Mustang Rear Disc Question

[jleas524]

I have a 94 2wd, super cab ranger Splash that I am upgrading the brakes on it.
The fronts have been converted to '95 2 piston disc brakes.
I am working on the rear now. Plans are to install Mustang rear disc set up.
The ranger does not have ABS.
Who has done this conversion and what are your results?
Do I need to proportion the line to rear for the disc brakes or do I need to change to a different master cylinder?

I'm upgrading the brakes now because a V8 swap is in the near future.

 

[RonD]

1994 Ranger should have RABS

If its been disabled/removed then yes add an Adjustable proportioning valve to rear brake line, they don't cost much more and then you can adjust how much rear brakes you get now and with rear discs, and also if you drive with canopy on and/or with tools in the bed most of the time

 

[rubydist]

I have done it twice, both on a 28 spline 8.8 Ranger and more recently on a 31 spline torsen 8.8 Ranger.

The 28 spline takes a rear disc setup from a Mustang as described here: https://www.therangerstation.com/tech/ford-ranger-bronco-ii-rear-disc-brake-conversion/

The 31 spline takes a rear disc setup from a 2005-2010 Mustang which is available in a FRP kit that is labeled as being for a 9" axle. I had to do a little clearance modification to the caliper bracket to make it not rub on the disc, but otherwise it just bolted right on.

In both cases I did not make any changes to the master cylinder or to the proportioning, and the brakes function just like they should. If you get on the brakes real hard with an empty bed, you can get some chirp from the rear tires before the abs kicks on, just like with the drum brakes. As Ron suggests, without abs you might consider an adjustable proportioning valve so you don't have the back end trying to get ahead of the front end.

 

[don4331]

There are a couple things;

1. Improved braking:
As @rubydist alludes, Mustang discs aren't really upgrade - they both will just barely lock up rear wheels when you stomp on the pedal.

They are upgrade in so much as they work more reliably - most people don't do any maintenance on their drum brakes and as result they aren't working. Functioning discs are much better than non-functioning drums.​

The Mustang calipers were designed to engage the parking brakes using arm strength. On Ranger, you would set up the parking brake to be foot activated. For most people their legs are much stronger. So, parking brake function works much better on Mustang brakes.​

​

On other hand, Explorer discs ('95-02 Explorer axle swap) are a significant upgrade

Rotors are 1-5/8" larger diameter than Mustang V6 ones (same diameter as the GT rotors)​

Calipers pistons are much larger (48mm vs 38mm) <- This is real upgrade (60% more pressure)​

​

2. Pad wear

Drum brakes have a couple substantial springs to pull shoes off the drum. As a result, there is a pressure valve in the line to keep 10psi on the line (prevents the shoes from completely retracting, so brakes come on sooner). Disc brakes don't have the same springs, so don't need the same pressure - stock setup for discs is 2 psi.​

If you don't pull the pressure relief, your pads will wear like crazy. (In many 30 year old vehicles the spring is shot, so doesn't keep pressure in the line, which contributes to drum brakes no working like they should)​

The engagement of the parking brake "adjusts" the pads on the caliper. As the parking brake is applied with more (too much) force in Ranger set up, the pads tend to have to "wear" a little each time they are applied before they completely release. More so if they were engaged....firmly. Again contributing to pad wear. My son had issues with pad wear in his Mustang as he overly engaged parking brake, but then he is very big boy.​

​

The Explorer disc brake set up uses a "drum in hat" of the rotor solution. This was designed to be used with the same foot pedal as the Ranger. So, it...sort of works (about same as your Ranger parking brake worked).​

​

With '94, you might not be using Explorer as donor for the V-8. Otherwise I'd be pointing out you would be getting Explorer brakes as part of the swap.

 

[mikkelstuff]

I wrote a journal article with photos when I did the Mustang rear disk brake upgrade to my 2002 Ranger. PM me with an email address if you would like a copy.

 

[sgtsandman]

One thing to note with the Explorer brakes, the 2010 & 2011 Rangers share a similar. The parking brakes are NOT auto adjusting. Like trailer brakes, you have to MANUALLY adjust them from time to time.

For what it’s worth, I would make sure your existing brakes are in top working condition rather that “upgrade” to discs. Being that I have two trucks with rear disc brakes, I haven’t seen any benefit to having them. I’m sure in certain applications, they are superior to drums but I haven’t seen it.

