Master cylinder gone south AGAIN

[Makaio]

I am having major problems with my master cylinder. This is the THIRD time it has failed on me. They are all new in the box, from NAPA, and made in Italy, if that makes any difference. They all lasted about 3 to 4 months and then the pedal gets soft or the brake light comes on. It's fine when newly installed. Pedal is rock hard. No leaks anywhere either. Should I just get another through warranty or buy another brand? I'm on a rock so parts stores are limited. We have NAPA, Carquest, Checker and the Dodge dealership. Possibly a bad run of master cylinders? Is the heat killing the seals? I am dead ended.

[burnt_servo]

what fluid are you running in them ?

[Renigade]

Love your avatar Man





I wandering also what type of fluid are you using.

[Makaio]

what fluid are you running in them ?

I can't even remember what I put in it. I think it was the NAPA brand Dot 3 or Prestone Heavy Duty. One of the two.

[Makaio]

I didn't even think about the fluid I put in it. I just bought the cheapest DOT 3. Is there a preferred brand that can better handle the heat from our engines?

[burnt_servo]

i was thinking that maybe you had like a 5 gallon pail of brake fluid that you where using for all the master cylinders ...... that may have become contaminated .

maybe you need to closely look at the rest of your braking system , maybe the master cylinder isn't going bad , but something else is causing spongey brakes.

[Makaio]

Well, there are no leaks anywhere and when I did install a warrantied master cylinder with a new one, the pedal was rock hard again. Then after 3 or 4 months, the soft pedal came back. I also bypassed the ABS valve and went with a solid line.