jmlcolorado

So I decided to flush the system and put in new synthetic dot 3 this morning.
A couple curious things I noticed.
1) seems to be water in the system. This COULD explain the locking brakes. If the fluid had ingested a significant amount of water, after a while of driving, the water could get hot enough to boil, then expand while trying to turn into a gas, producing pressure on the system.
I'm guessing that if water began to boil at only 1 caliper, it COULD affect the whole system, thus applying pressure to all four corners?
Is my thinking correct here? (See photos)


This is the bottom of the reservoir. You can clearly see small water droplets.



2) there seemed to be a TON of air in the system. Now this could be user error.
I have a hand pump which I pumped up to 20 HG, then broke the bleeder loose, then as it sucked fluid out, I kept pumping to keep vaccum up.
I eventually got tired of the hand pump so I hooked up a shop vac to the container. The shop vac has no where NEAR the vaccum power of the hand pump, but I required less effort.
I seemed to be able to pull air using both the hand pump and the vac. (See videos).
Notice in the following video, I had the bleeder open, it was pulling air. I then closed the bleeder while maintaining vaccum and the air stopped.




Similar video, but on the front right side of the truck.




Now it would only draw air when the bleeder was open. Never when closed, even with vaccum applied. With the bleeder closed, it held vaccum at 20HG for as long as I wanted it, and air was never indroduced.

I did apply wheel bearing grease around each bleeder threads before opening the system to avoid air being introduced at the threads.

Commen sense tells me that if there was this much air in the system, I would have a soft pedal. It also tells me, if im pulling air from a leak from an outside sourse, i would hopefully see a leak when the system is under pressure. This is a fairly small vaccum, so with it oulling this much air, it would have to be a significant leak. And I was NEVER able to pull enough out to stop the air bubbles at any wheel.
Though I did completely rid the system of the old, dark looking fluid until new clear fluid had come out. Once the new fluid started filling the container, I dumped the container and filled it with 4oz of fresh fluid to assure I pulled as much of the old fluid as possible.

jmlcolorado

Well, 150 mile trip, mostly highway, some stop and go traffic, and zero signs of any problem. Time will tell, but a full fluid flush and change seems to have solved the problem. I'll keep my fingers crossed.

Bark

Hope that was it.
Unrelated (sort of). F-in laws 2001 Jeep Cherokee brakes were doing the same thing and after cooling would be fine. Turns out it was because he had way over filled the brake reservoir.

Dr.Dizzle

I have been following these threads regarding the braking issues. This sounds like the brake fluid may have become contaminated with another type of fluid. The fluid pictured looks a little odd;however, I am looking at them on my phone.

jmlcolorado

Well I haven't put any other fluid into the reservoir except standard dot 3.
If there was synthetic in there before, and I add in regular, would that cause an issue?
Flushing everything and going with straight synthetic seems to have helped.

Totallyrad

I don't know if it matters but, I thought the 3rd gens used regular DOT 3 fluid. I always understood you should not mix the different types.

Dr.Dizzle

No, all dot 3-4 brake fluids are synthetic. The truck was factory filled with dot 3 fluid. The term synthetic was used for marketing about 15 years ago and is on most labels today. Just makes the masses feel like they are getting a better product. No problems will arise from it.

If the fluid was contaminated with another fluid, the symptoms will reoccur.Many times, the rubber gasket under the master cylinder cap becomes distorted and wrinkled dependent upon the fluid added.

Dr.Dizzle

Dot 3 and 4 are compatible;however they have different dry and wet boiling points. Adding dot 4 without removing most of the dot 3 first would lower the dry and wet temperature ratings. You just don't get the full benefits of the fluid (dot4). Some fluids are marketing dot 3 and dot 4 rated fluid in a bottle. Valvoline and NAPA (Macs) are two that come to mind that do this.

