front wheels/brakes get hot


prohard
10-09-2004, 09:44 AM
2000 Windstar 3.8L, 80k just purchased.
The front wheels (brake disks) are getting hot after several miles (when I drove continuously 60 miles town&highway they had a persistent burning smell and extremely hot) The pads are almost new and brake works fine. I removed the calipers and cleaned cylinders which push the pads.They work fine but front wheels still getting overheted. Some forums recomended to disconnect ABS - not acceptable for me. Any ideas before I take it back to dealer? Other reasons for overheating besides brakes?
Thx

DRW1000
10-09-2004, 12:16 PM
Perhaps the pads are draging on the rotors. I think this is unusual for rotors but often occurs in drum brakes when the return springs are weak or the parking brake does not fully release.

There is of course, no return springs on the rotors but dragging rotors would certainly cause overheating.

rodeo02
10-09-2004, 02:25 PM
I'm with DRW1000 on that one. Your pads are dragging somehow. Did you ensure that the caliper pins are lubed & sliding smoothly and make sure the caliper slides are clean & lubed? Pulling the ABS fuse will do nothing for you aside from turn your van into a non ABS equiped van.
G/luck
Joel

prohard
10-09-2004, 03:47 PM
Yes they are lubricated... In fact, I lift the whole front of the van, removed wheels and rotate the disks with bare hands - works fine, the only effort is against transmission not brakes. Then I started the engine, put on gear and disk spins fine (left one, the right one I guess doesn't spin due transmission - is it called satellite mecanism?). When I apply brakes it stops and when released it spins again like it should (remember - car is on jackstands with no wheels). So I guess that's the ultimate proof that pads don't drag on the disks. My only guess is that something during roadrun would keep the pads pressed (brake liquid pressurized) . Thank you for answers so far.

Another clue: I think the previous owner just replaced the pads... meaning that they are thicker... anything out of this?

Question: Does the parking brake apply on front wheels too?

DRW1000
10-09-2004, 04:14 PM
The parking brake is on the rears.

Replacing the front Pads will of course mean that the static non-applied position of the calipers is now in a differrent position. This should not cause your dragging. Once the brakes are applied they "find" their new positions. The difference between applied and not-applied is not that much of a distance and there is generally less than 1/8" or so between the pads and the rotors when not applied.


The drag can be slight. It can still allow the wheels to spin but cause friction and thus heat.

Perhaps the wheel bearings too but I sincerley doubt they could generate enough heat to affect your rotors and not fail completely.

I still think the rotors and pads are the best bet. The pads run on metallic sliders. They should be greased with anti-seize during installation of the pads.

Are both sides getting hot? Perhaps they were not lubricated during assembly. You may wish to dismantle and reassemble ensuring you lubricate the sliding mechanism.

12Ounce
10-10-2004, 10:38 PM
I have two guesses:

1. Rodeo and DRW have both mention lubrication. I really think this is probably the problem. Remove the pads and hardware from one caliper. Attempt to move the caliper, by hand, inboard/outboard. The caliper should slide effortless on its supports. Repeat for other wheel.

2. This is a long shot, but I've seen it happen. DRW mentioned that there are no return springs in calipers. True. But the retangular o-rings that seal the caliper pistons sit in a groove that holds the o-rings at a very slight angle... the result is that the o-ring will retract the piston (just a bit) away from the rotor when the pedal is released. ...that is , they will if the master cylinder check valve is working properly... allowing a free flow of fluid back into the cylinder.

As I said, this is a long shot ... but I've experienced a master cylinder that would not allow prompt retraction of calipers. But before changing out the master cylinder, I would suggest you do a washing of the hydraulics by changing the fluid a couple of times.

2a. An even longer shot ... but one that I've experienced and know that others have also: Failing brake fluid hoses (to calipers). I really doubt that your 2000 would already have this problem .... But it is possible to get a similar condition, to above, when hoses have internal wall collapse. The fuid is forced through when you put on brakes, but will not return properly to the master cylinder.

12Ounce
10-10-2004, 11:13 PM
Hold the press .... another (hot?) late hour guess just in!

3. Dirty caliper pistons. ... perhaps caused by a damaged/missing piston boot. When the pads were replaced the pistons (along with dirty external walls) were force-retracted into the caliper cylinders. Now you have pistons that are rather jammed in the o-rings and cannot retract freely.

Fix: rebuild calipers... cleaning/replacing pistons, replacing o-rings and dust boots...lubricating well with hi-temp syn grease or silicone paste.

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