pressure test / vacuum test

[billbayliner]

Hello All: Pulled my Alpha 1 gen2 outdrive off as I was concerned about water in the drive. I have searched every where for the specs on the vacuum test and cannot find them.

Every place in town I called said they only do pressure tests (said should be sufficient) and have never done a vacuum test on outdrives. What I have read, this is not so and a vacuum test is required for proper diagnosis.

How many inches of vacuum should the Alpha 1 gen2 hold when testing? My outdrive will only hold 6 inches of vacuum. If try to get it over 6 would drop to 6 and hold steady.

Held 15 pounds of pressure for 2 hours.

Thanks for the help.

 

[Haut Medoc]

Re: pressure test / vacuum test

Yup, that is fine...........JK

 

[milkyway]

Re: pressure test / vacuum test

Outdrive does not produce vacumm on its own.

Your steady pressure means the seals are ok.

Did you see any water in the gear oil when you drained it?

 

[tommays]

Re: pressure test / vacuum test

A lot of times you need to move the shifter and spin the drive shaft to find small leaks

tommays

 

[Don S]

Re: pressure test / vacuum test

Do to the design of the input shaft seal on the drive, vacuum usually only holds around 6 to 9 inches of vacuum. Did you check your bellows for water? If it has water in it, the water will get into the drive very easily. When the drive is hot and starts cooling down, it does create a little vacuume. When the bellows is dry, only air enters the drive. When it's full of water, then water gets sucked into the drive.
The water also gets into the gimbal bearing and ujoints. and rusts them up also.
Since the drive holds 6 ok, my guess is water in the bellows as your problem.

 

[billbayliner]

Re: pressure test / vacuum test

Thanks for the replies....

Not a drop of water in the drive bellow. Changed those last year as preventative maintainance.

In the oil reservoir it looked milky at the very bottom. I was not taking a chance and pulled the boat and removed the drive for testing. Even though not much, I still think that there was some water no matter how small, in the drive.

Did change the oil reservoir hose that comes from the transom to the outdrive as it was dried out and cracked. Even though cracked and brittle, it did hold pressure.

Time will tell, I reinstalled the drive, making very sure the gasket around the reservoir fill valve on the flange of the outdrive / bell housing was perfectly placed. Am going to pull boat next week and drop the oil from drive to see how it looks.

Upper and lower seal kits on their way just in case.

Better to be safe than sorry.

Thanks

BILL

 

[peacekeeper6]

Re: pressure test / vacuum test

how did you do a pressure test? i have both my alpha ones gen I and want to make sure i dont need seal kits, i have them here anyway

 

[Reel Poor]

Re: pressure test / vacuum test

You can make one like this.

 

[billbayliner]

Re: pressure test / vacuum test

I used the tubing / fitting from my outdrive oil fill pump and connected it to a male X 1/4 barbed fitting.

Then that went into a black maliable tee (standard steel fittings found in hardware strore).

Top of the tee is the pressure guage. on the inlet is a nipple and stop valve.

going onto the valve would be how you would connect to the pump / air pressurer supplier.

I have a set up that I use for pressure testing gas lines so I used my compressor but you can rig it up to connect it to a bicycle pump.

Remember to check your fittings on the setup for leaks by spraying soapy water on them. This way you do not mistake a leak in the outdrive when it is the fittings that are leaking.

BILL

 

[peacekeeper6]

Re: pressure test / vacuum test

i have a compressor also, so i need a T fitting and attach a pressure guage to it? i actually have a fuel pressure guage i guess i could hook up can you pressure test the drives with them on the boat and together?

 

[Reel Poor]

Re: pressure test / vacuum test

Use a small hand pump. You don't want to pressurize over 15-16 psi. Yes they can be tested on the boat, but they must be drained of lube oil. If you have a leak it could be at the upper front seal, to check it, the drive must be pulled.

 

[KaGee]

Re: pressure test / vacuum test

Drive should hold pressure for a couple of hours... at least. Use a spray bottle with a soapy mix in it and spray it on everything looking for bubbles. A lot of times leaks are at the fill and vent screws because you did not use new washers.

 

[peacekeeper6]

Re: pressure test / vacuum test

what about taking the drives apart?