Drive falls down over night
 

On a bravo 1 , if I leave the drive up over night it will fall right to the bottom by morning and while driving it I have to correct the trim every few minutes because it keep moving down. I never seen any kind of oil leaks on the ground or in the boat. Its got to be internally some where and more than likely a O ring from what I guess but where would it be, in the pump or in the ram. I kind of feel it is in the pump because if I had one bad ram wouldn't the other hold it up????? If it is in the pump can I rebuild it. I know that the pump section isn't cheep.

HotBoat,
It is probably the popet valves in the pump. Merc has a rebuild kit for the pump. It is a very easy installation.
Dan

Seen this same thing several times before. Usually one of the rams was in need of a rebuild or replacement depending on extent of wear. Fluid leaking past the seals from up side to down side of piston. Both rams are teed together (this keeps them both applying equal force) so if one looses pressure, both loose pressure. For lack of better description.

Mine was doing the exact same thing last year. It was bad valves in the pump assembly.

I am going to take a gamble and go with the trim pump. it seems a easy place to start. anyone have a part # on the rebuild kit.

Sometimes it's a cylinder but 8 out of 10 it's the pump thing. Get Merc part # 99073 "Trim Pump Rebuild Kit" Has more stuff than you'll need and good instructions. Good luck. --- Jer

By The Way, drives should allways be left in the down position during storage/overnight,,, only put them up to trailer to/from lake. This is to keep the bellows in the realaxed position rather than fully stretched out.

I had the same problem and it was the pump. Having heard that the kit installation was tricky, I decided to replace the pump. Replacing the pump was still less than having the dealer fix it.

BTW-I discovered the problem only after I dragged the drive while going down the highway. Now I always use the merc trailering clips.

My drive had the same troubles maybe not as bad drained and blead the fluid refilled according to Merc and has worked fine ever since.

First thing you need to do is find the source of the problem. You do that by isolating the rams from the pump. It is relatively simple to do it.

Go to a hardware store and buy some brass caps to plug the ends of the hydraulic lines that go into the pump. Make sure you get the right ones so you don't damage the threads on the lines and you get a tight seal. Block the drive in the UP position before you remove the lines or you will get oil everywhere. After you cap the lines, remove the block under the drive and let it set overnight. If it still goes down the rams are leaking internally. If it stays up it means the rams are OK and the pump is leaking internally.

Save yourself some grief and just get a new or rebuilt pump. I tried replacing the valves on mine when this happened to me and it was a waste of time. Most Merc techs I have talked to say the valves usually do not solve the problem.

Good Luck, Doug :cool: