Bravo I leaking down

[brwn234]

The last couple of days I've noticed that my lower unit is falling to the ground in about 12-24 hours. If I hold the trailer button and raise it to its highest setting, the next day it will be on the ground. There are no external leaks. I've got a Merc manual and it suggests it may be an internal leak in the rams, a relief valve, or a thermal valve. How do I test each? I wouldnt think that its the rams because if one went the other would still hold and and what are the odds of both of them going at once. Any ideas?
Oh yeah, the first time I had the boat out the other day I forgot to put up the ladder and drove around for awhile with it down. I didnt notice any resistance in the steering or anything odd about the trim. Could this have put any strain on the trim pump and blown or weakened any seals?

[blackhawk]

Did you check the fluid? Low fluid will also cause this. Of course then you have to find out why you're low on fluid but at least it's a start.

I can't imagine the ladder doing anything. Having to hold trim position while pushing a boat puts a lot more strain on the rams.

[ky-donzi]

One cylinder can cause the other to "bleed" off to. It depends on hou the valve is plumbed. My backhoe had same problem, was one of the lift cylinders

What can happen is one cylinder has a internal leak and allows fluid to by pass the piston from the lower side to the upper side of the cylinder. Then since there is fuild moving inside of the bad cylinder the other side can't hold ..so fuild from the left can go threw the hose into the leaking right cylinder.

You could raise the lower unit, block it up (support it) plug one of the cylinders with fittings while leaving the other side undone, remove blocks and wait 24hr. THen do the same for the other side. This would determine whether or not it is internal leaking or valve leaking... Lot of work tho. Someone may have a better idea.

[BigGrizzly]

There is an Orinat the bottom of the cylinder that will cause this. I had had both ram on merc and pump on the Volvo do this. Also the pump has a check valve that will do this. It was common on Volvo pumps on the spool valve. nine had a problem and made a o ring for the Volvo but actually found one in an O ring kit for my Merc ram

[MOP]

The rams feed off a common manifold at the transom shields base so yes you can not tell which ram is giving you a problem if in fact it is a ram. The pump can be tested with gauges to see what it is doing, the rams if in real decent shape not corroded are well worth rebuilding. Ram kits are cheap pretty easy to redo but you need a spanner to get the end off, without test equipment it is almost impossible to check the piston ball checks unless you physically see something stuck in one then you need a piston.

[BigGrizzly]

MOP, when I bough my spanner wrench kit 40+ years ago I was wondering how many times I would use them. Well years later I have a bunch more that I have fabricated. what a useful tool for a stupid looking looking piece of metal.

[MOP]

Even being in the biz I only rebuilt a few early on, turns out at $85 an hour plus parts it is better to slap a new one on and know exactly what you have. My own I will still tear into them, cheap old bugger that I am!

[GeneD]

Same thing was happening to me.
I took my pump apart and cleaned it.
Problem cured.

[brwn234]

What did you do as far a cleaning it? The fluid looks dirty and old but it may be motor oil or ATF. I'm not sure I've read you can put just about any oil in there that will resist moisture and corrosion.

[bob haver]

What did you do as far a cleaning it? The fluid looks dirty and old but it may be motor oil or ATF. I'm not sure I've read you can put just about any oil in there that will resist moisture and corrosion.
dude i am having the exact problem ,i have another pump that i swapped out but now there seems to be some different fittings so now i am chasing some fittings.If you want to try and clean the pump its not hard at all just take it of the bracket dump the fld pull the res of its a 5 16 size wrech on the bottom of the tank or 4 phillips heads on the top pull the tank off and be careful of the pick up screens then thier is two valves take them apart one at atime unthread slow because there is spring and seat with a ball rinse with a solvent and put back together and make sure the jam nut is tight do the same for the other side there is also two 7 /8 side nuts on the side of the pump treat them like the others and make sure the area is clean i am replacing with atf fluid it is faster than strait 30.everybody i talked with say they never seen the cylinders go bad so lets hope that is the case ?????GOOD LUCK :smash:

[GeneD]

We use brake cleaner to clean parts like this in the field. It's not rocket science, just be careful to remember where everything goes.
As for using tranny fluid...I've seen it used...don't care for it.
If you've got a leak, say red fluid in your bilge, is it the power steering or the trim pump? Could drive you crazy.
I'd stick with the SAE 30W.

[Air 22]

We use brake cleaner to clean parts like this in the field. It's not rocket science, just be careful to remember where everything goes.
As for using tranny fluid...I've seen it used...don't care for it.
If you've got a leak, say red fluid in your bilge, is it the power steering or the trim pump? Could drive you crazy.
I'd stick with the SAE 30W.

