Hydro Assist - "How To" Writeup

[robselina]

Hydro-Assist for Dummies

I spent a lot of time researching how to do hydro assist on my 81 Wagoneer and I?m hoping I can make it substantially easier for the rest of you IFSJA folk who want to do this mod

Tools Needed:

Assorted Wrenches (5/8, 11/16 and 3/4 were the most used)
Large set of Channel Locks
Drill
7/16" Drill Bit
Two (2) 1/4" NPT Taps
Not needed, but useful: 1" hole saw, welder, grinder, 5/8" drill bit, 5/8" tap, 9/16" drill bit

Materials needed:

2x8 Hydraulic Ram - I used a Lion 2500 from Northern Tool. A 1.5x8 may be more appropriate for people who drive a lot on the street. I?d suggest you look into a ram that has heim joints at the ends instead of large pins like mine does. They?ll make installation much cleaner IMHO.
Two (2) 1/4" NPT to 3/8" pipe adapter
Two hi-pressure lines with 3/8" fittings at each end. One female and one male. Make sure one end is a swivel type end.

Background:

Here?s a little background info on how the system works. Below you can see a diagram of the steering box internals. Note the locations of high pressure when turning left or right.



Basically you want to tap into a spot that will give you access to this pressure to push the ram in either direction. Here?s a diagram showing the locations of where to drill and when they apply pressure:



The exact tap locations are more visible in the picture below:



The left pressure tap is centered on the seam of the box, the right pressure tap is identifiable by a small spot weld at the end of the housing where the red arrow is pointing.

[ May 16, 2004, 09:58 PM: Message edited by: robselina ]

[robselina]

Procedure:

1 - Remove the box from the vehicle. Note: The pitman arm does not need to be pulled.
2 - Turn the input shaft all the way to the right. Do not force it once it reaches its internal stop. Remove the steering shaft assembly from the input shaft of the steering box. Note: The bolt that holds it on must be removed completely, not just loosened. If you try to manhandle it off, you?ll ruin the splines.

3 - With the steering shaft assembly removed, it should look like below:



You need to remove the large nut visible in the picture. This is best done by bolting the box down to your bench or some similar method of keeping the box from moving. I used a set of large channel locks, but you could use an appropriately sized wrench if you have one of course.

4 - With the nut removed, the input shaft assembly should be removable. It threads out and then slides out as a complete assembly as shown in the pictures below.





If you peer into the box at this point you should see the end of the worm gear:



DO NOT REMOVE THIS. LEAVE IT BE. Make sure it is turned all the way in and just leave it alone.

[robselina]

5 - drill a pilot hole at both the locations discussed in the background section. Make sure not to drill through the box on the right pressure port. Also try to catch as many of the shavings as possible as you go. I found that having a helper with one of those magnetic parts finders catching my shavings to be a great help. When drilling the left pressure port, be careful not to drill too far and damage the worm gear end.

6 - drill out the locations with the 7/16" drill bit. Try to go down to the end of the port on the right pressure port. This will give you enough thread when you tap it so that the fitting is sitting in there securely. The left pressure port is pretty straight forward, just be careful towards the end about hitting the worm gear end.

7 - Now you?re ready to tap your box. You?ll need a 1/4" NPT Tap for this job. Note that a 1/4" NPT tap is rather large, since it?s related to pipe diameter. It?s NOT a regular 1/4" tap. Taping the box is easy, just start threading it in by hand, then use a socket wrench or pipe tap wrench. Use plenty of taping fluid and take your time. I go 1 turn in, then back it out 1/4 of a turn. Once the first tap has bottomed out, you?ll need to find a way to tap further down the hole. They supposedly make taps for this purpose, but I couldn?t find one so I simply cut off the bottom of a second tap as you can see below. I did this with an angle grinder.



8 - Next clean off any shavings you can with the magnet. These shavings will ruin your pump if you leave them in the box, so take the time to get rid of them. After you?ve got as much as you can with the magnet, I used brake parts cleaner to flush out the rest. Cleaning out the shavings in the main cavity (below the left pressure port) is relatively easy with one caution: do not let the worm gear turn out. If it does, it will loose it?s ball bearings and you?ll be stuck with rebuilding your box. Don?t let it tun out and you won?t have any trouble. The right pressure port can best be cleaned by forcing fluid through a small line into the main cavity. If you look closely, there is a small line going through, and forcing material down it to the main cavity allows you to clean it out with ease. I mounted the box with the cavity facing down and then shot a lot of fluid at the right pressure port (making sure that the worm gear doesn?t slide out of course). I used about 2 cans of brake parts cleaner doing the cleanup inside the box.

9 - Reinsert the input shaft assembly and tighten down the lock nut. The box is done! At this point, it?s time to visit NAPA (or anywhere else that sells hydraulic lines and fittings). I?m pretty sure all the hoses I got were had 3/8" pipe fittings, but the best thing to do is drag the box and ram down there and get the right fittings without any guess work. Make sure you have the female end with a swivel connector. A friend of mine forgot this and had to turn his hose 10 turns before installing it so it wasn?t all twisted up when he was done....I?d suggest you get 90 degree fittings on the ram side, they come in handy and don?t interfere with the steering assembly as much. This was pretty much the case with every location I considered mounting the ram at. Also be sure to allow enough length for suspension travel. Mine were 2ft and 3ft long for reference.

