Thread: This has never happened to my Patrol...

Educated guess here.
Had this happen on a non LR years ago. Pulled up at a level crossing and that was that, no moving it until I cracked a brake pipe union to release pressure. In my case it was eventually diagnosed as a blocked compensating port in the MC. This car did not have ABS though. But that or something similar would be my first port of call. Maybe when all that work was done some dirt or other contaminant was allowed into the system. If you have access to a Nanocom then I'd suggest a complete flush of the system. or take it back to the shop that did the work.

I’d check that the brake hoses haven’t swollen AND that if the master has been rebuilt it’s been done right. Had it happen on a Range Rover and a rebuilt master was at fault.

Thanks guys.

I've had a chance to get a bit more into it since my original post. The PO has a new master cylinder coming because the existing one was only recently purchased and installed. However, cracking the unions open at the master cylinder does not release the pressure off the brakes. This morning, I stuck the front axle on jack stands then cracked the bleeder on a caliper and got the wheel to release with some remaining drag (more on that below). The other side's brake remained locked. cracking the unions on the respective outlets of the ABS modulator released the frozen brake. This kind of eliminates dud hoses (I think?) and I'm now a little concerned that somehow the ABS modulator has something to do with this, but searching this Internet thingy (probably poorly) hasn't produced any hits of similar problems.

As to why the brakes still drag, this has kind of been resolved. The PO had the calipers overhauled off the car and he refitted them with new pads but hadn't serviced the slider pins. I've only done the front so far but they were horribly gummed up with what looked like the remains of old bearing grease and dirt and one was seized pretty solidly and took a bit of effort to extract for cleaning. I've sorted that out and expect to find similar situation with the rear brakes when I go over them tomorrow. I doubt dragging due to gummed up or even seized slider pins would be causing this problem as a whole, but who knows?

Sounds like the cartridges in the ABS unit are seized also.

Get a Nanocom and cycle the shuttle valves and see if you get any joy.

My bet is neglect has resulted in the cartridge valves sticking, or the system gummed up, as well as your noted neglect of the pins.

I had a think about this over lunch and I'm reasonably confident I've worked out this little mystery.

I reckon the PO has accidentally topped up the brake fluid with power steering fluid or similar a little while back. They'd then replaced the master cylinder and overhauled the calipers and given the system a flush to fix their snafu, but the ABS modulator has suffered swelling seals and I think when the TC has activated (I assume) while driving on sand the swollen seals have caused the valves that let fluid return from the calipers to the master cylinder to jam closed. So closed that the pressure never releases from the calipers.

How does that sound for a theory?

ABS modulator aside ( very likely culprit ), sticking slider pins play havoc with brake, ABS, TC and HDC performance.

Originally Posted by Tombie

Sounds like the cartridges in the ABS unit are seized also.

Get a Nanocom and cycle the shuttle valves and see if you get any joy.

My bet is neglect has resulted in the cartridge valves sticking, or the system gummed up, as well as your noted neglect of the pins.

$$$$$ I seen some mention of group buys and discounts. Are they still a thing?

Originally Posted by Tins

ABS modulator aside ( very likely culprit ), sticking slider pins play havoc with brake, ABS, TC and HDC performance.

I've grabbed a used one off eBay for a decent price (I'm guessing I can swap over the old one's electrics if the replacement starts lighting up the dash like a christmas tree). The PO said he'd replaced all of the brake gear because of a sticking caliper yet failed to clean and grease or even inspect the sliders. Cool story, Bro, lol.