master cylinder bleed-by

[lunchbox660]

for the past 1000 miles or so my brake pedal has been REALLY squishy. i assumed it was air in my lines, since i have a habit of being pretty hard on the brakes. i didnt have time to get around to bleeding them cus i was so busy, but when i finally got around to it, i did a full system flush and replaced the fluid with full synthetic fluid. after bleeding them, the pedal still felt squishy, so i bled them like 4 more times, still doing it.

my buddy used to be a tech at an Audi dealership, so he's a pretty smart cat. he told me that he thinks the master cylinder is getting what he called "bleed-by" where the seals in the master cylinder are allowing fluid to pass around the piston. the brakes still work perfectly fine, but the pedal travel is WAY more than desireable.

i wanted to just rebuild the MC, since that is usually pretty cheap, but i canot find a MC rebuild kit for this car. i priced a new MC and it was $129 PLUS a $30 core fee. does anyone else have this problem? if so, what have you done about it? i dont really wanna deal with the dealership. my car is still under warranty, but with all the mods ive got on the car, i know how they are gonna treat me when i go in.

for those of you who dont know what im talking about, try this:

start the car. while its running, but not driving it, press the brake pedal. does it stop moving pretty quick or does it slowly keep moving in? if it slowly keeps moving in then you have the same problem ive got.

[el_jefe]

check the brake pedal height. It should be adjustable, if it is off it will make the pedal feel like shit. The FSM should have the spec somewhere

[lunchbox660]

that would make sense if it was somting that happened ever since i had the car, but i have had it for 2 years/55,000 miles and this is a totally new issue, and i have never touched the height adjustment. seriously, the pedal has like NO feedback at all when sitting there. the only time i can get ANY feedback from it is when i am actually driving it, but even then, it still goes all the way to the floor.

[el_jefe]

I think it's warrentytime then.

[liteshow]

I think it's warrentytime then.
Haha what's a warrenty? Does anyone still have those anymore?

[el_jefe]

Haha what's a warrenty? Does anyone still have those anymore?

Heh. I am the only person I know that killed my warrenty through mileage rather than mods.

jeff

[geekmonster]

i have around 3k left and i intend to get every little thing taken care of before then.

[lunchbox660]

Heh. I am the only person I know that killed my warrenty through mileage rather than mods.

jeff

legally they cannot void your whole warranty if you have not messed with the affected part. my WGA and fuel return have absolutely nothign to do with the brake master cylinder, so it is still covered legally, however, i KNOW they will try to play the "voided warranty" card, cus they tned to do that, so i just dunno if i even wanna deal with it. i will prolly jsut suck it up and buy the new one an install it myself.

[blackbird]

Push the pedal to the floor and hold it down. If it slowly creeps all the way to the floor you might have a problem with the master cylinder. If it stops a couple inches up (and you'd need to look and not go by feel) my first guess is that the system still needs bled. Besides just bleeding the calipers there's also procedures to bleed the hydraulic control unit for the ABS and the master cylinder, but you'd need a DRB-III scan tool to follow the factory procedure.

Also what fluid did you replace it with? The SRT-4 should use a DOT 3 fluid if I remember correctly. If you replaced and flushed it with a DOT 4 fluid but didn't get all of the old DOT 3 fluid it it will work but have a reduced boiling point. And hopefully by synthetic that doesn't mean you went with a silicone DOT 5 fluid which can cause major problems with ABS and isn't compatible with even a small amount of the 3/4. There's also a few DOT 3 fluids out there that are better than others.

[lunchbox660]

no, it does indeed go to the floor when you push and hold it.

i replaced it with valvoline synthetic which the MFR claims is DESIGNED for ABS and has a higher boiling point than 3 and most 4's.

here is the fluid i used....
http://www.valvoline.com/pages/products/product_detail.asp?product=51

[geekmonster]

how's the brakes? did you find out what was wrong?

