Author Topic: Hydro assist on the cheap  (Read 225515 times)

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  • Offline Rock Crawl'n
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Re: Hydro assist on the cheap
« Reply #420 on: Dec 07, 2010, 04:16:02 PM »
I was reading Fred's40 write up on his steering box mod for hydro assist on another thread somewhere in the Marlin site forum, and I'm confused as to where to tap my box. I have an '89 runner and would like to perform the hydro assist mod as well. In another thread that Fred's 40 posted, he added some info done up by a guy named Rick into his thread. Rick's info is as follows and my question are at the end of this info: Re: Hydro Assist:box and pump mods
Reply #28 on: April 17, 2005, 04:55:59 PM  

Rick posted some info for working the FJ 80 boxes. Here it is borrowed (with Rick's permission) from the Tuki build:

 I wanted to abbreviate a few differences in dealing with the FJ80 box. (Its
my understanding that the FJ-80 box is also identical to the FJ55/60/62.)


0.) Remove and thoroughly clean outside of the steering box.

1.) Center the pitman arm.

3.) Remove the pitman arm.

4.) Remove top 4 bolts above sector shaft, 14 mm.

5.) Remove Sector Shaft.

6.) Turn input shaft so internal piston moves toward input end.

IFS box - CounterClockWise
FJ80 box - ClockWise

7.) Remove centering valve, 10mm allen. (if required)

8.) Remove 4 bolts from input shaft housing, 14 mm.

9.) Remove input shaft, don't let the internal piston spin off the input shaft.

10.) Clean the housing and stuff rags into sector shaft bearings and seals.

11.) Drill and tap housing. Typically on IFS boxes, people tap one hole in the
top and then one on opposite side of the TOYODA. But I've found that the top
hole is really difficult on the FJ-80 boxes since there appears to be less meat in
the top of some of the steering box housings plus you can't drill completely
though the box in that location. So what I've see other people do and did
myself, was I tapped a hole in the end of the box. Anywhere in the end will work

12.) Clean out the shavings and re-assembly with some lube.

13.) Plumb box to ram assist cylinder.

IFS - Top/End hole has pressure when turning left,
IFS - Side hole (TOYODA) has pressure when turning right.

FJ80 Box - Top/End hole has pressure when turning right,
FJ80 Box - Side hole (TOYODA) has pressure when turning left.

Hopefully that helps you other guys when dealing with these reverse rotation FJ80 steering boxes.

My question is: 1.) Under # 11 above, Rick states that people typically drill one hole on the top and one on the opposite side of "TOYODA". From everything I have seen on sites dealing with this mod people have been drilling either on the "TOYODA" or as member Fred's40 did just off to the side of it for clearance later if the box needs to be moved forward. So, do I tap the hole on the "TOYODA" side, or do I tap it somewhere on the engine side?


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