92 explorer brake issues

BUDFAN8 · 06-26-2009, 02:50 PM

changed rotors and pads on a 92 explorer as i inspected the calipers when i took them off one had been through a few too many high heat cycles so i went ahead and replaced both calipers also. everything went fine on the right (passenger) side. got to the left (driver) side and there is where my troubles began.

after bleeding the right side the truck had a good petal. then i changed the caliper on the left and never got the petal back. the truck had already had a new master cylinder that was still under warrenty so i went ahread and replaced it again to make sure it hadnt been damaged internally (person helping bleed the system was stomping the petal too hard until i realized she was doing it). ive bled 3 of the small cans of brake fluid through the truck tring to make sure there is no air left in the line and still no pressure to the front. i can see the calipers pulseing a very little when the brake is pushed so there is some pressure going to the front but not alot.

the truck is 4x4 front disc rear drum it only has rear abs and yes the calipers are on correctly the piston is to the inside of the rotor.

any help is apreceiated

thanks in advanced
Bud

**octaneman** · 06-26-2009, 08:59 PM

Hi BUDFAN8

Did you bleed the master cylinder before you put it on ? The master MUST be bled properly in order to build up pressure. There are 2 ways to bleed the master: 1) On the bench with adapters attached to a vice. 2) On the car with adapters attached while pumping pedal. Once the master is bled and you are certain there is no air in it, then you must bleed all 4 wheels in sequence starting from the farthest wheel to the closest: Right Rear, Left Rear, Right Front, Left Front. Make sure that the master does not empty when you bleed the wheels ( 2 or 3 pumps and check level) or else you will do it all over again. On some abs systems the engine has to be running in order to bleed the system.

BUDFAN8 · 06-26-2009, 09:14 PM

yes i used the fitting and tubes that came with the new master to bleed before i attached lines. also ive tried bleeding from far to close and cross pattern. a ford tech told me that it needed bled in the cross pattern is why i tried that but i didnt think it was going to work because the front and rear lines arent going to the same point anywhere except in the master its self.

ive also had a guy telling me it is the porportioning valve that is the problem but unless the porportioning valve is in the abs motor i cant find one. the line closest to the firewall goes to the frame into the abs motor then goes to the rear where it splits into 2 lines going into each of the drums. the farest line away from the firewall on the master goes straight to the frame into a T and then to both front calipers. so if there is a porportioning valve i have no idea where it is.

Bud

**octaneman** · 06-28-2009, 09:36 PM

The proportioning valve is usually bolted under the frame on the drivers side just near or next to the shifter lever, if it's not there then the valve is incorporated into the abs system. There is a simple way to see if pressure is actually going to the wheels. Take vice grips and clamp the brake flex tubes and see if the pedal becomes rock hard. If it doesn't become hard then there is air in the master or the master leaks internally. If the pedal is hard, release 1 vice grip at a time and see if there is air in the line, by doing it this way you are forcing the brake fluid into 1 wheel instead of all of them. Start the engine when you bleed the wheels in the back, look and see if pressure builds with the abs engaging. If master proves to be OK and pressure still doesn't build, consider using a hand vacuum pump and force bleed it that way.

post your findings.

**octaneman** · 06-29-2009, 11:59 AM

Here is a diagram of your brake system with instructions on how to bleed this particular system: (Picture 1 a)

When any part of the hydraulic system has been disconnected for repair or replacement, air may get into the lines and cause spongy pedal action (because air can be compressed and brake fluid cannot). To correct this condition, it is necessary to bleed the hydraulic system after it has been properly connected to be sure all air is expelled from the brake cylinders and lines.

When bleeding the brake system, bleed one brake cylinder at a time, beginning at the cylinder with the longest hydraulic line (farthest from the master cylinder) first. ALWAYS Keep the master cylinder reservoir filled with brake fluid during the bleeding operation. Never use brake fluid that has been drained from the hydraulic system, no matter how clean it is.

It will be necessary to centralize the pressure differential value after a brake system failure has been corrected and the hydraulic system has been bled.

The primary and secondary hydraulic brake systems are individual systems and are bled separately. During the entire bleeding operation, do not allow the reservoir to run dry. Keep the master cylinder reservoir filled with brake fluid. (Picture 1)

Clean all dirt from around the master cylinder fill cap, remove the cap and fill the master cylinder with brake fluid until the level is within 1 / 4 in. (6mm) of the top edge of the reservoir.
Clean off the bleeder screws at all 4 wheels. The bleeder screws are located on the inside of the brake backing plate, on the backside of the wheel cylinders and on the front brake calipers.
Attach a length of rubber hose over the nozzle of the bleeder screw at the wheel to be done first. Place the other end of the hose in a glass jar, submerged in brake fluid.

Open the bleeder screw valve 1 / 2 - 3 / 4 turn.
Have an assistant slowly depress the brake pedal. Close the bleeder screw valve and tell your assistant to allow the brake pedal to return slowly. Continue this pumping action to force any air out of the system. When bubbles cease to appear at the end of the bleeder hose, close the bleeder valve and remove the hose.
Check the master cylinder fluid level and add fluid accordingly. Do this after bleeding each wheel.
Repeat the bleeding operation at the remaining 3 wheels, ending with the one closet to the master cylinder. Fill the master cylinder reservoir

Master Cylinder Replacement Proceedures.