[Jeff]

A tech friend of mine was telling me that once you get air in the master cylinder it's extremely hard to get it out, and that you probably won't get it out just by simply bleeding it once or twice.

May I recommend taking it to the dealer? :smiley: I have a pretty extensive modification list, and I get warranty repairs done frequently. Instead of fucking with it and potentially making the problem worse, go to the dealer and get the problem documented. That way if this becomes an issue in the future, you've got some sort of record established there. Besides, something tells me that they may have a little more experience with this kinda thing than you.

[lunchbox660]

how's the brakes? did you find out what was wrong?

nah, it still does it. we did a complete system drain and flush and replaced with fully synthetc and it still does it. im gonna try it one more time before i break down and buy a new one.

[lunchbox660]

A tech friend of mine was telling me that once you get air in the master cylinder it's extremely hard to get it out, and that you probably won't get it out just by simply bleeding it once or twice.

May I recommend taking it to the dealer? :smiley: I have a pretty extensive modification list, and I get warranty repairs done frequently. Instead of fucking with it and potentially making the problem worse, go to the dealer and get the problem documented. That way if this becomes an issue in the future, you've got some sort of record established there. Besides, something tells me that they may have a little more experience with this kinda thing than you.

um....my buddy IS a tech. we did a complete drain flush and replace on the system, not just a bleed. i checked a few other SRTs out and they all did it too, just not as bad as mine. seems to me like this might be a problem area on these cars...maybe improperly fitting seals or parts. for three of them to all be bad when i checked them, that seems like a ridiculous percentage of lemon master cylinders. im not going to waste my time taking it to the dealer. my warranty is stil good, but i just really dont feel like dealing with them. i can fix it faster than they can and quite frankly i just dont trust them sometimes. last time i took my car to them they fixed it all up and got me back on the road, and then about 200 miles later all my belts started going out on me for no apparent reason...i think they just rush things to much.

and by the way, i have plenty of experience with brake systems. ive built several cars for the track, and done all of the work to them myself and brakes is one of my specialties. i have rebuilt more master cylinders than most people have even topped off with fluid.

[Jeff]

Easy there, chief. I'm not saying that you don't know the difference between a rachet wrench and a slice of bread. I'm saying that it's worth the vast majority of owners' time to have a dealer look at the problem. The reason? This way you not only have the problem documented by Dodge (because it WILL come up again), but they'll replace it for free if you're still under warranty. Which you are. If you try to fix it on your own and are unsuccessful I seriously doubt that Dodge will be willing to clean up your mistake, and you're still stuck with a non-functioning master cylinder. Which you'll have to fix yourself, again.

I'm on your side, I really am, I don't trust dealers either. They consistently over-promise and under-deliver. I once wouldn't let a clueless "Viper-tech" that I met even rotate my tires. But it's not really worth my time to take a day off of work to throw parts at my car. And as a Marine (I'm assuming here, since you live in 29. . .) I would assume it's probably not financially worth your time either. Unless you really just enjoy working on your car for other reasons. Pride and a feeling of self-accomplishment come immediately to mind.

I don't know or care what your car knowledge and background is, because that's not my point at all. I'm not saying that you don't know what you're doing - since you say you're building track cars, you're more advanced than a lot of people. My point is that for the vast majority of people, having the dealer fix the issue protects them.

Which reminds me, a friend of mine got a check in the mail yesterday from an auto manufacturer for $30 K - they bought back his car after only 18 months under the lemon law. If you continue to have this problem, you might wanna look into that.

I say all this, trying to be helpful. Since you don't seem to want my help and I've obviously offended you somehow, I'll move along.

[lunchbox660]

na na, you didnt offend me, it just seemed like you were kinda pointing fingers like i didnt know what i was doing. i aint mad atcha. the only reason why i started this thread was cus after seeing all my buddies cars have this problem too, i am wondering how many others have it and i wanted to let people know what to look for and in case anyone else had the same problem and mebbe already found the cause, thats all. thanks for your reply!