The pedal feels really spongy and only does something when it gets near the floor, though it is plenty capable of stoppign the truck fast.

I bled my brakes after my 4.56 third install and I was getting tonnes of air bubbles during the bleeding process. I bled the brakes using clear aquarium hose just big enough to slip over the brake bleeding nipple (what's it actually called?)and bled it into a beer bottle, like this:



I've put a quart of brake fluid through the system, never exposing the master cylinder and now the brakes are spongy as ever. I would top up the MC, then press the pedal to the floor ten times, then refill and repeat. Each time, there were more and more bubbles. How is air getting into the system?? I bled the passenger rear, drivers rear, then LSPV.

 

How are you doing this? The only time I ever see this happen is when someone bleeds it wrong.

This is how you do it:
1) pump brakes a few times (4 or 5 times is fine)
2) hold brake down as far as possible
3) have assistant crack open the bleeder
4) once pedal is to the floor, close the bleeder
5) release pedal
6) repeat a few times until the brake pedal feels stiff

The most important steps are 4 and 5. Make sure to close the bleeder before you let off the pedal or else you're going to suck in a rather copious amount of air back into the lines.

Also, if you have drums in the back, having the shoes out of alignment will make the pedal feel spongy. I'd suggest checking that too.

 

Doing it the way you are with the tube works well but you must put the jar above the nipple, preferably as high as you can. The air bubbles rise in the tube so you'll be sucking them all back in.

With the jar up high and the tube on, loosen the nipple and pump the brake pedal until there are no air bubbles near the nipple end of the tube. Tighten nipple, remove hose/jar and that wheel is done.

Repeat for all corners starting with the passenger rear, then driver rear, then pass. front and driver front last. Obviously don't let the reservoir get too low on fluid.

If this doesn't work check your wheel cylinders for leaks, the seals could be gone. Master cylinder would be the next thing to check.

Brake fluid absorbs moisture over time so if its really old could just need new fluid right through.

Good Luck.

 

Have you adjusted the rear brakes? Properly adjusted rear shoes will affect the height and of the pedal.

As far as bleeding brakes you might consider a vacuum bleeder. They are $20 at Harbor Freight, or $40 if you get a stainless steel model online. This makes bleeding brakes a 1-person job and it is very simple.

 

Nah...that won't happen. The brake pedal would have to be released before the bleeder valve is retightened to create the vacuum to suck air/fluid back in. Otherwise, the pressure is greater inside the brake line than the air in the bleeder tube.

 

sounds like you might have a small air leak somewhere.... double check all of your fittings that you un-hooked and re-connected

 

when i did my big fix up i had to gravity bleed both front and rear and lspv with about 2 LITRES of break fluid over about 4 hours worked GREAT!

 

My brakes worked perfectly before I touched them for the locker install. I've only touched the brake line-to-baking plate connection (to remove axles) and the bleeder valve. I have also tried to bleed the LSPV. Logically then the problem should lie in the way I've bled the brakes as opposed to a mechanical failure somewhere.

 

yup i had really low pedal till i bleed the lspv.

 

Thats what I mean, I assume that's what he is doing. The way I described can be done by a single person. Theres nothing worse than trying to bleed brakes with someone that doesn't know what they're doing or wont listen.

 

The LSPV was harbouring some of air. The pedal is firmer now. The pedal will still hit some sort of stop when press really hard, but that's many times harder than I would ever brake.

 

have you tried gravity bleeding?

 

I know some people swear by the tubing in a bottle of fluid method, but I've never had good luck with it. Try bleeding all four corners again with another person pumping the brakes (pump pump hold, then you crack the bleeder valve and immediately close it again) and see what that nets you.

 

I've had a heck of a time bleeding my brakes, and everything has been replaced including a nice new Aisin MC from Marlin, rebuilt calipers, new wheel cylinders and adjusted brakes. I currently have 1/2 pedal and it takes about 2 pumps to get some brakes. I've tried gravity, pump then hold, vacuum bleeder pump and a gravitron bleeder bottle. Marlin wrote on his forum that the 'pump then hold' method works, but you have to pump slowly, not jamming the pedal fast like most people do. He said to push down slowly, let up and wait a few seconds for the resevior to refill before pushing down again. I don't know, I'm still bleeding mine and they are getting there, but wow it's a beeeeaaaatch.