DP290A guru's needed - leaking input shaft seals

[Scott Danforth]

Here is the story in a nutshell.

Drive is a 1988 DP290 A hanging off the back of a modified 271C

a few weeks back, took the drive off to replace the bellows. While I was at it, going to paint it.

when I pulled the drive, I could smell a faint wiff of gear lube. then when I undid the bellows, the bellows was full of gear lube. So, I picked up a seal kit for the drive as well

dissassembled the drive, replaced every seal from the input shaft to the 4 on the counter-rotating output shafts.
Also bought a new spacer washer (the one the seal rides on) for the input double bearing box.

Each seal was glued to the housing. each seal was lightly lubricated with grease.

painted the drive with POR15 and their hardnose paint. ordered dark grey vs light grey, however that is a different story

put the drive together, pressure tested it at 12psi for about 30 minutes. all good. rotated the input shaft a few dozen times while moving the drive into forward and reverse - all good.

so, I fill the drive with oil and install the drive late last week. Oil level to the top of the flattened area on the dipstick.

Saturday we take the boat out for about a 100 mile jaunt burning fuel watching dolphins, the sunset, etc. with some friends

Saturday night while washing the boat and flushing the motor, I noticed a faint wiff of gear oil.

this morning, I pull the dipstick (you can hear the air sucking in as I unscrewed the dipstick). the oil is low
pull back the bellows and there has to be about 8 oz of gear lube in the bellows.

re-checked and the drive still holds pressure this morning.

why is it leaking out the input shaft? Is there a trick I missed?

Each seal area was cleaned, then the seals edge coated with permatex #3 when the seals were driven in.

This re-seal is kicking my butt

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

Anyone have any suggestions?

 

[K-2]

Re: DP290A guru's needed - leaking input shaft seals

I'm stumped. Every time I have done a pressure test to find a leak the leak was readily apparent.

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

maybe I should push the pressure up to 15-18psi?

 

[captmello]

Re: DP290A guru's needed - leaking input shaft seals

I wish I knew...My only thought is that the outdrive got hot, built up pressure until it blew lube through your seals, then cooled, resealed, and created a vacuum when you opened up the outdrive. Does the gear lube your using expand when it heats up? I know if you get water in your bellows, the outdrive will suck the water through the seal when it cools. Did you reshim etc when you replaced the seals?

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

using amsoil synthetic gearlube. been using it for years and never had a problem until now.

Had the wife and her friends along, so I dont even think I hit 3000 RPM other than the initial hole shot. most of it was cruising at low RPM. Water temp was 72 degrees. dont think the drive would have gotten hot. most of the time it was submerged.

I did not pull the double bearing box apart, so I should not have to re-shim the bearings or change the crush sleave. I left the shim alone between the double bearing box and the main upper box. so I should not have to re-shim that either. When I replaced the shoulder/spacer washer, there were no shims under the old one, and the new one measured the same with my dial calipers.

I pulled the old seal off the front of the double bearing box by putting a screw thru it and using the claw on the pry bar to pull it before cleaning up the surface, gluing and driving in the new seal with a bearing driver.

going to pressurize again tonight, however with a bit more pressure. I am also going to spray the seal/driveshaft area with soapy water to see if I have any faint bubbles.

maybe I was the lucky one that got a bum seal.

 

[muc]

Re: DP290A guru's needed - leaking input shaft seals

I’m confused.
It’s been many years since I did this job. But I don’t see how that seal could be replaced without disassembling the double bearing box and replacing the crush sleeve. Isn’t the u-joint yoke in the way?
The 290A shouldn’t have any shims under the shoulder washer.
Did you replace the o-ring that is between the shoulder washer and the u-joint yoke? That would cause it to leak if it was missing or fell out of place.
If you take the bolt out that holds the gear to the yoke, the crush sleeve must be replaced and rolling torque set.
Like I said don’t know how this job could be done without taking the double bearing box apart.
Can you post pictures?

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

Muc,

you can remove the retaining bolt from the u-joint yoke, and remove that from the double bearing box. then you can remove the o-ring, shoulder washer, and the retaining ring. then all you have to do is pull out the seal.

yes, replaced the o-ring as well.

pics on my phone, will be posting shortly.

On another note, the gearbox has been holding 18psi for the past hour. WTF..... seriously WTF.

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

View attachment 228652

upper gear double box removal a week ago
View attachment 228653

what I drained from the bellows



pressure testing again, and spraying with soapy water hoping for bubbles

 

[captmello]

Re: DP290A guru's needed - leaking input shaft seals

can't see the top two pics.

 

[Grub54891]

Re: DP290A guru's needed - leaking input shaft seals

Did you drain the drive when testing? You have to to get a good reading.

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

the drive was empty the first time I pressure tested it when I re-assembled the drive. It is currently drained, except maybe a few ounces.

held 18psi all night, even with me prying on the u-joint yoke and turning the driveshaft for about 30 mintues.


Captmello

here is the photobucket links, I cant see the first two here at work either.

