Not sure if this is a mechnical question persay...

[Wind_Danzer]

Why do people put their rigs in neutral on a steep decent (mainly auto guys I keep reading)? How does this give you more control? Neutral to me would speed you up on a decent, not keep you under a limited control decent. Wouldn't it be better to just get the proper gears or eventually a new t-case (TeraLow, Atlas, Klune).

Just curious.

[PK99TJ]

If people actually do this, I'm curious myself. That's the last thing I would think of doing (auto other otherwise) on a steep descent!

[Wind_Danzer]

I've seen it posted on a lot of the forums I frequent over the last 6 months (Q-Tec, JU, RD, POR) but it's not something that I see all the time, just every once in a while.

[Scott Hill]

Well for me I have done it only backing down a hill. I will pop ot to N so I can stop the rear drums get over powered going in R so as to not smash into the rig I am backing down to help in N it goes.


as far as forward down a hill I have no idea whay anyone would.

[mrblaine]

WD, the correct thing to do is to not overbuild certain aspects of your rig without taking all things into consideration.

The majority of jeep owners spend endless amounts of time and money on everything but brakes. They almost always increase the capability and performance of all other systems whether it be suspension, steering, tires, and armor without ever considering that the stock braking system is very quickly overpowered.

Then they commit the next cardinal sin which is trying to make their jeep stop better by upgrading the rears. Even with discs, the rears are very quickly overpowered due to their smaller physical size.

What should be done is to upgrade the fronts first since they do about 80 percent of the braking or more going downhill. Uphill, they have a tendency to lock very quickly because the weight is transfered to the back.

Start at the front and go from there.

[Wind_Danzer]

blaine,

So what you are basically saying w/o saying it, is that people will throw the rig in neutral either to save brake or after the brakes overheated to the point they don't function because they didn't upgrade their braking system?

That sounds really freaking stupid (not what you wrote or what I'm gathering from it, just that people would do something like that...) *shakes head*

[mrblaine]

Originally posted by Wind_Danzer
blaine,

So what you are basically saying w/o saying it, is that people will throw the rig in neutral either to save brake or after the brakes overheated to the point they don't function because they didn't upgrade their braking system?

That sounds really freaking stupid (not what you wrote or what I'm gathering from it, just that people would do something like that...) *shakes head*

It's not that they overheat, it's that the physical dimensions and style of components do not generate enough braking force to adequately control the vehicle.

Big tires need big brakes.

Another thing often not taken into account is the weight almost everyone adds to their shiny new toys.

A stock control arm is very light and very strong for it's weight. Most aftermarket suspension makers either don't have the engineering ability or the money to pay someone to engineer something as high performance as stock. Instead, they just overkill it with beef which adds weight.

Same with coils, skid plates, bumpers, winches, hi-lifts, batteries, roll cages, armor, and then they start tossing in tools, spare parts, spare fluids, ice chests full of ice and water, trail racks, roof racks, and never once do they consider that not only have they increased their weight, but the larger tires now have a mechanical advantage over the brakes.

The really bizarre part is that I rarely see people really worried about this. I would guess that that is because they add this stuff so incrementally that it never really dawns on them how much their braking performance has deteriorated from stock. This is especially true with the TJ. The stock braking system is very adequate for the jeep as is, and with the smaller tires.

However, it is not anything remotely resembling overkill and is also not very amenable to easy upgrades. The knuckle design does not lend itself well to adding larger calipers and discs. The booster and master are not much different but can be swapped out for higher performance. The downside there is that you are just increasing clamping force and it is easy to start shredding stock parts when your weight and braking demands go up.

At one point in time I had enough clamping force on the stock components that I could fold over the ears on the stock pads up front and wad up the rear brake shoes almost at will. The backing plates would distort, along with taking out my rear wheel cylinders.

That led me to start looking at alternatives or at least try and figure out what was going on. Eventually I came to the conclusion that big tired, heavy rigs need big brakes. What a concept!

[truckjohn]

Blaine

That is a good point, what sort of solutions have you seen used successfully? Like you said, the stock knuckles don't really lend themselves to much bigger stuff.

I know the rear disc conversion is popular, but what about upgrading the fronts? I am not real sure that Grand Cherokees have much larger stock brakes than the TJs' do... but I have also not recently climbed under them for a look-see.

