Trying to get my braking system functioning on my 03 D2 has been a nightmare. I Bought the truck after sitting for a while and the brakes had gone hard. I figured the booster was bad and discovered the master cylinder was leaking as well. I unbolted both and got a new master cylinder but a used booster. I have since been unable to get any braking pressure out of the right rear line and front left lines. Left rear has tons of pressure and front right has decent pressure. I’ve tried pumping the brakes, jumping the abs pump and nothing has worked. Brake pedal also goes to the floor no matter what. Any thoughts? I know I should probably buy a new booster and maybe even a higher quality master cylinder but I don’t want to throw parts at it if it’s something else like a sticking valve in the abs modulator. I was thinking about getting a Nanocom to cycle the system but I figure it won’t do anything different from what it’s been doing now. The video I’ve attached is the flow at the right rear brake line when engaging the pump by jumping the abs relay. Any thoughts or tips are appreciated as I’m ready to roll this rover into a lake.

 

My first guess is that the brake lines need a more thorough bleeding.

 

I’ve bled at the master cylinder, I’ve bled at the modulator, I’ve bled at the caliper, I’ve removed brake hoses to see if it was a collapsed hose, I’ve done this atleast 2 or 3 times and am kind of fed up with it. I also just had the engine rebuilt and haven’t even been able to drive it anywhere.

 

There have been a lot of threads on here lately about failed master cylinders out of the box. Seems to be a trending thing.

 

Well the thing is this is my second new master cylinder I've received but I will say it was just an ebay part. I've always had good results with ebay parts though.

 

I'm in your same boat. I bought a new master from Autozone, its a Duralast, if you look at the Rockauto part it matches the Cardone master perfectly. Did you bench bleed the master just after installing to the booster before connecting the hard lines to the the ABS modulator? This process can remove a lot of air from the master cylinder. Instruction in the box require this process on mine. Although I had never done it previously other MS swaps. I had a very soft pedal and 2 pump pedal for a few days but now seems to have worked itself out. Probably could do one more ABS bleed. I probably have some sticking caliper guides pins, which I suspect I need to check all calipers pins for proper lubrication. I did brakes for 10-12 years on this Rover and never ran into these issues. Just replaced front LH caliper and 4 new extended Stainless Goodrich lines. Brakes from hell but now nearly acceptable now. I'm at 4-5 quarts of bleeding DOT5.

 

Do you think there is sediment in a line via the abs module? Would disconnecting line from the abs unit and the caliper & blowing out the line?

 

That's a good thought, we considered blowing compressed air through the line going to the right rear to look for a blockage but when we bled the modulator that's where we discovered what I would say is likely the root of the pressure issues. When attempting to bleed the lines that come out of the top of the abs modulator, just like the when bleeding at the calipers, no fluid would come out from the line that goes to the right rear and the left front. At the time we were triggering the modulator via a switch we plugged into the ABS relay. I'm wondering if the switch is not engaging all of the valves since were just plugged into it triggering the pump, or if there are some stuck valves inside the modulator. That's why I'm considering getting a tool that can trigger them but don't want to buy an expensive tool just to be out 500 more dollars and still have no brakes.

 

So the first master cylinder I had I did make the mistake of not bench bleeding. When I got a replacement I did bench bleed and actually it was fine for a little bit with some resistance at the brake pedal but as I bled the system by pumping the brakes, suddenly the pedal was just going to the floor again and it never gained the resistance back even after swapping boosters back and forth in an attempt to see if they were at fault. Well I've done all kinds of services on discoveries, power steering pumps and lines, head gasket jobs, pulled motors, transmission services, ect, but I had no experience with brakes other than doing pads and rotors and I know my own mistakes are probably most of my issues here but I just can't seem to catch a break on this system. No D2 I've owned have I ever though the brakes were great on but I've never had one have no brakes at all. Was just hoping someone could suggest something so that I don't have to admit defeat or just throw more parts at it.

 

Old thread here....

This is what I am seeing with my ABS pump, I'm getting some fluid, but barely... did you ever fix the issue? (If you are even still on here)?