View Full Version : Porting a 79 bronco ps box for hydro assist

m j
12-30-2008, 02:01 AM
or maybe HOW NOT TO DO IT :) we will see.

I have never had one of these apart before and have no clue how they work so any corrections you have to add feel free to jump in.

First image is the victim.

m j
12-30-2008, 02:03 AM
Center the sector by spinning the input all the way right,
and then counting revs all the way left, divide by 2 and turn right that many turns (about 1 Ύ – 2 turns)
then remove the two sector cap bolts, they are Ύ”
soft hammer smack the sector shaft up (peer inside to make sure you did line the teeth up with the slot so it comes out)

m j
12-30-2008, 02:04 AM
Now you can remove the four 9/16 bolts from the spool valve section.
Give it a whack to loosen it off but do not yard it off yet.
You want all the guts to come out now in one piece, so don’t let the input shaft turn as you pull the spool and piston out of the housing.

m j
12-30-2008, 02:05 AM
There are 28 little balls that will fall out if you let the input spin so best to do that on the bench in a pan

m j
12-30-2008, 02:06 AM
You can take the ball guide off now

m j
12-30-2008, 02:07 AM
There is a rubber O ring under the telflon seals

m j
12-30-2008, 02:07 AM
Now the fun stuff.
There is a little set screw that has to come out, and then you can remove this lock ring, I hope you have a spanner type wrench that fits it so you don’t have to bash it like I did.

m j
12-30-2008, 02:08 AM
The spool should slide out now.
Notice the 4 seal bands and I added what I think each area does

m j
12-30-2008, 02:09 AM
You can remove the input seals now

m j
12-30-2008, 02:10 AM
I ran some dental floss through the 5/32” holes that feed the pressure to the power steering piston to show the grooves you have to intercept for porting the box at the spool. Kind of amazing that your assist is through such small passages.
And a couple of images a few inches back to give you an idea where the passages are

m j
12-30-2008, 02:11 AM
This is the 11/32” drill bit that you would use to tap for 1/8” npt

m j
12-30-2008, 02:12 AM
I got one dead on, and the other close with a 5/32” drill bit.
From the input side I measured 1.375” to the first groove and 2.175” to the second one.
I then of course second guessed my self and marked it at 2.125”.

12-30-2008, 03:02 AM
thats a different way of doing it. hopefully you got the holes in the right passage ways. im guessing you didn't want to drill and tap the housing so you didn't have to dissassemble the whole thing?

what if i told you there is actually 29 ball bearings.... would you sleep at night?

m j
12-30-2008, 03:09 AM
what if i told you there is actually 29 ball bearings.... would you sleep at night?

I think you would have to change the "is 29 ball bearings" to "were 29 ball bearings" :)

obviously I havent been sleeping at night lately its after 2am now.

this is where the Pros port it. I thought "Hey if they can does it why wouldnt I be able to does it"
and I think I am about to find out why I cant :)

oh and this thing leaked from every seal so it was done anyhow

12-30-2008, 11:27 AM
Did mine some time ago but never install it ,broke to much other
stuff . Nice pics. ,both tap points on your input shaft houseing ?
Did mine 1 on input housing and the other on end of the main box.

m j
12-30-2008, 05:07 PM
opening up the passages.
I had to shorten my tap a couple of times to get threads to the bottom of the drilling.

m j
12-30-2008, 06:08 PM
1/8 npt to -06 JIC steel fittings installed
now to finish the rebuild

12-31-2008, 02:30 AM
Very nice .... can't wait to see how it all turns out [cheers]

m j
12-31-2008, 03:35 AM
it is all back together
except for, I dont know how to set the sector shaft preload screw on the top
once that gets set it should be ready to run.

12-31-2008, 03:36 AM
sounds like a cool build. let us all know how it works out for ya

12-31-2008, 10:04 AM
Wow, jeeps are so much easier to do that too, did mine and wont ever look back, works fawkin awesome.

m j
12-31-2008, 11:11 AM
Jeeps use saginaws dont they?
I chose to do this one the hard way
there are several flat surfaces that work just fine if you want to drill in the housing body
I think there are about 20 pics of people doing ford boxes different ways on pirate, I just liked this way the best.
dunno if it really makes a difference where you do it, but having both your ram and the stock piston fed by a single 5/32" passage vs having each getting a 5/32" passage was worth the effort.
I had to fully tear it apart to fix all the leaking seals anyway as this box is an original 1978 vintage and was very wet

this is how PSC does chevys and Jeeps. same way they do fords. same way I just showed.

01-02-2009, 06:11 PM
nice placement on the ram assist ports. most are pointing in different directions which make it hard for a clean install :cool:

m j
01-02-2009, 07:32 PM
nice placement on the ram assist ports. most are pointing in different directions which make it hard for a clean install :cool:

I noticed yours are done real similar to the PSC Jeep ones I posted above.
you moved the one on the left to below the one on the right.