1984 Merc 50 Tilt/Trim Pump Leaking questions -ADDED VIDEO INSIDE

[groundshock]

Hey guys, have a 16' Lund Mr. Pike that I'm helping on this week, and if has a pretty severe fluid leak front the valve body on the tilt/trim pump. Motor is a 1984 Mercury 50 hp.

Looking at diagrams of parts online, it looks like I'll be replacing about 8 O-rings to solve the issue.

Question is this: The owner of the boat has put in only-God-knows-what to top off the fluids, and to be safe I'd really like to change the fluids out and replace with what belongs there. What fluid is recommended for this application, and does anyone have a procedure for flushing the components so that fresh, clean, and correct type fluid can be used?

Thanks for any help.

 

[Chris1956]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

You may use Dextron II ATF

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

OK. Is there a way to flush out the system to get the old stuff out? Whatever is in it looks like motor oil.

 

[Chris1956]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

5w-30 motor oil was also acceptable to use. I wouldn't mix them, but if the current stuff is clean, just top it off...

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

OK, I've replaced all the o-rings, still leaks. Found the problem though. It's pissing out of a weep hole in the valve body.

There is a large knob on the bottom of the valve body, and in line with that there is a weep hole with a check ball down in there. No matter what I do that hole leaks and the check ball doesn't move regardless of the thumb knob position. I pulled the Allen cap out and everything in there looked OK, no broken springs or etc.

This is driving me MAD. This leak is holding up the whole project. Any help would be outstanding.

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Quick video of where it's leaking from. ANY help would be phenomenal.

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Anyone at all? I'm dying here!

 

[Chris1956]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

There should be several orings on each side of that aluminum plate that is sandwiched between the PTT pump/reservoir and the control valve. It appears that at least one is leaking. Are the mounting bolts tight? If not, maybe you can just tighten them up. Dont strip them. If the mounting bolts are tight, remove the bolts and replace the orings. I would think you can use any orings of the same size that you find at a HW store.

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

All of the o-rings have been replaced and aren't leaking. Bolts are tight. That hole is what is not sealed. The oil comes POURING out of that hole when the pump is activated, and doesn't change when i turn the thumb knob located in line with the internal check ball that's in that hole.

I will get a couple better pictures to show where the hole is and how it isn't sealed. I keep thinking that maybe there is a ball that is supposed to be pressed in that hole that somehow popped out, but that just seens so unlikely. Wish I could find someone with the same pump/valve body to take a picture of theirs to prove/disprove that possibility.

Thanks so very much your help.

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Figured I'd just give another video. Helps more than a static pic. Video is 1080p HD so you can use fullscreen and get a good look.

 

[Chris1956]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

So the hole is up on the pump/reservoir, 1/2 inch above the plate? Is that what I am seeing? I do not remember seeing anything like that on my PTT system. Merc normally does not press balls to seal holes.

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions

The hole is in the valve body on the top just below the sandwiched plate.



It literally POURS out of this hole. There are no threads in the hole. There is a check ball down in that hole, with a spring on each side of it, and in line with that is the reverse lock knob.

 

[Charlie61]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions -ADDED VIDEO INSIDE

it look like its an over load vent one of your check vale , or if it has sping not working. your going to have to take it complete apart and see how the fluid is getting there you may be able to backpress air there the hole is good luck

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions -ADDED VIDEO INSIDE

I've got no problem taking it apart if I know what I'm looking for. Unfortunately I'm a little sketchy on what may be wrong. I've tried to find an exploded diagram of the valve body, to no avail.

 

[groundshock]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions -ADDED VIDEO INSIDE

Took the valve body apart, noticed no dirt, broken parts, etc.

The only conclusions I can draw are that it's either been screwed with by someone before me and put back together wrong, or that there is supposed to be a plug in that hole that's missing.

 

[mattibaby1980]

Re: 1984 Merc 50 Tilt/Trim Pump Leaking questions -ADDED VIDEO INSIDE

Any luck with this problem? I have exactly the same problem. Oil slowly leaks out of that small hole (1/16 in diameter approx) and it shoots out when the pump is activated. I have taken everything apart and found no problems like broken springs or whatever. Frustrating as hell because it never leaked until this weekend....

 

[Rustyforever]

I really hope someone can answer your question because I have the EXACT same problem.. I just signed up to post this problem and noticed yours. Great pics and video by the way.. Also does anybody know of a replacement 4 hose pump for this ?

 

[OCboat]

N/M

 

[Charlie61]

sorry it's been is long I have been ill , it looks to me if you replaced the o ring you may have a hair line crack.in the pump housing good luck. there is a red die you may be able to buy at auto parts to check for crack

 

[Poverty barge]

I have isolated this issue if anyone else needs help with it. It took me hours of searching the internet and scratching my head and talking to people until my dad who is a heavy duty mechanic suggested what the problem might be. And sure as sh*t he was right!! That hole is was left from when the valve body was machined. There is a little tiny ball that is pressed into the valve body in that spot to retain fluid. Luckily for me I found the ball in the bottom of my boat after my trim pump started puking oil all over the place on the middle of the lake.
So the only purpose of that hole was so a drill bit could be inserted through it for machining the valve body, and the ball pressed into it was a cheap way for Merc. To cap the hole. I put the ball back in the hole. Pressed it a little farther into the hole with a hammer and a punch. Don’t go to much or you’ll crack the aluminum valve body. I just pushed it in far enough to say it moved. Then I pushed the aluminum around it in with the hammer and punch securing it in place. To add a little bit of extra holding power I covered that ball with JB weld. Reassembled the system and it works great. Another option would be to tap threads into that hole and put a plug in it. As long as it seals up the valve body you are good to go. I know this is an old post but if it saves 1 person the hours of frustration or the $1000-$1400 CAD to buy the new replacement unit it’s worth it. Seeing as Merc no longer sells that valve body just replacement pumps. Also this pump is harder to find complete as is it a high pressure low flo unit and most of the new stuff is a low pressure high flow set up. Long story short all you have to do is plug that hole good enough to hold hydraulic pressure and your back on the water catching fish. Hope this helps someone!!