Humblecowboy

My 99 stage 2 did the same thing today but it seems to be the fronts. I limped it home which was probably not a great idea but I'm starting to get to know the wrecker driver on a first name basis darnit!. Speedometer quit so I guess I fried it. jml, are your brakes still working as they should from the flush? I'll tear into mine tomorrow to evaluate the damage I inflicted. The ABS on mine quit qorking years ago so I don't think it has anything to do with that.

jmlcolorado

Yeah! I'm about 800 miles into it since the flush and not any sign of problems!

Humblecowboy

Thanks jmlcolorado. I went out later to move over to the barn to start trouble shooting and this time the peddle went to the floor but still stopped. I reckon I wore the pads down real good. Only thing is, the fluid level hasn't dropped any. I crawled underneath and found the ABS wire at the driver side brake plate is fried. I first thought I may have overheated the brakes more than I thought but the pass side is fine and it was the hottest. the more I look at it the more I'm convinced it was shorting there and that may have caused the constant brake pressure. I pulled the 40amp fuse (after the fact). Since ABS isn't required down here on this 1 ton I am going to figure out a way to totally abandon it. Never liked that crap to begin with. Too many stops in the middle of intersections. While I was looking around under the hood I happened to notice that I may also have a radiator leak. Hopefully it's just water from when I was spraying through to cool the engine since it got a little warmer than it's been before.That's all I need to make the rest of the misery. I don't know if they are serviceable but hope so. I think this trucks worse enemy is non-use. I only have 83k on it. I'll post back with any info I find out.

Humblecowboy

Well jmlcolorado, seems I have the same problem with the moisture. I finally got around to pulling the front calipers and hubs on the beast. Pulled the pass side bleeder plug and it has considerable rust on the tip. I pumped fluid into a jar and, DANG, it was rusty and trashy. Reckon I'll just replace the calipers, hoses and the master. $$$$ What's anybody's thoughts on blowing the rigid lines out with brake clean then air to clear the brake clean? Since my front suspension is about shot I may as well yank the whole front end down while I'm this far into it. I promised myself way back that I'd never ever rebuild another front end this late in life. Oh well. promises are made to break. Dodge and Cummins probably have big meetings and sit around laughing their butts off saying things like "Can you believe all these fools we have addicted to and in love with these old trucks?"

jmlcolorado

I don't see the water drops like I did mine, but there are some nasty particles in there. Replacement front calipers are probably the best idea!
I wouldn't blow out the lines with air as that would add air to the ABS module, and you would have to take it to a dealer to bleed the system properly.


As far as rebuilding the entire front end goes, I don't blame you! I don't care how young you are, rebuilding these is a PITA!!
I rebuilt the whole front end on mine a year after I got the truck and its lasted a few years (about 120k) so I guess I can't complain. I saw the other day some ripped ball joint boots, so I know I'm in the same boat really soon. Steering is still tight, so I'm gonna hold out a bit longer. Not a fun project!

Humblecowboy

My parts house gave me a price of $31 w/core for the calipers. That was a sigh of relief. Now the speed sensors I fried are a different story, $238+ each. I'm looking online and finding some under $100 but not sure if they are the right ones for my model. Going to do a search for Dodge Parts catalog to get the exact OEM part#. All in all I'm looking at close to a grand on the complete rebuild plus the rear brakes and cylinders. In the old days I just rebuilt the cyinders myself but not gonna do it now. I think it's cheaper just to replace. There's a place in town here where I can get the A-frame bushings and ball joints pressed out and in, I think. If not, I'll do it the old fashioned way, big C-clamp and a socket to fit.

Humblecowboy

It's baaaaack!
Does anybody know if any part of the ABS system being bad can cause the front brake pads to stick and not release?
The Speed Control Servo popped it's hose nipple on me back around 04 and I lost my ABS and cruise. Never had a brake sticking

problem until last year when they stuck and I fried everything on the steering knuckle. Rebuilt the whole front

end and new Master, new hoses, calipers and pads. Everything fine until yesterday when I felt the brakes let go

after putting in gear. Got home and the right spindle was too hot to hold my finger on. The left was warm to hot

but could hold my finger on it. Any ideas would be apreciated.