When it comes to maintenance, yes the drums are a huge, frustrating pain the rear to work on when they need it, many years in the future.

Discs, while less so, need maintenance much, much more often to keep them operating properly since they catch all the road spray from the front wheels.

And you have to deal with rotors rusting out much sooner than you do with drums.

If you are fine with that, I wish you well.

 

[rubydist]

There is no such thing as a "pressure valve" that holds pressure in the brake line. It is actually a check valve. With the heavy springs on the drum brakes, you will possibly have about 10psi in the line, but that is due to the springs trying to retract the shoes, not a "pressure valve". It turns out that the disc brake pads do not need to move off the disc very much, so the existing check valve works just fine for the disc setup - that is why no changes are required to the master cylinder when you make the change to rear discs. And since the braking force is about the same between the disc and drum setup, no changes to the proportioning valve are required.

Pad wear is only an issue if you reef on the parking brake regularly. I rarely use a parking brake, and I had no issues with excessive pad wear on the Ranger in 10s of thousands of miles of use.

I personally find the Explorer rear brakes an ugly mess. Since they have both drums for parking and disc for stopping, they have all of the negatives of both systems.

I have no idea what sgtsandman is talking about with saying there is lots of required maintenance on disc brakes. That is the opposite of the facts, which is that they require virtually no maintenance. As long as the caliper pins are lubed, they just work. And they are 100x easier to work on when needed.

 

[sgtsandman]

There is no such thing as a "pressure valve" that holds pressure in the brake line. It is actually a check valve. With the heavy springs on the drum brakes, you will possibly have about 10psi in the line, but that is due to the springs trying to retract the shoes, not a "pressure valve". It turns out that the disc brake pads do not need to move off the disc very much, so the existing check valve works just fine for the disc setup - that is why no changes are required to the master cylinder when you make the change to rear discs. And since the braking force is about the same between the disc and drum setup, no changes to the proportioning valve are required.

Pad wear is only an issue if you reef on the parking brake regularly. I rarely use a parking brake, and I had no issues with excessive pad wear on the Ranger in 10s of thousands of miles of use.

I personally find the Explorer rear brakes an ugly mess. Since they have both drums for parking and disc for stopping, they have all of the negatives of both systems.

I have no idea what sgtsandman is talking about with saying there is lots of required maintenance on disc brakes. That is the opposite of the facts, which is that they require virtually no maintenance. As long as the caliper pins are lubed, they just work. And they are 100x easier to work on when needed.

Keeping the pins lubricated and making sure the slides are clear and clean is what I’m talking about. You want to check and lube those once a year, at minimum, but I have seen where twice a year is needed since the pins can start binding up if they are only checked once a year. You also want to use a silicone based brake grease to prevent swelling of the rubber boots.

Drum brakes rarely need anything as long as you make sure the mechanism is relatively clean and not binding and you don’t have to take the brakes apart to do it. You just slide the drums off to check and slide them back on.

 

[pjtoledo]

a quirk about disk brakes in the rust belt:
damn salt

I have found on several vehicles that corrosion forms on the mounting bracket behind the stainless steel slider plates.
this pushes the plates against the pads, sometimes hard enough to lock the pads in place.

taking the plates off and scraping the rust off puts the brakes back to normal operation.
a dab of grease or never seize delays the next round of corrosion.

 

[sgtsandman]

a quirk about disk brakes in the rust belt:
damn salt

I have found on several vehicles that corrosion forms on the mounting bracket behind the stainless steel slider plates.
this pushes the plates against the pads, sometimes hard enough to lock the pads in place.

taking the plates off and scraping the rust off puts the brakes back to normal operation.
a dab of grease or never seize delays the next round of corrosion.

Yep. I do that every time for the very reason you state. Sometimes the grease is still there and other times it’s all washed off.

 

[rubydist]

Well even when I lived in the rust belt, it was never necessary to lube caliper slider pins annually. I have literally never needed to lube them between pad changes. If you have to do it that often, you are not using the high temp grease that is needed.

 

[sgtsandman]

Well even when I lived in the rust belt, it was never necessary to lube caliper slider pins annually. I have literally never needed to lube them between pad changes. If you have to do it that often, you are not using the high temp grease that is needed.

It says right on the container high temp brake grease.

Most times, the slider pins are still good but stiff. I have also found the first time I skip them on the 2011, the pins are a S.O.B. to get out of the boot.

