Disc break conversion not working

[Fossiljager]

I've swap the 94 explorer innards into my 90 Bronco II. Being the 94 X had rear drum I upgraded using the breaks from a 96 8.8. Problem I'm having is, know that the disc breaks are on the truck, I can't get them to work. I've bleed them a number of times, I did notice the pressure wasn't great, but neither was it with the drums.. The old drums worked fine so I can't understand why the new disc set up is not working hardly at all. Any help would be greatly appreciated.

Would the proportioning valve have anything to do with it?

PS, I have a new not re-maned master cylinder for a 96 explorer coming.


Thanks, Jager

 

[arco777]

Try changing the master cylinder out and report back... otherwise look for a kinked brake line. There shouldn't be a proportioning valve to worry about anywhere in your system, and if you don't have ABS then I don't see why there would be a problem. I swapped to a disc rear using a 95 style M/C and had no issues. Do you have a firm or at least normal feeling brake pedal, or is it spongy?

 

[rickybobby]

the only way for the brakes to function properly is to use a master cylinder for a 95 explorer without ABS. the 96 master cylinder will work better than the 94 but wont be quite right

 

[arco777]

the only way for the brakes to function properly is to use a master cylinder for a 95 explorer without ABS. the 96 master cylinder will work better than the 94 but wont be quite right

I used a remanufactured A1 Cardone 13-2695 master cylinder. Cheap and worked great.

 

[Fossiljager]

The breaks hardly work at all, the pedal goes all the way to the floor, if I didn't have front breaks, I would have no breaks . I went under the truck today and traced the line forward to the proportioning valve. All looks as it should. I have the old 95X master but with over 150K on the truck when I did the swap, I thought a new master would be in order. The master I have in the truck know is the original B2 master, maybe I should install the 95 X's master and see what happens while I wait for the new 96 to arrive. An interesting factoid, the bore of the master on the 96 is the same as the B2, the 95 has the larger bore.

Thanks for your help guys, I'll let you know how things turn out. Not into pitching over some washout with only front breaks, can you say Chinese wheelie. A little disappointed, I was hoping these slotted and drill bad boys would be the cats arss.

Jager

 

[arco777]

I wonder if your brake bleeders are leaking around the threads and introducing air into the system. I had a real hard time getting the rear brakes to bleed when I did my 2nd gen axle swap, even using a vacuum pump. I installed Dorman 12701 Speed Bleeders on the rear brakes and simply attached a catch cup onto the new bleeder nipples. Worked AMAZING and let me quickly flush out all the old fluid quickly. Might give this method a try!

 

[Fossiljager]

I was thinking when I do the 95 master swap, (if it ever stops raining) I should also pull all the lines down an blow them out, just incase there is something stuck in one of the lines. I see no signs of crimping. The pressure to the rear breaks has been less than adequate from the start. I was even thinking the line size was wrong. I have a set of James Duff braided stainless lines feeding the fronts and the rear axle so I know they are the correct size. Question is, why would the pedal go to the floor and no signs of leakage anywhere. The level in the reservoir stays the same, I see no sign of fluid on the ground, very strange......... :scratch:

Jager

 

[jd4242]

Starters like everyone said you need a 95 master without cruise control, without abs and without a proportion valve.but sounds like to me you have air in the system still ontop of it.that or your rear abs valve is stuck, if you have it still.

 

[Fossiljager]

No ABS on the truck, that's long gone. I need cruise for those long road trip to Canada fishing and rock hounding. Air in the system might be an issue but, I've bled the bejesus out of the lines with no change. I've taken the proportioning valve off the truck, the electronics weren't connected anyway and I'm sure it was restricting flow to some degree. I'll just connect the two ends with a coupler, thank God the two ends are the same size thread.

