BMW Mk2 outdrive Hydraulic Lock

[Simon RBG]

Hello, I'm completely lost with this fault and could do with some help/advise. I have a fault with my BMW out drive leg trim system. I can make the leg rise to the rams full stroke but I can't reverse the action. Its like I have hydraulic lock. Motor attempts to lower the leg but stalls out.

I have replaced all the Hydraulic lines and blown through, stripped and re sealed the two cylinders in the system and electronically bench tested the pump and motor, works perfectly but as soon as I plum is up and test on my craft it just won't work. leg goes up, won't come down. I've even switched the hoses round and re wired the motor feeds.

I can't figure out what else I can do

Has anybody else come across this fault and can advise what I should be looking at doing?

Simon

Relcraft Boaters Group

 

[volvopaul]

Hello, I'm completely lost with this fault and could do with some help/advise. I have a fault with my BMW out drive leg trim system. I can make the leg rise to the rams full stroke but I can't reverse the action. Its like I have hydraulic lock. Motor attempts to lower the leg but stalls out.

I have replaced all the Hydraulic lines and blown through, stripped and re sealed the two cylinders in the system and electronically bench tested the pump and motor, works perfectly but as soon as I plum is up and test on my craft it just won't work. leg goes up, won't come down. I've even switched the hoses round and re wired the motor feeds.

I can't figure out what else I can do

Has anybody else come across this fault and can advise what I should be looking at doing?

Simon

Relcraft Boaters Group

Sounds like the motor is rotating but the valve isn't opening to allow oil past, check the connections on the pump and clean out the valve block assembly. If it's had water in it this would cause it to stick shut.

 

[R1chB1ch]

Could it possibly be a faulty/dirty switch. In that it makes a connection to lift, but not to lower?

 

[Chris_d]

I used to have a BMW mkII drive and it did this occasionaly if you went fully up, I just used stand on the leg and it then went down.
I guess you are aware that you must never fully raise them with the engine running or start the engine with it up as the UJ will knuckle out, not a clever design feature but otherwise I found it more relaible and smooth than the leaky Volvo's I have now.