Rear disc Brake conversion COMPLETED

OKay so many of you guys have installed a 8.8 with discs on the back of your truck, or simply converted your 8.8 from drum to discs.

Brett wrote an article on this a while back, taking you through the entire process.

Brett helped me convert a 97 31 spline AWD disc brake 8.8 to spring over and set it up for a BII a few years back. I have had the disc brakes on the back of my truck for about 3 years now, everything worked OKAY.

At first the rear pads and rotors showed basically no wear, so I adjusted the front/rear biast per Brett's article until I could feel the rear discs grabbing.

Braking performance was far better then a stock BII.

Well on my list of things to do was to COMPLETE the disc brake conversion by using the CORRECT master cylinder.

Last weekend I finally got a chance to do so.
What a job it turned out to be!
For my truck, being a 88 BII, originally with 10" rear drums, and crappy RABS, the research I did pointed me to a 1995 Explorer master cylinder, with disc brakes, no ABS and no proportioning valve. (Your Explorer may be different, if you have 4wabs, then get that, research is key)

OKay so everything is going smooth.
First thing I did was replace my front rotors (needed it) and slide pins. I noticed my slide pins were in horrible shape, they should be, if I am correct they have 250K miles on them. So I replced them with new, $20 at Pep Boys.

then on to the rear:
I disabled/removed my rear anti lock brake setup years ago, since I have had the BII it never did work quite right and it was more then just a little scary when it would kick in. Call me old school but I prefer to pump my own pedal, even in a lifted BII.
The RABS valve (on the BII its on the drivers side frame rail just above the rear axle) was still plumbed into the brake lines. This little beauty is about $350 new from Ford and when they go bad all sorts of stuff can happen, so I disabled it. Well now I finally completely removed it. This required a standard 1/4" brake line coupling and a 1/4" to 5/16" adapter. Car quest had both of the fittings I needed.

Now on to the good stuff:
I also figured my brake booster has 250K miles on it, so I mine as well ditch it. Luckily Brett parted out an Explorer recently and I got the brake booster from him. Fresh coat of paint and its bolted in.

Now for the master cylinder. The 95 Explorer master cylinder is cast aluminum, I opted for a new unit instead of rebuilt, I have had problems with rebuilt masters before. I got this sucker at Car Quest for $150 (roughly)
I also picked up a new rubber brake line for the rear axle, since mine has 250K miles on it I figured it was about time.

Well The master cylinder bolts to the booster no problem at all. Here's the dilema, the brake lines on the BII are a totally different size form the inlets on the master cylinder.

The master clyinder is plumbed with METRIC bubble flare brake line outlets. In order to plumb my brake lines into the master cylinder I went back to Car quest. For the front brakes it was a simple metric bubble flare to standard 1/4" brake line adapter.
For the rear line it was another story. In order to make the jump from the metric bubble flare to the 5/16" brake line on the truck, I would have had to stack 8 adapters.
No thanks! I dont even think that would fit under the hood.
So back to Car Quest.
Best solution:

replace the actual metal hard line for the rear brakes, it was only necessary to replace the first section. this required a 60" standard 1/4" metal brake line.

It took some doing to bend this sucker and route it on the truck, from master cylinder, down to frame rail, along rail to coupling. Took about 2 hours actually, quite a PITA. I imagine it would be easier with no exhaust installed.

So when all was said and done I now have a 4 wheel disc brake master cylinder and a freshened booster.

The rear disc brake performance is NIGHT AND DAY.
I highly recommend for any of you who have replaced your rear drums with discs to FINISH the job, get those discs the correct porportioning and pressure they need to work right, install the correct master cylinder.

The BII now stops straight and true and I have a hard pedal with complete control. I would say this is a 150% increase in braking over my old setup.

I will try to get some pictures of the new master installed with the fittings, but if you have any qestions let me know.

I had to make 9 trips to the parts store last weekend, this is what happens when you are entering un charted waters.

Hopefully this post will help keep you from having to do the same I did, stop and go get parts, stop and go get fittings, etc etc.........

As always with stuff like this, research is your friend....

Hope that helps!!

-410

Nice. You said Brett had a write up before....was it as detailed as this? The two could be merged and put into useful threads if so...

410Fortune: Great info seeing how I will have to do the same thing now that I have the discs in the rear. Thanks for the write up!!!

Brett's post is on here somewhere...........I believe its on the Explorer mods page...let me look.......

Well when I replumbed my brake lines from Master cylinder to rear wheel cylinders I just cut the hard lines and used my tube flaring tool and got the fittings I needed to make the connections. I made 3 trips to parts store to get hard lines, then fittings and a last one cause I had no brake fluid. I had some fitting adapters but they were more of a PITA and I had a hard time with them leaking under pressure even using teflon thread tape. Which I used on all fittings from master cylinder to wheel cylinders.

That was my next option, double flaring tool.

Here's the problem with that, the master cylinder uses a metric bubble type flare, I do not know of a flaring tool that can do that.........

Do you?