Volvo QS BP1200 bow thruster replacement

[Alaska 530 Voyager]

Hello, I had this exact problem on my 530 Voyager. The seawater intrusion purged the gear oil right out. I would be willing to bet that your oil plug, which is brass, has eroded away as mine did. And you are correct, the zinc bolts to the bottom of this plug. I was able to dive and replace this plug while my wife was reverse purging sea water out while pumping gear oil in from above. I later hauled out and changed the oil. My Thruster continues to work flawlessly. I believe you can save it if you act quickly. As for finding a new plug, it's just a brass plug with an o-ring type gasket. You should be able to find one third party somewhere. Unfortunately, I don't recall the thread size or thread design. Dave.

[Royb]

Hello,
I’m new to this forum and would like to offer some information on this particular thruster. Although many of the parts are no longer available, most of the parts used on this thruster were not fabricated by Volvo and are from other manufacturers. The bearings and seal kit can be obtained from SKF and even have the numbers marked on all the bearings. The Motor is in fact a forklift motor that can easily be rebuilt at most electric motor repair facility for around 500 (even if it was submerged). Shafts within the drive unit can easily be machined at any machine shop for 350 labour. If you search 24v reversing relay online you’ll find 100’s of pages that come up selling them for as cheap as $75 as they are commonly used on dump trailers or smaller dump trucks. Should you require additional assistance just post and I’ll respond as soon as possible.

[Midnightsun]

Thanks for the info and welcome to the forum.

[Bianco80!]

Source of the post Hello, I had this exact problem on my 530 Voyager. The seawater intrusion purged the gear oil right out. I would be willing to bet that your oil plug, which is brass, has eroded away as mine did. And you are correct, the zinc bolts to the bottom of this plug. I was able to dive and replace this plug while my wife was reverse purging sea water out while pumping gear oil in from above. I later hauled out and changed the oil. My Thruster continues to work flawlessly. I believe you can save it if you act quickly. As for finding a new plug, it's just a brass plug with an o-ring type gasket. You should be able to find one third party somewhere. Unfortunately, I don't recall the thread size or thread design. Dave.

New thruster gears can be obtained at thrusterparts.com

[Bianco80!]

Source of the post New to this post! 2003 Carver 564
I have a BP1200 bow thruster. Found water in the oil reservoir. The gear case turns freely.
When the boat was pulled in July and zinc replace, the mechanic said the screw holding the zinc would not tighten all the way. After finding water, I looked at the parts diagram and see the zinc screws into a oil plug. Could it be the oil plug is lose or broken. I called my local Volvo dealer to order a new oil plug kit and was told they are no longer available. Can anyone provide me a source or idea?

Typically it's the gears that are ground down. You can buy a replacement gear kit at thrusterparts.com

[Bianco80!]

Source of the post Hey, I was scouring the internet looking for parts for a 2000 Carver Voyager 530 bowthruster, BP1200 QL, when I stumbled on this forum and joined up. Hey everyone.

The shaft is bent on it, and so I need the shaft and any seals and gaskets that are bad, or the whole lower unit as the upper unit is fine. Do you know anyone that might have this lower unit, or some parts by chance?

Thanks for any help you can provide.

Yes.....usually it's the ground down gears. Try thrusterparts.com

[Bianco80!]

Source of the post Hello, welcome to the Forum. I was part of this discussion earlier. I have a seal kit but I need to hold on to it in case I ever need it. That just reminded me that one of our members sent me a message inquiring about the kit. Very sorry, I forgot to respond. Anyway, please keep us posted and let us know if you find a good Parts Source, or replace it. We would like to know what you replace it with if you do. It's a great Thruster, lots of power. I really appreciate mine. Good luck, Dave.

There is a company that machines new gears for the BP1200's. ThrusterParts.com

[km1125]

I've read a lot about different thrusters having "water intrusion" issues over the years, and these Volvo units don't seem to be any different. Seems like there'd be a way to slightly pressurize the gearcase with just a SLIGHT amount of pressure (say, 5 PSI) that would force lube OUT if there was a leak rather than let water in. You could rig it with a gauge or even an alarm so you'd know if you were losing pressure and needed to do some maintenance before major problem developed.

[Viper]

It builds up a slight pressure under normal operation anyway but the main concern should be to keep oil out of our waterways. Having it pressurized all the time will ensure it pukes everything into the environment through a leak. It would be better to simply have a water sensor trigger an alarm in the presence of moisture so you can address the problem sooner before it results in releasing all the oil into our waterways and needing a new leg.

[km1125]

Source of the post It builds up a slight pressure under normal operation anyway ...

I would think that's part of the problem. There's no where for that pressure to go, so if there's a leak then oil goes out and when it cools back down again water comes in. It would be interesting to see how much pressure builds up during use. I suppose it's not much different than any lower unit on any outboard.

Source of the post...but the main concern should be to keep oil out of our waterways. Having it pressurized all the time will ensure it pukes everything into the environment through a leak. It would be better to simply have a water sensor trigger an alarm in the presence of moisture so you can address the problem sooner before it results in releasing all the oil into our waterways and needing a new leg.

It would only be pressurized initially. It wouldn't be much different than hydraulic trim tabs.