Just wondering if anybody has any advice about removing the t-case brake completely and installing a line lock instead? Any negatives that I can't think of? Do the line locks work well?

I've installed them before. I think they are okay. Some line locks are better then others though. Go with a good quality one and you will most likely be happy.

What do you anticipate as a problem with the idea?

I've installed them before. I think they are okay. Some line locks are better then others though. Go with a good quality one and you will most likely be happy.

What do you anticipate as a problem with the idea?

Maybe nothing, but I wonder about the effectiveness of the line lock. I also wonder if there will be any issues mounting the driveshaft to the smaller area without the drum there. Or if the drum somehow integrates into the case in a way I can't think of that causes it to be a bad idea to run without it.

the biggest problem I can see is this: you're losing the gearing advantage of having the parking brake before the gear reduction in the differentials. So, depending on what ratio you're running, you will need that much more clamping force to keep the vehicle stopped... having said that, it should be fine keeping it from rolling (for a while, at least... these things will start to bleed off after a while).

if you do go with a hydraulic "parking brake" you should plumb a high-pressure ball valve in each brake circuit. this is the simplest and most effective line-lock you can do, and the least likely to lose pressure over time.

the biggest problem I can see is this: you're losing the gearing advantage of having the parking brake before the gear reduction in the differentials.

x2. i used to drive an 88 ford dually with a 460. with a couple thousand pounds on the flat bed, and towing a 12,000 trailer w/bobcat you could park it in neutral on a hill with just the transmission mounted drum brake on and it wouldn't budge. the 02 GMC that i used for the same stuff, sucked. i constantly adjusted the rear brakes. no matter what, it had to be left in gear. the brakes wouldn't hold just the truck alone. i've never found any wheel mounted parking brakes that could outperform the transmission/x-fer case parking brakes. the only argument against them is that they fill with crap if you drive in a lot of mud.

transfer case mounted disc brake like something all-pro sells would be the ticket. if someone designs a bracket and rotor using an off the shelf caliper, i'll machine them. (i want stainless rotors) i've seen one that some british company sells for rovers, but they want 300+ dollars for it....i just don't have time to pull mine off to make the measurements.

constant pressure on your brake cylinders isn't great for the seals either and is sure to find any pinhole in your brake lines and make it much larger.

X2 on the driveshaft mounted disc brake. I have one, and its great. Can't drive through it. I've tried a few times (by accident) and it won't move, even in low range.

When I last spoke with Bill at GBR he said that he was working on a bracket for this...basically a less expensive X-Brake kit as I recall. Those things are crazy expensive!

I've seen one "good quality" line lock fail on the trail. A nice tacoma mini truck with an SAS rolled off the top of a big fall during a lunch break.

alright, i finally decided to take some action. i just ordered a really nice looking mechanical caliper with enough clamping force for 3 rovers. hopefully in two weeks or so, i can mock up a bracket and such.

When I last spoke with Bill at GBR he said that he was working on a bracket for this...basically a less expensive X-Brake kit as I recall. Those things are crazy expensive!

Less expensive? are you sure you don't mean more expensive? or much much much more expensive?

Less expensive? are you sure you don't mean more expensive? or much much much more expensive?

So I was told...he was making a bracket to mount an off the shelf rotor and caliper that you can buy on this side of the pond. You couldn't get much more spendy than those X brake kits. I assume I'm missing your point.

yeah. Bill is known for charging as much as he can get away with, typically significantly more than the item is worth, at least when there is no strong competition. and even when there is, he still charges more.

One question: Why do you want to remove the drum?

--D

it holds mud, dirt, and water. it weighs a lot. is complicated compared to a disc setup.

The X-Brake is pricey but a damn good bit of kit, the caliper is monsterous although I guess the postage might hurt a bit. I know SimonR tested a lot of different setups during development and making a disc trans brake that really works is harder than you'd think. There's probably still his original writeups on LR4x4, I know he grenaded a Wilwood mech caliper early in the game during testing.

Mud & water is probably less of an issue for crawlers than over here in the UK where trucks spend their lives in mud and LR handbrakes last all of 5 minutes between seizing up or failing.

The issues I can see with line locks is that any loss of pressure and your truck is rolling away, plus you have no backup if you bust a line or damage something (could you stamp hard enough to hold your truck on a hill with no servo if the engine died, for instance?). At least the transmission brake will work independently, and with CDL and lockers it's acting on all four wheels.

Less likely but worth thinking about is this story: There were a spate of Citroen cars over here which had the parking brake act (mechanically) on the rear calipers, which worked OK unless you'd been driving in a spirited fashion and then parked up on a hill - the discs & calipers then cooled down and contracted enough to release the brake and your car disappeared down the hill :D gotta love the French.

toyota supras and some others, had small drum brakes inside the center hat of the rear disc.

here's the one i'm going to use. uses a .25 inch rotor between 6" and 16" diameter. static braking torque on a 6" rotor is 428 ft. lbs.

here's the one i'm going to use. uses a .25 inch rotor between 6" and 16" diameter. static braking torque on a 6" rotor is 428 ft. lbs.

So 428 ft-lbs through a 3.54:1 diff and 33" tyres gives about 1100lb of braking force at the tyre contact patch.
16" rotor would give roughly 3000 lbs braking force. More if you've got lower ratio diffs and less if you've got bigger tyres.

Sounds enough, but how "optimistic" are their figures? Guess you'll have to build the first one and see how well it works.

We run the simple swagelock 1/4 turn vales in our brakelines, one for front and one for rear because you never know which end you'll need it on. You can shove the front one under the hood at the MC for an emergency, and run the rear one on the floorborad next to the seat in most cases. Keep in mind, we have no "park" or any gearing at all to hold us back as we use the Lovell T-case...no air means no engagement of any kind. We leave them on for sometimes a month between events and no bleedoff.


http://i187.photobucket.com/albums/x152/RedBullRockIt/Misc/shutoff-valve.jpg

We get them from www.PolyPerformance.com Though they do not have them listed on their site, they do have them.

Early Saab 900's use a real nice caliper that is mechanical on the fronts. the rotor is a nice size as well and can be drilled to accept the drivleine flange.and can be sourced easily at a pic your part yard. the Saab is a 3000#+ car and has tremendus brakes. just a thought.