Great suggestions all

jager

 

[jd4242]

No ABS on the truck, that's long gone. I need cruise for those long road trip to Canada fishing and rock hounding. Air in the system might be an issue but, I've bled the bejesus out of the lines with no change. I've taken the proportioning valve off the truck, the electronics weren't connected anyway and I'm sure it was restricting flow to some degree. I'll just connect the two ends with a coupler, thank God the two ends are the same size thread.

Great suggestions all

jager

You still need to purchase one that says NO CRUISE...your cruise is a separate unit..what I suggested is the only mc that works with our trucks 100%

 

[jd4242]

Also depending on the rotor and pad choice, they may need to be broke in.what rotor and pad did you go with?

 

[Fossiljager]

As far as rotors and pads I got these;

http://www.rockauto.com/catalog/moreinfo.php?pk=3805851&cc=1119653

Break in wouldn't explain the pedal to the floor syndrome. I took the B2 MC off and found where it was leaking a tad out the back. I installed the MC off the 94X I got everything else from. Now the proportioning valve is history, I hope these mods will solve the problem.

J

 

[jd4242]

The mc from a 94 won't work...and those rotor and pads do need to be broke in
Good luck

 

[rickybobby]

you have to have a proportioning valve, or you are gonna end up with some major problems.

 

[jd4242]

you have to have a proportioning valve, or you are gonna end up with some major problems.

I don't know, many first gen uses bypass their rear abs/proportioning valve.including me

 

[Fossiljager]

why won't a 94 MC work?

 

[jd4242]

why won't a 94 MC work?

Not made for rear disc brakes

 

[Fossiljager]

I guess it's a good thing I ordered a brand new MC for a 96 X.
Can you share what the difference is between a drum break MC and a disc MC?

FYI,I did manage to get a bit more rear break by removing the rear calipers, compressing the pistons then pumping the breaks until the pads touched, I did this a couple of times to make sure the pistons that I rebuilt weren't stuck. I have about half a pedal now, at least I can drive the truck and stop when needed.

This has been a great learning opportunity for me. Every time I do anything to this truck, it's by the skin of my teeth. As you all know, to install the discs break backing plates you need to remove the axels. I have an aussie locker in the rear, to access the "C" clip you need to pull the pinion shaft, unfortunately I broke the locking pin and had to grind off the end of the pinion shaft to access the broken pin... what a nightmare

Thanks guys,

J

 

[jd4242]

I guess it's a good thing I ordered a brand new MC for a 96 X.
Can you share what the difference is between a drum break MC and a disc MC?

FYI,I did manage to get a bit more rear break by removing the rear calipers, compressing the pistons then pumping the breaks until the pads touched, I did this a couple of times to make sure the pistons that I rebuilt weren't stuck. I have about half a pedal now, at least I can drive the truck and stop when needed.

This has been a great learning opportunity for me. Every time I do anything to this truck, it's by the skin of my teeth. As you all know, to install the discs break backing plates you need to remove the axels. I have an aussie locker in the rear, to access the "C" clip you need to pull the pinion shaft, unfortunately I broke the locking pin and had to grind off the end of the pinion shaft to access the broken pin... what a nightmare

Thanks guys,

J

The amount of psi that is sent to the rear and the travel of the piston.belive me the only mc that works is the 95 without any options.there is a very good thread on here somewhere that explains it much better, can't find it at the moment.

O and I know all about having to take apart an aussie, I'm aussie lock front and back.I have a whole collection of spare parts and SPRINGS now.seems like I break or loose something every time I take the cover off

 

[Fossiljager]

I'm hoping the 96 MC will do the trick, after all, it was designed for discs on all four corners.

Speaking of Aussie lockers, because the "C" clip is such a joy to remove, I set off to invent a tool that will extract the "C" clip almost painlessly. After all, necessity is the mother of invention. When putting everything back together, I mistakenly put the spring pins in wrong, so I was forced to but my idea to work a second time. As long as you passion the "C" clip so the ends face away from you, my idea works every time .

The brakes are still not right, better but not great. I am hoping the new MC will handles it.

jager