Excellent! Glad to hear this! Can I assume from this that you're running the Windows version?

FORScan is a very powerful utility, even without the extended license. It can be very frustrating and unintuitive at times, but IMHO it is well worth the effort to learn because it can save you so much grief, time, and money.

I don't have the extended license, so I've never done ABS bleeds with FORScan, but from a screenshot from someone else that I saved, the ABS bleed function should be under the "Service functions" tab/page -- it's the page selected with the icon that looks like a large open-ended wrench. At the top, there should be a "Service Procedures" tab. I'd expect there to be a line with "ABS" under the "Module" column with a "Name" of something like "ABS Service Bleed". If you don't see that, then either you don't have the (trial) extended license properly installed, and/or your scantool doesn't support ISO 9141-2 protocol, and/or the ABS bleed function is not available for your particular vehicle.

BTW, I believe that your vehicle only has a single wheel speed sensor for the rear axle, not one for each rear wheel. So it would be worthwhile, if possible, to determine if only 1 rear wheel is locking up or both.

Regardless, if it were me, I'd be leveraging the power of FORScan, using the "Oscilloscope" tab on the page that's selected with the icon that looks like a graph, to plot the various wheel speed sensor values and perform a braking-induced wheel lockup, to see what FORScan shows. I'd be hesitant to replace the master cylinder without a bit more diagnosis, especially since you now have the tools to do that diagnosis. Having a helper (either to drive or to handle the device running FORScan) would be useful, of course.

As already stated by @pawpaw and myself, I'd also be checking for ABS DTCs. It's easy, free, and might give some insight. Even if there are no DTCs, that will help narrow the diagnosis, so please consider doing that soon. Just go to the page with the icon showing "DTC" in a big yellow triangle. A screenshot would be best, but barring that, please report back with a list of every module shown in the "Module" column and any DTCs ("Code" column) associated with each module. I'd especially like to be sure that your new scantool is communicating with the ABS system and by doing what I've suggested, it will confirm it.

If you have any issues with FORScan, just report back and we'll work through them.

 

@ Creaky - thanks for the info. I did just purchase the 12 dollar year version and installed but still do not get any ABS items in the 'wrench' Icon. I do however now see wheel speed sensors in the other one. I'll try checking those out on a short drive tomorrow. I'm still leaning towards the ABS control module proportioning valves being the issue - or - possibly the master cylinder. I do have a couple of other error codes - I'll post them all tomorrow sometime.
Also I'm guessing that the USB vLinker is not up to the task of displaying the ABS items in the wrench icon. I now have an invitation code so I'll be joining their forum and asking a few questions. On U-tube I see examples of the ABS Bleed along with a host of other ABS items using the wrench icon so it's gotta be something I'm missing.
Thanks
Jan

 

Since my last post, I looked up the info for your 2006 Ranger and confirmed that there is only 1 wheel speed sensor at the rear, i.e. for the rear axle. But you probably already know that by now.
When you mentioned rear wheel lockup, I was thinking about brake front/rear "proportioning" as well, but (A) I'm not sure how it's done on a 2006 Ranger and (B) IMHO, it still makes sense to first carefully check the operation of all of the wheel speed sensors because without them working properly, the ABS cannot effectively do a good job.

The "proportioning" thought is also partially why I asked about whether one or both rear wheels are locking up. If only one rear wheel is locking up, I think that, barring a secondary (probably mechanical) brake issue of some type, it would exonerate the ABS system and any "proportioning" that's being applied, but I'm open-minded and prepared to be proven wrong about that if anyone has a counter-point.

It may simply not be supported by FORScan on a 2006 Ranger. As a paid customer, you might have some "say" in suggesting that they add support for it for vehicles like yours, though.

We really should conclusively confirm if your 'Vgate vLinker FS' scantool is truly communicating with the ABS. In FORScan, when you go to the page with the car icon and select the "Modules" tab, you should see a list of all the modules that FORScan is communicating with. On your vehicle, this should include:

• PCM (under "PWM" branch)
• OBDII (under "PWM" branch)
• IC (under "HSCAN" branch)
• RCM (under "ISO" branch)
• GEM (under "ISO" branch)
• ABS (under "ISO" branch)
• 4X4M (under "ISO" branch)

If you don't see "ABS" (and "RCM", "GEM", and "4X4M") in that "Modules" list, then that's a strong indication that your scantool does not support ISO 9141-2 protocol. Hope that's not the case....

 

If not done already, I would pull both rear drums and check for rust, brake fluid leakage, axle leakage, ect.

When doing that, I would jack up each wheel and spin by hand looking for any side to side wobble of the wheel, checking for possible bent axle.

Any out or round or contamination can cause a rear wheel lockup,

 

Might be worthwhile to pull that ABS fuse and see what happens while you're working on Forscan. Since the problem is reproducible it should tell you something.

ABS is pretty sensitive to proper operation of all components involved. If there's no ABS light on it seems unlikely that there's an ABS problem.

