Pulsing brake pedal

[cooljerki]

I am having a problem with the brakes on my 2000 Ranger 4x4. The brakes are powerful and smooth until just before I come to a complete stop. Right then, the brake pedal pulses and the brakes feel like they let go. I do always manage to come to a complete stop, but it's not a comfortable feeling, and I'm afraid I'm going to rear-end someone. It feels like the ABS is coming when it shouldn't be.

Any help would be appreciated.

Thanks,
Jason

[AllanD]

Sounds like an ABS issue to me to.

Seek profesional Help.

Or atleast take it for a short test drive with the ABS relays PULLED fron the power distribution box (On fords with the relays pulled the system reverts to "normal" power brakes.)

AD

[cooljerki]

Do you know which fuses are for the ABS?

Thanks,
Jason

[cooljerki]

Oops, I meant relays.

[njshaman]

I just purchased a 97 ranger. I also have the same issue with the brakes. Any conclusion as to what the problem was?

[rparker]

I have same issue. 1998 Ranger. Any answers on what it could be?
TIA

[Carlos Murphy]

I'm surprised nobody said the rotors are warped :icon_rofl:

Most of the time this symptom is the result of the buildup of brake pad residue on the rotor surface.
It builds up in one spot and when that part of the rotor passes through the caliper it spreads the pads apart causing the pulse.
Clean your rotors with fine sand paper and "brake clean" and change to a performance pad.
I've had MUCH experience with this issue while turning wrenches on BMW's for 33 years.

[metalmacguyver]

I'm surprised nobody said the rotors are warped :icon_rofl:

Most of the time this symptom is the result of the buildup of brake pad residue on the rotor surface.
It builds up in one spot and when that part of the rotor passes through the caliper it spreads the pads apart causing the pulse.
Clean your rotors with fine sand paper and "brake clean" and change to a performance pad.
I've had MUCH experience with this issue while turning wrenches on BMW's for 33 years.


if you re-read the first post, youll notice that it only happens when the truck is almost to a stop.

if the problem was pulsing at all speeds when the brakes were applied then yeah warped rotors would be the likely culprit.

[Sunk]

It could be possible that the pulse can't be felt and higher speeds due to the higher revolutions, and once you slow down they become more pronounced. Mine does this slightly. I can feel it at higher speeds, but more at lower speeds.

[Carlos Murphy]

What Sunk said.

The higher the road speed the higher the frequency of the pulse and it is not so evedent (if the build-up is minimum), the slower you go the more you'll feel it.
From say 20 mph to 0 you should be able to count them and the last 12 feet or so of roll out you should feel maybe 4 pulses and they'll be very pronounced.

[Chic N Stew]

if they are hubbed, check the wheel bearings, or it may be runout rotors, maybe need to be replaced or turned

[metalmacguyver]

What Sunk said.

The higher the road speed the higher the frequency of the pulse and it is not so evedent (if the build-up is minimum), the slower you go the more you'll feel it.
From say 20 mph to 0 you should be able to count them and the last 12 feet or so of roll out you should feel maybe 4 pulses and they'll be very pronounced.


ok i see what you mean. however what i gathered from the Cooljerki's post was that the brakes were fine til almost stopped and then he was experianceing a severe pulsing that started at a specific point and didnt come on gradually as you say.

it doesnt matter anyway because Cooljerki hasnt logged in since october 29th. its been a week for the other two people with only one post each. so i think they have forgotten about this thread.

[Chic N Stew]

true /\

[Earl43P]

I am having a problem with the brakes on my 2000 Ranger 4x4. The brakes are powerful and smooth until just before I come to a complete stop. Right then, the brake pedal pulses and the brakes feel like they let go. I do always manage to come to a complete stop, but it's not a comfortable feeling, and I'm afraid I'm going to rear-end someone. It feels like the ABS is coming when it shouldn't be.

Any help would be appreciated.

Thanks,
Jason



Sounds like one of your FRONT ABS sensors is bad. It is NOT the rear because it isn't affecting your speedometer. It may be worth the $ to go to Ford, it takes a specialized reader to retrieve ABS codes. Front sensors run over $100 each.

YOUR ABS fuses are: under the hood, fuse 3 and 7, in the cab, fuses 9, 11, 14. I can't remember which fuse to pull to disable the ABS (14?), but I CAN tell you that when you do so, you WILL lose your speedometer and odometer and Cruise (on a 2000). Try fuse 3 first (50A abs pump motor).

Without ABS enabled, you will also lose your front/rear proportioning function, which may make a panic stop interesting if you aren't expecting the degraded handling.

There is NO ABS relay.

[rparker]

I don't believe that the problem is warped rotors. The problem only happens (to me) just as I am coming to a stop - barely moving. There is no other time it happens. Then the pedal drops/pulses and there is also a noise (hard to describe) that is comming from the pedal area (maybe behind the firewall). Kinda sounds like a very quick series of clicks. I thought master cylinder but there is no leakage.
Any additional info / help is appreciated.

[Chic N Stew]

This is gonna sound kinda stupid, but have you checked the pads, they may be cracked or chipped or something like that

[metalmacguyver]

I don't believe that the problem is warped rotors. The problem only happens (to me) just as I am coming to a stop - barely moving. There is no other time it happens. Then the pedal drops/pulses and there is also a noise (hard to describe) that is comming from the pedal area (maybe behind the firewall). Kinda sounds like a very quick series of clicks. I thought master cylinder but there is no leakage.
Any additional info / help is appreciated.

that clicking sound is the ABS activating.

