Replacing hydraulic trim lines

GeorgeKohler

GeorgeKohler

Member
Joined
Feb 3, 2015
RO Number
33821
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159
Hi Fellas,

One of the hydraulic trim hoses that goes to the trim rams has bent and now has a nice kink in it. I'm afraid to bend in back in fear that it will snap. I've ordered a new hose for about $30, and it looks pretty easy to change out - both sides of the hose are very accessible with an open end wrench.

My question is, how do I bleed the system to remove the air that will be in the new hose? I don't see any bleed valve.
 
What brand tabs? If Bennett, they are self bleeding so simply running the tabs up and down several times will purge the air. However, you may want to check their website to confirm nothing else is required when replacing one of the lines.
 
Sorry, I wasn't clear. It's the hydraulic lines on the trim/tilt rams on a Bravo III.
 
Safest to use a Tubing Wrench for the loosening. The threads could be corroded and stuck. Last thing you want to do is round the hex off on the fittings.
image_20637.jpg
 
Just did two in 20 minutes. Spray them well in advance with wd40 or other penetrating oil. I cut the line just above the nut with a dykes since I was replacing them and used a hex socket to crank them out.
 
Can't say for sure with a Bravo, but I just replaced all the trim cylinders and hoses on my Alphas. Keeping the reservoirs full, I ran 'em up and down a few times and they were bled. Took a quart of fluid to do both.

(5/31 update - According to a technical article I just read on SEI's site, that bleeding method appears to work for all)
 
Tubing wrenches are great if you will reuse the tubing but Steve's idea of cutting off the tube and using a six point socket is a brilliant solution to an often difficult problem.

Has anyone sucessfully used anti seize on those?
 
OK, great. So, hookup the new lines, fill the reservoir, and run the lower unit up and down a few times to bleed it out. Sounds weird that there's no bleed valve, but I've only bled brakes before, so I'll take your word for it!
 
Those flare wrenches are way better than open-end for this type of use if hoses are not cut and sockets used.

There are a lot of purging descriptions available:
https://www.google.com/search?q=pur...ome..69i57.14775j0j7&sourceid=chrome&ie=UTF-8

Sounds like the ticket is to just ensure the reservoir level stays high enough so more air cannot be sucked in when running trim tilt up/down to purge to highest point.
 
Inspect the fitting area where it screws in to the ram. The aluminum is notorious for pitting from electrolysis. If you can see it from the outside, likely the threads are in too bad a shape to safely depend on it. You can buy the ram cylinders and sometimes the whole ram, used at your local marine repair shop.

Exactly where is the kink in the line? At the ram or the distribution block under the transom plate. If it's a matter of alignment, you may be able to loosen the fitting and rotate it to try to get it lined up a little better.
 
quote:
Originally posted by GeorgeKohler

OK, great. So, hookup the new lines, fill the reservoir, and run the lower unit up and down a few times to bleed it out. Sounds weird that there's no bleed valve, but I've only bled brakes before, so I'll take your word for it!

Click to expand...


There's no bleed valve. All the valves are in the manifold that the lines tie into. It worked fine for me, but don't take my word for it- check the 'sterndrive.cc' site and read the technical bulletin. Merc has a method, too. Complicated and tough to do by yourself. You should use whichever makes you comfortable.

As for cutting the old lines to remove them, that'll work, too, but you still want a 3/8" line wrench to tighten the new ones. Here's the kicker. According to SEI, Alphas and Bravos use the same set of hydraulic hoses. I ran into a problem with one connection on each cylinder- not enough space between the hose part and the flare nut to fit a line wrench. They're thicker than open-end wrenches. Luckily I have an old craftsman (good quality) open end wren that I was able to use successfully on those nuts.

Good luck!
 
quote:
Originally posted by SandySounds like the ticket is to just ensure the reservoir level stays high enough so more air cannot be sucked in when running trim tilt up/down to purge to highest point.
Click to expand...

Off the main topic, but at mention of brakes, I find it's possible to bleed new calipers on an ABS equipped vehicle by keeping the master full. Keeps from getting air into the ABS unit where it takes a tech with a special scanner to bleed it out.
 
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