sound like a stuck caliper?

[Runnin'OnEmpty]

Thanks for the kind words, 410.

The MC pushrod length is critical on older Ford trucks, and I assume the Explorers would be also.

Maybe that hottie counter girl will be working tomorrow .......

 

[410Fortune]

Yes but if he never took the master off the pushrod length should not have changed.
The pushrod adjust the front/rear biast.

Haynes or Chiltons shows you how to build a simple jig to measure the correct length.

 

[jgilbs]

The pushrod adjust the front/rear biast.

I thought the RABS proportioning valve did that?

 

[410Fortune]

No the RABS or rear anti lock valve controls the pulsing and locking of the rear axle, it is driven from the pressure it gets from the master and the signal it gets from the ABS computer.

on 4wABS trucks this module controls all 4 and is located on the frame rail just below the booster. ON the RABS equipped trucks like my 88 and pre 93 Explorers (is it 93 they went to 4 wheels?) it is located on the drivers frame rail just before the drop to the rear axle. The RABS unit has a bleeder on it, the ABS module does not.

The RABS gets bled before the rear axle..

 

[general x]

I do believe you are right about the explorers getting 4wABS in 93. Im not ENTIRLY sure but i know that my 92 has rear ABS only and 93 seems stuck in my head

 

[jgilbs]

so bleed RABS, then bleed (looking at truck from behind it) right rear, lr, rf, lf?after i get the new master cylinder, that is. my RABS never worked. guess its about time to get under there and find out while im doing everything else with the braking system.

 

[jgilbs]

If you do change the MC, make sure the pushrod is adjusted to the correct length. If it's too long, that will cause the MC to hold pressure and give the symptoms you describe.

how do i adjust the pushrod? i just got the new master cylinder and my haynes manual doesnt mention it, but the directions for the new MC say to adjust it, but not HOW.

 

[Runnin'OnEmpty]

Jeff, the pushrod simply screws in and out for length adjustment. It's standard directional threaded. It'll be apparent when you get the MC off.

You can cut out a cardboard template to adjust it as 410 says (template is in repair manual), or you can measure it. What I do is run a phillips head screwdriver into the MC and measure the depth. Then measure the MC flange portion that sits into the booster housing, and subtract that from the MC depth. This sum gives the pushrod length that should stick out from the booster mounting surface. (I subtract 1/16" 'play' to allow for heat expansion, etc, and to make sure there is no pushrod pressure on the MC at rest. Use a straightedge on the booster flange to get the pushrod length.

I use a phillips screwdriver because the tip is similiar to the pushrod tip. The measurements have to be as precise as you can get them.

Was the hottie working today?

 

[410Fortune]

Jgibs, that RABS caused me so many damn problems on my 88.... I mean it worked when I first got the truck but holy cow it seemed to make things worse, especially in the snow, I prefer to control my own brakes thank you very much.

One of the first mods I did was disconnect the RABS computer, no more light, no more RABS. That RABS valve sat on the frame rail until last year, I finally finished my rear disc conversion and I got rid of it.

Here's what I had to do on my 88 with a 97 Explorer AWD rear:
95 Explorer master cylinder, no frills.
94 Explorer booster (junk yard, BII one had 240K on it
The drum brake lines on my 88 were a standard bubble flare, the new master is a metric bubble flare, which means that for the front brake line I was able to use a single adapter, for the rear I would have had to stack about 6 adapters to make the jump.
So I ended up running a complete new hard line back to the RABS valve. At the Rabs valve it was a simple adapter to bypass it, input line directly to output line.
RABS valve now sits in a box, along with the wiring and computer.

with the rear discs, D35 discs up front the little BII stops like crazy, even with the boat in tow its great! I played with the front/rear biast about 5 times before I got it just right, if I mash it the rears will lock just before the front...in a BII thats a good thing

 

