Aquadrive thrust Bearing - your operating temp?

[PhilC]

I have an Aquadrive assembly in my drivetrain and the thrust bearing measures 80-90deg C (176-194 deg F) while motoring at cruising speed.

We have removed the thrust assembly and the bearing appears smooth and and have reinstalled checking the alignment.

Anyone out there with one of these units and a digital thermometer that might like to check the temp on the aft end around the part attached to the shaft to see what the highest temp is that they record?

I'm trying to figure out if this is normal.

Thanks in advance

[skipperpete]

Originally Posted by PhilC

I have an Aquadrive assembly in my drivetrain and the thrust bearing measures 80-90deg C (176-194 deg F) while motoring at cruising speed.



We have removed the thrust assembly and the bearing appears smooth and and have reinstalled checking the alignment.



Anyone out there with one of these units and a digital thermometer that might like to check the temp on the aft end around the part attached to the shaft to see what the highest temp is that they record?



I'm trying to figure out if this is normal.



Thanks in advance

Is the heat coming along the shaft from the stern gland or is it just the bearing alone that’s hot? It might also be getting warm from mis alignment, the thrust bearing and carrier need to support the propshaft and not apply lateral load to it. What temp are you reading on the CV joints?

[PhilC]

]Hi Pete and thanks for your response,

The hottest part of the unit is the periphery of the thrust that mounts on the shaft. The temperature gradually decreases in toward the shaft and along the shaft aft from the aquadrive to <30deg C at the dripless seal about 200mm back from the thrust. The CV'S are at around 35deg.

The thrust mounts to a 'U' shaped heavy aluminium plate bolted onto some heavy tabbing.

The thrust assy is mounted to the alloy plate using four bolts through rubber bushes. I statically aligned the thrust assy to the alloy plate. The shaft is pretty well aligned up down/side to side. It needed a bit of shimming <1mm under one of the rubber mounts to get it (within 0.5mm at the bounting holes) of perpendicular but I figured shimming rubber mounts to be something that didnt need more precision. Anyhow my attempy at shimming made no difference to the temp it was running at.

This is what my unit looks like:[URL="https://www.nauticexpo.com/prod/blokland-non-ferro/product-54171-509867.html"]https://www.nauticexpo.com/prod/blokland-non-ferro/product-54171-509867.html[/URL

[tkeithlu]

Is the bearing lubricated and does it remain lubricated at the operating temperature? Is there any roughness to the bearing operation, or any noise such as squeals or rumbling?

The point here is do you have a properly functioning bearing that is not going to seize on you. That sort of temperature is not bad; axle bearings on a car must get at least that hot. But if the system is deteriorating, or headed for failure, then you've got a problem.

My recommendation is that you determine that you have a happy bearing, and if so, go sailing.

[PhilC]

The thrust is roller bearing protected by lip seals. Presumably it was lubricated on assembly but I cannot confirm this without complete disassembly. With the shaft disconnected it turns smoothly albeit with what feels like significant preload. I’d be surprised if the differential in my 4wd was running at 90degrees C but cannot say as I have never measured. To put this into context this bearing is hotter than my engine block.

[tkeithlu]

OK. That does, indeed, sound like a "hot bearing." That's an age-old classification which used to mean pour oil on it until you can replace it. Given that it's sealed, the first part won't work, so perhaps start looking at replacement. You don't need to determine exactly what's wrong. It is not a happy bearing.

[Copacabana]

Phil, can you take some photos to better illustrate the assembly and installation?

I have an Aquadrive on my boat, but perhaps not the same model. Mine runs cool- not hot at all. I have to imagine 90 degrees C is not normal. Have you pulled back the rubber bellows to see if it has enough grease? Are you certain the alignment of the Aquadrive and the prop shaft is good?

Some years ago I had to replace the rubber bellows and I spoke directly to the company in Sweden. They were very helpful. Have you tried speaking to Aquadrive? It's pretty easy to take the Aquadrive apart to check for wear or damage.