1992 Ford Ranger Brake Pedal Issues

You can't find any place that is wet?

There are no leaks at all. That's why I am so confused. It is fustrating the hell out of me. I even had a neighbor who used to work on cars all the time, and even he is boggled too. Do you think that if I take the master cylinder off of the booster unit and adjust the cable, do you think that might work? I just don't know anymore. The funny thing is, is that the truck still comes to a stop, even though the pedal bottoms out. I have been sitting around scratching my head trying to go step by step and following the brake lines around, trying to come up with something. I am up for any kind of suggestions. Thank you for taking the time to read my post on here.

that wouldn't do any good, because as you said you are loosing brake fluid. If you are loosing fluid and there are no leaks, there are only three things that I know that can be.

1. The ABS unit is not 100% bled and every time you drive you are slowly bleeding it.

2. Brake fluid is leaking pass the master cylinder seal and going into the vacuum booster (you would normally see a leak below it, but have seen this happening). you can try to remove the booster to see if it is full of brake fluid.

3. you have a manual transmission, that use the brake fluid reservoir as a backup for the hydraulic clutch system(I am not sure how they made those hydraulic systems on the Ford Ranger).

What is bugging me, is that you are loosing brake fluid.

If fluid is leaking into the brake booster very slowly, it is possible that the vacuum created by the engine is sucking the brake fluid and burning it out the exhaust. It is possible to smell it, but you would need a trained nose. I would say that this is the probable cause, out of the three that I suggested.

Hope this helped.

Thiago Omena

So you are suggesting that I try to remove the brake booster to see how much fluid is in that? The only 2 things that are tied into the master cylinder are the 2 brakelines for the front wheels and the back wheels. So if the fluid keeps dropping down, and say the fluid is somehow seeping into the brake booster, that's what might be causing my pedal to bottom out too? When the engine is in the off position and I pump the brakes, I get pressure built up. But when I turn the engine on, I lose the pressure. I will take the master cylinder off and try to pull the booster out and see what it looks like. How often would a problem like that occur? I will let you know as soon as I remove the booster. Thank you for the advice. I'm sure I will hear from you again before the week is over about this issue. You gave me a couple of good ideas to go back and look for. Thank you very much.

Forgot to also mention that I have an automatic transmission. Not a manual transmission.

take off the rear wheels and pull off the drums and check inside there.

I called a Ford dealership earlier today and was told that my problem is the brake power booster. They said that the fluid is seeping into the power booster when I depress the pedal. And another thing that was mentioned was that when the brake fluid seeps through the power booster, it is then running down the firewall inside of the cabin where I can't see it. The service tech also mentioned that the power booster is the culprit and that there really isn't much else to be replaced. So, I am going to replace that as soon as I get a chance to.

haha, I was right.

just keep us informed if the problem is fixed.

OF course, since Ford no longer supports that model year they probably will not have a replacement booster, new or rebuilt; and used one's could be scarce, or iffy, after so many years. Good luck finding the parts and supplies you need.

Since it is the booster, I can get a remanufactured power booster at any auto parts store. They will only cost around $58. There is no problem getting a replacement.

a few questions did you adjust the rear brake shoes to make light contact with the drums and did you replace the self adjusters.

did you adjust the brake rod on the master cylinder to specs before installing it.

did at any point during brake assembly did you push the pedal to the floor.

if you did not adjust the rear brake shoes you will have excessive pedal travel before shoes make contact with the drum. and if you installed the self adjuster jack screws on the wrong side they will back the brake shoes off creating excessive pedal travel.

the brake rod on the back of the master cylinder needs to be adjusted to spec to long brakes will lock up to short excessive pedal travel.

there is a proportioning valve in the system, the lines from the master cylinder run to it. this works in conjunction with the duel section master cylinder. there is a piston valve inside, if one brake system fails, the over pressure from the good system slides the piston to close the orifices of the failed system.

as far as the leak goes just because its new don't mean its good. there is a lot of junk parts out there now days.

hope this helps

Before you spend money on another brake booster, put this thought into play. You stated that you replaced the master cylinder. Do you really think that the replacement master cylinder has the exact same defect as the master that you just replaced? Or is it possible that you accidental reinstalled the old master, and sent the new one back as a core? Unless the master cylinder is bad, it will not leak fluid anywhere. Not even to the booster.

Try some checking before you start your own stimulus plan in the auto parts field. Buy a can of brake cleaner. Spray the entire area of the master cylinder. Once the area is dry, remove the master from the booster. Leave the lines connected, and the cover on tight. Look in the booster end of the master. Is it wet with brake fluid? If not, your master is not leaking.

Reinstall the master, and pump the brake pedal 50 times. Recheck the fluid level. Is the master cylinder still full or not. If not full, refill it now. If it is full, start the engine and pump another 50 times. Recheck the fluid again. If low refill and pump 50 times again. At some point there is going to be a puddle of fluid somewhere. Look for it.

