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Master Cylinder or Shuttle Valves?

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  #1  
Old 06-25-2014, 08:53 AM
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Default Master Cylinder or Shuttle Valves?

Hey all,
My wife has an '02 Disco II with 157K, I rarely drive it, just work on it when needed. :-) The "three amigos" have been on and off for about a year. She drives about 5 miles a day, tops. Anyway, I had the truck yesterday and noticed at a stop that the pedal would slowly sink to the floor. When driving the brakes worked, but the pedal was soft; I noticed pumping the brake had good stoppage and slow pushing on the pedal was not as good.

Usually I would lean toward looking at the master cylinder, but was not sure if the shuttle valve issue could be a culprit. We have a friend who is a Rover mechanic and does overflow for the Rover dealer, so he is supposed to be reputable. He changed the pads and rotors last year and bled the system.

When I call him, I am wondering what to ask him to check, should I get a new master cylinder, shuttle valve kit, both?

Any advice on what is most likely to cause the spongy pedal? Lastly, I hear a soft pedal alone could trigger the 3 lights? If it's just the MC, can this cure the three amigos?

Thanks!
Jamie
 
  #2  
Old 06-25-2014, 08:58 AM
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are you still running the original 12-year old rubber brake hoses?
 
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Old 06-25-2014, 09:07 AM
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I would not know, but would guess yes. My wife bought the truck new in 02 before we were married last year. I have only known the truck about 2 years. She has kept up with maintenance and we have had very few issues with it. I replaced the radiator 2 months ago when I snapped off the overflow nipple. I replaced the valve cover gaskets and that's about all I have done personally.

So, my guess is most everything is original under the hood.
 
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Old 06-25-2014, 09:20 AM
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the rubber brake hose over time have a tendency to weaken which causing them to swell when the brake are applied. often the it is the cause of the Disco Two Step.
Thats what I call it, your pedal is fair, but if you give it two quick pumps it will get rock hard.
 

Last edited by drowssap; 06-25-2014 at 09:23 AM.
  #5  
Old 06-25-2014, 10:09 AM
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I recall yesterday when driving that two quick pumps got the brake sensitive, but of course it went back to the way it was under normal conditions. Any way to inspect or test the hoses?

Trying to think how to rule out parts.
 
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Old 06-25-2014, 10:10 AM
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how many hoses are there? I am looking on the Parts website and I see left front, left rear, right front, right rear, and modulator to rear. is there modulator to front and do I need ALL these hoses?

maybe this?:
http://www.roverparts.com/Parts/ABP218SKA

So here is where I stand now:
1) the master cylinder $350
http://www.roverparts.com/Parts/SJC100432

or

2) the modulator shuttle valve kit $73
http://www.roverparts.com/Parts/SWO500030

or

3) the hose kit. $150
http://www.roverparts.com/Parts/ABP218SKA

or a combination?????
 

Last edited by jamieb; 06-25-2014 at 10:21 AM.
  #7  
Old 06-25-2014, 10:16 AM
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There are six hoses on a D2. The lines that go to the modulator are metal, and shouldn't need to be replaced (with some exceptions of course).


 
Attached Thumbnails Master Cylinder or Shuttle Valves?-brake-hoses.jpg  

Last edited by jafir; 06-25-2014 at 10:20 AM.
  #8  
Old 06-25-2014, 10:33 AM
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Thanks Jafir. That would seem to be what is in the hose kit.

Any idea how to rule out the Master Cylinder? That's $350 and the hoses are only $150.
 
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Old 06-25-2014, 10:38 AM
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Personally, I'd inspect all of the lines first. If I don't seen cracking or deformation, I'd replace all of the brake fluid, and make sure everything is well bled before replacing parts. That should only cost about as much as two big bottles of brake fluid.

If that doesn't work, or if I see visible damage to any of the hose, then I'd worry about replacing them.

Also look for where the master mounts onto the booster. If it's wet there, replace it. The master can still be bad without leaking, but sometimes they leak.
 
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Old 06-25-2014, 10:54 AM
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OK, sounds like a good start.
 


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