[jgilbs]

i just cant beleive how much of a PITA this is. Originally I just wanted to get my rotors turned to stop the pedal puslating and repack my bearings - cost: $25 max. Now, I've ended up having to buy new rotors, a new front caliper, new flex hoses, new master cylinder and about a gallon of brake fluid. and i got a new master cylinder, but the bleeder kit it came with SUCKS! first, the tube adapters(what u screw into the cylinder and attach the hose to) wont fit in the line for the rear brakes, and there are 2 pieces of tubing - but they are attached so they are one piece running side by side! i tried to slice them apart but ended up gashing both tubes, ruining them. so now i gotta shell out more $$ for a bleeder kit!! and i cant even get my MC off, because the bolts were so rusted. I rounded off one nut using a flare wrench! Right now im soaking it in PB Blaster so when Im done reading your guys advice i can go yank it off. Goddamn It's like fix one thing, and you find 10 new problems!
[RANT OFF]

 

[410Fortune]

Hey in 7 more years you will have a truck like mine! hahahaha
Everything on my truck comes apart like butter now because its all been replaced, disassembled, re assembled so many friggin times...you have no idea.
Good luck!
Use a 12 point socket on that master nut....

 

[jgilbs]

so, i FINALLY got that damn bolt off of the brake booster. it took 1/2 can of PB Blaster, an 8 lb sledge, a 9/16 deepwell socket, my trusy husky ratchet and a handy 2 ft length of 3/4" conduit as my breaker bar. the nut is fubar'd, but the threads are pristine so i pried off the resivour for the master cylinder, and as i was dumping it out into my fluids pan, i noticed there was a great deal of black SLUDGE coming out. Could this have caused my master cylinder to fail? Now I'm worried about the condition of the hard lines. Also, there was so much sludge, I flushed it out with water(doh!) instead of new brake fluid. I am letting it air dry now - I'll let it sit for about an hour. Do you guys think it will be OK? I know moisture + hard lines = rust BAD BAD BAD! I'm gonna flush the entire system and this time im gonna get those damn rear bolts!(lets hope i dont have to goto the ER again!)

 

[410Fortune]

Did you get replacement bleeder valves to install?

The resevoir will be fine as long as its dry when you install it.

The black sludge could very likely be from the O ring that was destroyed inside the master when you bottomed it out.

When you bleed make sure it all runs clear.

Now bench bleed that sucker, it will save you a ton of problems, it doesnt take much, just like 3-4 cycles.
Also you can gravity bleed the system to really help get you started..once the master is installed open all 4 (5 with RABS) bleeders and let the fluid from the resevoir fill the system via gravity.

Its almost over dude!!

 

[jgilbs]

ha! almost over? I still have to install the pass side flex hose - in addition to the MC. that retaining clip behind the bracket is a b!tch to get off and then back on! My advice to anyone trying to replace the flex lines in the future is this: On the clip, there is a channel that slides around the channel on the flex hose. On the entrance to this "channel" on the clip, there are 2 very small pieces of metal that "stick out"(its more obvious when you are holding this clip in your hand) and help keep the clip on the hose at all times - but it is IMPOSSIBLE to get back on. Just grind these pieces down as little as required to get them to fit back in.

also, for benchbleeding the MC, it says i need a bench-vise. I dont have one - threw it away last time we moved. Can I just put the MC on the floor and brace it against a wall to bleed it?

 

[410Fortune]

Yes you can, I do it that way, you dont need no friggin vise

What bracket are you talking about? the little clip that holds the hard line to the coil bucket?

 

[jgilbs]

yep. mine was all rusted so it wasnt very springy anymore.

 

[96kenex]

Are you using the blue anti-squeel on the pads? If so, be sure that none got on the face of the pads or the rotors.

 

[jgilbs]

nope - im not using any antisqueal - just siliglide from napa on the caliper slide pins and the inboard pad. after i isntalled the new lines, i cleaned the rotor(both sides) and both pads with brake cleaner, so hopefully ill be able to stop! would be a shame if something malfunctioned due to dirt after i replaced my entire front braking system.

 

[410Fortune]

I dont use any of that anti squeel stuff either and I use good old napa wheel bearing grease on the slide pins. Everything is cleaned, all surfaces and I have never had a problem with noise, I also have no vibrations, nothing.

 

[jgilbs]

just replaced the MC - and still they stick!!!!! i only bled one because i was sop tired from doing everything else. could this be because only one wheel was bled? wtf?!

EDIT - looked on fordpartsnetwork:http://www.parts.com/partlocator/in...&make=10&model=Explorer&year=1992&catalogid=1

is this the RABS valve? i def dont want to spend $150 for it.