165 trim pump valve body R&R?

ziggy

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Jun 30, 2004
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so i got a leak at the valve body on my 75 165hp (L6) mercruser large reservoir trim pump.
question is. is there anything that can fall out of the valve body? all i think i need to do to stop the leak is R&R the orings.
if i had the room, could i even get away w/o removing the trim hoses? just drop the valve body down a little to get at the orings?

any insight at all that could be helpful.
orings will hopefully be here thursday..
 

Don S

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Re: 165 trim pump valve body R&R?

All I can say is give it a try. If it doesn't cure the leak, then you will have to dig deeper.
I replaced those orings on a 120 a couple of years ago, and it hasn't leaked sense, and I know the guy uses the boat a lot.
 

picklenjim

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Re: 165 trim pump valve body R&R?

Actually you are dropping the manifold. The valve body is built into the bottom plate of the reservoir. No, nothing will fall out of the valvebody if you remove the manifold. You could probably leave the lines connected if thats the way you want to do it. You will need some type of sticky grease to hold the 4 o-rings in place on the bottom of the valve body as you put the manifold back on. The bottom of the valve body has recessed areas for the o-rings to sit down in. You sure it's not the large o-ring which seals the bottom plate(valvebody) to the rest of the reservoir? There's 8 screws on the bottom plate (valvebody). Be sure their tight. I would almost bet that's whats leaking and not those little o-rings. Should have ordered one of those seals along with the 4 little o-rings and done the whole bottom. By the way you can get those 4 little o-rings at any hardware or auto parts store.
 

ziggy

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Re: 165 trim pump valve body R&R?

yep, gonna give it a try. sure looks like where my leak is at.
IMG_4551-1.jpg

it's been leaking for a while. like last year... :rolleyes: i tightened the bolts and it stopped, for a while. now it's back. like usual. leaks don't fix them selves.
don't sound like anything will jump out at me. so that's good as i think i have access to remove the valve body only, but not a lot of room like usual too. that was part of the reason for my question. that and i'm working on nla parts that i'd just as soon not break or loose parts to..
thanks
edit. thanks pj. that's helpful info...
i understand about the other oring in the plate that i now understand is where the valve body is at. yes it looks like a manifold. cool. i think....

from my pic is why i think it's only the orings on the manifold..
 
Last edited:

picklenjim

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Re: 165 trim pump valve body R&R?

As easy as it is to disconnect the 2 lines it would sure make removing the manifold easier. Also be sure you have the drive completely down before disconnecting any lines or the manifold if you leave the lines connected. If you have it up any it will fall when you disconnect the UP line and shoot fluid everywhere. The higher the drive is the more it will shoot. UP line is the one you see in the pic that comes straight down out the bottom.
 

picklenjim

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Re: 165 trim pump valve body R&R?

One more thing, if you do remove the lines do not remove the 90 degree brass fitting that is screwed into the end of the manifold for the DOWN line. It does have a check ball , 2 springs and a small washer between the 2 springs in there. You don't need to remove it to disconnect the line anyway.
 

ziggy

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Re: 165 trim pump valve body R&R?

Thanks pj for the insight.

so i just gotta ask. i don't see any other seal for the manifold other than the 4 orings. is that it? no gasket or oring to seal the manifold itself to the valve body? least i don't see one in the parts diagram. http://www.mercruiserparts.com/Show...r=100&bdesc=HYDRAULIC+PUMP+ASSEMBLY,+COMPLETE

in the s/m and the parts breakdown the manifold is still with the valve body. please don't tell me i need to order item 5 too. item 5 seems to have 2 orings, is the smaller oring being for the manifold... ???
 

picklenjim

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Re: 165 trim pump valve body R&R?

Thanks pj for the insight.

so i just gotta ask. i don't see any other seal for the manifold other than the 4 o'rings. is that it? no gasket or o'ring to seal the manifold itself to the valve body? least i don't see one in the parts diagram. http://www.mercruiserparts.com/Show...r=100&bdesc=HYDRAULIC+PUMP+ASSEMBLY,+COMPLETE

in the s/m and the parts breakdown the manifold is still with the valve body. please don't tell me i need to order item 5 too. item 5 seems to have 2 o'rings, is the smaller oring being for the manifold... ???

No other seal or gasket.You will just be removing the 4 bolts w/a 7/16" wrench. In your link it does not even show the manifold, just the 4 little o-rings (part #1). You are seeing the base on the valve body which the manifold bolts to. It's shaped just like the manifold. It has 4 recessed circles which the depth is 1/2 the thickness of the o-rings. This is where you will need to install the o-rings with some sticky grease to hold them in place. Then the manifold is machined perfectly flat and will go against the o-rings and smash them tightly into the recessed circles you install them in. It's very simple as you will see once you remove the manifold.

The reason you don't see the manifold in the diagram is they have several different manifolds for those pumps. Some have 4 ports to connect lines to as they are also used for trim tabs. If you buy those pumps they sometimes do not even come with the manifold.

With all due respect to you Don there seems to be some discrepancies in your post. The diagram does not even show the valve body separately. However it does show the manifold or control valve as they are referring to it as being part #3. Part #4 is a plug which goes in the manifold and part #6 are the lock washers which go on the 4 manifold bolts.
 

ziggy

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Re: 165 trim pump valve body R&R?

thanks for the help folks. the deed was done.... whether or not it stops my leak time will tell. i will say the old orings looked a little shredded around the perimeter of them. 2 of them especially, towards the side that leaked.

fwiw for others.
i did leave the trim hosed connected to the manifold.

the orings are in a vertical line under the manifold. i thought they went under the bolts but they have nothing to do with the bolts. they seal 4 small passages that lead from the trim pump and out to the hoses.

i did drain the fluid out of the trim pump reservoir prior to removing the manifold. i didn't ask that question as i assumed you did and that was correct. it would have been a mess w/o draining. side note on extracting the fluid from the reservoir. an oil extractor siphon pump worked well. so there's another use for a oil extractor siphon pump.

pj, your heavy grease (waterproof grease in my case) idea worked well to stick the new orings to the valve body, i think. kinda hard to say. my working quarters were kinda tight, but best i could tell with my mirror, they stayed in place during the install. they must have since i've run the drive up and down 3 times now and if one fell off, surely it'd have leaked pretty bad.

now to water test it this weekend...
 
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