 

All good points in the above 2 posts, especially the point quoted above, which got "lost" as the thread drifted into scantool/FORScan discussion. A worthy test, indeed!

Also, I forgot to mention this... Even without the extended license, FORScan allows you to control the ABS pump motor and the ABS inlet/outlet valves. It's one of the least intuitive user interfaces I've ever encountered, but it works. In fact, in theory, you could bleed the ABS by manually manipulating the valves and the pump in the proper sequence, even though it would be rather difficult and error-prone.

 

Again, thanks so much for the time and effort.
A few things:
Rear brakes - I did pull the drums to check things out, the passenger side wheel cylinder was leaking for what looks like a long time as everything was coated with brake dust with a touch of fluid added. The wheel cylinder has since been replaced and the entire area well cleaned.
On the drivers side the bleeder screw was frozen so that wheel cylinder has been replaced as well. Both brakes have been bleed using a suction bleeder - seems to work ok.
The issue persists - when braking suddenly the driver side rear skids - I need to somehow see if the passenger side skids too - not sure.

Tried pulling the fuse - ABS solenoids - 30A - Forscan did detect the fault but in driving the truck the brake locking did not change - a sudden brake yields a skid.

Forscan - I joined their forum and posted my issue - they replied: I need to gather a debug log that Forscan creates, zip it up and send to them.
I'll be doing that later today 8/13, I'll also be checking the O'scope screen in Forscan and see what I can see for wheel speed sensors while driving.
Where I live I have a large grassy area - I'm going to have the wife see if she can see which wheels lock when braking hard.

I'll be sure to post all my findings - again thanks so much for the support !

Jan

 

You get an attaboy for not tossing any more parts at this problem on a hunch & beginning to do a proper diagnosis sequence although a bit out of order.

Having found the leaking wheel cylinders also called for replacing the rear brake shoes, as brake fluid on them will soak into the friction material & can't be cleaned up, so probably why the problem is still there after cleaning, pulling the ABS fuse & driving, as wheel lock up is a sign of brake fluid contamination of the friction material, so also replace the rear shoes on Both sides with a good quality product & retest with the ABS fuse removed & let us know how it goes.

 

Do as the pawpaw said. If the problem still persist, which it most likely won't, move the brake drums to the opposite side then drive to see if the sliding wheel follows the drum. You could possible have an out of round drum.

Do as posted above first, as the shoes need replacing after being wet with fluid.

 

Ok - I'll replace the shoes - not terribly expensive anyway and I'll then have 'new' brakes all they way around.
Also on my 06 Ranger there are NO brake hoses going to the wheel cylinders - each has the brake line going right to the cylinder.

Regarding shoes - are Autozone expectable? Napa ? The ones on there were from Autozone installed about 4 years ago - They still had over 1/2 of their material in tact.

Regarding drums - they were replaced about 6 years ago, I do not get even the slightest pulse so I don't think an out-of-round drum is the issue.

Regarding brake lines - when I replaced the wheel cylinders both lines broke off - I repaired using a copper-nickel line piece and a couple of brake union couplings. I am able BTW to do a double flair connection.
Thoughts on the copper-nickel line ? I rather like the original Ford coated steel lines but frankly they are a bitch to work with - taking several tries to get the ends right.

I've just downloaded the latest Forscan app and getting ready to check the wheel sensor speed.
Again thanks for the info. I'll be sure to post everything I find.

Personally I'm betting changing the rear brake shoes will not have any affect - we'll see...

Other: Frankly this truck does not owe me a dime - spending a few bucks on it is money well spent. Still runs great with just turning 80k.

Jan

 

I've forgotten to ask, when the wheel lock up occurs do you feel any pulsation of the brake pedal?

 

No pulsing whatsoever.

Jan

 

I've only had my ABS go off once, on an icy road, and the sound that the pump makes is very audible. The various service bleed videos have good examples. A pretty harsh buzzing noise.

I notice that you seem to be talking about the wheel locking up on gravel or grass. Is that the case? And how fast are you going when it happens? I'm not sure that ABS is meant for slow speed skid control. You might be expecting too much.

Besides that, there should be codes or the ABS light. Does the ABS light come on when you turn the key on, before you start the engine? The reason all of the dash lights illuminate before starting is so that the operator can verify that the bulbs aren't burned out. Maybe you do have an ABS problem but the bulb is bad.

 

Ok, that suggests the ABS system isn't causing the wheel lock-up & more likely soaked in brake fluid of the shoe linings is causing it, so those linings at least belong on the suspect list.
It's common good practice to replace the linings in a situation like you found.

 

Info: when I first turn on the key all the lights including the ABS do light momentarily, and then go off.
The wheel locking was first noticed at highway speeds 55+ when applying the brake suddenly - got worse with time. I do know what the ASB feels like when it kicks in and that was not happening.
No ABS light(s) come on when the wheel locking occurs.

Regarding brake shoes: are NAPA ones acceptable - they seem to be the least expensive - secondarily: Autozone ?

Thanks
Jan