Volvo Penta 290 Duo Prop Problems

Chaps,

Having a problems with my Volvo 290 dp leg.
When I first got the boat i noticed the leg would not stay trimmed up over night. It would always fall down eventually.
By the time the end of ths season came about it was tking less that 5 minutes to fall down.
I have done a bit of research on this and look like a bit of a job. I think the ram seals may be away. I have removed and opened up the trim pump, all is well here, Bugger ! For once I wish I was back to the old Mercruiser !!!

ANY HELP APPRECIATED

Hey,
I remembered reading this a while ago, don't know if you've seen it before of not but worth a look - http://www.ybw.com/forums/showthread.php?t=200129

Thanks For that,
These seem like the same problems but I believe that the problem lies in releasing retaining pins that hold the rams on the inside of the transom. I have talked to Crossan regarding this and it's apparently a nightmare of a job with out lifting the engine out.
allan

I have changed a few of these..

Can confirm the pins inside are the most difficult part and how bad depends on your boat builder.. sometimes they dont cut enough away round the drive plates to get them out... I used to use a load of washers and a bolt to make up a small puller.. u can also use a grease gun.. but fitting a grease nipply to a blanking plug on drive plate (this is how Volvo recommend you remove the pins)

Usually the rams corrode around where the hydraulic stainless steel lines enter the ram... the threads corode due to galvanic corrossion.. and they leak... unusual for the seals to go... last ones cost me £450 for a pair... also replace the plastic bushes.

The corrision which kills them is normally due to wrong or missing anodes, broken drive bonding wire. (stainless wire on drive) or fauly shore power.

Also when fitting the new lines dont cross thread them which is very easliy done..

Just to confirm though if you have a leak you will see this in the water when you move the drive up and down... if you dont see this them would look elsewhere for the problem

Best Regards

Craig

Craig,

Thanks alot for the info, you seem to be very well informed on the subject.
There is no oil leaking into the water, this is what was initialy confusing me. I can only conclude that the oil is not holding pressure in the ram cylinder and returning to the resevoir. The system is also drawing in sea water (loch water!) Not alot but certainly eneough for concern.
I have heard of the system you refer to of connecting grease nipple. This is what the workshop manual tells you but is reputed to be non effective in any case. You are right about the puller system, I am thinking this is the way to go !
It is good to hear that someone has carried out this procedure before. I think I will go along the path of repairing the rams instead of replacing (if these are to blame) them. A good hydraulic company should be able to do this, going by ast experience with other hydraulic systems.

Allan