Bleeding brakes

[jstagn]

Have a 91 Ford Explorer, replaced the brake master cylinder and I thought I bleed it correctly on the bench, but now the pedal is soft. Tried gravity bleeding with the front disks and this looked successful, but when I tighten everything up there still was some air so I tried again and nothing came out so I used to 'old' method of a tube in a jar of brake fluid and more air came out. However the rear (drum) air bleed valves are rusted shut and I am afraid to put too much pressure on them in an attempt to loosen (they may brake off). Since there is still air in the lines what should I do?? Can I just loosen the rear brake lines to bleed or can I somehow apply some heat to loosen bleeder screws?? Already put some wd-40 on last nite.

 

[Big E]

Sounds like you have air in the lines. I would heat the bleeder screws up and bleed the air out. Instead of gravity the brakes try this.

Take both rear wheels off.
Heat both bleeder screws up and break free. But before you do this. Wipe all the Wd-40 off, or you will have to worry about bigger problems than air in the lines.
Next have someone sit in the drivers seat and puch on the brake pedal with the screws closed. When they have pressure on the pedal open the bleader screw up on the pass. side of the vehicle. Then close the screw before they let off the pedal to insure air doen't get back in. And while you are doing this make sure to keep the master cyl full. And when you start to see ALL fluid come out, move to the driverside. And repeat these steps. And I would do the front the same way starting on the pass side. Oh one more thing. Make sure you put the cap on the master cyl each time you fill, or when your buddy lets up on the pedal you will have brake fluid all over. Use dot2 fluid I think someone can help me here. And that is all there is to it. I hope this helps


Eric

 

[FMNavajo]

jstagn,
I've always done it the old fashion way on bleeding brakes. I had the same problem with my 92' Navajo, one of the bleeder screws on the rear cylinder, (drum brakes), was siezed up and I tried everything and it wouldn't come loose. I went to the local autoparts store and they had two new cylinders on the shelf for $13.00 a piece, no core charge. All I had to do was remove the rear brakes and replace the cylinder and I'm glad I did because they were in bad shape.

After I had the old cylinders were I could put them in a vice and use a pair of vice grips, the screw finally came loose, it was unusable after I finished with it.

Hope this helps,
FM

 

[Barnstormer]

When the rear cylinder bleeder on my 91 froze, I was able to buy just the bleeder valve. Removed the old one with a set of vicegrips.

Bench bleeding can save some time, but if you get just a very small air bubble in the line, you will have mushy brakes. You need to bleed the rear brake lines! If you don't have a pressure bleeder, do the old jar and hose trick!

 

[FMNavajo]

Barnstormer,
I also purchased a spare bleeder valve but the condition of my rear cylinders warranted new ones, 145K+. I bought the truck used and I don't think anyone else had changed or serviced them.

Thanks,
FM

 

[george]

I had my rear brake bleeder froze on me too. The reason it did was the wheel cylinder was completely frozen so the bleeder was too. If i were you replace both rear brake wheel cylinder, there inexpensive about $15 each, then bleed the whole system.