Swapped explorer rear into 1998 ranger, brakes super soft

[Kiffmans]

I recently put a 8.8” axle from an explorer into my 1998 ford ranger 4WD, it had 10 inch drums before, now it has the explorer rear disk brakes. got the explorer brake line to connect into the rangers line, all seemed well. Until I road tested it, the pedal is very soft until the last 25% or so of pedal accuation, at 75 percent to 100% brake pedal accuation the brakes work wonderfully, but the pedal is very soft up to that point. Do I need to swap my master cylinder for an explorer one?

 

[Brain75]

does a '98 still have RABS? sounds like classic RABS issue... but I don't remember what year Ford went to full ABS...

 

[Kiffmans]

It does have RABS

 

[Kiffmans]

does a '98 still have RABS? sounds like classic RABS issue... but I don't remember what year Ford went to full ABS...

It has 4 wheel abs my bad

 

[19Walt93]

You need a master cylinder for 4 wheel disc brakes, calipers need more fluid volume than wheel cylinders.

 

[Kiffmans]

You need a master cylinder for 4 wheel disc brakes, calipers need more fluid volume than wheel cylinders.

I’ll try it and let you know, will an explorer master cylinder work?

 

[JoshT]

I’ll try it and let you know, will an explorer master cylinder work?

Yes. In fact, it's recommended master cylinder for the swap. Front calipers are practically the same between the Ranger and Explorer, you installed Explorer rear brakes. Where the braking system is concerned, aside from the ABS module, you are practically driving an Explorer now.

 

[Kiffmans]

Does the explorer master cylinder bolt right up ?

 

[JoshT]

It should. "Bolt patter" where it mounts to the booster is the same. Tube fittings should be the same, but I can't guarantee it.

 

[scotts90ranger]

Although I'll agree it's the best solution to change the master I've been running the Ranger master on my '90 (with disc brake Explorer axle) for a bunch of years and the pedal feels just fine. My best guess is there's some air trapped in the ABS valve/motor thing

 

[JoshT]

I aree with Scott. It's definitely worth trying before spending the time and money on replacing the master. If you didn't do it after installing the axle, I would get some help and try a flush and bleed on the brake system before changing anything else. If the cause is not bleeding then installing the Explorer master will have the exact same result.

 

[Shran]

If you never let the master cylinder run dry, you would not have introduced air into the ABS valve. Can you confirm that the master cylinder didn't run dry during your rear axle install?

If it never ran dry, my best guess is that you have air trapped in the rear somewhere and need to continue bleeding your rear brakes until you get it out.

I used a 1992 Explorer master cylinder on my '86 Ranger when I did an 8.8/disc brake swap on it, and I think I used a '97 Explorer master cylinder on my '88 when I swapped axles... my '92 Explorer also was converted to discs and I didn't change the master cylinder at all. All three of them work great - I can't tell a difference on the '88 where I used a master cylinder that was designed for disc brakes. Some of the tech articles on 8.8 swaps recommend doing that but I'm here to tell you that it doesn't matter much.

 

[don4331]

If you get air into the ABS module, it is a royal pia to get it bled (you get air into the ABS "pump" and you need to cycle it to get the air in it out.