Hi all,

(Didn't want to start a planned long trailer tow with recently acting up brakes):

I have an OBS '93 F250 7.3l that recently each of the last 3 trips the red "Brake" and amber "ABS" lights came on after about 20-30 minutes of driving. I felt that the vacuum assisted brake pedal began to feel different also at the time it happened and during the time those lights were on, a stiffer brake pedal, could brake and stop no problem, just felt different. I pulled over, shut down the engine, then restarted and then brakes were fine again. Just the normal red brake light until I removed parking footbrake and the vacuum pump came up to speed and the red brake light extinguished. The ABS light was also off now, as I drove off. I also had vacuum assist to the brakes again. Then after another 20-30 minutes of driving, both lights came on again, and the vacuum assist went away again (or possibly just diminished, but brake pedal felt noticeably stiffer again).

Anyone know what's going on? Other possibly pertinent details: I noticed one time out of the 3 trips that the little wire to the footbrake mechanism had become completely disconnected, and so I reseated it. Also, I've noticed a little more belt screech recently, but I've had a little belt screech since I bought the vehicle 3 years ago, and I replaced the serpentine belt and hit it with belt spray. Seemed to calm down the belt. But at the time for some reason (that I can't remember, but I do remember trying to source up a correct replacement online), I suspected the vacuum pump might be a future (or present) problem. Other things I recently did: Replaced all the 4 cables in the parking brake system, all OEM except for the intermediate (couldn't get the rear parking brake to hold on a hill until I replaced as much of the aftermarket parking brake cabling and even brake drum and shoes with OEM, and finally cut the intermediate cable and swaged in a small turnbuckle to get some adjustment leeway as well), serviced rear brakes (new OEM drum, aftermarket springs, motorcraft shoes, did not touch wheel cylinders, they looked ok, no leaks, didn't want to touch/possibly damage and replace brake lines at the time), but in the process of working under the truck during that time, I accidentally pulled on a wiring bundle along the driver's side frame, the 5 wire one with the connector that goes to the electric fuel selector solenoid switch. At the time I knew I messed up something, as both fuel tank instrument gages went immediately to very past full deflection (indicating Full tanks +) when I knew they weren't. I inspected and then reseated that electrical connector to the fuel selector, and the fuel tank gages indicated normally again, so I didn't go further with that. I bring this up, because the last time I had this brake issue yesterday, I also noticed that the fuel tank gage seemed to be indicating more full than it should be, not absolutely full deflection, but say 7/8 full, when I knew it was about 2/3's indicating earlier in the drive, but perhaps this is a simultaneous but unrelated problem. I went under the truck and pushed on the 5 wire connector, jiggled the wires a bit, then proceeded to the footbrake and pulled off that wire and reseated that connector too. I don't know if that did anything for sure, but the truck "seems" ok again. And also the fuel tank gage was indicating 6 tenths to 2/3 again (where it should have been considering the miles I travelled). I am not a car guy, just a shade tree one at best. Any of you guys know this truck model enough to help me troubleshoot this? I'm concerned the brakes will act up again at in inopportune time (while I'm towing a trailer).