1992 retrofit of 1994 Front ABS

I've got a WONDERFUL Ford Exploder with 277K+ on the original engine and running gear. I came across a 1994 XLT in a boneyard last weekend and pulled the front spindles off to find ABS sensors in them, and the rest of the '94's ABS was still intact. Has anybody else attempted a retrofit of the '94 front ABS onto an earlier XLT? I'm going back this weekend to take a gander at the rest of the ABS on the '94 in the boneyard...and rebuilding the front end with new bushing, ball joints, rotors, U-joints, bearings and pads.

I've never heard of anyone attempting this.. Usually its the other way around where people are by-passing the ABS system do to problems with the HCU or sensors. It would seam to me that if your vehicle has made it this far without ABS that you're driving & breaking skills are on par or better than ABS and that it isn't necessary.

That being said in addition to pulling the ABS computer & Hydraulic control unit you need to run new 3/16" hardline and ensure it has the wiring harness connections for the ABS sensors etc. BTW the '94 ABS system uses 3 sensors, 1 on each front wheel and 1 within the rear diff. The Master cylinder would most likely need to be bench bleed, while Bleeding the HCU would require a special scan tool to actuate the solenoid values to purge any air... After doing all this work the HCU could be faulty which would leave you to find another bone yard special (since this part is $$$ from a dealer). All in all this is not a project I would undertake due to the cost and potential component failures that could occur..

Thanks for the reply, and after looking at your U-joint pallaver I need to tell you that this little side project doesn't intimidate me, nor does your trepidation. The fella that suggested this is a Ford ATS, and the '94 has only sheet metal damage on the front end. We're replacing the spindles, is where I found the cutouts for those front ABS sensors, and the rear of my '92 has a fully and correctly functioning rear ABS on it already. I've actually used that HF C-Clamp tool for U and Ball joints, that's what the additional fittings in the box or for, and it's like having a portable mini-press at your disposal.

So, don't be insulted when I tell you that this little side project, or your trepidation, does not intimidate me. And, I'll let you know it turns out...

Its not too difficult
You will need the ABS computer and all wiring.

The ABS proportioning valve and all brake lines

The knuckles and spindles with the wheel pseed senors, and wiring to them

You will want to remove your 92 RABS valve and RABS computer

Since a 92 Explorer is the same truck as a 94 Explorer, with 4WABS being one of the only differences, this is a bolt in deal.

I personally cannot stand the Explorer 4WABS system OR the earlier RWABS system, I would rather have no proportioning, no sensors, and pump my own pedal, but to each his own

ironbandit said:

...So, don't be insulted when I tell you that this little side project, or your trepidation, does not intimidate me. And, I'll let you know it turns out...

Click to expand...

No insult at all. We are all here to learn from one another and I look forward to seeing how this turns out. I would suggest you take lots of notes and pictures documenting this project so you can create a "Retrofitting 4WABS" thread. This would benefit others and potentially allow you to get a free elite membership on this site...

'92 front ABS retrofit

Progress update:

We're gathering the pieces/parts slowly, picked up the knuckles w/sensors on board, but destroyed the sensors removing them so the knuckles could be brushed/cleaned/painted. I then purchased another pair of sensors on Ebay, for <$50 w/shipping.

With highs not exceeding 40, and weekends limited by required overtime work, we're gonna tackle everything aft of the front sensors when it gets warmer, no chance for ice, and ABS really isn't necessary... :-D All that I want to get done in the next 3 weeks is rebuild the front end (BJoints, UJoints, Bushings, GearOil) with the fitments necessary for the ABS (sensors in the replacement knuckles, trigger ring on rotors). Pulling the knuckles on the boneyard '94 turned out to be pretty quick, and the old BJoints pressed out of it very readily.

Next weekend I'm off to Chicago for the IMS, and work on the front end may resume the weekend.

Later, 'mater. ;-D

Eureka, I have found it!

Update on Progress, have gotten no further aside from procuring the knuckles, spindles, ball joints (it's a DANA 28 Pinch) and front sensors.

