Hydraulic Steering Installation by Donald B. Ketcham

dbketcham@mmm.com (e-mail)


What the hell is wrong with my steering?

Have you ever gotten tired of excessive wheel torque in your steering setup?

Are you afraid to let your friends drive your rig because your steering sucks?

Have you already dumped money into fixing or replacing your cable steering system only to have it fail again?


If any or all of the above apply to you then a hydraulic steering system may be the answer for you.  They have ALL applied to me at one time or another and I had grown to HATE my steering setup but I had learned how to drive it…so I just learned to live with it.  I had learned just what trim and throttle positions to use when turning.  Problem was, I like to water ski so that means that somebody ELSE has to drive my boat.  That’s when “the incident” happened that motivated me to make a move to hydraulic steering for my rig.  I was going into the water to water ski and my good friend, who has driven my boat many times, was going to do the driving.  Even though he is an experienced driver, I was compelled to give him detailed instructions on how to drive because of the extremely shitty steering situation which had developed in my boat.  A combination of shitty cables and excessive wheel torque made hard cornering at skiing speeds and “down” trim positions (for skiing) almost impossible.  We were on a narrow section of the Minnesota River and it requires a pretty sharp buttonhook turn to get around.  I had advised him to slow down prior to attempting the turn.  So away we go……I like to go 34 mph.  Then it is time to turn and I see him struggling to complete the turn…and NOT slowing down….I become nervous…..bunch of rocks and downed trees on the bank.  Headed right for the bank……oh no!  I thought I was going to witness my boat being driven right up onto the bank…..dam….and I knew this could happen.  Somehow he managed to muscle it around with only about 20 feet to spare.  Before I even finished my slalom run I knew that was it…something HAD TO BE DONE about that steering or something BAD was going to happen.


The decision…..new cables or hydraulic?

I had replaced steering cables on my boat once before and not only did the job suck but they didn’t last long before they were very sticky again…..less than 3 years.  I wasn’t going down that road again.  Shitty system to start with…then only got shittier.  I had driven several boats with hydraulic units on them and was quite impressed with their operation. “Teleflex” was the brand name on the units and I have seen them on many medium horsepower SeaRay runabouts and several high horsepower Hydros, Checkmates, Mirages, and one Allison.  I also know that you can get hydraulic steering as an option from both Hydrostream and Checkmate on new boats today.  I made the decision to purchase and install a hydraulic steering setup.


Purchasing you Hydraulic System

I shopped around for units and there are several manufacturers…Teleflex and Hynautic are popular brands.  They are expensive…..but don’t be shy…..they are WELL worth the price in my opinion.  About $700 or $800 for everything you will need.  I settled on a “Teleflex Sea Star Pro” unit from the Cabelas superstore in Owatonna, MN.  It features a 1500 psi hydraulic system which is higher than most….I thought that was a good idea……you know….bigger is better.  The system is rated for up to 300 outboard horsepower for single ram systems…more with multiple ram/engine setups.  It comes as a kit, which includes the helm unit (pump), hydraulic hoses (2), hydraulic oil and filling/bleed fixtures, and hydraulic ram assembly.  All components appeared to be top quality and had nice fit and finish. It also came with an adapter kit for Mercury outboards.  The kit I chose came with several choices for hydraulic hose length…..the idea is to measure the amount of hose you need to run from behind your steering helm back to where they will hookup to the hydraulic ram on the outboard.  My advice here would be to make the best length estimate you can and then round up to the next size……better to be too long than too short.  Use a rope and route it in exactly the path which you plan to use…then round up to the next 2’ increment.  16’ was the right amount for my boat…..I almost bought the 14’ kit and that would not have been enough…..that would have been a big project setback…..everything done except the hoses are too short…bummer.   I just looped the extra in a small 6” diameter loop behind the dash….it worked much better than trying to stretch the hydraulic hose…which doesn’t stretch. Now you have the kit and you are ready to start!


Step 1:  Demolition of existing cable system

Note:  Depending on your setup you may need an engine hoist for this part so plan ahead.  I have reinforced several of the rafters in the ceiling of my garage and use a “come-along” to hoist engines when I need to.


