my front brakes are locking up when i put my 98 v6 in reverse, it was doing it when ever i got below 10mph but i took out the abs fuses so now it only does it in reverse but i havent driven it far to see if it still does it going forward only a lil roll and when im driving on the highway and press my brakes i hear like an air sound....any help fixing this?

 

sounds like you need a new abs unit. are you getting a abs light, brake light and or a ses light? heres a couple things to look at that may help.
http://ls1tech.com/forums/suspension...ace-bleed.html

Bleeding ABS Brake Systems

 

If you getting an "air sound" when you press on the brake pedal, you need to take a good look at the brake booster, as it may be damaged. ABS shod not cause the brakes to lock up, its job is to prevent it from happening, however there is always a possibility. Brakes locking up without pressure on the pedal could be due to a bad master cylinder not allowing fluid to return to the reservoir when the pedal is released, possibly because of bad pedal linkage, master cylinder push rod too long, bad master cylinder.

 

Just adding to the above:
I have had customers complain of low speed front wheel lockup only to find out it issue was caused by a leaking caliper that has contaminated the brake pad. This condition is a lot more noticeable in reverse because when you step on the brake in reverse all the weight shifts to the rear and takes the weight off the front. Front grabby brakes will lockup very easily when in rev. FYI At very low speeds in reverse the front wheels will lock up under hard braking in all pre antilock brake system. Brake systems had a lot of thing to keep the back tires from locking up due to weight shift but all those things do not work in reverse because they do not exist for the front wheels. I am not a sure if the anti lock system is programmed to work in reverse?

Most antilock brakes systems have a isolation and a dump valve. This means the ABS can Isolate the caliper so you can not apply more pressure to the caliper and a Dump valve so that the ABS system can reduce pressure but I don’t think any 4th gens can add pressure. I read an article few years ago that the Mercedes benz newest systems can add pressure in a panic stop situation.

 

pete the way im reading it the brakes are putting themselves on. the only way i can see that happening is the abs unit. although without power i dont know how. why would a failing master cylinder only fail in reverse. how or why would it change with the abs unhooked. ive seen a messed up parking brake do the reverse lockup thing before but only in reverse and only on a drum brake. would failing/disconnected rear wheel sensors do this? maybe if it has traction control?