I just bought a 98 dakota with a 5.2 liter engine. It was sitting in barn for two years and needs some work. I am right now trying to fix the ABS and brake light problem (as at the moment it has zero brakes). I ram a diagnostic scan and it read code 36 rear sens sig missing. I was wondering if anyone here could help me try and figure out which sensor it is talking about. On a side note, I have also noticed that the master cylinder will not hold brake fluid longer than a day. I have filled it up once and it no longer has a drop in it (i almost used a fulled quart bottle of dot 3 brake fluid). I would be very thankful if anyone can offer some advice on these problems I am having.

 

If the Mc won't hold fluid, even when sitting, it needs replacement. Even a disco'd brake line should only leak when the pedal is pressed. If it leaks while sitting, it's getting past the plunger.

 

Ok, so new master cylinder? What about the ABS code? On a side note, I have a 2000 dodge dakota 4.7 liter. Do you think the master cylinders would be interchangeable?

 

Well i changed out the master cylinder. Seems like there is still a leak someplace. I have been working on it outside and it has been raining a lot here lately so I have no been able to isolate the leak as of yet. Any advice where to look for the rear sensor on the truck?

 

an MC should not be able to leak past the piston. If it looses volume when you push the pedal, it's a broken/disco'd brake line.

The sensor is on the forward top of the differential. Can't miss it. It counts teeth for the speedo, and also thusly checks for ABS working.

 

i have a sneaking suspicion it might be a drum cylinder that needs replacing in the rear. it is too late tonight, but once I get up in the morning I am going to see if I am correct. That sensor I am pretty sure I know where it is at now as well. I wonder if they go out often or not so much? This is what is making me think it could be a rear drum cylinder.

 

i know i have a leaking left rear wheel cylinder...but I'm under impression that an MC should not leak unless the pedal is pressed- the vacuum inside the reservoir holds the fluid in, I thought.

The rear sensor is in a pathway of the elements...not that difficult for a wire to get caught or the sensor to get all but destroyed to death by elements.

 

Well it looks to be a bigger problem than what I thought. I put in some brake fluid and got into the truck and started pumping the brakes. There is definitely a broken brake line or the booster has a leak looking into it now.

 

I would think with a leak that bad you would see the Dot 3 just gushing out of somewhere either a pool under the master or under a wheel... where are you working on this on the dirt or in a garage I could see on dirt it just may go un-noticed soaking into the dirt can you roll it into a concrete floor garage to see the leak.

Im not understanding how you cant see something like a big pool of Dot 3

 

Check the flex line from the frame rail down to the rear axle. Also check the flex lines on the front wheels.

Booster shouldn't cause leak- the booster just amplifies the force exerted on the piston.