2nd Gen Non-Engine/Transmission Brake System Gremlins ???

[DaveN]

I've got a 2001. 5 - 73,000 miles. About a month ago, I bled the brake system out since the fluid was looking pretty bad. Since then, the pedal has been a **little** soft - I think I have a small bubble but nothing that's really concerning. I'm about due for brakes, but they still work OK with no pulling, etc.



Yesterday, I'm on the way home, coming up to a stop sign. Hit the brakes, abut 25% and they started to work, then the pedal went to the floor. I released the pedal, pumped it again and the brakes worked fine, with good pedal and no fade. I thought that maybe I hit a slick spot on the road and maybe the antilocks got confused..... until it happened twice more on the way home. The last time I was hitting them pretty hard, since I was trying to get it to repeat. This time when it happened, my slight sponginess disappeared, and I got firmer pedal.



When I got home I took a close look at the whole system, fluid level is good, could not find any leaks.



Road tested it again this morning, and it seemed to work OK. No pulling, fading etc.



The pedal seems to pump up alright with the engine off. It's not as firm as I would like it, but to be honest with you I never paid attention to it before so I'm not sure if it's OK or not.



One idea that I thought of was that the air bubble I suspected was in the system worked it's way out of the master cylinder. But I wouldn't think that would happen three times. I know that the power steering system is integrated into the brakes somehow, so I checked that fluid, level is OK.



So - any ideas?

 

[Joe Mc]

Hmmm, I had this syndrome happen on another DC product and it ended up being in the master cyl. There are seals in the cylinder that when you apply pedal pressure expand between the cyl & piston with the fluid pressure and pump the fluid out to the system components. If the seal is kind of hovering between sealing and not - when the pressure is applied it allows the fluid to pass then all of a sudden seals. However, since all was well and theres only 73k on your truck my bet would be that when the system was being bled air was trapped in the m-cyl. Sometimes when we do something we hope helps it can react adversly and hurt. I think it might be the cheapest & best route to take it to a brake shop and have them perform a "power bleeding" on the system. This is performed with a tool that connects a fluid resivoir to the top of the m-cyl, applies slight pressure to the fluid container and then the bleeders are opened allowing all fluid, air, dirt & the like to be expelled from the system. I've seen this performed on early 4 disc brake Corvettes that you couldn't just get a good bleed on, and it did the trick. I think it shouldn't cost more than $100 and as you know anything that's only $100 on our trucks is "CHEAP". So, MHO, it's worth a shot to try first, cheaper than a new m-cyl, definitly cheaper than a new front end on your truck if you can't stop in time.



You could put a PM out to TDR member Sam Peterson (I'm pretty sure his last name is Peterson) he is "the" brake Guru for our trucks to get a professional opinion.



By the way my truck has 136k on the original m-cyl as far as I know, I bought it w/75k and it looked like the original one then???



Let us know how you make out.

 

[y-knot]

The Dodge trucks are set-up to display a "Brake warning" light or a "ABS Warning" light it the master cylinder malfunctions. Do you get any warning lights?

If your fluid is that dark, you should flush the brake system,and re-install fresh fluid, taking care to use the correct and recommended type. Also make sure you bleed the system as described in the manual . These systems are way to complicated for me to give you the step by step procedures, you will need to get yourself a manual.

 

[tjm]

power bleeder

If you plan on keeping your truck a long time you might try EGR's power bleeder. Essentially its your own pressure bleeding system. Google EGR Brakes



Google - my working brain.



TJM

 

[DaveN]

thanks for the quick response guys -



didn't get any warning lights, I do have a service manual that I cracked this afternoon. Based upon the check procedures in the manual and my test drives - I don't think I have a system problem - it's pointing to proper bleeding, pretty much what you've said.



I think I'll try bleeding it one more time, maybe this time without beer. If I still have the problem, I'll post back.



Thanks again,



Dave

 

[DaveN]

Well I found the problem.



I decided that it was time to do front brakes, even thuogh it appeared I had plenty of pad left.



Got the calipers off, and what was left of the friction material pretty much fell off the pads. about 30~40% of it had chunked off and was missing. I suspect my loss of pedal was due to missing material in the pad. The calipers are a dual caliper setup, I'm guessing that the sponginess was pad deflection, since the ends were gone? Road tested after new pads/rotors were installed, no pedal problems. Rebled as well, no air was in the system.



One observation that I had was that the spring "squeaker" clip was adjusted to start working when you had about 1/8" of firiction material left. By that time you're in big trouble. The new pads I got were the same way.



Heads up - if you're waiting to do your brakes until they start squealing - you could get yourself into trouble!