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Brake Problems with 1993 4x4 Explorer
After making a panic stop on interstate, my front disc brakes overheated as I continued driving. By the time I pulled into my driveway, they were smoking, and the rotors were blue and glazed. I replaced front rotors, bearings, pads, and installed two rebuilt calipers with steel pistons. I also replaced front brake hoses and rear wheel cylinders, and completely changed fluid and bled brakes. On successive test drives, my front brakes continue to get extremely " HOT ".
The caliper sliders are properly lubricated, and wheel bearing torque is correct. I am suspecting the antilock pump unit, but I do not want to replace parts on a trial and error basis. My Ford dealer said that if the antilock light comes on when the ignition swith is turned to on, and goes out when the engine is started, that then the antilock system is functioning correctly.
If it turns out to be the antilock pump module, my manual states that the average mechanic cannot replace this unit without " Expensive and Expansive " equipment. Is this a fact ?
Iam at a loss to find the problem. ANY SUGGESTIONS ?
The caliper sliders are properly lubricated, and wheel bearing torque is correct. I am suspecting the antilock pump unit, but I do not want to replace parts on a trial and error basis. My Ford dealer said that if the antilock light comes on when the ignition swith is turned to on, and goes out when the engine is started, that then the antilock system is functioning correctly.
If it turns out to be the antilock pump module, my manual states that the average mechanic cannot replace this unit without " Expensive and Expansive " equipment. Is this a fact ?
Iam at a loss to find the problem. ANY SUGGESTIONS ?
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I too had a 93 Explorer, and the front brakes were the low point of the vehicle. Meineke fixed them for me. I had no further problems. I traded it off at approximately 80K miles for a Ranger.
Have you checked for a crimped steel brake line somewhere. This would mimic fleetwood's suggestion.
First of all, you'd need to determine two things:
One, are the front brakes really dragging?
Two, all brakes get "HOT". What makes these unusual? Are you actually smelling them? Do the rotors glow red at night (seriously, they will if they are overheating).
if the new rotors aren't that hot, and no, don't touch with fingertips, even nice unhammered rotors on a one-mile drive with three to five stops raise a blister the size of a dime when touched... then you still have time to find the last problem.
if you had to hammer the brakes hard in a panic stop, it is not impossible to have munged a master cylinder.
dshepherd3's suggestion is not beyond possibility, either, for the hell of it pull and cap the vacuum line to the brake booster (and put a dust cap or bag and tape over the connection to the booster as well to protect it from road dust internally), and test it out in an empty parking lot.
yes, it will NOT brake right, you will have to push hard, that's why I say you don't want to test it on the freeway. but if you can come to a stop, jack the front wheels up and spin them, but get brake drag (they won't freespin) with the booster in, the booster is implicated. if it drags both ways, it's a line, the master cylinder and/or proportioning valve.
there are good calipers and bad calipers after rebuilds, white-box ones without labels are to be suspected as well.
if alcan drifts by this discussion, he will have tons of useful advice, and probably catch me in a contradiction since I personally haven't had this issue yet.
Adam
All you need to do is ascertain if there is or isn't spark during the no-start. If no spark, I'd go ask the Ford parts department which ignition part fails all the time on '94 Explorers and if he actually answers you, that could be it.
Intermittents are devils to fix because they are...well...intermittent. This sometimes requires parts substitution and a two week road test.
TO:# 2, fleetwoodsimca- Since I bought the 93 Explorer, the brakes HAVE BEEN and ARE the LOW point of the Explorer.I have flushed ALL lines, and the fluid flows without restriction, so I do not suspect a partial blockage at this time.
To:#3, Mr shiftright- The rear brakes are working and are getting slightly warm when testdriving vehicle. I have checked ALL lines and there are no crimps or external dents.I believe that the brakes have to be dragging because they are getting " HOT " .I have the luxury of having a 96 4x2 Explorer also, that I use for comparison. I drive the same test track ( i.e. 4 lane and two lane roads in my neighborhood ) with both vehicles under the same braking conditions, and the 96 comes back with the front hub slightly warm. When I return with the 93 Explorer, the left and right hubs, rotors, calipers and RIMS are so hot that I can only put my hand on them for about 2 seconds before quickly pulling my hands away. I have always monitored my brake temperature and tire pressure anytime I take a trip outside of my immediate area, and the temp on the 93 has always been comparable to the 96, or any other vehicle for that matter.I know that HOT, without a thermometer is relative, but the 93 is extremely hot after a few mile test drive. I am afraid to take it on a longer trip for fear of ruining the new parts, as well as getting stuck somewhere. I have taken the 93 on a testdrive, came home, and immediately jacked the front wheels and spun them. They do spin without restriction,other than normal pad drag. I then jack up the 96, and without having driven it or after driving it, the drag on both vehicles is comparable. I have gone as far as driving the 93 up my driveway ,after a test drive, making sure not to make any reverse motions in case whatever is dragging releases from the change in direction, left the engine run in order to keep booster assist the same, and have been able to spin the wheel without restriction, even though it has become excessively hot from the testdrive.
To: # 4 , dshepherd3- Because of the fact that the wheels spin freely when lifted, even thought they are hot I believe that your experience with the booster had a lot of merit, so I disconnected the vacuum line and plugged both the vacuum line and booster and took the vehicle for a test drive in my subdivision only, because the braking was so very poor. I need to get on a road where there is no traffic to get a more accurate comparison between booster in and out of system.Tomorrow, I plan on lifting wheels, starting the engine and bringing to about 2000 RPM, to simulate the vacuum during normal driving, and see if I am able to spin wheel freely,to determine if booster vacuum at driving speed causes brakes to be applied, and then released when engine goes back to idle.
also, try backing out the screws that hold the packs and tightening them back up, that's the ground for the HV. pull and poke the coil pack connectors to LV a couple times as well to clean them up, corrosion does not necessarily advertise itself with big green scum caps on the outside of the connector in every case.
also, do you have a system in which there is a smallish electrical module attached to a metal plate bolted to the engine someplace? about the size of a lockback knife? if so, replace that immediately on general principle... a California court has ordered those replaced as warranty failures because they get too hot and quit in normal operation. GM used to have a spark module in their distributors in the mid-70s, bolted to the distributor plate inside, and wonder of wonders, they had a lot of failures of that part, too.
ain't it amazing that a "heatsink" for a module that can be expected to heat up beyond the module's operating temperature in use causes failures? who would have thought it? 8th wonder of the world!
what was the grade point of those engineers, anyway? pinheads.
I made two changes, and the problem was alleviated. Unfortunately I don't know if one or both changes eliminated the problem.
When I purchased the rebuilt calipers from NAPA, they came with a package of Silicone based lubricant for the slider grooves and retainer clips. It's consistancy was similar to Vaseline. The kit also came with new retainer clips that are two pieces of metal bonded together with rubber. I cleaned off the lubricant and replaced it with Molybdenum based caliper slide grease which has a thinner consistancy, and reused the old retainer clips, whose rubber had been softened a little over time, and that were not as tight in the groove. Voila !!!! Problem solved.The
brakes work great, and they no longer get HOT !
THANKS FOR EVERYONES HELP AND SUGGESTIONS.