|08-13-2019 11:13 AM|
Jr4x thank you for posting this information. I'm modifing my trail 04 Tj to run Xrock Modstock next year you originally recommended a manual chevy box. But it looks like you have since figured out that that might cause shaking issues. With me not running high speed comps and occasionally running on the street would you recomend doing the 700 dollar modified servo, or modify my current Psc assist box. Also is there someone i can send my box off to to get the correct modifications done?
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|07-07-2019 09:48 PM|
Yes I am.
That’s for another post
|07-07-2019 08:28 PM|
Are you doing anything to negate pressure still being applied to the piston inside the box?
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|07-07-2019 09:48 AM|
|07-06-2019 02:05 PM|
Part 3 (final)
And weld a fitting to the servo housing for Ďleftí turn. Of course, you will need to drill the hole, 1/4 inch or bigger, depends what you can fit between the seals without getting into the seal area. That box has a hydro fitting cut down and welded. Your going to want too reduce the heat/weld as much as possible. Warping the servo housing is a serious problem. I have gotten away with some, but other boxes seals will fail and leak. Reduce the weld area from what Iíve shown here . This is where pscís box has good Benefits as itís cast larger here, and threaded fitting inserted.
I also spent time drilling the port, to the vein along the bottom of the box. Itís difficult to drill, and Iím guessing of limited benefit.
|07-06-2019 02:04 PM|
The bottom one is not something thatís been a problem, not much restriction
However, the one on the top can be improved.
Remove 1/3 to 1/2 the crests
This double the flow
It may not seem nessary, but this is low pressure return flow, and gains here have huge effects.
-torsion bar needs to be matched to your systems resistance. Core boxes can have many different sizes. Mark the input shaft before you take it apart. It will only work assembled one way. Any other way the box will not be centered, and turn one way as soon as pressure is applied.
These torsion bars can be turned down in lathe. Iíve seen .220 to .175 in factory boxes. The thinner this easily, the easier the steering feel will be.
This end comes factory just press fit.
Weld it. Why not. Label the end with torsion bar size so you never need to take apart again.
All these mods apply to the servo, which is the same in both the external servos, and steering boxes.
Mods to the steering box
-drill the input to the biggest you can fit between the seals. Deburr after. This gets rid of the check valve in the inlet. Run an external pressure relief valve (Howe/psc)
And drill the return as well. This can be made quite a bit bigger
Drill the Ďrightí turn into the usual spot for Saginaw, tapped to 3/8 npt
|07-06-2019 01:55 PM|
Fred (fwjeep) asked me to post these for him. I am doing the same mods he has been doing so he saved me quite a bit of time even though I had spent about 100 hours on this project. He has about 1000 or more into it so I'm very glad he shared this info. Hopefully it saves time for others too. I'll split this into at least two posts.
Gotten a few questions about modifications to Saginaw steering boxes for high flow.
Been running these mods, supporting a 2.5x1.5 double ended ram, with psc 1400 pump (4.5gpm?) and no lag.
Not meaning to show how to rebuild a box, just the high flowing of it.
Take your servo and drill the left and right turn 1/16th ports to 1/8. The first 3/4 of it will be in soft steel, the last bit is through a pressed in hardened race, and carbide is the best option. (A sharped concrete drill will work in a pinch)
-this needs to be carefully deburred after. I use a grinding stone on a dremmel. Keep going at it until the inner part of the servo fits smoothly and 360* turns. Donít let the holes get to big; reaching the void between them.
The inlet pressure holes (middle ones) are big enough already.
Iíve seen two styles of inner races. Some with 4 holes for return flow, others with 8
The cross sectional area of both are the same, no need for mods here.
The next most restrictive point is when the return flow travel along the input shaft to the front of the servo. I donít have a picture of a stock piece here.
This one has been lathed to remove material behind the seal position. So splines-seal surface-piece to be turned down. Itís the area that is in the inner race of the servo. The picture below shows the finished piece. You can notice the reduction of the input shaft, as it goes into the servo. It maintains this diameter right through. After the holes drilled in the servo, this area is the biggest restriction in the box.
Once the fluid comes out of the servo housing(along the shaft) it must exit radially through what Iím calling the seal head. I have seen two different styles in the factory boxes. The left style I have found in factory Jeep Cherokee boxes, the right found in a late model Chevy.
|06-12-2019 07:24 PM|
|06-12-2019 01:30 PM|
Yes I have an Toyota ifs box that I am using in this manner.
I am using the servo that’s in the Toyota box, welded -6 fitting right to the servo housing, (left turn) and tapped a set screw into the vein on top of the box. Right turn -6 fitting on the typical place. Piston has cuts to remove the pressure differential.
