Hello all,

I have 133k on my rover with Akebono pads and Brit Part rotors all the way around. I have had a very firm pedal with very reduced power for several months. I replaced the master cylinder a few months back with a new one from AB and did the 3 bleed process and confirmed no air was left in the lines. This did not change pedal feel at all. I still have good pad depth left all the way around. Probably a slight warped rotor on the front. When I swapped the in the new master cylinder I also swapped a known good used ABS modulator from eBay. No change what so ever in brake power. Pedal does not drop, it just has little power. I confirmed their is not a vacuum leak. I added some plumbers tape to the brake booster grommet on the upper manifold. Tonight the front brakes were locking up on my drive home from work and where smoking. I let it all cool for 3 hours and drove it around the block a few times and it all acted normal again. I have worked on this 2003 DII since 2007 and consider myself a decent shade tree mechanic. What am I missing? I own an ABS Amigo, it still shows a constant failed shuttle valve after I replaced it over a year ago. I'm about to break down and take it to a shop. All I know is to grease the caliper slides from researching tonight. This would still no help with weak brakes/hard pedal.

I have a full Christmas tree, 3-Amigos and brake light on. The brake light came on about a week ago, but has turned on/off intermittently. There is plenty of brake fluid and I have exercised the hand brake switch = no change brake light stays on. Unplugging the float cap switch = no change.

Please help, gotta get my brake power back.

 

Brake hoses can fail internally, creating a check-valve effect which will cause caliper lock-up. Likewise, calipers themselves can fail: the square cut seal around the caliper piston looses resiliency and does not retract the piston.

 

Seems odd they would all fail at the same time?

 

I suspect there is one hose common to both front calipers-- but I don't have rave here at work.

 

All Brake hoses were replaced with stainless in 2008/09 I believe. Not saying they could not fail, but would not be my next part to replace. I have heard that stainless lines just fail and you cannot really tell anything because they are wrapped.

Although I think I did figure out why the front brakes are heating up. I bent the drag link awhile back which creates a good shimmy at highway speeds. I think this is causing enough vibration to heat the front wheels. At 65mph its fine at 50mph its shaking like a paint shaker. I have new Terrafirma steering bars I am installing this evening. I will get the front wheels towed in and see if they stops the brake over heating. I will try to grease the caliper slides sometime this week and check all rotor thicknesses.

 

Is it possible the abs system is getting a false "slipping" signal and the the abs system is trying to stop a wheel from spinning?

 

However unlikely it sounds that more than one or even all four calipers are sticking...
This actually happened to me! It wasn't on my Rover, but I have seen it. Even worse, you could remove the calipers and push the pistons back in. They didn't move as easy as they should have, but I kind of forced them a little! They would come back out and stick again.
I would check to see what condition the calipers and sliders are in. Especially the fronts, if they were hot enough to smoke!

 

Guys and gals

Found my problem with the brakes I researched on several other LR forums. I knew it had to be something like this:

A bad master cylinder back flow valve with a clogged 0.2mm valve hole. As brakes heat up they need to release fluid back to the reservoir. A few pieces of debris or crystallized brake fluid clog that hole then after 10mins of driving all 4 brakes lockup like a nuns legs in a ***** house. Seems to happen on the highway only at first but then happened on city streets tonight. I ordered a new TRW master cylinder tonight. That is the genuine rover OEM brand. Just replaced it about 4 months back from AB. But I guess it was defective my brakes were still terrible after 3 bleeds. I've heard the master cylinders are not rebuild-able yet from a few mechanics.

This makes sense and I do not feel the ABS engaging at all. ABS amigos are on. And have been on for over a year. And heat generated from sticking pads would create back flow pressure in the master cylinder. I will update when the new master cylinder is installed. I will probably replace front rotors and pads once normal pedal modulation is regained. I will update the thread when this is done for reference...since this issue has not been solved/resolved/discussed on this forum yet.

 

2003 Land Rover Discovery I was driving and brakes locked I read this forum and I pulled the abs relay off and it stopped the locked breaks but it’s overheating I am getting new abs relay today I am not driving it. What else could it be

 

Did you ever figure out the issue? I know this is an old post, but I am having the exact same thing with my 1998 Disco II with the brakes locking up and found this thread. The issue started immediately after installing a new master cylinder and two different mechanics have yet to figure out how to fix it. I'd be really interested to hear what the issue ended up being for you