Brake Problems, Weak Pedal

[Subzero]

I think my truck is having some sort of overload of problems right now hence my very frequent posts for help. I've got so much to fix on it I lost count, from my idle problems to bodywork, and now brakes, I have to go into uncharted territory in order to fix them but I'm eager to learn. I've bought the most tools at one time ever this week too. I had my rear brake hose replaced and my rear lines rerouted so my exhaust doesn't burn the new hose. The setup is exactly like the 90s F150s. Last week I also found out that my axle seal could be leaking again on the passenger side and today I confirmed it. I'll need to add some more gear oil I'm sure. I went to go get gas today so I can fix my idleing issue with fresh gas in the tank and noticed my brake pedal was weak. I got home and I checked to see if the pedal becomes firm when the engine is not running to test the booster. It does not ever become firm and I have about 1 inch of actual brake pedal travel the brakes apply when the engine is running. When the pedal is first pushed there is approx 2-2.5 inch of free play. I did a road test in the neighborhood at 30 mph and pressed fairly hard on the brake. The tires did not lock up and stopping distance was not what it used to be. No obvious leaks are present on the ground. The fluid is filled to the brim and is an ugly black. My brake warning light has not ever worked to warn me of brake problems. I don't want to put safety at risk and the risk of my brakes failing. What should my next move be to make sure I don't have any problems? Thanks for the help everyone, I don't think owning this truck would be possible if it wasn't for this site.

[sargentrs]

If the fluid is black, that's not right. Should be almost clear. Drain the m/c, open the bleeder valves, keep adding new fluid and pump the pedal till clear fluid comes out of all the valves. Then bench bleed the m/c, tighten the bleeders back up and bleed nearest to farthest as usual.

[motzingg]

if its that bad that you need to flush the whole system, you might have to pony up for a vacuum bleeder, the harbor freight one is pretty decent for 25 bucks or so, but the auto parts store sells a name brand mityvac that looks nice for $35.

i have an electric vacuum pump dug out of the trash that is hooked up to a ball jar, almost too powerful it can suck the whole line out in a couple seconds.

if you've been messing with brakes there is a pretty good chance you have air in the lines... the black fluid also can indicate that the air is compressing and puking black back out the line when you release the pedal. If you keep cycling that master cylinder with all that s#it in it, you're likely to wear out the piston and clog up the check valve. Better to get the vac bleeder and suck it down.

you can also try pumping the brakes with the cover off the MC and see if a jet of fluid is puking back up, that can mean your check valve is jammed and your MC is shot. Thats what happend to mine. I couldn't figure it out until i left the cover off by accident and it sprayed all over my hood.

[Subzero]

Thanks, all the work the shop did could have caused that. I won't be taking the truck back there either. They should have made sure the fluid was clear when replacing the rear hose and $350 later I still have a carb problem they should have fixed. Is the vacuum bleeder the gun shaped tool with a pump handle on it or is that another type of blessed. I don't really want to fork over the cash right now for the vac bleeder so could I soak up all the fluid in the MC and put new fluid in ( dilution to make the fluid cleaner with new)? I've heard there is a way to gravity bleed brakes, how's that done?

I did some looking around online and found this pump bleeder for $8.50. Would this one work- http://m.autozone.com/autozone-mobile/e ... w?id=46839 ? Atleast for a couple times

[elgemcdlf]

Thanks, all the work the shop did could have caused that. I won't be taking the truck back there either. They should have made sure the fluid was clear when replacing the rear hose and $350 later I still have a carb problem they should have fixed. Is the vacuum bleeder the gun shaped tool with a pump handle on it or is that another type of blessed. I don't really want to fork over the cash right now for the vac bleeder so could I soak up all the fluid in the MC and put new fluid in ( dilution to make the fluid cleaner with new)? I've heard there is a way to gravity bleed brakes, how's that done?

I did some looking around online and found this pump bleeder for $8.50. Would this one work- http://m.autozone.com/autozone-mobile/e ... w?id=46839 ? Atleast for a couple times

To gravity bleed you open the farthest bleeder and let it run (lid off the master) until clean fluid comes out. Close the bleeder and move to the next wheel until you have all 4 done.

[motzingg]

I can (sort of) understand the notion that you've already spent a lot of money to have the work done and now don't want to spend more on tools plus having to do it yourself, but buying a pump (even the mityvac is only $35) is only 1/10 of what you spent to have the work done once. Buy the tool, learn how to do it, and rest easy knowing that you have the technology and skills to do it any other time you need to.

Plus the vac pump can work for lots of other stuff on a car, leakdown testing, testing your vac advance or finding vacuum leaks.... its a great tool to have if you plan on owning old cars.

You can gravity bleed by just letting it run out, but its way easier to just get the right tool for the job and be done with it.