I do not plan to do anything to the existing rear ABS, just leave it out of the wiring harness to HCU. Got a buddy who can get me the elex schematic... It's working just fine without any help from up front, and will continue to do so if I just leave it alone. We just rebuilt the rear brakes anyway, and I cleaned the RABS sensor when I had the pumpkin apart during the rear end bushing overhaul...

Progress

After looking it over, and at the behest of my buddy, the Ford mechanic, I've decided to do the full monty with the retrofit. I picked up all of the parts in the boneyard here in Southern MD for $115. That's for the ABS pump, HCU, lines to the master cylinder and the 3 lines out to the brakes, along with the hoses to the front calipers, the 1994 Power Distribution Block and the harness.

The job starts this weekend, with the replacement of the radius arm and axle pivot bushings. The I-Beams and radius arms have to come out, so I'm replacing the U-Joints and Ball Joints, but I'm fitting knuckles and spindles from a 94 in place of the originals. Whilst everything is apart, I'm cleaning, derusting and painting the parts. I-Beams and radius arms will be Ford Blue, half-shafts and Knuckles John Deere Yellow, rotors and calipers bright red. I have 3" lift springs up front that are yellow, so the spring seats will be hammered silver, to match the front pumpkin. The retrofitted hard lines are J-D Yellow, and the pump is Ford Blue. I'll clean and derust the frame and cross-member, and they'll be Ford Blue as well.

I've dissected the Power Blocks from 1994 and 1992 Explorers, and this retrofit will greatly simplify the wiring harness in the engine well...the 1994 has the fuses and relays under one cover, the 1992 splits them up. That won't be happening until I replace the timing set and water pump tho'; gotta pull the radiator out to get at the wiring harness that crosses the front of the engine well. And, I'll likely be replacing the fuel pump in the tank at the same time, so I have access to run the rear hard line for the ABS - the rear ABS unit will be removed, along with the old rear hard line at that time. So, this weekend I get the new lines on the front and to the master cylinder, with the new caliper hoses for support of the sensor lines up front. The sensors will go in with the new spindles.

I'll be back with more after this step is complete. If nothing else, this weekend will tighten the front end back up...

Forgot something...

If anyone has a line on Ford Explorer service manuals on CD, I'd greatly appreciate it.

Further progress, electrical this time.

This past week I had the water pump meltdown, and I replaced the timing set whilst I was doing the pump. With the radiator out, I installed the ABS harness that I got off of a '94 Sport in the boneyard. I also replaced the Power Distribution Block, and that's where the fun began.

I moved all of the appropriate lines/fuses from the old '92 PDB over to the '94, just by taking the yellow lock out of the PDB's and using mech probes to releases the lines. That part was pretty easy, just deciding what would be powered by what. The fuse panel in the cab is now supplied with 60A, up from the 40A in the '92. Power seats? Nope. The secondary panel supply in the '94 went to the rear defroster, which had been wholly neglected in the '94. It was in the relays where the fun started. I began by clipping the old relays out and just matching colors, but I forgot the LtGreen/Red going to the one diode, which then went Tan/Black to the EEC, Fuel and A/C WOT relays pogoing in a red line. I also forgot the black/yellows going to the A/C control grd, and the green/yellow alt field grd.

Right now, I'm waiting for a Chilton's manual, an OEM 1992 EVTM and a 1994 Wiring diagram to tie up all of the loose ends. But, she's running like a top now. Next, I'm installing the ABS pump and front lines tomorrow.

Oh yeh, and I forgot to report on the front end rebuild. Took twice as long as I planned, due the the pass side radius arm and bracket being trashed. We found a bolt unit in the boneyard, and cut the old bracket out with heat. Shock mount broke off, so we moved the good one from my old arm to the "new" one. Decided to wait on the brake installation until later, after the water pump.

More on the 4WABS retrofit

It helps if you have complete wiring diagrams, and I do now. Got both the 1992 and 1994 Explorer OEM Wiring diagrams from FactoryAutoManuals.COM at most excellent prices. Has answered a lot of questions about errant wires hither and yon. I do have pics from the front end rebuild, just haven't downloaded them from my buddy's camera yet. And, we're just about ready to cut it over to the 4WABS from the RABS. I have fed the 2 most crucial conductors thru the firewall connector (C147) that supply the ignition feed to the ABS HCU (LtBlu/Pk) directly from the internal fuze panel, and that DkGrn that needs spliced into the same color lead from the RABS HCU-it goes for the warning lamp in the dash.

