1995 DRW with 175,000 miles.

I put new front pads on my truck and when I was done I couldn't get the pedal to hold pressure. It is good and stiff when you first hit them but then the pedal just slowly bleeds down to the floor. I didn't have time to screw with it so I took to the mechanic. He said it was a bad master cylinder and replaced same. Still didn't help, he said to come pick it up and take it to the dealer. I hate taking it to the dealer!!!! I think it is the ABS, I am contemplating plumbing around it and to see what happens but that doesn't seem so easy since there are two lines coming off of it. I looks like the ABS is only on the front wheels.
Any advice would be appreciated. I did a search already and read 5 pages of posts but nothing seemed like it was pertinent.
Rick

 

Nothing? Am I taking this thing to the dealer?

 

Maybe R. wheel cylinder leaking , but not coming out the drum yet , its also not uncommon to get defective parts , then I have seen new masters get ruined during installation .

 

i have the same problem, my front left cylinder is leaking, if i hit the brakes they are firm for a second or two then it loses pressure and i can put the pedal on the floormat

 

Can the ABS unit cause this?

 

If you have a brake cylinder leaking you will be using fluid... and covering the brakes with oil... Do that a few times and check the res- if you're not using fluid it's the replacement master cylinder- it basically has to be. If the seals in the master don't seal the pedal leaks down- commonly caused by brake pad and shoe changes because compressing the wheel cylinder forces the fluid and contaminates back up in to the master cylinder which can prevent the seals from sealing.

Look for leaks, check the condition of the fluid in the res- contamination of the fluid or particles means it fluid flush time. Are you sure the mechanic replaced the master (is he honest?) Did he use a reman or a bone yard pull? If it's contaminated it's your problem, but if it is leaking and is a reman it should have a warranty.

Mine has had a minor master leak for years- it doesn't affect the stopping, only when I am at a stop if I increase pressure on the pedal will it drop. Cleaning the master res and flushing the lines made a huge improvement.

FWIW in 1995 the only ABS offered was rear wheel only.

 

The ABS can leak , but not make for a low peddle .

 

The master cylinder is definitely new, or at least he cleaned the crap out of it. The fluid is new and clean, he said he bled the whole system out to make sure it wasn't air. I don't seem to be using any, but I guess the leak could be small enough that I am not really seeing it yet. No way I can drive the truck this way, I tow a big boat and backing down a ramp is no time for a soft pedal.
When I get home tonight, I will mark the level of the fluid in the master cylinder and pump the brakes, alot!!! I will let everyone know what happens.
Thanks again to everyone for all the input. I was getting ready to bypass or change the ABS because I was convinced that was the problem.
Rick

 

OK, I pumped the brakes for a half hour and no fluid loss. I dropped it off at the dealer this evening. I will let everyone know what they say as they.

 

seems like when the fluid becomes contaminated with water it rots the lines and the fluid turns black.
The end of the bore in the master cylinder gets pitted from the water and you dont see the leakage unless youre holding firm pressure or youre in a panic stop and you hit the end of the travel.
Im gutting mine pretty soon. new lines, master and calipers.

 

So the dealer said they flushed the lines and bled all of the brakes, and it didn't help. The technician is convinced that the new master cylinder is also bad, he says that is the only thing it can be. The original mechanic quoted ~$350 to install the master cylinder, but when it didn't fix the problem, he didn't charge me anything. The Dodge Dealer wants $900. I think I am going to pay him the fee for diagnosing the problem ($129) and do it myself.
I am still not convinced it is the master cylinder....
Rick

 

Rick, I have seen it before............... Sometimes the quality of rebuilds just plain sucks.