Pressure test

[PabloPicasso]

I had milky brown oild in a 120s saildrive, now drained, boat ashore.

To pressure test to check the seals I'm thinking of fitting a schreader valve into the oil filler cap. Then I can pressure check the seals even with the boat afloat.

Anyone forsee any issues with this. I could try and get a spare filler cap without the valve in for normal use.

The pressure is only low air pressure to 11psi max.

 

[Boater Sam]

11psi is much more than it will get when in use. I would not go over 4psi.

 

[PabloPicasso]

Yes, I think that's good advice, just inflate to a low pressure. I thi k the manual said 11psi was the max. I'd use a hand pump, with manometer, very gently.

I just need to find a spare filler cap.

 

[Plum]

I had milky brown oild in a 120s saildrive, now drained, boat ashore.

To pressure test to check the seals I'm thinking of fitting a schreader valve into the oil filler cap. Then I can pressure check the seals even with the boat afloat.

Anyone forsee any issues with this. I could try and get a spare filler cap without the valve in for normal use.

The pressure is only low air pressure to 11psi max.

Does your saildrive, as is typical on gearboxes, have a vent/breather that would need blocking?

www.solocoastalsailing.co.uk

 

[Daydream believer]

Does your saildrive, as is typical on gearboxes, have a vent/breather that would need blocking

No.
There is a thread where a member suggested using a header tank to the sail drive to balance the pressure of the water against the header tank.
I queried how he would connect header tank to the dipstick hole & he posted a picture of a standard filler cap complete with a hose coming out of the top. If one can find this thread- posted in the last 3 months- one can trace the supplier of the cap & just put the valve in the pipe. This would save any adaptions.
However, there are 2 ways that water can get into the oil. With me, it was because I used the wrong washer on the DRAIN ( edited) plug. I used a copper one, instead of the correct neoprene one. That cost me a haulout in Cherbourg, mid holiday & lots of worry & frustration. In emergency, I took the washer from my jabsco wc handle & used that & I have been using if for the past 5 years.
Alternatively, it is the seals & if there is any doubt , then change them BEFORE they start to score the shaft. It is not rocket science. I would , therefore, check the washer then change the seals. I now change the seals when I change the main saildrive hull seal every 7 years. The saildrive being on the bench.
When checking the oil level one should feel an intake of air, as there is a pressure differential build up in the saildrive after use. If there is none then that might suggest a leaking seal.

 

[VicS]

No.
There is a thread where a member suggested using a header tank to the sail drive to balance the pressure of the water against the header tank.
I queried how he would connect header tank to the dipstick hole & he posted a picture of a standard filler cap complete with a hose coming out of the top. If one can find this thread- posted in the last 3 months- one can trace the supplier of the cap & just put the valve in the pipe. This would save any adaptions.
However, there are 2 ways that water can get into the oil. With me, it was because I used the wrong washer on the filler plug. I used a copper one, instead of the correct neoprene one. That cost me a haulout in Cherbourg, mid holiday & lots of worry & frustration. In emergency, I took the washer from my jabsco wc handle & used that & I have been using if for the past 5 years.
Alternatively, it is the seals & if there is any doubt , then change them BEFORE they start to score the shaft. It is not rocket science. I would , therefore, check the washer then change the seals. I now change the seals when I change the main saildrive hull seal every 7 years. The saildrive being on the bench.
When checking the oil level one should feel an intake of air, as there is a pressure differential build up in the saildrive after use. If there is none then that might suggest a leaking seal.

Do you mean drain plug ?

.

 

[sailaboutvic]

Most likely the seals is leaking unless you used the wrong plus O ring ,
I never known a plug O ring to leak unless as I said its been chnge for one that's not suited.
Not sure why you want to pressure test it ,
I'd its out the water so change the seal and be done with.
Don't forget any score marks on the shaft, sleeve it lol it won't be long be fore the oil,will be milky again.

Going back to posting 5# what DD was referring to,
This may be some help , you see comment from people who unless they come up with the idea they doubt it , no different to some posting on YBW.
Saildrive Header Tank to Protect Against Seal Failure - Cruisers & Sailing Forums

And another link
https://sailing-luana.com/2020/05/avoiding-salt-water-in-the-saildrive/

And another link

Sail Drives

If you,look hard enough you find a few more dozen too.

 

[Daydream believer]

Do you mean drain plug ?

Yes I do. Thanks for the correction i will edit my post
Brain fade

 

[VicS]

Yes, I think that's good advice, just inflate to a low pressure. I thi k the manual said 11psi was the max. I'd use a hand pump, with manometer, very gently.

I just need to find a spare filler cap.

I dont know what pressure you intend going to but I'd have thought worth going to something approaching the max is sensible if its worth doing.

in choosing a pressure gauge/ manometer bear in mind thet 1 psi is equivalent to just over 27 inches water gauge Any meaningful pressure will need a rather large water manometer

Outboard engine gearboxes are also vacuum tested, after all what you are really interested in is whether the seals will prevent water ingress. It's probably not possible to vacuum test a sail drive gear box though because air will very likely be drawn in via the input shaft seal which is only a single seal to prevent oil leaking

 

[Daydream believer]

Apart from the cost of the seals, it is not rocket science. There are shims, which need to be refitted with care. However, provided everything is kept clean & normal practices are observed , the job can be completed in less than a couple of hours by an average DIY sailor.
So why not just change them & know that the job has been done. One can check for shaft scoring at the same time. One assumes that the OP has been checking the oil regularly & the water egress is not due to some long term issue.

 

[PabloPicasso]

I dont know what pressure you intend going to but I'd have thought worth going to something approaching the max is sensible if its worth doing.

in choosing a pressure gauge/ manometer bear in mind thet 1 psi is equivalent to just over 27 inches water gauge Any meaningful pressure will need a rather large water manometer

Outboard engine gearboxes are also vacuum tested, after all what you are really interested in is whether the seals will prevent water ingress. It's probably not possible to vacuum test a sail drive gear box though because air will very likely be drawn in via the input shaft seal which is only a single seal to prevent oil leaking

I'm only going by the manual that you linked to earlier.
Is this not common practice?

 

[PabloPicasso]

... And yes, it was the wrong type of O ring.

 

[PabloPicasso]

Yes, it seems more sensible to just change the seals.

 

[ClarkT]

I'm making up my own pressure test rig for my saildrive SE120 rebuild. Does anyone know the thread pitch of the saildrive drain plug? There are not enough threads there to measure it with confidence. Both an M10x1 and 3/8 BSPP look like they might work, but by my "eyeometer" I think it's a coarser thread. Any ideas here?

 

[ClarkT]

I'm making up my own pressure test rig for my saildrive SE120 rebuild. Does anyone know the thread pitch of the saildrive drain plug? There are not enough threads there to measure it with confidence. Both an M10x1 and 3/8 BSPP look like they might work, but by my "eyeometer" I think it's a coarser thread. Any ideas here?

I wish I'd found this thread before. My local Volvo distributor knew nothing about that pressure test rig. There's the Volvo part number for me in black and white. SIGH.

 

[Ammonite]

It's 3/8"-16 UNC
If you search for gear lube oil pump on eBay there's loads of kits for less than a tenner that include the adapter and pipe to make up a test kit

 

[PabloPicasso]

If the seals are suspect just change them. Not too expensive and not too difficult a job with the boat ashore. Then you won't have to worry.

Its a routine service item.

I'm glad you, eventually, found this thread helpful.