First thing to think about here is, “Am I going to try and save this old cable system for anything?”  The correct answer here is “NO, it sucks and I don’t wish this system on my worst enemy”.  So grab a hacksaw and cut the cables  near the engine and start pulling them out of their routing path  as they travel through the boat towards the steering helm….probably under the starboard gunwale.  Be careful as there are probably a bunch of other wires tie wrapped to the steering cables for support.  Release the cables from under the dash by disassembling the rack and pinion assembly, which is probably under there.  Again watch out for wires.  Remember that the free end of the cables has been cut with a hacksaw and it is probably sharp and full of grease so wrap it in a rag so it doesn’t gouge or soil your interior.  At this point you can probably save the rack portion of the helm unit if you really wanted to.  I saved mine, but damaged it removing it, so I am not sure why the hell I am saving it……I’ll have to remember to pitch it!   Now you should have the cables completely out of the boat.  Remove the steering wheel and steering rack.  Disconnect the remainder of the steering linkage back by the motor.  You will need to remove the cables from where they feed through the motor center section bracket…this is where you may need to hoist the engine to get them out from inside the splash well…this is going to depend on your particular setup and splash well design.  Its no big deal but does take some additional time to do…..unbolt the engine and move it out of the way of the interference point so that the cables can be fully removed.  If you have to do this you will probably have to do the same thing when reinstalling the hydraulic ram support bracket so don’t rebolt the engine yet.


  That should complete the demolition portion……wow….that went pretty quick!  Remember taking stuff apart is a whole lot faster and easier than putting stuff back together so don’t make boating plans for the rest of the day yet!


Step 2:  Helm installation

The Teleflex helm unit required a 4” hole in the dash to accommodate it.  There was a template in the instruction manual which I used to make a practice cut on a piece of ¼” exterior plywood.  The 4” hole was surrounded by 4 - ¼” holes for mounting the helm to the dash.  I cut the practice holes in the piece of ¼” plywood and verified that the helm unit did in fact fit nicely.  I then used some clamps to clamp my plywood template to the front of the dash and positioned it such that it completely covered the old hole and didn’t interfere with any other gauges or bezels.  Then I got out my big ass ½” drive Dewalt VSR drill with side handle and 4” hole saw.  After triple checking the location of the helm hole I bored a 4” hole in the dash using the plywood template……first through the gel and then through a ¾” thick sheet of marine plywood and fiberglass.  Hang on tight….that drill hurts when it torques on you!  Next I installed the helm unit using my ¼” plywood template as a backer plate behind the dash for additional support…..the helm unit is quite heavy and will be heavier yet when full of hydraulic fluid…..it contains a small reservoir of fluid.  Use locktite here…you don’t want your helm unit working its way loose.  You can reinstall the steering wheel here if you like….the helm unit has a standard keyed and tapered shaft on it.  Don’t bother to try and center a spoke or logo on the steering wheel or anything on the steering unit….it is impossible to do with a hydraulic system due to a small amount of hydraulic “slip” inherent in ALL hydraulic systems.….I repeat,… IMPOSSIBLE!


Step 3:  Hydraulic Line Installation

Locate the best routing channel for the hydraulic lines….there are 2.  They should be out of the way and should NOT be used to support others wires and control systems.  It is entirely possible that there is no good way to do this….without adding some support loops.  My boat only had a couple of fiberglass rings for routing wires and stuff under the starboard gunwale.  To properly support the hose I cut up about 5, 4” long sections of PVC pipe and fiberglassed them under the starboard gunwale.  After they cured, I then used these new loops to route my hydraulic hoses such that other wires and stuff did not interfere with them.  That worked real well…..spend the time to do this correctly.  I left them unhooked at the helm end at this point…..leave the protective caps on them as well….they are brass fittings, which could be damaged if banged around too much.


Step 4:  Hydraulic Ram Installation.

