bad becasue the shaft or bushings are worn making the shaf move around too much. Need to check that carefully. There not too hard to change. Tom

I bought the drive from Kaama with only about 20 hours on it (the skeg didn't and still doesn't have a scratch!!). Since then I';ve put about 80 hours on it. Think it could be worn already??

Not likely. Check to make sure the 3 bolts holding the back cover on are tight and check the back cover o-ring. My latest drives have over 400 hrs and the seal and bushing are fine. The o-rings were not. I shouldnt really call them o-rings but they are round and seal the back cover.

Formula 31... I looked on the BAM site for the exploded views of the shifter and couldn't decifer the seal that you are talking about. I'll have to take it apart and see. I have so much stuff apart now I can't hardly move, so after I get some of that back together I'll get back into the drive. Please stayed tuned. I'm sure I'll be needing more help. ;)

BT (aka Dave) :p

http://www.mercruiserparts.com/Show_...ND+DRIVE+GEARS

Its item 10. My book has a much better picture

Oh and I know the feeling, Im not taking another thing apart till my transom assemblies go back on. Parts everywhere.

Formula31;

I put only about 7 p.s.i. on the pressure test. Then pulled about 10 inches of vacuum. Those are the numbers I was told by the guys where I store the boat. I can say that the drive passed both tests, and the oil was clear all year.

Cool thats what I needed to know. Thanks. We never used to do vacuum tests but it makes sense. My leak (if I even have one) is so small I may not find it but will try. When you pull the vacuum, did you then shut the valve and see if the gauge dropped? How long did you wait?

Formula 31;

Thats exactly what I did. I pulled a vacuum and just left the pump and guage in place. I left it on for hours and it held vacuum and pressure.

thanks thats what i will do too. if it drops, any idea on how to figure out where?

Formula 31.. Thanks, I'll have a close look at the seal and bushing (9 and 10).

Checckmate... thanks for the numbers. Formula 31 and I were getting worried that no one would ever fill us in on the pressures!

BT

Formula31 and BT;

If it leaks on the pressure test, you should have no problem finding the leak. Being that the drive is full of oil when you apply pressure, you should be able to see oil seeping out from somewhere. On the other hand, if the drive fails a vacuum test, I don't know how to determine which seal is at fault. Personally, I would just get an entire upper and lower seal kit to be sure. I feel it's better to do the work now in the off season, than have problems in the already toooooo short North East Summer.

I totally agree. Just trying to figure out a way of not having to pull the lower carrier. I imagine its gonna be fun with 14 yr old drives. And, I barely had a whisper of water evident in my reservoir. Ill check every possibility before I tackle the prop shaft seals. It makes my skin crawl to lay the torch on that aluminum torpedo. :eek:

Formula31;

I wouldn't heat that lower unit to remove the nut. I have gotten stubborn ones out by cutting it in half with an air sawzall. Then just break the nut out and get a new one. Of course, be careful NOT to cut the treads in the lower unit. Good Luck :eek:

Hmmm, I use that trick all the time to get out broken pipe nipples, never though of it for this. Thanks

Checkmate,

Do you by chance have the part numbers for the upper and lower seal kits? I'd like to go through the whole thing, but haven't found a pre packaged kit.

BT

BT,

I don't have the part #'s off hand. I usually just go to my Merc. Dealer and pick up the seals. I am sure you can get them from mercruiserparts.com if you wanted too.

I'm also having a problem that I noticed last winter. The cavity where the shift linkage apparently is getting some water in it. Thats the lower section if you remove the rear cap. Oil is clean w/ no water signs & I just pressure and vaccum checked today as previosly explained.(BTW, Thanks for the numbers) Passed the test. Last winter I replaced all the external o-rings in hopes of fixing it, but Noooooo. Linkage and cavity was again rusty and the grease I used last winter there is now a glob. The o-ring was replaced that goes between the bell housing and outdrive too. Everything looks fine and checks flat at the mating/ o-ring sealing surfaces. The only place I see for water getting in is at the cable where it goes thru the bell housing and uses a sealing washer, item #21, behind the cable nut. Does this sound likely?
http://www.mercruiserparts.com/Show_...ND+SHIFT+CABLE

Thanks,
Jerry

[ 02-10-2002: Message edited by: US1 Fountain ]

Jerry... That sounds like the shift cable bellows to me. What did you use to do the pressure part of your outdrive check? What level of vacuum did you use for the vacuum portion, and how long did you let it sit before deciding all was good?

BT

[ 02-11-2002: Message edited by: blue thunder ]

bt,
I used a hand held vaccum/pressure pump that I just bought from Pep Boys. Vacccum @ 11", pressure @ 12 #. 15 min and no drop. This reaffirms it to be a waterproof outdrive from the absence of water in the oil and leaks.
A torn bellows would allow water into the engine compartment, which I don't have. Another option would be a hole in the shift cable housing in between the bellows and the bell housing, which I don't see either with it removed from the bell housing now. So that leaves either a bad o-ring seal between the outdrive and the bellhousing(twice now, so coinsidence?) or it has to be seeping past the hard plastic seal that seals the cable at the bell housing. RTV at those 2 places should do the trick since there is a no pressure in this cavity.
I'm open for thoughts incase I'm misunderstanding something.
Thanks
Jerry

[ 02-11-2002: Message edited by: US1 Fountain ]

US1 Sounds like youve got a handle on it. My old merc manula even calls for sealer on those shift cable threads where they attach to the bell housing. I have also had leaks through the back cover. Make sure the cover is flat and the mating surface on the housing is flat. With only those 3 bolts holding it, I think some of them warp when the bolts are torqued. I have notice my old 88's are twice as think as the newer back covers. Probably a cost reducion on merc's part. Let us know what you find.
Tom

Tom, did you ever pick up another set of heads? BTW, I pressure test mine dry then use a squirt bottle with a soap and water mixture and spray around drive. Also, to remove a frozen ring nut you can drill the face of it with a 1/4" bit in various locations then break the nut apart with a chisel. I have used this method on several drives and haven't damaged threads yet. Remember to check your bearing preload when you reinstall the carrier, too.

Hi Maxx, No, not yet. But at the rate the money flow is going, Im not gonna do the second engine this year. Between all the projects and doing one engine right, no money left. Doing the full rebuilds on the transom assemblies hurt me more than I expected. Havent done the drive test yet but soon. Thanks for the tip, Ive also been soaking it with PB Blast for a while.

All right fellas, I need help again!

I pressure and vacuum test my outdrive (bravo 1) after replacing the o rings in the top plate and back plate. The pressure test went well. With 10-15psi and a bottle with soapy water, no leaks found. When I did the vacuum test, I couldn't hold vacuum. I could get it up to about 7 in. hg and then it would slowly fall to under say 3 in hg. I thought maybe I should be doing the test with a fill of gear lube so I did that and re tested. This time it went to about 9 in hg. then started to drop. Dropped at about the same rate, but would hold for 10 seconds or so before starting it descent. Sounds like the propeller seal to me, but I don't really know. Any advise would be majorly appreciated!!!

BT

Could the shifter seal be causing this and I just can't see it on doing the pressure test?

BT