Bkennedy's SAS and Rebuild Thread

As some of you know, I am working on building a parts list for a shortened Dana 44, long radius arm with coil overs SAS. 5:13 gears to match my rear axle and an ARB, maybe an electric locker. I have a pretty good list so far. At the same time, I am going to swap out the rear drum brakes for discs off of a 99 Explorer.

Please note: The plan is to keep this project as simple as possible with mostly off the shelf parts. I am not a fabricator, just a decent welder with a what I would consider the minimum required tools (chop saw, cut off wheels, air tools, welder, etc.), who likes doing his own work. Your opinions are welcome, but what I really need is technical advice. I have been thinking about this for several years and now have the time and cash to make it happen. Please keep on topic with your advice and don't go off on a side track about how you would do it as a four-link, or caged arms, or leave the axle full-width because that is not what I want. I want a simple-ish set up that works.

 

[gmanpaint]

Yes, the HCU is the abs pump unit.

I like the idea of using an F-150 master. Almost did that in the 2nd gen when I was having peddle issues. I was afraid of the booster working or not working, and getting the push rod set right. I settled for a new Ex master. I think the fittings match on the F-150 pump, but I would check to make sure.

So here is what I found (the hard way) out about deleting the ABS pump and adding a Prop valve to compensate. .... The stock prop valve is set for a minimal pressure block. The aftermarket Prop valve must match the stock pressure setting or you will have peddle issues. I installed an adjustable prop valve, so it was a simple matter of turning the knob to lower the pressure. I thought it was the MC, then the booster, then the calipers, and lines. I replaced pretty much everything on the entire system before I learned it was too much pressure to the rear.

Too much rear pressure will cause leakage from one chamber to the other inside the MC, and cause the soft peddle, or a complete bypass and peddle drops to the floor. When this happens, it takes a few seconds for the system pressure to stabilize, and the peddle returns. If there is a weak spot in the push rod plunger seal, the fluids will leak here with too much back pressure. Hard to spot this leak sometimes, as it empties at the booster.

Edit: I am tempted to remove the prop valve and run without. The pressure amount used is very small, and it still worked fine with it as low as it would go. I did a simple test with vice grips, and gently closed the soft lines before the rear calipers. Tested it, and found the soft peddle issue was gone. Removed them, and the soft peddle was back. This is how I learned the pressure was too high. Sounds weird, as you would think there is more pressure by doing this, but it actually just stops use of the rear chamber in the MC. Try it, but use care not to crush the soft lines. Just a little squeeze is needed.

 

[BKennedy]

I'll return the leaking MC as its still under warranty, then try the F-150 MC. If that doesn't work, I can go with the new 99 MC. The only issue I was worried about with the F-150 MC is that it is for a disc front, drum rear setup. I already have a adjustable proportioning valve in the rear line.

 

[gmanpaint]

Sorry for the long winded posts.

I have been learning tons from you with this thread, and I guess I was excited I finally had something to contribute, and went overboard.

Hope the F-150 MC works as it is still something I'm interested in doing.

 

[BKennedy]

gmanpaint, your posts are helpful and not long-winded at all. After I get it back together, I plan on pinching off the line if I have any more pedal issues to see if that is the problem.

Got it all apart today. Did a bunch of routine maintenance before (oil/filter, fuel filter, oil pressure switch). F-150 MC has the wrong size fittings, and the piston is actually smaller in diameter than the 99 Explorer MC. It does bolt right up to the booster, but the outer diameter of the MC where it fits into the booster is also slightly smaller. Larger diameter piston means more hydraulic force / pressure. I am going to replace the 99 MC and see how that works. I spoke to a guy who does disc brake conversions on early Broncos and Jeeps. He says what I have should work as long as the bore of the piston is over 1" diameter. The 99 MC is 1-1/16"

 

[BKennedy]

Turns out the MC is not under warranty so I am free to purchase what I want. I was looking at the NAPA super supreme, or whatever they call it, MC to try one of those as the AutoZone MC's do not seem to be of any quality. I have never had good luck with them. Anyone have any experience with NAPA MC's?

I have put the Explorer on hold for now, might get to it in a week or two. My father is losing his battle with liver cancer and I need to be at his house most of the day/night.

 

[Stic-o]

Brian,

Very sorry to hear about your father's health deteriorating further. I remember you telling us about him at TDS. Please give him our best, as we have always enjoyed his company on all of the runs. Please let us know if there is anything we can do.

All the Best

 

[Kirby N.]

Hey Brian I have been reading your whole build this morning. Did you have to build a new tranny crossmember with the duff arms? Did they interfere with your stock one? I am trying to decide if I should start building one now or if I can get by with the stocker and build one later.

 

[BKennedy]

Thanks Steve. He is sleeping and only wakes up briefly. Not eating or drinking. Won't be long.

Kirby, the cross member was originally made when the 700R4 trans and NP231 transfer case were installed. Its slightly in front of the Duff mounts. The bolt heads miss the arms by a fraction at full stuff.

The frame where the Duff mounts ended up is double-walled. Instead of sleeving bolt holes I just welded the mounts directly to the frame.

 

[5spdman]

Everything takes a back seat to family...

Sorry to hear about your father Brian. Know that we'll be keeping you, your father and your family in our prayers.

 

[BKennedy]

Everything takes a back seat to family...

Sorry to hear about your father Brian. Know that we'll be keeping you, your father and your family in our prayers.

Thanks. Sarah already asked if she could move in with her grandma so she doesn't have to be alone. What a great kid I have.

 

[RockRanger]

Sorry to hear Brian. Always enjoyed your parents at Truckhaven.

 

[GRNMACHINE]

Thoughts and prayers for you and your family Brian.

 

[BKennedy]

He passed quietly about 45 minutes ago.

 

[james t]

He passed quietly about 45 minutes ago.

Sorry to hear it. You and your family are in my thoughts tonight.

 

[Kirby N.]

I am sorry brother. I will remember you and your family in my prayers as you morn and remember.

 

[Stic-o]

So sorry to hear Brian. He was a great man and will be missed dearly.

 

[BKennedy]

So sorry to hear Brian. He was a great man and will be missed dearly.

Thanks to everyone. I know I will miss him every day for the rest of my life. Its been busy with meetings but should settle down next week.

I have a master cylinder question. Yesterday, I picked up a Napa MC. It is a little longer than the Autozone version and has the line fittings reversed (bigger diameter fitting on rear instead of front). No big deal to swap them as I have a double ferrule kit, but what the heck? I also looked at one for the Sport and it has a much larger rear line fitting. Don't front brake lines always go on the front fitting of a MC?

I did some research and found my question above to not be accurate. Does anyone know with a 99 MC which fitting do the front and rear brake lines connect? On the 94 it was front to front.

 

[gmanpaint]

I'm so sorry for your loss. This is one of the hardest things to go threw in life. My sincere condolences Brian.

As far as the MC fittings, I thought all the MC's were the same with the front to front fittings and the rear to rear fittings. This front to rear fitting issue is new to me. :scratch:

 

[Stic-o]

I know we talked Brian, But for future reference to this thread, the MC on the 99 goes through the ABS module then to the actual brakes. The Module splits the front left and right and rear is single till the rear axle.

 

[BKennedy]

So the rear line coming off the master cylinder goes to the rear brakes? Or does that go through the ABS stuff as well?

I think it all goes through the ABS stuff, since if I remember correctly, my 94 did the same thing.