[gsxrken]

Sounds like an ABS issue to me to.
Or atleast take it for a short test drive with the ABS relays PULLED fron the power distribution box

AD- would you know where the appropriate relays are on a 99 4x4 4WABS? Thanks

[rparker]

Not sure if it is applicable but: had to go into 4wd and the ABS light came on. Stayed on after I took it out. Did not come back on after shutting down and starting again. Also after I took it out of 4wd, was going down a slight hill, snow covered so going slow, put the brakes on and rears locked.
The real puzzler is that the pulse does not happen every time. It happens most of the time so now I am looking for it and when it does not happen it startles me.
Do I admit defeat an go to a dealer?

[metalmacguyver]

AFAIK, the 4wd part should not affect the abs. i would recommend having a dealer check it out.

[Yellowsplash]

I had the same problem. Its actually quite common. The abs sensor isnt getting a good reading on wheel speed and when you slow down to under 10 mph the abs kicks in. Seems to do it more often with only slight pressure on the pedal, and less often under hard braking. Either way, the sensor (which I believe is magnetic) is dirty and not getting an accurate reading from the rotor ring. Just remove the rotors and clean the sensor on each side with some brake parts cleaner and wipe it off real good. Should clear up your problem...

[shadetree]

The problem only happens (to me) just as I am coming to a stop - barely moving. There is no other time it happens.
This is one symptom of a warped rotor. As the vehicle slows, the pulsation begins, then slowly dissipates as the vehicle comes to a stop, not saying you don't have other problems, just that this is one symptom. shady

[bigredneck61088]

i have this same prob on my 2001 2wd and its not warped rotors, anyone come up with a solution???

[MAKG]

This is one symptom of a warped rotor. As the vehicle slows, the pulsation begins, then slowly dissipates as the vehicle comes to a stop, not saying you don't have other problems, just that this is one symptom. shady

And runout is very easy to measure, so it should be done before going after the ABS system. While you're at it, mic the rotors, since thin rotors can cause warpage when hot, that goes away when cool.

Though pulling the ABS fuse is a good idea.

No one asked what the conditions were. If this is on slippery surfaces, the behavior described might be normal.

[Joshs93four-oh]

He says that just before drawing to a stop that the pedal pulses and the pedal drops. The ABS pump is activating. I have had this problem many times with customer cars and they have all been Fords. Is the abs lamp iluminated? If not, maybe one of the speed sensors has an intermittent output but the duration of the fault is not long enough to set a code? Maybe one of the front hub assemblies is starting to go bad and there is metal particles/comtamination on one of the tone rings internally? Another possibility is that the hub assembly housing is corroded and scaled enough that the speed sensor mount surface is actually "raised up" and away from the tone ring engough to affect the air gap. If it is a rapid pulse then there is no way that it is a warped rotor because the vehicle is not traveling fast enough to create that frequency of pulses. An abs pulsation feels like the brake pedal playing a "bass note" through your foot. Josh

[fastmaxx400]

I had this problem with my ranger when I first bought it. I replaced the rear sensor, and it still did the same thing. If I pulled the abs fuse it would not do it. I took off the front wheels to look at the sensor and everything looked fine so I took it to get the codes read. They told me left wheel sensor. Replaced that and still had the problem. Ended up saying what the heck and replacing the other sensor on the right wheel and it fixed it. I was about to pull out my hair. Later talking to a tech, he said that the sensors were not reading the same causing the computer to think at low speed one of the wheels was locked up. I am so glad its fixed

Kevin

[4.6StangRage]

mine does the same thing i checked my pads and they are thin and need to be replaced.

[gbadgley]

That is a very common problem with the Ranger/Explorer. I can tell you right now it is in all likelyhood in the ABS. I put 4 new rotors on my explorer and cleaned the sensors, No difference, It's just one of those things that I will have to dig into to find the real problem.

[yuzr]

disable the ABS... lose your speedometer and odometer

2000 2.5L auto. 22k miles, a few every day.
Drove 10 miles, 2 hours later returned to truck and found:
- ABS light
- inactive (spee)(o)dometers
- NO UPSHIFTING (so, I drive in 2nd, not revving).
Those three symptoms, no others. Invariable and permanent.
Fuse 14 visibly intact. Fluid fine.

What is your take on this interrelationship of ABS and shifting?

[westonoto]

AFAIK, the 4wd part should not affect the abs. i would recommend having a dealer check it out.


4wd does have some effect on abs. I don't know the mechanism of action, but when driving on ice or packed icy snow, having the vehicle in 4wd seems to greatly lessen the tendency to activate ABS. Thank God it does. The ABS is dangerous on those road conditions in my truck. No front braking power at all. Far better with 4wd on.

[Sasquatch_Ryda]

That is a very common problem with the Ranger/Explorer. I can tell you right now it is in all likelyhood in the ABS. I put 4 new rotors on my explorer and cleaned the sensors, No difference, It's just one of those things that I will have to dig into to find the real problem.

You are right that it is a very common problem on rangers/ explorers. The problem is usually a cracked tone ring inside the hub assembly and usually just replacing or cleaning the sensor itself will not solve anything. You need to have the entire hub assembly replaced. As far as I know Ford as updated the hub assembly and recommends that they be replaced in pairs. This is definitely not a warped rotor issue.