Had a minor bumper-bender a few weeks ago in the wet going about 35MPH in my '95 Edie Bauer. The guy in front of me was stopped dead in traffic. I pushed the pedal to the floor and felt SLIGHT pulsing in the pedal as if the anti-locks were trying to work, but I was not stopping! Hit the guy in front of me at about 10MPH and had to replace almost all the components on my front including the bumper, grill, and lights. No other damage until I got rear-ended a few seconds later, and also had to get a new rear bumper. :eek: Talk about a sandwich. Good news is that nobody was hurt, except for my pride which was a little damaged.

Here's my questions:

After repairs, I'm now paying a little more attention to the bake operation, and I noticed that the brake pedal seems to be a little mushy. Also, I had 4W-High selected at the time, thinking I would get better traction in the wet.

I was wondering if there is a difference in brake operation if you have 4WD selected instead of Normal?

Also, has anybody had any problems with the brakes and/or anit-locks that may shed a little light on my situation?

Thanks,

As far as I know, there is not any change in brake operation between 2WD and 4WD modes.

Have your brakes been bled properly? Is the brake fluid dirty, or does it have moisture in it? Is there a vacuum leak around the brake booster? Are the pads down? Are the rotors warped?

I'll assume the road was snow covered since you had it in 4x4. If the tires can't grip, doesn't matter how good your ABS is, you won't stop on a dime. What tires do you have and what condition are they in? Since you have to be able to grip to stop, that's where I'd start. If your brakes didn't lock, then the ABS is working.

Thanks Guys,

Good questions Rhett. I haven't had time to check my records yet, but I'm going to see the last time I had brake service.

It was actually raining at the time TPLYNCH and I must assume the roads were pretty slick with oil & rubber residue. It felt like I was on ICE at the time.

I'm using Dunlops with about 50K on the tread. The tread only looks as if it's about 1/2 gone. The Dunlops are rated at 500 A B on the sidewall.

Just checked my records, and I last had brake flush & service at 70KMiles. According to the current ODO, that's about 35KMiles ago. I did a quick visual on the resovoir and it lools to be at the correct level, and the fluid is clear.

I tried pumping the pedal with the engine off, and then held pressure on the pedal as I started the engine. The pedal went almost to the floor. Since I am over 40, I can't seem to remember what this indicates, but I remember that this is a test for something. :confused:

Any other ideas?

Sorry about your accident. I just wanted to comment that its probably not a good idea to use 4 High on only wet pavement.

Jason

Thanks Jason....

It's my understanding that when you are in the 4WD AUTO Mode instead of the 2WD Mode, the computer will automatically switch you to 4WD, but only if necessary. I think it keeps you in 4WD until it senses the slippery conditions are gone, and then automatically switches you back to 2WD.

My logic was to put it in 4WD AUTO because the tail had in fact tried to come around in a turn while I was in wet conditions previously. I know this will probably only help give you traction while accellerating, but my basic question is, does being in 4WD affect the anti-lock functions when you are braking?

I'm thinking that maybe the computer may get confused if the antilock sensors are sensing lock-up AND you are in 4WD at the same time. Does anybody know if thery are related, or am I way off base?

Thanks,

Originally posted by DonL
T


I'm thinking that maybe the computer may get confused if the antilock sensors are sensing lock-up AND you are in 4WD at the same time. Does anybody know if thery are related, or am I way off base?

Thanks,

Antilock module controls the operation of the ABS, the GEM (generic electronic module) controls the operation of the Control Trac transfer case operation. They are separate computers. They are not related in the way you are suggesting, and they do not use the same sensors.

The ABS uses tone rings in each of the front wheels (part of the sealed hub assy) and a tone ring on the ring gear of the rear axle (a tone ring is a notched ring which interacts with the Hall effect sensor to create a signal for the computer).

The Control Trac 4wd system uses tone rings mounted to the front and rear driveshafts inside the transfer case. The GEM monitors the signal produced by the front and rear driveshafts to determine how to engage the clutch inside the transfer case.

The GEM does receive a signal from one of the ABS relays to determine when the ABS is active, according to the electrical schematic for my 97, but I don't know how the GEM uses this information. It is somehow used to modify 4wd operation though, not the ABS system.

On your 95, you should be okay to use 4wd Auto on wet pavement (or even on dry pavement) if your system is working correctly. On the earlier 91-94 Explorers you should not use 4wd on pavement and on the 97 and later Explorers you shouldn't use 4wd High on pavement, but you can use 4wd Auto (the 97 and later are in 4wd Auto by default).

I'm sure that is more than you possibly wanted to know ;)

Great explanation dogfriend. That's exactly what I wanted to know. :)

I guess I'm just trying to eliminate a problem with the brakes as opposed to my "following to closely" when I had my bumper-bender. In my opinion, I was far enough back that I should have stopped in time if everything was working correctly.

Here in Southern California I don't get the opportnity to drive in slick conditions too often. I learned to drive in Pennsylvania on pretty slick roads in the winter, but this was a complete surprise to me. Flooring the anti-lock brake pedal and not stopping within 7 car-lengths was just completley alien to my way of thinking. Pretty scary when you think about what could have happened if I had been doing the posted speed limit of 55, insted of about 35 at the time. :eek:

I would check the following with the brakes:

1. Check to make sure rotors aren't warped. This was already mentioned by Rhett. Warped rotors will cut down the effectiveness of the brakes.

2. Check and relube the slider pins that mount the calipers. Sticking slider pins may cause the rotors to warp and may cause the pads to wear unevenly.

3. Make sure the brake booster is working correctly. The test that you referred to is to test for a vacuum leak in the booster. I'm not sure whether your results indicate a problem or not.

This link may help: http://www.autozone.com/servlet/UiBroker?ForwardPage=az/cds/en_us/0900823d/80/0b/ce/8c/0900823d800bce8c.jsp

Don, in your initial post you mentioned being in 4HI. That's why Jason mentioned not using it on rain. I was going to do the same thing if it wasn't snow and you were using 4HI. Auto is ok. I forgot '95 was 2wd 4Auto 4Lo. Sorry can't help more with the brakes.

Whoops..... :banghead: Sorry JasonF, TPLYNCH, and others. I didn't identify the setting correctly in my initial post. I was actually in the "4WD AUTO" setting on my switch vice 4W-High.

I will check all of these things out when I get a chance. I really appreciate all the inputs. :)