If you are not loosing fluid, start by rechecking the rear brakes to be sure that the wheel cylinders are actuating the rear shoes correctly. If the shoes are connected correctly, make sure that the brake shoes are adjusted correctly. Poorly adjusted brakes will give you a very low brake pedal.

Are you sure that you have bled the system correctly?. Have someone that has successfully done the procedure before help you. Good luck, let us know what you find.

Try this post I wrote a while back "Bench Bleeding"

http://cr4.globalspec.com/comment/431795/Re-Testing-a-Master-Cylinder

Jim C

Jim C is correct. If you are not sure that all of the air is out of the master, that will help you.

I have a question for you. What changed when you changed the master cylinder. Was the pedal any higher? Any firmer?

Hi Justin

After gone through your reports about all what you have done, tells me that all what you have done is not the correct thing. Now I don't know too muchabout the ford ranger, but as breaking system is concern, i will advice you to check your vehicle and see if its Alternator have an Exhauster which link to any area of the breaking system, if its so then the problem lies with the exhauster. Its flapping plates that create air is worn, they need to be replaced or you replace the exhauster or the Alternator.

I'm pretty sure it will help

Rgds

Aisha

First of all, the entire brake hydraulic system will only hold about 2 pints of fluid. If you have added more you have a leak. If there is no moisture on the ground or on any component indicating a leak then the only option is that fluid is seeping into the booster. If the amount of fluid is large enough, the fluid will be sucked through the motor via the vacuum supply hose attached to the booster and burned in the motor. You may or may not see white smoke depending on the condition and temperature of the catalytic converter. The best way I've found to bleed brakes is to construct a bleed bottle. Use a gatorade sort of bottle or at least one that allows a snug fitting small diameter hose to fit through a drilled hole in the top of the bottle. If you can find some small diameter Tygon (clear) tube that will snug/tightly fit the bleed screw nipples all the better. Put enough clean brake fluid in the bottle to allow the hose end to be submerged in the fluid. Attach the other end to the bleed screw and open it slightly. Depress the brake pedal slowly and repeat until the fluid runs clear no bubbles). Lock the screw shut. Starting with the left rear wheel (farthest from the master cylinder) continue with progressively shorter runs until ending with the left front. Pump up the peal until it is rock hard. Hold pressure on the pedal to check that it doesn't sink towards the floor. Release the pedal. Reapply pressure. The pedal should not sink. Start the motor, the pedal should drop slightly. If any of the tests fail repeat the procedure. Button up the wheels and tires. Test drive the ABS by accelerating to 30 mph or so and slam on the brakes. The ABS should operate normally and the pedal should remain at the normal height. Do this several times. If there is any air in the ABS modulator it will be apparent. If you have the RABS (rear ABS only) system you will need two people to bleed the RABS device underneath towards the center of the truck. Have a helper pump up and keep pressure on the pedal, crack a tube loose, tighten and repeat. They are notoriously hard to bleed and it may be bad.

Good answer wrench.

By the way, those RABS modules tends to break a lot. I normally use a pressure bleeder on them.

But I bet you problem is that you have brake fluid leaking into the vacuum booster. Which it is not that uncommon.

I notice everybody pretty much saying the same thing. That it might be the booster. I appreciate what eveybodies been commenting on. I didn't expect an outpouring of information. Thank you to everybody on here. I will try to keep everyone updated as soon as I get the booster replaced.

If your master cylinder is not bad, it will not leak into the booster. Why don't you test as outlined in post #13.

This may be obvious, but we're human, so it can happen. I don't think I saw it suggested, but did you make sure that the calipers were on the proper sides, so that the bleeder valve is at the top? If they are on the bottom, the air will stay trapped in the top of the caliper and never bleed out. It happened to me before on my 2000 Ranger, luckily I just bled it over and over before I figured it out, rather than throw more parts at it. Sometimes the simplest things get overlooked b/c they're just too obvious. I had a feeling it was a simple solution. I had replaced all of the brakes (drums, shoes, rotors, calipers and master). There were absolutely no leaks and the pedal sank to the floor with no resistance after ignition. Turned out that in my rush to finish a fairly routine job, I switched the calipers. Once the calipers were on the proper sides with bleeders on top, I bled the system and POOF! The brakes were back with a good pedal. Hopefully it's as simple as that, and it won't cost you anymore money or headache.

i have a 1992 ford ranger that has the same problem....it will stop but when i ease my foot of the brake and try to reapply it the pedal dissapears

You need a new/rebuilt master cylinder. If the pedal will drop to the floor, or close to it when lightly pushed, the piston seals in the master are allowing fluid to bypass the seal and return to the other side of the piston seal. Do not drive like this. It will deteriorate very quickly.

Bob,

I have fixed the problem 2 weeks ago. I had already replaced the master cylinder almost 2 weeks prior. The mechanic I took it to ended up replacing the front driver side brake hose (it was busted), both the rear bearing and seals, new shoes on the rear, new calipers on the front, and new hydraulic cylinders in the rear. All that actually took care of the problem. Thanks for all the input from everybody on this blog site.