I'll tellya, it helps immensely to have a boneyard with these models in it close by. You can dissect one of them to figure stuff out while your ride is still functioning. The new 4WABS Pump is in the hydraulic system, and feels to be completely bled, even without the service tech cycling the pump. All we have to do now is either replace the rear line completely, or remove the RABS Pump and place a jumper pipe in where it was. Latter avoids dropping the fuel tank, which I'd rather wait until I have to for the fuel pump. The fuel pump, BTW, seems to like the new 20A circuit just fine, where it was on a 30A circuit in the 1992 PDBlock.

It did take quite a bit of soldering to get the 1994 PowerDistributionBlock into the 1992 wiring. What's nice, tho', is Ford did something right and kept colors the same between 1992 and 1994. Pay close attention to your grounds, I forgot one and left my A/C WOT relay non-functional... and the rest of the A/C in the same shape. The 1994 PDBlock moves the 4 relays that were outside of the 1992 PDBlock-EEC,Fuel Pump, A/C WOT and the Blower.

Good progress there, I know what you are feeling. I've added ABS to a 95 Crown Vic from a 97 police model, those are four wheel ABS systems. I bought rear brake lines from two cars, R&Ring rear brake lines is no fun. I was able to remove them in halves, and then cut/flared them in the middle.

You may not have ABS module bleeding problems, not all have to be machine cycled. My 95 did, most all mid 90's and newer ABS modules have to be cycled with a special machine.

The wiring is the hardest part, now you know. I used the harness from the 97 PI, and it wasn't too bad because the newer models keep it separated well from the other wiring circuits.

More on the 4WABS retrofit

I found that the easiest way to make good connections between the 1992 wiring and the 1994 PDBlock was to use butt connectors with the insulation stripped, a piece of heat shrink tubing and a soldering iron to do the deed. I set up the iron with a 45W element and a big pyramid point end to apply the heat with. You could see the connector "change" when it reached solder temp.

I did have to flare a couple of lines, at the tranny cooler (I was doing a timing set/water pump replace in the midst of this) and the rear brake fitting on the "new" pump. Tranny line twisted off even tho I used line wrenches, and the old rear line used a larger flare nut and was too big to fit into the pump. I took a length of the rear line that I got in the boneyard and fit it into the old rear line on the vehicle, flaring the old line while it leaked. For the tranny, I got what was left on one 1992 in the boneyard that still had the radiator in it, and used a compression union for it. I did have one leak after I buttoned it all up, I'd replaced the front caliper lines and forgotten to do a final tightening on the driver's side. But after a couple of days just driving it, the pedal firmed up - I left the side ports on the pump housing loose when I switched the master cylinder over, and got a gravity bleed going there while I was assembling with the new lines up front.

Newest information on the Retrofit, is pictures. I'll include some before and after shots in my next message, with captions to boot.

Had a recent task which involved towing an empty trailer about 400 miles, and then towing it back with a '65 Comet on it. A/C was working fine, but engine cooling wasn't, had to run with the heater on full bore to keep it in the normal range, and it was sorely tested by a few mountains on I-70 in MD. The A/C didn't survive the task of towing the car trailer, it gave up and wouldn't cool a week later. Recharged with dye, looked it over during the next 2 weeks, found no sign of leakage anywhere.

I just straightened out the cooling and heating systems of both the cabin and engine. I replaced the original radiator, and cracked open the evaporator housing. I had something setting up a household on one side of the evaporator, which I initially found when I removed the blower resistor. We replaced all of the cooling system hoses after finding that one of the heater hoses was leaking over the blower resistor, which prompted the removal and ensuing discovery. Pulled and flushed the heater core, as the hoses needed to be removed to facilitate the evap housing removal.

Also had to go over the entire A/C system with the black light, after putting dye in. Recharged again today with R-134a and Sealer, we'll see where that goes.

Still waiting to do the final electrical hookups for the 4WABS. Got involved in the A/C again. After putting the dye in and recharging with sealer, I opened the evaporator housing, pulled the heater core and flushed it, and examined the evaporator for ANY sign of the dye...none such to be found. The ONLY sign of the dye is at the pressure switch assembly on the receiver/drier.