With the engine turned off, push the brake pedal down to expel vacuum from the brake booster system.
Disconnect the brake fluid level sensor wire from the reservoir.
Disconnect the hydraulic lines (use correct tool, a Line Wrench) from the brake master cylinder.
Remove the brake booster-to-master cylinder retaining nuts and lock washers. Remove the master cylinder from the brake booster.

Before installing the master cylinder, check the distance from the outer end of the booster assembly push rod to the front face of the brake booster assembly. Turn the push rod adjusting screw in or out as required to obtain the length shown.
Position the master cylinder assembly over the booster push rod and onto the 1 studs on the booster assembly. Install the attaching nuts and lockwashers and tighten to 13-15 ft. lbs.
Connect the hydraulic brake system lines to the master cylinder.
Bleed the hydraulic brake system (refer to procedure in this Section). Centralize the differential valve. Then, fill the dual master cylinder reservoirs with DOT 3 brake fluid to within 1 / 4 in. (6mm) of the top. Install the gasket and reservoir cover. Roadtest the vehicle for proper operation.

When replacing the master cylinder it is best to BENCH BLEED the master cylinder before installing it to the vehicle. Mount the master cylinder into a vise or suitable equivalent (do not damage the cylinder). Fill the cylinder to the correct level with the specified fluid. Block off all the outer brake line holes but one, then, using a long tool such as rod position it in the cylinder to actuate the brake master cylinder. Pump (push tool in and out) the brake master cylinder 3 or 4 times till brake fluid is release out and no air is in the brake fluid. Repeat this procedure until all brake fluid is released out of every hole and no air is expelled.

**octaneman** · 06-29-2009, 12:00 PM

master cylinder replacement procedures continued...

**octaneman** · 06-29-2009, 12:03 PM

more pics ..

**octaneman** · 06-29-2009, 12:05 PM

and still more..

**octaneman** · 06-29-2009, 12:09 PM

The booster rod adjustment is very important and must be done accordingly.

good luck !

06-26-2009, 02:50 PM	#1 (permalink)
BUDFAN8 Registered User Join Date: Apr 2007 Posts: 205 OS: XP	92 explorer brake issues changed rotors and pads on a 92 explorer as i inspected the calipers when i took them off one had been through a few too many high heat cycles so i went ahead and replaced both calipers also. everything went fine on the right (passenger) side. got to the left (driver) side and there is where my troubles began. after bleeding the right side the truck had a good petal. then i changed the caliper on the left and never got the petal back. the truck had already had a new master cylinder that was still under warrenty so i went ahread and replaced it again to make sure it hadnt been damaged internally (person helping bleed the system was stomping the petal too hard until i realized she was doing it). ive bled 3 of the small cans of brake fluid through the truck tring to make sure there is no air left in the line and still no pressure to the front. i can see the calipers pulseing a very little when the brake is pushed so there is some pressure going to the front but not alot. the truck is 4x4 front disc rear drum it only has rear abs and yes the calipers are on correctly the piston is to the inside of the rotor. any help is apreceiated thanks in advanced Bud

06-26-2009, 08:59 PM	#2 (permalink)
octaneman Mentor Join Date: May 2009 Posts: 487 OS: WINXP	Re: 92 explorer brake issues Hi BUDFAN8 Did you bleed the master cylinder before you put it on ? The master MUST be bled properly in order to build up pressure. There are 2 ways to bleed the master: 1) On the bench with adapters attached to a vice. 2) On the car with adapters attached while pumping pedal. Once the master is bled and you are certain there is no air in it, then you must bleed all 4 wheels in sequence starting from the farthest wheel to the closest: Right Rear, Left Rear, Right Front, Left Front. Make sure that the master does not empty when you bleed the wheels ( 2 or 3 pumps and check level) or else you will do it all over again. On some abs systems the engine has to be running in order to bleed the system. Last edited by octaneman; 06-26-2009 at 09:11 PM.

06-26-2009, 09:14 PM	#3 (permalink)
BUDFAN8 Registered User Join Date: Apr 2007 Posts: 205 OS: XP	Re: 92 explorer brake issues yes i used the fitting and tubes that came with the new master to bleed before i attached lines. also ive tried bleeding from far to close and cross pattern. a ford tech told me that it needed bled in the cross pattern is why i tried that but i didnt think it was going to work because the front and rear lines arent going to the same point anywhere except in the master its self. ive also had a guy telling me it is the porportioning valve that is the problem but unless the porportioning valve is in the abs motor i cant find one. the line closest to the firewall goes to the frame into the abs motor then goes to the rear where it splits into 2 lines going into each of the drums. the farest line away from the firewall on the master goes straight to the frame into a T and then to both front calipers. so if there is a porportioning valve i have no idea where it is. Bud

06-28-2009, 09:36 PM	#4 (permalink)
octaneman Mentor Join Date: May 2009 Posts: 487 OS: WINXP	Re: 92 explorer brake issues The proportioning valve is usually bolted under the frame on the drivers side just near or next to the shifter lever, if it's not there then the valve is incorporated into the abs system. There is a simple way to see if pressure is actually going to the wheels. Take vice grips and clamp the brake flex tubes and see if the pedal becomes rock hard. If it doesn't become hard then there is air in the master or the master leaks internally. If the pedal is hard, release 1 vice grip at a time and see if there is air in the line, by doing it this way you are forcing the brake fluid into 1 wheel instead of all of them. Start the engine when you bleed the wheels in the back, look and see if pressure builds with the abs engaging. If master proves to be OK and pressure still doesn't build, consider using a hand vacuum pump and force bleed it that way. post your findings.