Weak Brakes

[TallGuyJeep]

Seems my brakes have been inadequate lately, makes me nervous to drive the jeep. I bled them at the wheels saturday, no air came out and didn't make a difference. I can put the pedal to the floor and it still takes a bit to stop just driving in the neighborhood. A while back they got mushy all of a sudden, checked the fluid and it was WAY low, so I'm positive that's when air got introduced into the system. Topped off the fluid and it helped for a bit but now the brakes suck and the fluid is full.

Did some reading online, someone said if there is air in the master cylinder you can't bleed it out normally but you can crack a line at the master cylinder and bleed it that way. Anyone have experience doing this, or other suggestions?

Also note that I've got a ford 8.8 swapped in the rear with discs so it's not mis-adjusted drums.

Thanks for the help,
Josh

[GoneWithTheWind]

Here's one way, you can use some old brake line instead of buying a kit.
https://www.youtube.com/watch?v=kEPXgDGU6_0

[TallGuyJeep]

Thanks! Guess it's just 4 bolts and disconnect the rod behind the dash to take out, hopefully i can find some time tomorrow night to do it.

[4.3LXJ]

I had that same trouble. Turned out my front pads were glazed. Had to push the pedal hard enough to reach the headlights.

[TallGuyJeep]

That's interesting Steve, I'll check that out too.

[nickyg]

My brakes felt a lil spongy till I did a fluid replacement with one of these. Mostly cause it hard for me to find a helper. Most people run the other way when I say. "Come here and get in the car"

But seriously. Fresh fluid and properly adjusted drums is what it took to get mine back to right.

Amazon.com: Motive Products 108 Brake System Power Bleeder: Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41xKVwHAmjL.@@AMEPARAM@@41xKVwHAmjL

[slvmart]

The pressure bleeding with the Motive Products product make a world of difference.

Just curious, was there any correlation between swapping in the 8.8 axle and the brake problem ?

I installed discs on my 8.25 and had to swap in a rear disc, GM style proportioning valve to get great braking. With the standard drum brake proportioning valve the pedal and brake application was always weak and spongy.

[TallGuyJeep]

The pressure bleeding with the Motive Products product make a world of difference.

Just curious, was there any correlation between swapping in the 8.8 axle and the brake problem ?

I installed discs on my 8.25 and had to swap in a rear disc, GM style proportioning valve to get great braking. With the standard drum brake proportioning valve the pedal and brake application was always weak and spongy.
No, the swap was done before i bought it. Braking seemed fine before, i noticed it right when the fluid level got too low. In the future i may end up swapping the valve out to get more out of 'em, we'll see how it goes after i get this sorted out.

[Cheromaniac]

Seems my brakes have been inadequate lately, makes me nervous to drive the jeep. I bled them at the wheels saturday, no air came out and didn't make a difference. I can put the pedal to the floor and it still takes a bit to stop just driving in the neighborhood. A while back they got mushy all of a sudden, checked the fluid and it was WAY low, so I'm positive that's when air got introduced into the system. Topped off the fluid and it helped for a bit but now the brakes suck and the fluid is full.

Have you checked the thickness of the brake pads at all four wheels? Pads that are worn to the limit could cause the symptoms you've described.
Air in the system can also cause a spongy pedal with increased pedal travel needed to produce adequate braking. In the absence of air getting in through any cracked brake lines, the most likely source is the master cylinder so you could have fluid leaking internally from the master cylinder into the booster servo. If your pads check out OK, you may need to replace the servo and master cylinder as a single unit.

[TallGuyJeep]

Have you checked the thickness of the brake pads at all four wheels? Pads that are worn to the limit could cause the symptoms you've described.
Air in the system can also cause a spongy pedal with increased pedal travel needed to produce adequate braking. In the absence of air getting in through any cracked brake lines, the most likely source is the master cylinder so you could have fluid leaking internally from the master cylinder into the booster servo. If your pads check out OK, you may need to replace the servo and master cylinder as a single unit.
Pads are all still fresh. I'm quite positive the prob is air in the system. Fluid has stayed full, but i haven't been driving her much lately. Hopefully i can get away with just doing a bench bleed on the MC. We'll see tonight hopefully.

[GoneWithTheWind]

Hopefully i can get away with just doing a bench bleed on the MC. We'll see tonight hopefully.

Don't forget to bleed the lines, you'll have a little air in them when you reconnect. :beer:

[TallGuyJeep]

We have decent brakes again! Doing the bench bleed did the trick. Wasn't too bad, major pain to bolt and unbolt it from behind the dash, but with some extension and u joint magic i could get at it with the cordless impact which made quick work of it. Got it out, bled, back in and the lines bled in about 3.5 hours!

Braking power is back to when i first got it, but still seems weaker than it should with discs on all corners. I'm going to take a real good look at the pads and rotors, maybe get new ones then we'll see about swapping the proportioning valve.

Thanks for the help y'all.

[slvmart]

That pressure bleeder would have made about a 1/2 hour job of it. Just saying. It's really nothing more than a garden sprayer with a cap to allow attaching to the master cylinder, along with a pressure gauge. You don't want to go too high on the pressure. But like a cooling system pressure tester, it can tell you if you have a leak somewhere.

[TallGuyJeep]

Sounds like i need to pick one up then for next time since it seems everyone loves theirs so much!

[slvmart]

It helped tremendously when we installed a new Master Clutch cylinder, in my sons pickup. At the time he was in a auto shop class and they couldn't get bleed the air out of the system. The master cylinder was high on the fire wall. It didn't take long to fix the problem once he got it home.

I'd say, if you frequently end up working on brakes, or the rapidly disappearing clutches, then it will likely come in quite handy. And depending on what attachments you might need, they are not that expensive.

[XJ Wheeler]

You don't have to bench bleed with the power bleeder?

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[slvmart]

I never have.

[XJ Wheeler]

I never have.
That'd be great. I'm planning on swapping in a later booster and mc so that would be nice, although it's not hard to bench bleed since it's already gonna be out. Money may be my decision...

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