So, my next thing will be to replace the soft parts and the drier, and recharge again.

Front End Pic Question

Let me start by saying that this has been a HUGE learning experience, and the primary reason that I want to fit the 4WABS is due to an accident that I had on ice in Dec 2003. I was rolling along at less than 30MPH when I hit black ice on a slight incline down to a stop sign, where a Grand Vitara was waiting. I did the normal pumping of the brake, and the front locked every time they were applied. This happened for more than 10 seconds as we traverses the 300m to that GV at the stop. I had the Exploder slowed to 5-10MPH by the time of impact, and managed to keep the Exploder out of the weeds on either side, but Front ABS would have stopped me long before the impact.

With that said, the retrofit was still an afterthought to the replacement of the spindles...

I've got the pics of the F/E before and after, in JPEG from a digital camera. I'm trying to figure out how to insert these images into the message, and having little success! A little assistance, here?

First pics of disassembly

The job started with setting the front end up on jackstands, as you see. We then proceeded to tear the front end apart, and a high powered impact gun made it real quick. Everything had been treated with penetrating oil prior, and some parts, namely the axle pivot and radius arm nuts, had been treated all the weekdays before. So, here we go:


This is the full frontal view underneath, with all of the parts out. We started at the rotors, followed by the spindles, and there is special tool (slide hammer) used to pull the spindle off of the knuckle. The brake calipers were left intact, suspended on bungees. Check out the Performance Products 3" Lift coils, and the U-joint of the front drive suspended in the breeze... And do you see how dusty red the front and underside of the mill/undercarriage are? That was the water pump telling me it was about to meltdown...

After the spindles were off, we removed the front half-shafts, just removing the boot clamps, marking alignment of the starboard spline with the stub out of the front pumpkin, and pulling them out of the pumpkin.

Once the axles were gone, the ball joints and knuckle were next, going from top down with the C-Tool. The I-beams were then supported with a second set of jackstands, and copious amounts of torque were unleashed on the radius arm nuts and the bolts at the I-beam...getting the long bolt off of the top took creative tooling, as we did not have the correct metric socket with a deep well to grab it. We did get them off, and removed the coil springs.

Next was the shock mount nut, which came apart without difficulty...a week's worth of treatment with penetrating oil saw to that. Now, with the bolts anchoring the radius arm to the I-beam gone (oh, and the sway bar brackets came off with those bolts), we finished removing the radius arms.

Now, for the REAL Showstopper: When we removed the radius arms, on the starboard side, this is what we found:


And the bracket that this radius arm went through came out like this:


Here the fun began, Port side was fine, showing a normal amount of wear, but it's bushing was pretty well shot. The Starboard bushing was loose on the shaft and in the socket. More on this part later.

On to the I-beam axle pivots. They succumbed to the impact gun fairly quickly, and we dropped the I-beams out gently. With the half-shafts out, it made it easier, but the port side carries the pumpkin, and that we had to manhandle.

Now that everything was out, cleaning, painting and reassembly could begin. I started with what I couldn't take off, the flaking rusty shock towers.


This is the starboard wheel well, sans fender liner, as it would've gotten in the way. Scrubbed was I could off with a wire brush, shot the tower with Rust Converter, and covered it with hammered silver Derusto.


Port side, same treatment. You can see a bit of the hammered silver overspray on the frame rail behind the tower...

Now, a bit closer:


In this, not only can you see the tower, you can see the sway bar dangling in its brackets, which I welded gussets on to keep from bending, and those are Prothane bushings in the bracket. I need to get a new swaybar, the 31X10.5 tires rub this one when the steering is at the locks. A rollover in 1999 is still revealing itself...:roll:

So, this is the disassembly of it. Now that the major work is done, I think that I can do a better job documenting the rest of it.

Sorry I only have a minute to post... To use the photo feature you need to upload photos to a site that allows them to be shared. When you use a site (yahoo groups) they 1st require a viewer to be a registered member of yahoo, and 2nd they require the viewer to be on the approved member list for the group (snapfish is smiliar).. If you upload pics to putfile and other sites you can directly link them and they will work ok...