Help with Bleeding Brakes, Please

[guava_jelly]

I'm trying to flush the brakes on my 89 Comanche using the factory service manual instructions.   I didn't make it very far.  I started and stopped on the passenger rear drum brake.  Seem to be going as expected until it wasn't.  I had someone press the brake, I opened the valve, waited a bit, closed the valve, and signaled to have my helper release the brake pedal.   After several cycles, brake fluid didn't seem to be flowing into the hose/bottle I had attached to the bleeder valve.  When I went to check on the master brake cylinder, the smaller front reservoir was empty and the larger rear reservoir was full.  Is that normal?  Is the smaller front reservoir for the drum breaks? And, the larger rear reservoir for the front calipers?  I also noticed that the rubber gasket in the master brake cylinder cover looked as if pressure sucked it out of shape. 

 

I'm also wondering if I have to clamp the cover on the master brake cylinder every time I check it during the bleeding process, or can I just put the lid back without the clamp until I get all the brakes bled. 

 

Any advice would be appreciated. 

[fiatslug87]

The smaller front reservoir is for the rear. It sounds like you just have to do it several more times, there’s a lot of air in your system, assuming the fluid isn’t leaking out somewhere else. Are you bleeding the rears with the front passenger caliper bleeder opened? Follow the procedure in the ‘92 FSM manual, it’s on here somewhere. You should bleed with the cover off.

Edit:

From the ‘92 factory service manual:

Release emergency brake

Open the right front bleeder

Depress brake pedal and hold

Start engine, brake light should stay on after engine starts indicating bypass valve has moved (sensed front brake leak)

Turn off engine, leave bleeder open

Bleed left rear 

Bleed right rear

Bleed righ front (close bleeder when done)

Bleed left front

then repeat bleeding with right caliper closed

[fiatslug87]

If I were you I would first try to get fluid to come out of all bleeders before following the procedure. Just gravity should fill the lines unless there’s a restriction/obstruction.

[guava_jelly]

right = passenger side? 

 

Just to double check.  I do this procedure first?  Then, I bleed all of the brakes again?

[fiatslug87]

Yes, right = passenger side

 

Yes, the FSM says to follow this procedure and re-bleed normally following the same sequence: left rear, right rear, right front, left front.

[AZJeff]

23 hours ago, fiatslug87 said:

If I were you I would first try to get fluid to come out of all bleeders before following the procedure. Just gravity should fill the lines unless there’s a restriction/obstruction.

Gravity bleeding the system is quite helpful in gettin about 80-90% of the air out of the lines.  It can be messy, unless you have four hoses and containers to collect that coming out of the bleeders, but having all four bleeders open wide, while keeping the master cylinder full, will shorten the final “pressure bleeding” sequence quite a bit.

[75sv1]

In some or most part stores, there is a brake bleeder from Mint Craft or others. It cost about $10. Its a small plastic bottle, with a plastic line coming out the top. It looks like it won't work. One of the plastic fitting on the tube coming out, must be a one-way valve. Anyways, a small section of rubber hose or Vacuum hose to attach to a bleeder nipple. Then open the bleeder nipple and pump about 10 times. Check bottle and repeat. Follow as above, Rt Rear, Left Rear, Rt Front, Left front. Also wonder if your master cylinder is bad. 

     Also, on flushing the system. I suck or pump out what I can from the Master cylinder. I might do that a few times. Some sections of the newer ones, are hard to get to. Then bleed the system. 

[Weston Brown]

You will need to bleed the whole system using a traditional method of your choosing and then crack the front brake bleeders to create a low pressure indicator for the load sensing valve to reset. Tighten the front bleeders.

Bleed them all again and you should be good. It worked on my ‘91 Comanche. 

[PIKE]

If you have replaced the front calipers or rear cylinders make sure you have them oriented correctly.  There is a left and right.  Please don't ask me how I know this.

[AZJeff]

1 hour ago, PIKE said:

If you have replaced the front calipers or rear cylinders make sure you have them oriented correctly.  There is a left and right.  Please don't ask me how I know this.

 

[watchamakalit]

8 minutes ago, AZJeff said:

 

X3

[75sv1]

Yeah, and its mo fun, if you have ABS to deal with.