I turned the torsion spring down to .200, and drilled every orfice in the box possible.
The Toyota boxes have hardened shaft and servo.
I have also done the same to Saginaw boxes, and while also hardened material, it’s much easier to modify. I recommend using a Saginaw box, or a jk/wj box
|06-12-2019 09:57 AM|
4500 vs 4800
Thank you, this is really good info! I was looking to build a 4800 over a 4500 because of the no full hydro steering rule. Thanks
|06-12-2019 09:55 AM|
4500 vs 4800
Wow, this is really good info. I was looking to build a class4800 over a class4500 because of the hydro steering rule. But this is good info!!
|06-09-2019 09:38 PM|
Did anyone ever get a IFS Toyota box to work? I'm trying to plan out my steering for my 67 Commando I'm building and I am really interested in doing this same set up. I'd run all the parts suggested. I have a 5.3 which is about the only thing other than the Toyota box that I'm pretty set on.
Thanks a ton for the help.
|04-21-2019 02:03 AM|
I have used them on a few builds. Worked great.
|04-18-2019 04:30 PM|
Jr have you tried these KRC race pumps? pricey, but adjustable output and trick..
|03-19-2019 11:14 PM|
Sorry it is a 97 TJ. I need to look at the Astro box more. I thought I had read it was for going 6" or more forward and I'm not sure I want to go that far.
My Jeep is a little different and there are some things I am trying to keep becasue of an injury. I have the Off-Road Only AiRock kit on my Jeep. It has air bags in place of the springs and is rated as a 6" lift. I'm a right lower leg amputee and being able to lower the Jeep down to get into and out of it really helps. So I have to keep stock type coil spring mounts.
What you came up with is very interesting and I liked reading the thread just for the tech. It might be something I do to my Jeep at some point. Good luck with the rest of the racing season.
|03-19-2019 07:01 AM|
|03-19-2019 06:49 AM|
Well as many others have said I have read and reread this thread 3 times to try and make sure I am understanding everything.
I'm more interested in this application for a trail/street rig. I'm not racing or anything just trying to build a bulletproof rig. Since I have never broken any steering parts other than a few hoses I don't know if this applies to me. I started reading it for the possibilities of a way to be able to push my front axle forward without having to go full hydro. But since there is still a draglink it doesn't help.
So if anyone has any input into my application I'd love to hear it. I like the idea of this and like even more the fact that it wouldn't have to worry about my thumbs getting broken or the steering wheel whipped out of my hands.
|02-22-2019 09:18 AM|
Another option is the 2005+ superduty box. They have a front facing pitman arm and are massive all around.
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|02-22-2019 09:13 AM|
Personally I have a JKU frame and some 1 ton axles and just want it to steer good on and off road. my full hydro on a buggy is great but might be more than the wife wants to daily
ie - what's the best box to use - strength/packaging/ratio
then is there anything suspension/link wise that would be recommended? 4 link, 3 link, watts link, crazy swingset stuff - also with KISS in mind.
thanks for sharing your knowledge! need more of it around here
|02-21-2019 11:45 AM|
|02-21-2019 10:54 AM|
|02-20-2019 07:51 PM|
The 4500 steering that won a national points Championship
If Iím following along correctly:
Iím currently running an Astro van box, matched custom Pittman arm to 60 hi steer arm length.
Drilled and spring modded stock tc style yj pump. Big huge cooler and filter.
Planning for a redo of the front and want to fix the steering at the same time.
I need more power in high load slow speed, and quicker reaction at higher speed stuff.
I can do a scout 2 box, to get it outside the frame rail and still have forward swing?
If sourced from PSC , it will be quicker than a stock replacement scout 2 box?
Put Astro van internals in scout box?
Iím currently drilled and tapped in the regular diy Saginaw location.
If I do the free float piston to the scout box with Astro internals, add the sweet servo, and swap to a double ended ram or larger SE ram, that would be a good start?
Thinking about one of Scott trimarcos gear pumps with external relief.
Any specific posts or threads to find that detail the free float piston mod, and welding the torsion bar in the scout/Astro box to turn it into a ďmanualĒ box?
Running leafs now, but going to a 3 link with panhard, and cutting the front frame off.
Application is trail jeep on stickies with some prerunning on the lakebed, with some street/beach time in the summer.
Thanks in advance.
|02-20-2019 03:27 PM|
|02-20-2019 03:15 PM|
Good idea on taking the cap off.
|02-20-2019 03:02 PM|
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