The brakes on my 91 Explorer 4x4 seem spongy and the pedal travel excessive. The pedal does not sink down and they do not pump up if I pump the pedal. I adjusted the rear drums manually, but it seems the self adjusters are working since I barely turned the adjusters to get the little drag. I've bled with a mighty-vac pump, and I did a complete front brake job (new rotors, pads, etc.) since when I was poking around I found the pads to be down to about 25%. I've checked for leaks at all four corners, the master cylinder, and every connection in the brake lines and there are none. There is no pulling going on. Nothing seems to change the spongy feeling though. What am I missing here? Thanks for any suggestions.
Ken
91 Explorer 4x4

 

try bleeding the brakes ... see if that helps?

 

I don't think having worn pads on the front is your problem. Does the pedal feel the same if you are backing up and pumping the brakes??

 

The brakes feel the same either backing up or going forward. It really feels like I need a brake bleed, but I've bled them again and again with no difference. When I bleed, I use the mighty-vac pump, and start from the furthest corner and work toward the closest corner to the master cylinder. I pull the brake fluid thru a clear line and I do not see bubbles. Since it is a 91, it has the rear ABS and I'm not sure if I have to bleed the ABS valve a different way. My Haynes manual says the '95 and up needs a special procedure since they are 4 wheel ABS. The Haynes doesn't give the procedure, it just says there is one for the '95 and up, but for the '91 to 95 it doesn't say there is a different procedure. I'm almost ready to take it to a brake shop, but I hate spending the money if its something I can fix. Thanks.
Ken

 

I have a '91 with the same problem. Feels like the pedal will got throught the floor before it stops. I have replaced all my brake pads as well. Any help would be appreciated

 

[updated:LAST EDITED ON 11-Dec-02 AT 11:40 PM (EST)]Find some place that you can safely get to around 40 mph. Once you hit 40 do a panic stop. Just barley hold the wheel. Do this two or more times. If on more than have of the test your car pulls to one side, then you have air or a leak on the opposite side of the pull.

If this doesn't help, it might be the rubber brake lines expanding.

Chris

 

I had a similiar problem with my '91 Explorer. I found the problem to be the ABS module on the frame rail. The rear brakes were barely working. I tried to bleed them and it did not help. I replaced the master cylinder and it did not help. This sensor is about $300 from Ford. I found a junk truck with one. The abs sensor also hooks up to it. It only controls the rear anti-lock brakes. The best way I found to test it is to lock up the brakes on ice or gravel. If rear does not work at all I would check this out. When I took the Explorer to the emission testing station they could not stop the truck when they applied the brakes. The rear wheels are the only ones that were moving. I hope this helps.

 

TTT for ya! I've got the same problem, posted about it yesterday. SAME exact problem! Was it the RABS madule on the frame? I need to know, I've changed everything and it's driving me crazy.
John

 

I dealt with spongy brakes for a while as well after replacing all my lines including between the master and ABS pump (HCU) on my 94 Explorer. I bench bled the master 1/2 dozen times, bled the system for days on end using the standard pump method, pressure, vaccum. I even did the panic brake idea but it didn't help. I was pretty certain it was air in the HCU and I am too cheap and stubborn to have the dealer do it. But I finally came across a DIY procedure on another site and I have a firm pedal again. Thanks should go to SigEpBlue on FullSizeBronco.com for first sharing this method.

Notes:
*It is possible to damage your ABS module if you don't follow the instructions below carefully. This may work for other model/years as well. If the pin #'s/wire colors do not match up, DO NOT ATTEMPT THIS!
*While this may remove air trapped in the HCU it is possible for a valve to be faulty.


Here's the link:
Ghetto 4WABS HCU Bleed Procedure - FSB Forums


1. Perform conventional brake system bleed.
2. Prepare an appropriate method of connecting individual circuits and wires to ground. This connection must be sound, with very low impedance to the battery negative terminal (I used some stainless hat pins and alligator clips on test leads).
3. Turn the ignition switch to the ON position.
4. While an assistant presses down on the brake pedal:
* *a. ground circuit 599 [PK/LG], pin 19. (4WABS Relay #1)
* b. ground circuit 510 [T/R], pin 27. (Rear Dump)
* c. ground circuit 498 [PK], pin 15. (Right Front Dump)
* d. ground circuit 496 [O], pin 26. (Left Front Dump)
* -- the pedal will fall.
5. Disconnect the ground connections made in parts 4b, 4c, and 4d. *Leave the connection made in part 4a. Allow the brake pedal to return.
6. Repeat steps 4 and 5 once more.
7. Ground Circuit 539 [PK/LB], pin 29 for one minute. The ABS pump motor should run for the entire minute.
8. Perform conventional brake system bleed.



If you don't have an assistant I found having power seats and jack handle to be very helpful. Also, I did have to this twice to get all the air out, though I may have just messed up the first time. So don't be shy about repeating the process.

My preferred method to bleed brakes is to wrap teflon tape around the bleed screw and attach a 1-way valve to a length of tubing or you can use the one-man bleeder kit. Loc-Tite on the threads seems to work as well so long as you have something to plug up the cylinder/caliper and have time to wait for it to cure. Of course if you don't mind shelling out for speedbleeders go for it.

I hope this helps a lot of frustrated Ford owners out there.

 

On my way home from the mountains my brakes went completely spongy and at first I was able to pump them to get the car to stop but that didn't last long.. they completely stopped working all together. Even the emergency brake wont work. The brake light came on along with the anti lock light. I noticed the caliper pins on my front 2 calipers were half way out when I was bleeding my brakes. I fixed them..finished bleeding the brakes. Checked the seal on my master cylinder, checked the brake lines and still no brakes. I just replaced my driver side rear wheel cylinder about 7 months ago, replaced the master cylinder 5 months ago and did a complete brake job about 3 months ago. Do u think my master cylinder failed? The only thing is I have no brake fluid lose at all so I'm kinda not sure it would be the master again.

 

Your initial description sounds like an issue of old brake fluid that overheated and "boiled" to the point where you were compressing air rather than hydraulic fluid. With all the work you had previously performed did you flush the brake system with fresh fluid from a sealed container? With the Explorer wheels of the ground, safely supported by jack stands, if someone steps on he brake pedal are you still able to spin the wheels by hand, or is there at least enough fluid getting to the calipers to grab? What was your process for bleeding the brakes (sorry, but I have absolutely no idea what your experience level is to just assume you did it correctly)?

Regarding your comment about the caliper pins being "half way out" - are you saying that the pins were effectively just resting in the calipers? Because if only half of the pin was in the caliper, there would be no threads holding the pins in, so I think I'm not correctly interpreting what you're meaning.

-Rod

 

This may seem like a strange question, have you worked on or changed the calipers prior this issue.?

If you have, are the bleeder ports at the very top of the fluid chamber (caliper|) ?