10 - Assemble all the hoses, connectors, etc on their fixed ends, so you only have to do two connections once everything is on the vehicle. This will make life a lot easier. Make sure to use teflon tape, around 4 turns to prevent leaks.

11 - Remount the box on the vehicle and mount up the ram in whatever location you decided upon. My installation is shown below.



Here?s a close up of the mounting points and hose assemblies.





Now you?re probably wondering what?s going on with the mount on the knuckle. I drilled the knuckle out with a 5/8" bit. I then had a machine shop drill and tap the pin for the ram for a 5/8" bolt. I intend to use grade 8 hardware for this bolt, even though it?s not visible in this picture. This is my ?fuse? for the system. I have a spare pin that?s also been drilled/tapped and I?ll cary an extra bolt too. This way if it blows I have a trail spare that can be on in five minutes. I?ve seen knuckles fail before with hydro assist setups and I did not want to be in that situation.
As for the axle housing side, I used some 3/8" flat bar I had lying around, drilled a 1" hole though it and welded it up.

12 - Once everything is mounted up, you?ll need to bleed the system. This is done by turning the steering left to right with the engine off. I had the front axle up on jack stands so this was very easy to do. It took a good 50 turns, lock to lock, to get all the air out of the system. Keep topping up the power steering pump reservoir of course during this procedure.

13 - Fire it up and check for leaks! If you don?t have any you?re set!

[robselina]

Driving Impressions:

Okay, no mod is perfect and this one falls under that same banner. Overall I?m very happy with my setup. Here?s the skinny. Good: steers like crazy, no effort, no matter what your tires are up against. Bad: steers kinda slow. Maneuvering around parking lots and the like can be a little hard, since you have to let the system turn at it?s own speed, you can?t make it go any faster. If you use your rig as a daily driver, you can do two things to remedy this: get a high-flow pump or modify yours for high-flow, or go with a smaller diameter ram, say a 1.5x8. I?m leaving mine be. It?s ?good enough? for my use.

Costs:

- Ram $70
- Hoses $50
- Misc. Fittings $12
- Two Taps and Tapping Fluid $15
- Brake Parts Cleaner $6
- Scrap metal and paint - $8
- Teflon tape and bolts $8
- Taping pins (@ Machine Shop) $20

Total cost: $189

If anyone has anything to add/correct to this please let me know, and I?ll edit what?s above. I think this was actually a pretty easy mod once I knew what I was doing, and if we just spread a little info around, it could really help some folks out.

Cheers,
Rob

[robselina]

One last note:

You can get these little plugs that thread into the taps you made on the box and the ports on the ram. I picked up a pair of 1/4" plugs for less than a buck a piece. Keep these in your tool box incase you have a failure on the trail. That way you can just remove your two lines fromt he box, put in the plugs and you're good to go with stock power steering.

[youngjeeper]

you tha man rob!!! thanks!! lol i JUST sent you a PM about this an hour before you wrote this..

[robselina]

Originally posted by youngjeeper:
you tha man rob!!! thanks!! lol i JUST sent you a PM about this an hour before you wrote this..

LOL. Just checked my PMs, I think I covered your questions

[Merc69]

Thank you

[Lister]

Great writeup! Now the question for the less knowledgeable...what's the advantage?

[robselina]

Originally posted by Lister:
Great writeup! Now the question for the less knowledgeable...what's the advantage?

do you do much rock crawling? looking at your sig, you're locked out back but not up front. Basically, if you're locked up front, have big tires or mess around on rocks a lot, you'll notice that the power steering doesn't cut it sometimes and you just can't get the wheel to turn when you need it to. The ram helps you out and lets you turn regardless of whats in your way. You can literally park the jeep next to a brick walll and push yourself off it by turning the wheels against the wall. This is completely effortless with the ram. I sprained my wrists more than once tyring to get this sucker to turn! not going to happen anymore!

[Lister]

I certainly do, do rockcrawling and have been in that same situation more than once. I'll certainly put this on my list of upgrades. Thanks.

[some guy]

Very cool. Thanks.

[Elliott]

Nicely written, I was wondering how to keep the shavings out of my system ifn I was to tap my own J20 box.
Thank you!

[HeepofaJeep]

Looks good! Good, simple write up too.

Do you think having a resvoir for the power steering fluid would help at all?

Again, excellent writeup!

[ May 20, 2004, 07:55 AM: Message edited by: HeepofaJeep ]

[robselina]

Thanks guys!

Originally posted by HeepofaJeep:
[QB]Do you think having a resvoir for the power steering fluid would help at all?
QB]

I'm working on increasing the bypass pressure at the pump first. This is often done to increase flow from the pump. It's an easy mod and if it works, I'll add it to this writeup. If that doesn't do the trick, a remote reservoir will definitely be the next step.