# Changing out fluid in a Bob's JackPlate



## huntnetime (Jul 23, 2004)

I've searched high and low and cannot find a procedure for this. Anybody know the procedure for completely replacing the hydraulic fluid in a Bob's Jackplate? Thanks.

Sonny


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## Sonnysmarine (Mar 18, 2007)

Why are you changing it out?? THe fluid they use gets a milky look even if it never had any water in it. It's almost impossable to get all the old fluid out of the system unless you take every thing off and apart, The old fluid will stay in the lines and cly. and make the new fluid look just like the one after a couple times up and down.

You can drain the container, add fluid run it up and down and do it 4 or 5 times to get most of the old fuild out but will have to remove the pump and take off the resevior and clean each time. to flush the system.
Sonny Also.


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## Durtjunkee (Mar 23, 2007)

I did mine a couple of weeks ago.
1. Jack the motor/jackplate all the way up. Tilt the motor up as well, so you can access the jack plate.
2. Place an oil catch pan under the jack plate. It gets a little messy.
3. Loosen, but do not completely remove, the lower hose/hydraulic fitting on the cylinder. BEWARE!!! The motor and the jackplate are going to come down as the old fluid is forced out!
4. Now with the jack plate in the lowest position, try to raise it up. This will force some of the remaining fluid out of the resevoir and down the line, and out into your catch pan.
5. Open the resevoir and use some sort of suction device to remove any remaining fluid.
6. Fill the resevoir with your choice of oil. Bob's calls for 20w20 non detergent oil or a quality hydraulic oil. I have found that hydraulic jack oil works like a charm in the bobs and power pole both. It's about $4/quart at your local auto parts store.
7. Again try to raise the jack plate. This will purge old fluid from the line replacing the old oil with new.
8. Tighten the lower fitting. If you cant reach it with a wrench (like me) just finger tighten it for now.
9. Check and fill resevoir with fluid.
10. Raise the jack plate. It may take a few seconds for the pump to purge any air out. But keep at it. Eventually it will come up.
11. Fully tighten the lower fitting, this time with a wrench.
12. Cycle jack plate up and down several times. Add fluid if necessary.

My fluid had about 5 years worth of condensation mixed in it. It was milky and nasty, and my jack plate was laboring and slow. I repeated this procedure twice that day, and plan on doing it once more here in a few weeks in an attempt to completely remove all the old oil. My jack plate now runs like new, sounds great, and is as fast as it was on day 1.

Good luck!


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## huntnetime (Jul 23, 2004)

Sonnysmarine said:


> Why are you changing it out?? THe fluid they use gets a milky look even if it never had any water in it. It's almost impossable to get all the old fluid out of the system unless you take every thing off and apart, The old fluid will stay in the lines and cly. and make the new fluid look just like the one after a couple times up and down.
> 
> You can drain the container, add fluid run it up and down and do it 4 or 5 times to get most of the old fuild out but will have to remove the pump and take off the resevior and clean each time. to flush the system.
> Sonny Also.


Hmmm...I assumed the milky color was due to water in the fluid. My pump/reservoir sits at the bottom of a rear compartment and it has had quite a bit of water in it in before, so I figured water got in the fluid. It's just been my experience that when any kind of oil turns milky in color, it has water in it. Is this not true with jackplates? Also, the boat is several years old and I bought it new a couple of years ago. Just figured maybe it's time. I don't know...what do you think?


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## Redfishr (Jul 26, 2004)

My last BOB's Jackplate on my old Transport was 7 years old when I sold the boat.
I never changed out the fluid and NEVER had a problem with the Jackplate.


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## goodwood (Mar 30, 2009)

considering doing this or just refilling. It's at the low mark.


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