Ford Aerostar: Smoke/Burning smell from wheel well

[Mr_Accord]

I have a 93 Aerostar RWD 4.0L that I was driving around town a few weeks ago and I noticed it wasn't braking that well. The pedal is usually firm but easy to push and very sensitive...instead it was a lot firmer and didn't brake as quickly when i put my foot down. The van itself felt a little under powered, like something was holding it back and I had to put my foot down a lot more to get it up to speed. After awhile I began getting a really bad burning smell coming in through the driver window. I pulled over and saw small faint lines of smoke coming out of the front driverside wheel well, upon closer inspection I got a good scent of burnt brake pad and the hub cap on the wheel was really hot. I automatically assumed the caliper was ceased. Later when I had free time took the wheel off removed the caliper from the wheel and everything looked fine. I was able to push the piston back in with ease using a C-clamp, but there was a lot of corrosion in and around the piston, I wire brushed it off and greased and cleaned everything up. I took it out since then on a few short trips to the store, everything seemed fine, wheel wasn't hot. Today however it happened again, and I began smelling burnt brake pad from the same wheel well. It only seems to happen when I have been driving it for a long time like 30mins to 1hr, short trips everything is fine. Is this the caliper or the Master cylinder? Due to the excessive heat around the wheel hub should i maybe think about replacing the inner and outer wheel bearings as well?

 

[97prizm]

My parents had a 95 aerostar but never with this particular problem. I would definitely replace the wheel bearings if it's had this happen twice. I was thinking maybe a the brakeline had become pinched restricting fluid? I would assume the master cylinder is going bad, if you were able to clean and reassemble the caliper with ease.

 

[wrcsixeight]

This can happen when the flexible brake hoses begin to fail. Internally it can act like a check valve only allowing brake fluid to push the caliper closed, but not retract.

New lines are pretty cheap and not difficult to replace, but take precautions not to shear off the steel lines when doing so, like I did in the recent past.

 

[JHZR2]

I had an issue once where the piston and everything was fine, caliper looked good, but grit on the slider pins caused the capiper to not be able to engage/disengage properly. As a result of the improper sliding, the holes in the caliper had gone oblong, causing it to get worse.

Initially it was a matter of squeal. After a while it was a matter of enough drag to cause burning scent.

 

[Mr_Accord]

Quote:
My parents had a 95 aerostar but never with this particular problem. I would definitely replace the wheel bearings if it's had this happen twice. I was thinking maybe a the brakeline had become pinched restricting fluid? I would assume the master cylinder is going bad, if you were able to clean and reassemble the caliper with ease.

Quote:
This can happen when the flexible brake hoses begin to fail. Internally it can act like a check valve only allowing brake fluid to push the caliper closed, but not retract.

New lines are pretty cheap and not difficult to replace, but take precautions not to shear off the steel lines when doing so, like I did in the recent past.


Really? I never knew that could happen with those rubber lines, but they are the original lines. Well I'm probably going to have to replace the steel lines as well there is a lot of rust around where the rubber attaches to the steel lines, I doubt I could get it off without snapping something. Lucky for my though the Master cylinder is right above the wheel so i only have to run a few feet of new pipe.

Quote:
I had an issue once where the piston and everything was fine, caliper looked good, but grit on the slider pins caused the capiper to not be able to engage/disengage properly.


I was thinking the same thing the first time it happened to me, but I removed the caliper, pins, brake pads and cleaned and greased everything and it happened again yesterday.

Thanks for the info guys I'm going to replace the rubber lines and maybe pick up a used caliper from the scrap yard just to be sure.

 

[berniedd]

Originally Posted By: wrcsixeight
This can happen when the flexible brake hoses begin to fail. Internally it can act like a check valve only allowing brake fluid to push the caliper closed, but not retract.


Yes, this happened to me too. BraKE was locking up in that wheel.