First time poster but long time Porsche owner/forum poster and home mechanic. This is my 3rd Disco II in addition to an LR3, LR4, and Range Rover Sport.

Picked up this current D2 from a tow company after the PO abandoned it due to what I suspect was loss of brakes and fluid. That probably should have been my sign.
First thing I did was fill brake fluid reservoir and bled the brakes with a motive power bleeder. Following that normal brake function was restored. However, due to condition of the parts I had to replace several items to include: 4 calipers, all hardlines and rubber lines, and MC. The rear calipers were so rusty that you could see fissures in the metal and it was apparent they were about to split apart. Hardlines actually had rusted thru in a few places and after one power bleed with Hawkeye they were literally spraying fluid out mid line. Rubber lines were on 149k miles so were replaced as recommended by LR. When removing them damage was done to a few hardline fittings as the threads had fused together.

Here is the problem: I have bled and bled, and bled the brake lines. The MC was bench bled and also bled on the truck during install. I have firm pedal with car OFF but when ignition is turned ON the pedal sinks almost directly to floor under pressure. I drive around the block and can get brakes on about the 3rd pump. Also the front calipers have a drag now and after one 10 to 15 minute test drive around the neighborhood were very hot to touch.

I've searched the forum(s) and found a similar thread from 2016 where the OP replaced most of the parts I have replaced and had same issue with lack of pressure and brake pedal to floor. Bad news was he did not report back on whether he actually found a fix.

I've checked the calipers for movement and actually ensured the pins were properly lubed.

Is it likely that I got a bad MC? I've bought so much stuff that I really don't remember where it came from and can't find receipt. I seem to recall it being a TRW unit but there are no markings. I have a spare ABS pump and exchanged them just to see if that was the problem, it was not. Ditto for exchanging booster.

Thanks for any help given. This is one of my kid's college vehicle so I need it to stop properly and sooner so he can get back to school.

Matthew

 

Oh and one more thing... since this all began the brake lights now stay lit after first use. I'm hoping that is just the switch.

 

Check the hard plastic line from the booster to the intake - those things crack really easy and you will end up with little or no vacuum

 

Forgot to say that I've checked that line for vacuum and the check valve as well. Both are working as intended.

Thanks for the response.

 

It is possible you have air or another issue in the ABS pump, there are few threads on how to actuate the pump for bleeding without a device that will do it.

But try this :

• Low range
• 1st gear
• About 10 KPH
• Press the hill descent
• You should hear the ABS pump kick in

Once you are slowed right down turn Hill descent off try the brakes

Does it make any difference ?

Also check for codes all the brake light on is a new one to me

 

Thanks Richard.

I've done the 3 step bleed and power bleed with Hawkeye.

One occasion with the regular bleed using Motive, I pushed about 7 litres thru the system on R Rear. Still nothing.

 

so everything was replaced except the calipers? maybe all the caliper pistons are stuck? I had this on rears, but not fronts. Maybe bad master cylinder even though you replaced it. even with power bleed, I had to bleed the top of the ABS box where the lines connect. There is a pressure tester made to go where the caliper bleed screw is located. You could test for pressure at the end of the line......
https://leedbrakes.com/i-23439488-br...iABEgK6MvD_BwE

 

@matthewb0051 I am with Xrad here it has to be a blockage or something not right, could it be the MC to Booster connection not set right. It seems to me someone else had an issue with the master cylinder push rod being a hair to long resulting in the brakes being on a bit, the other possibility is the rod inside missed the hole

 

Xrad,

I replaced all 4 calipers. The rears were beyond any safe condition for use. They are all moving freely. Did a bleed on the lines from MC to ABS pump yesterday. Unless I'm doing something very wrong, there is not any air in that, or it is trapped and being stubborn.

That pressure tester link you sent is very cool. Any idea what sort of PSI you would be looking for ?

 

Do you think the internal hole in the MC where that push rod could be blocked off too short? I have 2 MC's.... One is the new unit and the other is an old spare. I've had them both on the truck and same symptoms for each. I even have a spare booster and the symptoms are the same regardless of which one of those is used.

It could be that my spare MC is clapped out and the new one is defective???

I'm trying to stop spending on this thing. We are well past the budget at this point. There were things that absolutely needing replacement but the list just got too long.

Matthew