94 Grand Cherokee with ABS, can I bleed the brakes myself?

You are describing back brake shoes out of adjustment. They usually need to be hand set up before the automatic adjusters start working. The automatic adjusters adjust when you hit the brakes in reverse after hitting them in the forward direction to c*ck it.

This also usually means the emergency brake will be at the end or almost all the way out.

Mike

snipped-for-privacy@airmail.net wrote:

snipped-for-privacy@airmail.net did pass the time by typing:

That section only applies if you get air into the system or want to do a full up flush. You don't need the DRBII to bleed just the calipers.

What you do need to do is double check you put the adjustment stars in the correct side and that the pads have been adjusted out so the drum just slides on with a smidge of friction. To me it sounds like your pads are not adjusted properly.

To adjust the brakes simply tug up on the emergency brake handle a few times till it firms up about half way up. If they are way loose this can take quite a few tugs.

Just to add to this - when I replaced my shoes I didn't replace the auto-adjuster springs. For several months after I would hand adjust them out every few weeks only to have the brake pedal start sinking again and a knocking sound produced from the drums.

I found some auto-adjuster rebuild kits at Napa (includes new springs and adjuster bolt) and put them on, and they've been working great ever since. If you still have a problem with them after you do what Mike suggested and you don't mind getting back into the drums, you might give those kits a shot. The springs get pretty tired over time.

I just had the jeep in for regular maintenance and the guy told me I needed my rear brakes to be adjusted. And I brought up the 'automatic adjustment' thing and he said that's an old wives tale brought in, probably, from some import car design that didn't catch on.

I've had the rears apart (different vehicle) and do see the adjusting 'star' but don't see how it would auto adjust with the whole brake on reverse thing. Was he feeding me a line to get more business out of me?

SteveBrady did pass the time by typing:

That mechanic is about as full of s*it as the U.S. sewer system during SuperBowl half-time.

L.W. ("ßill") Hughes III did pass the time by typing:

Vac bleeder or having someone press the brakes can't damage anything in the system. The only probaem crops up if you let the brake fluid get too low and get air into the ABS pump. At that point you have to have the Scantool.

replying to SteveBrady, Rick Nock, ASE Master Tech, retired Auto Tech Instructor wrote: Self adjusters have been around on drum brakes for decades. Some are cable, some are linkage and a few odd ones out there. Bendix self energizing brakes use vehicle direction to multiply the stopping force. These type of brakes have the shoes installed against a top large anchor pin, with the adjuster on the bottom. When installed, the lower end of the shoes will move freely with the top against the anchor pin. When driving forward applying brakes, the shoes expand against the rotating drum. The rotational force tries to turn the brake shoe assembly which can't move because the anchor pin stops them. The front shoe pushes the rear shoe against the brake drum which pushes against the anchor pin at the top. When operating in forward direction, the rear shoe does most of the work as the front shoe does not even touch the anchor pin. The front (primary) shoe usually has a shorter friction pad than the rear (secondary shoe). The adjuster star wheel generally is closer to the rear shoe so it can engage in the self adjuster lever. The movement of the shoes reverses when you back up. It is this motion that allows the adjuster to catch the next notch on the star wheel. When you release the brake, the return springs pull the brake shoes back to the anchor pin. If the brakes have worn enough to require adjusting, this is when the lever will move the star wheel. Hope this explanation wasn't too complicated.