When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am under the car.
My wife is in the driver's seat.
Do you really think that I am going to give her the key?
In other words, no key.
I'd say it depends on just how large your wife is. If she's a large woman and you're brave enough to get under the truck with her in it, then you should be brave enough to let her hold the key.
The good old non-abs method isnt working for me. After I get done bleeding the brakes out, the pedal is nice and firm. Two days later the pedal is back to being mushy again. In a panic stop the pedal goes to the floor, and the truck doesnt stop too well. I have changed the pads, rotors, master, calipers, and swapped the rubber brake hoses for braided ones. There has to be air trapped somewhere, and I feel its in the abs unit.
After I get done bleeding the brakes out, the pedal is nice and firm. Two days later the pedal is back to being mushy again.
You have a microscopic pinhole leak in a brake line. If there were air in the system, the pedal would not be firm. When you bleed them you're getting the air out, but it works it's way back in there over this two day period.
If there is air getting in, would some fluid leak out of the same hole? The only things I havent changed are the hard lines and the abs unit. Even with the firm pedal the brakes just arent right. With the truck in the air, I can hold the brake pedal and give the truck a little gas and watch the rear wheels spin. There is just no holding power in the rear. I cant lock the rear wheels in the rain no matter how hard I try.
The good old non-abs method isnt working for me. After I get done bleeding the brakes out, the pedal is nice and firm. Two days later the pedal is back to being mushy again. In a panic stop the pedal goes to the floor, and the truck doesnt stop too well. There has to be air trapped somewhere, and I feel its in the abs unit.
I have not tried this technique, but a Big 3 brake engineer posted it a few years ago:
Purge the system as best you can. Then in a big grass field, get up a little speed and slam on the brakes hard enough to get the ABS to pulse. Do this several times. This should force some fluid throgh the ABS module.
Once again, I have not tried this and it is not my technique.
If there is air getting in, would some fluid leak out of the same hole?
Nope, not if the hole is small enough. Air is a gas and brake fluid is a liquid. Because of this, the air can pass through a smaller hole than the brake fluid can. Of course if the hole were large enough for fluid to pass through, then the air would also pass through. About 25 years ago I worked on this same problem on a Dodge Dart. It drove me nuts for a week until I discovered that one of the fittings wasn't making a tight seal.
I like your theory on this. But I have some questions on this: If I had a pinhole air leak, wouldnt the problem slowly get worse? Also, whenever I have bled the brakes recently I didnt get any air bubbles. This is really starting to get to me. I have been chasing this problem for 3 years now.
When you changed out your calipers, did you get them on the correct side? they are handed.
A few years ago, someone posted that they had a problem with their brakes and it turned out that they had the calipers on the wrong sides. Flipping the calipers meant that the bleeding screws were on the bottom of the caliper rather than the top, so air was always going to be trapped inside.
The calipers are on the correct sides with the bleeders facing up. This is not a new problem, I actually bought the truck this way thinking it just needed a brake job. Boy was I wrong.
I am considering removing the abs from the system and just running straight lines to see how that works. This is really frustrating. A while back I read on all-data that these trucks were notorious for having air trapped in the abs unit and I was thinking that removing the unit would remove the problem.