This is the part that took me the most time.  The reason it takes so much time is you need to MAKE SURE that fuel lines, shift cables, and battery cables ARE NOT in the way of the hydraulic ram.  This ram itself has a travel of about 6 inches both ways and it will probably tear out stuff which gets hooked on it….after all, it IS hydraulic and you probably won’t even feel it if you were to hook some wires or something else.  The ram itself is installed using a support/pivot rod through the motor center-section bracket.  You again may have to hoist the engine to get this support rod through the center section bracket.  Use this opportunity to thoroughly clean and grease this cavity before reinstalling the support/pivot rod.  Check the clearance at “full engine tilt” for the ram/piston assembly….if there are tabs on your motor bracket they may have to come off to avoid interference.  I had to cut off these tabs on my motor.  This was accomplished using a high RPM, rotary cutting tool.  It worked pretty well and with a little cleanup with a file you could hardly see the amputation.  If we wouldn’t have cut them off there was the potential to pinch and damage the ram/piston body when the motor was tilted up all the way…..not a common thing to do but may still be necessary on occasion.  Damage the ram body and I think it is nothing but expensive junk.  Attach  the ram to the motor bracket using the Mercury (or other as appropriate) adapter kits.  My kit came with Mercury parts…others needed to be purchased separately.  Now the engine and ram will tilt together as one unit…as they are attached.  At this point the engine should turn freely both ways to the stops and tilt up and down freely without pinching the ram/piston assembly.  Congratulations you are almost there…..make boating (and water-skiing) plans for the morning….then call a friend….you will need help with the next part.


Step 5:  Hydraulic Line Hookup and Bleeding

Like any other hydraulic system they don’t work worth a crap unless ALL OF THE AIR is bled out of the system properly.  Start by making the final adjustments to the hydraulic line routing and then attach both ends of them to the helm unit and piston/ram assembly.  Make sure to get them on the right way so you don’t turn left when steering right!  That would be a BAD thing!  The Teleflex unit came with 2 quarts of hydraulic fluid and a flush/bleed kit.  You will need another body to assist you.  On the helm end remove the fill port plug and attach the supply fitting and invert the fluid supply such that no air can enter the system.  On the ram end loosen the bleed nut on one side of the ram.  Then turn the steering wheel to pump fluid through one side of the system….forcing air out the other end by the ram/piston end of the system.  Collect extra hydraulic fluid coming out of the ram bleed hole by using the little extension tube that comes with the kit.  You will have to replenish the fluid fill supply several times during this process until the lines are FULL of fluid and NO AIR comes out when operating the helm unit. The instructions call for two bleed cycles….I found that about 4 were necessary when first filling the unit to get all of the air out.  It is tricky and time consuming but probably worth it to do it properly when first filling the system.  The firmness of your steering performance will depend on doing a good job here.  You will need to save and reuse the excess hydraulic fluid or you will not have enough….and apparently it is special as they say to NOT use brake fluid or transmission fluid.  Once you and your partner develop a system it will go much quicker….be careful not to spill hydraulic fluid on your carpet and seats!  Repeat this procedure with the other side of the ram/piston unit.  Verify that all fittings are tight and leak check by turning the steering all the way over to the stops and apply pressure.  Check all fittings for hydraulic fluid leaks.  If a leak is discovered…tighten and re-bleed that portion of the system.


Step 6:  Go Boating

As in any setup modifications be sure to FULLY check operation of the system and inspect prior to operating at full power.  Check everything on the trailer first and then a quick trip to the lake.  If there are problems with the system this will allow early identification before equipment damage or unsafe conditions occur.  If every thing was done properly I bet you are going to be VERY happy with the results and performance of your hydraulic steering system.  After returning my boat to the water after the retrofit I was so excited….it was like having a brand new boat….I was amazed at how well it turned and handled.  Steering problems develop so slowly that you never seem to notice them until they are REALLY bad….by then you forgot what a properly operating system should feel like.  With your new system tight maneuvering around the dock will no longer be a pain in the ass…..you can practically parallel park a boat with this type of steering system  The only thing I was left wondering about is why didn’t I do this sooner?  Good luck and happy boating!!!!! 


Donald B. Ketcham                                          

Lakeville, MN