pressure testing outdrive

[bobhol]

All summer I have added oil to my reservoir,about an ounce now and then.I have hooked up a gauge and pressurized the drive to 14 lbs.It has been 4 hours and it has gone down 1 lb.I have sprayed everywhere and cant find the leak.I drained the oil from the drive but did not take it off. What else can I try? ....Bob

 

[fat fanny]

Re: pressure testing outdrive

Are you geting any oil in the bilge? if so the main seal to the output shaft could be jeprodized and leaking into the bellows if you don't remove the drive you wont be able to see any bubbles from that area that could be leaking from the output shaft yoke seal plus as soon as you remove the drive if that's the culprit you will know instantly there will be oil pouring outof the bellows also you could be losing oil from the fill drain plug

 

[bobhol]

Re: pressure testing outdrive

No oil in the bilge..it is bone dry. I wondered about the drain plugs and if I was leaking from them...I had to remove them to drain for the pressure test.Is 1 ib. of pressure drop over 4 hours typical?.Do I have to remove the drive (probably) but where would it likely be leaking inside?..thanks,Bob

 

[bobhol]

Re: pressure testing outdrive

Should I try more pressure...20 lbs.?

 

[Alpheus]

Re: pressure testing outdrive

No!!!

Spin the drive shaft while its in gear by hand and watch for pressure drop...

 

[bobhol]

Re: pressure testing outdrive

Thanks Alpheus.I will try that...if I lose pressure where should I look for the leak?..over 21 hours of use I have topped up about 1/4 bottle of fluid...regards,Bob

 

[dubs283]

Re: pressure testing outdrive

yep, with the drive off the boat, drain gear lube, pressurize to 15 psi and rotate the driveshaft while shifting from fwd to neu to rev - should not drop more than 1 psi in ten minutes, really shouldn't drop at all, but ten minutes is all you need to test it for

for whatever reason, the shift shaft seal is usually the culprit on alpha drives

also, inspect the monitor hose that goes from the transom to the bell housing

 

[bobhol]

Re: pressure testing outdrive

I came out this morning and found a puddle of gear oil on the ground .It is coming out of a hole on the lower unit .The hole is under the front bolt on the starboard side of the lower unit just above the bullet shape .What does that mean? Could it be the o-ring between the upper and lower units ? Is there any other seal ? Could I have caused this when I changed the impeller?where else should i look? I am relieved to have found the leak but what is the next step? So many questions ,so little time ...LOL...Bob

 

[bobhol]

Re: pressure testing outdrive

Should I crack the upper and lower and pressure check the lower...just plug the oil hole with your finger ,right?

 

[Gary H NC]

Re: pressure testing outdrive

Pull the drive and test....the only way to know if the input or shift shaft seals are leaking.
Plus it needs done yearly anyway to inspect the u-joints,bearing,bellows,ect...

No need to split the drive in half.

 

[nola mike]

Re: pressure testing outdrive

Pull the drive and test....the only way to know if the input or shift shaft seals are leaking.
Plus it needs done yearly anyway to inspect the u-joints,bearing,bellows,ect...

No need to split the drive in half.

I found it easier to pinpoint my leak when I split the drive, plugged the oil passage, and pressure tested each half individually.

 

[bobhol]

Re: pressure testing outdrive

I am changing the bellows,bearing and shift cable so I will have the drive off,but my first chore is the leak so I may just split the drive as it seems obvious it is the lower that is leaking...does that seem logical? ...thanks,Bob

 

[dubs283]

Re: pressure testing outdrive

pull the drive before your pressure test it

it makes it much easier to see any leaks

once the leak is located, then you can split the drive and repair the bad seal(s)

 

[paultjohnson]

Re: pressure testing outdrive

Just cuz its leaking out of that lower strbd weep hole on the lower unit [gear case ] doesn't necessarily mean the lower unit is the culprit. U said u changed he impeller R U sure u got that little O ring- dang forgot the proper name for it- That goes btwn the upper and lower unit. its smaller then a dime Stbd side a little fwd of center. It seals the oil passage from upper to lower. Is that reinstalled properly. At all? Somebody help w a pic plz.

 

[bobhol]

Re: pressure testing outdrive

I know which seal your talking about and my fear is that it is not in properly...when I changed the impeller i had a real chore putting the lower unit back on . I wondered if that seal shifted a bit as I didnt use anything on it to make it stay in place ...that would be great if that is all it is...by the way pressure has held for more than a day now but I still have the puddle there.I let that drive drain for over two hours but there still must be fluid in there..wow...Bob

 

[brhodes]

Re: pressure testing outdrive

Paul I think some call it the quadring?

 

[bobhol]

Re: pressure testing outdrive

UPDATE!! Yesterday I jumped in and took off the drive.Surprise surprise!!It came off just like I read it should and fit on my stand perfectly.I split the drive and could see an oil trail from the o-ring to the weep hole.I cleaned everything up and pressure tested it .I blocked the oil hole with my finger till it turned purple. I sprayed and could see no leaks . I replaced the o-ring ,put it back together and I pressured it upto 15 lbs. It was a little over 14lbs this morning after 16 hours.I presume it is ok?.there was no oil in my bellows ,just a well greased gimball bearing . I have a transom kit and cable to install this week I have read lots here and hopefully it will go correctly ...if not I will post with my questions,thanks,Bob

 

[paultjohnson]

Re: pressure testing outdrive

Paul I think some call it the quadring?

Thats It !!! Your last pressure sounds good 2 me But I D K what the acceptable rate is. R U supposed to spin the prop and shaft while testing? I did my imp this summer and had the wresteling match u did . I had stuck the quad ring [ Thank u BRHODES ]on with grease. Finally got - Upr and lower seated together [ hadnt tightened anything] but didnt trust that the ring was still in place, so I split it back open an inch and it WAS still in place. Better safe then sorry! Good luck to u that thats all it is/was !!! Let us know