So i have been having an issue of my front side of my master cylinder going empty and have not been able to solve it. Back side staying full so i narrowed it down to front brake system problem.

Things i did:
New calipers on front
new lines to calipers (ss lines)
new rubber gaskets under tank

So after all of that and i gave up and moved on to other tasks. I placed a piece of cardboard under the truck to check for leaks after i replace the power steering hoses. I noticed a large clear stain on the back right of the cardboard away from the tires. This made me look even harder at the area and i think the ABS Pressure Reducing Valve is the culprit of my diapering brake fluid. Is that a part I can just pull out and replace or do I need to have it adjusted when i install the new one?

 

Diapering brake fluid, must be very young.

It's already calibrated if it's OEM. The performance market has adjustable proportioning valves. I don't think it's the valve per se but I do think it's a connection/line at the valve that's leaking probably due to a fractured nut or line split. Why don't you remove it to check it out?

 

Yep fresh out of the bottle.

Damn auto correct on the phone.

I plan on pulling it out tomorrow when i get off. Could i just cap off all the ports but one,and give it a shot of air to test it out, or is there a better way?

 

I love autocorrect especially when I'm trying to create my own words - it's a battle with a silicon brain. Mine wins, it's squishy.

Anyways..... I'd personally go the Full Monty and want to see it with my naked eyeballs. It's a pain no doubt but it's your safety and what price is that worth eh? A few scraped knuckles aint so bad. Your going to have to do a bleed anyways so might as well. If the leak is that heavy your going to find the reason fairly quick and won't need compressed air. You can do whatever you want though, it's your equipment so whatever makes you feel comfortable.

 

I pulled it and could not find any fluid at any of the lines but did see fluid on the back of the unit. Looks like a new one is going to have to go in.

 

Bingo! Dang good job man! Yep, new is in your future. Thanks for doing it, I'm sure you're not the only one who's gonna run across this. Whole bunch of others are probably gonna see it happen too eh. Wow is all I can say. That is blown out big time.

 

Yea I really like stopping when i hit the brakes. It was very easy to remove. So far no busted knuckles or blood. I have always said its not fixed till you bleed all over it. So hope i bust a knuckle when it goes back in.

I hope this helps out others that are experiencing the same issues. Nothing like coming home after a long day at work, crank up the tunes and relax as i wrench on the beast. I may be sick in the head but it's therapy for me.

 

for what it's worth, i was able to get a used proportioning valve cheap and install it with out needing to bleed the brakes.

probably just got lucky with not needing to bleed them but after switching it out i had no more leaks.

 

That's good to know too, not having to bleed Disco brakes is a good thing.

 

Just changed out my ABS Pressure Reducing Valve this week. I replaced the front calipers last weekend and went to bleed the brakes. Found out no brake fluid reaching rear wheels.

We all know our trucks don't stop on a dime, but can't really say how long I have not had rear breaks. Installed new PRV last night and bled the brakes; all OK now. I obviously can see a noticeable difference in stopping distance.

I took apart the old PRV and found it to be really dirty and gummed up. I guess the built up crud clogged the outlets to the rears.
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'98 Disco LE - Cobar Blue with 174K original owner miles