OutlawBiggie

Not sure if i do or not, just baught truck last month, has front disc, rear drums. Both lines coming out of master cylinder go into the abs box under the air filter, but i didnt hear nor feel the pedal vidrate and push back when the rear locked up.

papa tiger

Rear wheel anti locks came standard. The Lariat got 4 wheel ABS standard. ABS was optional on rest of the F150's for 97. Probably need to check out your VIN also. If you have rear anti locks you have a rear abs module dirrectly below the master cylinder, check its condition and reset it. It may be locked/stuck in the rear position.

4everford150

Unplug the power to the comp on top of the ABS unit and see If it solves your problem (u want have ABS if u slam on breaks ) if not than u can remove that from the equation. Its easier to remove the air box before messing with it

OutlawBiggie

Wont unplugging the abs power throw a CEL?

papa tiger

Also bleed with motor running to use the Antilock systems push. Some hate the mess if not contained.

OutlawBiggie

Thanks, ill attach a tube to bleeder valve and run it into a jar.

4everford150

Have u checked to see if its thrown codes yet? Unplugging will throw a code but its not going to effect anything if it doesn't fix ur problem plug it back up and have some one clear the code .Could be master cylinder leaking there are tons of issues it could be u will just have to take one out of the equation at a time.

redseal97

4WAL the HCU is under air box, 2WRAL the HCU is near the firewall closer to under the master cylinder, if you get air in the abs unit, it must be "turned on" to purge, or they call it re homeing the motors, usually a high priced scan tool has the ability to turn the abs pump on,..........or you can drive it and rebleed every couple days.....it takes about a week but you can get all the air out that way,