The contact points under the hardware are a mixed bag. Some still have grease, others are bone dry and starting to rust. The same with the contact points on the pads. This goes for both the 2011 and the 2019.

The pin setup on the 2019 is superior (like front brakes) to the 2011 and those tend to be pretty good and really don’t need relubed.

Of course the 2019 has those crank pistons that need the special tool to push them back in for easier installation. The benefit though is that the parking/emergency brake uses the caliper instead of a drum in the rotor and is self adjusting.

Anyway, I could probably let the 2019 skate a little but not the 2011. With that brake setup, you have to stay on those like white on rice or brake work is going to be a bad day. Those barrel slider pins that the caliper mount bolts go through bind up quick.

 

[don4331]

Pad wear is only an issue if you reef on the parking brake regularly. I rarely use a parking brake, and I had no issues with excessive pad wear on the Ranger in 10s of thousands of miles of use.

I personally find the Explorer rear brakes an ugly mess. Since they have both drums for parking and disc for stopping, they have all of the negatives of both systems.

Some on us use the parking brake multiple times daily.

The Ranger I converted to Mustang discs was a 3.slo manual. So, every day when my daughter went to school and when she got back home, she set the parking brake (using it daily does wonders to keep it from seizing).
There are also several hills on way to/from school. As we know the 3.0 doesn't make gobs of torque low down/M5OD doesn't have a real low 1st and the stock 3.45 gears weren't ideal. So, when cars behind stopped within a meter of the rear bumper, she used the parking brake to prevent roll back - as a beginning driver she wasn't real good at heel/toeing the brake/gas while easing the clutch.

Applying the parking brake 10 times a day resulted in going through 5 sets of pads and 2 sets of rotors (when we didn't get to the pads in time) in <2 years when she was in high school

Changing to Explorer differential meant we never had to change pads in the 4 years she was in university.

I don't disagree Explorer discs are a belt and braces solution but you don't see the drum parking brake. And its still used on a number of vehicles, so I'm not knocking something that works. (The new electric motor parking brakes make me nervous...)​

 

[jleas524]

1994 Ranger should have RABS

If its been disabled/removed then yes add an Adjustable proportioning valve to rear brake line, they don't cost much more and then you can adjust how much rear brakes you get now and with rear discs, and also if you drive with canopy on and/or with tools in the bed most of the time

I will be pulling the rear this weekend. Hopefully everything is still there.

 

[jleas524]

There are a couple things;

1. Improved braking:
As @rubydist alludes, Mustang discs aren't really upgrade - they both will just barely lock up rear wheels when you stomp on the pedal.

They are upgrade in so much as they work more reliably - most people don't do any maintenance on their drum brakes and as result they aren't working. Functioning discs are much better than non-functioning drums.​

The Mustang calipers were designed to engage the parking brakes using arm strength. On Ranger, you would set up the parking brake to be foot activated. For most people their legs are much stronger. So, parking brake function works much better on Mustang brakes.​

​

On other hand, Explorer discs ('95-02 Explorer axle swap) are a significant upgrade

Rotors are 1-5/8" larger diameter than Mustang V6 ones (same diameter as the GT rotors)​

Calipers pistons are much larger (48mm vs 38mm) <- This is real upgrade (60% more pressure)​

​

2. Pad wear

Drum brakes have a couple substantial springs to pull shoes off the drum. As a result, there is a pressure valve in the line to keep 10psi on the line (prevents the shoes from completely retracting, so brakes come on sooner). Disc brakes don't have the same springs, so don't need the same pressure - stock setup for discs is 2 psi.​

If you don't pull the pressure relief, your pads will wear like crazy. (In many 30 year old vehicles the spring is shot, so doesn't keep pressure in the line, which contributes to drum brakes no working like they should)​

The engagement of the parking brake "adjusts" the pads on the caliper. As the parking brake is applied with more (too much) force in Ranger set up, the pads tend to have to "wear" a little each time they are applied before they completely release. More so if they were engaged....firmly. Again contributing to pad wear. My son had issues with pad wear in his Mustang as he overly engaged parking brake, but then he is very big boy.​

​

The Explorer disc brake set up uses a "drum in hat" of the rotor solution. This was designed to be used with the same foot pedal as the Ranger. So, it...sort of works (about same as your Ranger parking brake worked).​

​

With '94, you might not be using Explorer as donor for the V-8. Otherwise I'd be pointing out you would be getting Explorer brakes as part of the swap.

This is great information... Thank you.