Brakes won't bleed

[BDM]

98 D1. Brake pedal had no pressure. Put in a working booster and master cylinder from Will. I can get the back brakes to bleed but the front calipers just pump air. Had my wife pump the brakes for 10min (which she was thrilled to do) while I was underneath bleeding and closing the valve. After 10min on the front passenger side I gave up.

This same thing happened before I replaced the booster/cylinder but naturally just thought the unit was bad so I replaced them.

I've bled this system before but never experienced something like this. Any ideas would be appreciated!

 

[WILL.TILLERY]

try breaking open the line from the master to the abs modulator and see if you have any pressure. (on the mod side of course)

 

[BDM]

Thanks Will. I'll give it a shot.

 

[BDM]

I got pressure from the modulator side, spurts fluid.

 

[BDM]

Any other thoughts?

 

[discostew]

You probably didn't get the master cylinder bled before you put it on. Hope your girlfriend never let the pedal rise with the bleeder open. With someone putting light pressure on the brake pedal crack a line loose at the master. When the pedals all the way down close it.do that till you get all the air then do the other fitting. Once you get that bleed hopefully you get flow from all 4 wheels. If not you have a proportioning valve slammed to one side and need to recenter that.

 

[publix_deli]

Are you getting pressure from the modulator output? If you're getting good pressure from the master cylinder, you could have a stuck valve in your modulator. If the modulator is pumping out fluid, too, it could be a clogged line, but I think it would be unusual for both front lines to be clogged. My bet is a stuck modulator valve or your master cylinder isn't bled fully and it's only sending out good pressure to the rear lines.

 

[mlnnc]

You might try Googling "gravity bleed brakes." I helped a friend a few years ago with the brakes on his '04 DII. We were having trouble getting them to bleed. We took a deep breath, pulled up some patience and tried the gravity bleed. Worked like a charm. Good luck.

 

[BDM]

Ok thanks guys. Almost there.

I replaced ABS mod with a good unit from a Will. Now the only side left not bleeding yet is the front driver side.

Would a power bleeder help? Not familiar with the gravity method. Thanks

 

[AbnMike]

Ok thanks guys. Almost there.

I replaced ABS mod with a good unit from a Will. Now the only side left not bleeding yet is the front driver side.

Would a power bleeder help? Not familiar with the gravity method. Thanks

Gravity method: park the caliper in question downhill (if the fronts then back your rears onto ramps, or just jack stand the rears). Throw a rubber hose on the bleeder on your front caliper, stick it in a jar, crack the bleeder and then go have some beers, dinner, check on it, watch a movie, check on it, etc. Eventually it -should- start getting fluid. It could take awhile, but I wouldn't let it sit overnight or you may drain your MC and have to start all over again.

I have a power/pressure bleeder that I use all the time, but it doesn't necessarily work better than having someone pump the brakes correctly - it just removes the need for someone else to help you out.

 

[squirt]

I've used gravity method as well as Mityvac setup in the past. Both have always seemed to do the job.

 

[BDM]

Gravity method worked great! Got all 4 calipers to bleed now but pedal is a bit spongy. Big improvement from no pressure.