IMG_20140323_112758_946_zps7202e47b.jpg Photo by scott_danforth | Photobucket

IMG_20140323_140528_102_zpsbc5cc507.jpg Photo by scott_danforth | Photobucket

I took most of the photos to remember the sequence of putting things back together, as well as to document the parts needed when I re-sealed.

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

Well, over lunch, started googling this issue.

turns out this phenomenon has raised its head up only a few times

Volvo 290 DP low on oil sometimes - The Hull Truth - Boating and Fishing Forum

# 14206: Volvo outdrive problems! 3/6/00 3:37:00 PM

only one post mentions never to over fill the gearbox because it pushes oil past the seal

it could be I overfilled the gear box. I also had not done a vacuum test. Will do that tonight per the manual.

Then I am going to re-hang the drive. Getting good at it :facepalm:

If that does not solve the burping issue, then I may consider adding a remote reservoir from a mercruiser

 

[muc]

Re: DP290A guru's needed - leaking input shaft seals

Sounds like maybe you skipped this step.
“If you take the bolt out that holds the gear to the yoke, the crush sleeve must be replaced and rolling torque set.”
As soon as the retaining bolt is loosened from the u-joint yoke the crush sleeve MUST be replaced.
If rolling torque is to low it will allow the yoke to wobble when drive is running. That would allow lube to leak into the bellows.

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

Muc, good point.

However I did ask the local Volvo mechanic the question on re-sealing the gearbox if I had to fully disassemble the double bearing box. I was told that the crush sleeve only needed to be replaced if I disassembled the double bearing box and replaced the bearings. Simply verify the rolling torque is still within tolerance (1.6 - 2.2# for used bearings) which is what I did. I was at 1.8#, however still within the spec.

I will re-check the rolling torque again

 

[muc]

Re: DP290A guru's needed - leaking input shaft seals

Some guys will use that method --- but to do it like that --- you need to first measure rolling torque BEFORE you loosen the bolt and then when you put it back together make sure rolling torque is a little higher. That is the only way you will know that the bolt is now tight enough.
P.S. Neither Volvo or myself would ever recommend doing this. I have seen it done and work and I’ve seen it done and go bad ---- lots of $$$$$ when it goes bad ---- way more than what a new crush sleeve costs!

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

Rolling torque still at 1.8#

If the bearings were loose, I should see some side-to-side play in the u-joint yoke when I pry between the casting and yoke with a prybar. I am not seeing any signifficant movement, only about 0.002, and I cant tell if that is becaust I am flexing the casting, that is the amount of movement in my dial indicator, or that is the amount of play in the bearings

 

[Fun Times]

Re: DP290A guru's needed - leaking input shaft seals

I'm right there with you Muc, It's been since the mid 90's since I have been inside one of these upper units. But I do recall they are very sensitive to over filling with oil. Also they/(Volvo service school) tell you that any time the crush sleeve is disturbed in any way shape or form it needs a new one.

Unfortunately there's not a whole lot of forum "posters" that really know all the little tricks to these type of drives anymore, so it makes it challenging to help out when some of these harder tech questions pop up on the forums nowadays. These style drives can be challenging at times to figurer out. I wish we could help you by saying THIS is your problem. Good luck to you with narrowing it down.

 

[Scott Danforth]

Re: DP290A guru's needed - leaking input shaft seals

Fun Times, Muc

looking at the cut-away view of the double box (page 35 of the manual), the crush sleave is between the races, and the stub of the gear and the shoulder washer are in contact.

based on this view, the crush sleeve would not be affected by removing the yoke of the driveshaft, unless I were to follow the manual and press out the bearings, gear, crush sleeve and seal. I pulled the seal out the front and replaced it in the front. It should not have affected the crush sleeve in this manor.

also, based on reading the operators manual, I have overfilled the gearbox by about 3/8" to 1/2". the manual states to read the dipstick without threading it in. I had been threading it in all the way, and filling to the top of the dip stick read area.

At this point, just going to swap out the crush sleeve, reset the rolling torque to where it currently is, and fill it only to about half way up the dipstick gauge.

 

[muc]

Re: DP290A guru's needed - leaking input shaft seals

Scott
If you fill to the top of the flat area on the dip stick when it’s threaded in then the level should be a little lower when the stick is just resting on the threads. So I’m not so sure that’s your problem.

I think changing the crush sleeve is a good idea because otherwise there is no way to know if the bolt is tight enough. They do require a lot of torque ---- I use a ?” drive ratchet to tighten that bolt.
Always a good idea to have an extra crush sleeve or 2 on hand when you do this job. It’s a little tough to get a feel for how much the rolling torque changes as you tighten the bolt. Nothing changes until all of a sudden ? turn is way too much, so go slow and remember that the bearings must be well lubricated and spun a few times after each time you tighten the bolt and before you check the rolling torque. If the rolling torque goes too high you HAVE to start over with a new crush sleeve. Most of the young mechanics I have trained at the shop ruin at least one sleeve learning to do this job right.

P.S. I don’t agree that the bearings need to be pressed out to require a new crush sleeve. I think that as soon as the bolt is loosened that changes the tension on the sleeve. But I think how much interference fit there is between the bearing and gear would make a big difference. MerCruiser has pretty much the same set up and they don’t use a crush sleeve.