brake fluid leak

energumeno · #1 07-28-2009, 07:13 PM

I have a 1998 4x4 dakota with rear wheel anti lock.
When i bought the truck (3 months ago) i noticed that it was or had been leaking brake fluid because the frame on the drivers side front wheel as well as the brake lines behind the master cylinder had fluid on them, also the brake fluid reservoir was bellow the "ADD" mark.
At that time i cleaned everything with a rag and checked it for some weeks and it didn't seem to be leaking more so i left it like that (without refilling the reservoir)
One week ago i finally refilled the reservoir just above the "ADD" line and today i noticed that the leak is back again. I cleaned everything, turned on the truck and pressed the brake for a few minutes to check where the leak was coming from and it is on a black button on the rear of what i think is the combination valve, I am attaching some pictures of it,

What do you recommend me to do? Is this button something replaceable or do i need to get a new complete valve? Is this something that i can buy at autozone or only a dealer item?
Thanks

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DRLDallas · #2 10-12-2009, 02:56 PM

What happened? Did you end up replacing the whole thing? I've got the exact same situation on my 2001 Dodge Ram 1500, except my valve is mounted vertically so that the 'button' is on the bottom. Logically, I assume a torn o-ring or something, but I can't figure out what the purpose of the 'button' is. The dealer wants $145 for a new one.

Independentfool · #3 10-12-2009, 11:55 PM

that is the proportioning valve. see if you can take that black cap off and if there is any o-ring in there that is replaceable.

DRLDallas · #4 10-13-2009, 12:01 PM

I was hoping to hear from someone that's done it before I pulled mine out of the truck. I don't think I'll be able to see it well enough without taking it out of the truck, and realize that if I take it apart and can't fix it, I'll be down until I can get the new part in from out of town. Also, if the drip is like a weep hole on a water pump, I obviously don't want to mess with the safety of the brakes.

I spoke with the service foreman at one dealer and the parts guy at another and neither one really understood how the proportioning valve was constructed well enough to know why it might be leaking out of the end like that. Only that they don't sell any kind of repair kit and could only recommend replacing the whole thing.

D

cbh · #5 10-13-2009, 09:35 PM

You can remove that part of the proportion valve without removing the entire assembly. I think it takes a 3/4" wrench. Be careful to not let it fly apart, because there is a spring inside there, and it comes flying out as soon as you get that plug loose! There is an O ring there on the back side of the plug that may be bad...or maybe the plug is just a tad loose and needs snugged up.

energumeno · #6 10-17-2009, 07:29 PM

To the original poster.

I researched a little on this matter and everywhere they told me that the combination valve is not a "serviceable" part, which means that once it goes bad, it must be replaced as an entire part.

What i did was to search ebay for a few weeks till i found a dakota that was being parted out and got another valve for 25, shipped.

I havent't had time to replace it, I may be doing it in two weeks.

cbh · #7 10-17-2009, 10:15 PM

Quote:

Originally Posted by energumeno

To the original poster.

I researched a little on this matter and everywhere they told me that the combination valve is not a "serviceable" part, which means that once it goes bad, it must be replaced as an entire part.

They're mistaken. You can take them apart to clean them out and put new O rings in. I've done it. I had to take one apart after someone put motor oil in the brake fluid reservoir and practically plugged it up!

DRLDallas · #8 10-19-2009, 02:51 PM

I took it apart this weekend and couldn't see a way to fix it. There is a thin o-ring around the threads but it was in good shape and not where my leak is. Mine is leaking from the hole in the middle of the plug piece that comes out. There is a metal shaft that comes down into this plastic lined part, but the plastic piece didn't come out with moderate pressure and I'm sure I couldn't find a replacement anyway.

There is a textured O-Ring on the valve that gets pushed into the body with a spring that seemed loose but would also be impossible to replace due to the surface dimples. I suspect you could find a regular round o-ring but the valve would not function properly if you did. So for me replacement ended up being the order of the day.