Power steering fluid is Clear these days??...atleast in the GM Ford Chyrsler auto-parts world it is...

Tranny fluid in the trim pump works well...easy to see the leaks:nilly:

[GeneD]

Mercury recommends SAE 30W in their trim reservoirs, and Dexron II or III (red tranny fluid) in the power steering reservoir.
There's got to be a reason behind this, and I'll bet there's a warrantee issue to consider too.
I've heard and seen of guys using generic hypoid 90W gear oil in drives instead of Mercury Hi-Performance.
As long as you feel comfortable putting in a non-recommended fluid in your equipment, that's all that matters.:shocking:

[Air 22]

Mercury recommends SAE 30W in their trim reservoirs, and Dexron II or III (red tranny fluid) in the power steering reservoir.
There's got to be a reason behind this, and I'll bet there's a warrantee issue to consider too.
I've heard and seen of guys using generic hypoid 90W gear oil in drives instead of Mercury Hi-Performance.
As long as you feel comfortable putting in a non-recommended fluid in your equipment, that's all that matters.:shocking:

Well here it is from Merc...
http://northamerica.mercurymarine.com/serviceandwarranty/outboardfaqs/fuel.php

What type of fluid is used in my power trim system?
We recommend either Mercury Precision Parts or Quicksilver Power Trim and Steering Fluid. This fluid can be used in any of our power trim systems. Acceptable alternatives will depend upon the type and age of the system. If the fluid is yellow, use automotive engine oil -- the heavier weight oil will cause the trim system to react slower in cold water. If the fluid is red or clear in color, use Dextron III automotive transmission fluid.

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[GeneD]

I guess the stickers on my trim pump and power steering pump (circa 1986) were placed there by some idiot.
According to my partner, Mercury trained and certified for 30 years now...Trim pumps take 30W oil, and power steering systems take Dextron II. This is on engines up to 1996. Mercury recommending this Quicksilver power trim and power steering fluid on all their new motors is just a new marketing ploy.
You guys do what you think is right.
All the fluids mentioned will work.

[Air 22]

Good luck...To each his own...I have a 1995 22C with a 502 that came with Clean GM power steering fluid...the trim pump has red dextron in it....no warranty issues Mercruiser cert mech as well..:)

[MOP]

30wt oil due to it's thickness compared to Dextron shorten the life of the trim pump dramatically!

[CHACHI]

ATF is a 15w oil.

Ken

[brwn234]

Regardless of fluid my drive still wont stay up. Heres what I've done so far as suggested by others:

1. Lowered unit completely. Removed UP/OUT hoses from the rams. Hit the trim button to try and lower the drive further to check for fluid leaking past the internal valves. No oil came out of the ports on either cylinder. Rams should be ok.
2. Removed, drained, disassembled and clean the entire pump. One of the filters has been rubbing against the bottom of the reservoir and a hole has worn in the mesh. I dont know what this could do or where the missing material has gone. Refilled with clean ATF and reinstalled the pump. Everything works as it should, but.....drive will not stay up.
3. Through my own thinking I decided the isolate the pump and the rams from each other. So i purchased an inverted flare coupling from the parts store. Unscrewed the IN and OUT hoses from the pump and directly linked the two hoses together. The drive stayed up all day long. Making me feel 100% confident that the leak is in the pump.

Now I dont know what to do because I've already gone through the pump. I have noticed that when raising the drive you can hear the pump "knocking" every time it makes a revolution. Could the springs on the poppet valves or the other ball valves be worn and not hold enough pressure on the sealing surfaces? I've got a Tractor Supply Company down the street that has all kinds of o-rings for hydraulics. Should I try an replace all of the o-rings? I'm kinda lost and on a budget. I'm mechanicaly savvy but I think this one I might be lost on. Thanks for all your help.

[bob haver]

replace the balls and make sure there is no dirt or nicks in the seats that should do it good luck:wink:

[brwn234]

Sooooo......I removed and disassembled the pump again. This time I paid closer attention to everything and found this. One of the seats in the valve body is worn crooked pretty bad. The seat is oblong instead of a circle. Now can this be fixed or replaced or is it part of the metal like I would expect? I can buy all the rebuild kits I want but they wont fix this problem. I think it would be better just to replace the whole pump and motor.

[zelatore]

I've got a Tractor Supply Company down the street that has all kinds of o-rings for hydraulics.

God I miss TSC...somebody should open that or a Rural King here in California...