HAVING SPONGY BRAKES

[94_PurpsRange]

On the minimal fluid coming from the rear brakes. Are you getting a lot of air at first or is flow just poor, as in really slow?

Air would be a leak somewhere. Slow could be a clogged line or the RABS module is having issues.

The one part that is going to be hard to look at if everything else looks good is the brake line that runs along the driver's side frame rail behind the tank. Eliminate everything else before opening that can of worms.

So, I don't get air from the rear brakes it's really slow and like i had said hardly anything comes out when i try to bleed them... the brakes aren't working properly, and I was told to do all the things I have done and the brake master.... I am afraid to take the truck much above 65 in case i have to stop on a dime... which isn't ideal because the brakes lock up when I do, and I go sliding.

a little more reference... the brakes have been weird and spongy since the truck was handed down to me 3 years ago. I didnt drive it too much and now that i am out of extra cars laying around i will be using this as a daily.

about 3 months or so ago I was driving and the brakes started to go bad (noises and it was time for the brakes) a few days later i went to take it up to the market and the brakes were grinding really bad... so I took it home and parked it for a month (was low on funds at the time) ... went to run it up the block to get a test pipe welded into it because I had removed the cat... and a brake pad fell out completely and I lost the brakes... I got it home (thankfully) and it sat for another 2 months until the last few weeks I have been putting it back on the road... from what I have gathered the master was probably already going out and then when this occurred the piston from the caliper pushed all the way out and I most likely damaged the master in the process.

If i was told wrong, i could understand that... I just already own a lot of new parts for the truck, and I have been swapping out bad ones until I'm confident this truck will take me anywhere.

Its only got 48K on it!

 

[94_PurpsRange]

On the minimal fluid coming from the rear brakes. Are you getting a lot of air at first or is flow just poor, as in really slow?

Air would be a leak somewhere. Slow could be a clogged line or the RABS module is having issues.

The one part that is going to be hard to look at if everything else looks good is the brake line that runs along the driver's side frame rail behind the tank. Eliminate everything else before opening that can of worms.

So i wrote this big ass thing and it never got posted lol

Anyways, about 4 months ago i lost the brakes all together... front driver went bad and i lost the brake pad all together... i think when that happened it fucked up my caliper and the brake lines were all shot and leaking... replaced all those... and i was told that because the caliper got pushed completely out from losing the brakes it most likely damaged the master and that's why im having so many issues.... but it being an ABS issue could be the problem too.... i own a new master and many other parts for this truck already so i have been swapping parts for weeks now trying to make sure i can safely use this truck to commute in for work...

right now it refuses to go up nearly any grade of hill and if i have to slam on the brakes i slide like I'm on an icy road haha... so i was going to start with entirely new front brake set up and a new master to see if that solves THIS issue lol

 

[sgtsandman]

The master cylinder is a possibility then. If the piston over travels where it normally goes, corrosion in the unused portion of the cylinder liner can damage the piston seal and cause sponginess and braking problems.

If the RABS module is bad, it could cause the poor flow issue. I've read about people fixing that problem by replacing the module.

Leaks will still need to be looked for and eliminated before throwing a master cylinder at it. The parts cannon is an expensive way to fix a problem.

 

[Uncle Gump]

Something else... and I agree with possibly damaging the master... is the rubber line that goes between the frame and rear axle. Those degrade and collapse. They allow minimal fluid... and potentially cause the rear brakes to drag.

 

[Josh B]

I would consider the line manifold inside the left front rail to be the most likely culprit

 

[94_PurpsRange]

I would consider the line manifold inside the left front rail to be the most likely culprit

Where might i find this at?
Unfortunately i am not a mechanic anymore... and i didnt spend enough time as one to know everything haha

What do you mean by line manifold?

 

[sgtsandman]

Something else... and I agree with possibly damaging the master... is the rubber line that goes between the frame and rear axle. Those degrade and collapse. They allow minimal fluid... and potentially cause the rear brakes to drag.

I didn't think about that. Good point.

 

[pjtoledo]

which wheels lock up? fronts, rears, or all?

if just one end locks up the other end is the problem because it isn't doing enough/anything.

 

[Josh B]

Where might i find this at?
Unfortunately i am not a mechanic anymore... and i didnt spend enough time as one to know everything haha

What do you mean by line manifold?

I really don't know what that thing's called, but just under the cab, around where your feet would be, my 93 it's tucked into the rail, actually hard to get to.
It;s where your front braking system meets the rear braking system
I have seen papers where they discuss just completely bypassing that brake valve in route to the rear, others where they tore them down and cleaned them out
It is basically controlled by a valve of some sort if I remember correctly, or maybe it is the valve, and I've seen write-ups ( no photos of this that I recall ) where they cleaned the valve up
I started to tear mine out once but decided to leave it alone, it's a real bugger just getting to it, and it's to my memory a spider web getting in there

 

[4.0blue98]

Something else... and I agree with possibly damaging the master... is the rubber line that goes between the frame and rear axle. Those degrade and collapse. They allow minimal fluid... and potentially cause the rear brakes to drag.

This gets my vote.

 

[Shran]

I really don't know what that thing's called, but just under the cab, around where your feet would be, my 93 it's tucked into the rail, actually hard to get to.
It;s where your front braking system meets the rear braking system
I have seen papers where they discuss just completely bypassing that brake valve in route to the rear, others where they tore them down and cleaned them out
It is basically controlled by a valve of some sort if I remember correctly, or maybe it is the valve, and I've seen write-ups ( no photos of this that I recall ) where they cleaned the valve up
I started to tear mine out once but decided to leave it alone, it's a real bugger just getting to it, and it's to my memory a spider web getting in there

That’s the rear ABS valve. It can be bypassed with a union as I mentioned earlier in this thread but you no longer have ABS then - I didn’t consider that to be a problem.

 

[Josh B]

That’s the rear ABS valve. It can be bypassed with a union as I mentioned earlier in this thread but you no longer have ABS then - I didn’t consider that to be a problem.

Did you maybe post a thread or article about doing it Shran? I've left mine all these years w/ basically no rear brakes :/

 

[94_PurpsRange]

***UPDATE***

So this past weekend, I replaced the brake master, the rear wheel cylinders, replaced the rear rubber brake line, cleaned the MAF sensor, replaced my O2 sensor, fixed the vacuum canister that sits attached to the A/C stuff on the passenger side of the engine bay, replaced my TPS sensor, cleaned out the throttle body, manually pled the braking system complete, and re-routed the brakes to pass the ABS unit.

So far, it's as if I am driving an entirely new beast. The brakes are working great! did a lot of hard stops and everything seems to be in good working order. My acceleration is back as well... after replacing the TPS sensor, cleaning the MAF, cleaning the throttle body, and putting the right spark plugs in. I didn't end up putting any zip ties on my throttle cable (even tho I am sure that would help too. I am just going to replace the throttle cable and kick down cable.

Thank you all so much for your help! I wish I would have taken some pictures for all of you, but I am not one for documenting my work haha.. or even taking pictures in general.