If you went to a D44 front and rear from a larger truck -- it would come with gigantic brakes on it already... but then you still need the master cylinder to compensate.

John

[TJRON]

Originally posted by Wind_Danzer
Why do people put their rigs in neutral on a steep decent (mainly auto guys I keep reading)? How does this give you more control? Neutral to me would speed you up on a decent, not keep you under a limited control decent. Wouldn't it be better to just get the proper gears or eventually a new t-case (TeraLow, Atlas, Klune).

Just curious.

So, why do they put in neutral? 'Cause the brakes aren't up to the task?
I've never met or heard of anyone putting it in neutral going down hills unless it was to save gas, but I'm always willing to learn.
Ron

[Scott Hill]

WJ knuckle swap will work on a TJ 30 it gives you massive dual piston calipers and larger disks. it also lets you set up histear if I remember all my facts right.



Scott

[mrblaine]

Originally posted by Scott Hill
WJ knuckle swap will work on a TJ 30 it gives you massive dual piston calipers and larger disks. it also lets you set up histear if I remember all my facts right.



Scott

Other than the fact that the knuckles bolt up to the inner knuckle, everything else has to be custom built. The track bar has to be relocated, the unit bearings have to be modified and re-spaced to line up the two axis, and you have to run about 2.5 inches of backspacing or 16" rims. Even with 2.5 inches of backspacing with 15's, there is still a good chance of having to grind down the rotors depending on rim style. If you don't run unit bearings and have a hub conversion, then you have to build a set of custom rotors from a CJ-7 and modify the spindles. Without the conversion, you still have to modify the bolt pattern on aftermarket WJ rotors and space the caliper saddles out correctly to line the rotor up in the center of the brackets.

The toughest part for a TJ is the relocation of the track bar and the swaybar brackets. I have a few ideas for this and am almost there.

But, you are right, the new brakes are awesome. Nothing at all wrong with dual piston calipers and 12.188 diameter rotors.

[mrblaine]

Originally posted by truckjohn
Blaine

That is a good point, what sort of solutions have you seen used successfully? Like you said, the stock knuckles don't really lend themselves to much bigger stuff.

I know the rear disc conversion is popular, but what about upgrading the fronts? I am not real sure that Grand Cherokees have much larger stock brakes than the TJs' do... but I have also not recently climbed under them for a look-see.

If you went to a D44 front and rear from a larger truck -- it would come with gigantic brakes on it already... but then you still need the master cylinder to compensate.

John

The ZJ has identical front brakes to a TJ. The WJ has the bigger front brakes with the 16" rims. That would be the only drawback to the bigger D44 brake set-up, having to find rims to fit over them.

Curiously, the WJ uses a master cylinder with the same bore as a TJ. I just can't find any info on the stroke or if the booster is similar. I do know that my wife's TJ can generate about 1300 psi of line pressure with the stock booster and a ZJ master. More than enough to stress her front Wilwoods. As soon as I figure out the track bar and swaybar mounts, they are going bye bye.

[Robert J. Yates]

One of things that will contribute to the deterioration of brake performance that has not been mentioned in this discussion is increasing the crawl ratio on a rig. WD mentioned that she reads about auto guys dropping their rigs into neutral - BTDT due to my combination of Teralow and automatic tranny. For some reason, you never really see much discussion of this on the boards and when you try to talk about it, the morons shout you down. In the past month or so, I was participating in a discussion wherein the guy was going to run 5:13's in a pair of D44's, a auto tranny and a 4.3 Atlas - he got pretty huffy when I casually asked him how he was going to stop his rig

The rear disks that we converted onto my rig (many thanx Blaine) have helped in that I can now stand on my brakes as hard as I want to without fear of folding the backing plates up but there are still ocassions where with the combination of the crawler gear, auto tranny and steep downhill terrain requires me to kick my rig into neutral to creep over something. That big slab past Little Sluice on the 'Con comes to mind as a recent instance of this

[derf]

This is a subject that I've been thinking about a lot recently.

I'm starting the buildup of a CJ7 that has non power brakes right now. Empty with 33's is about as much as it can handle. I'm only going to putz around with it as is for another month or two before I start the conversion.

When I'm done with the project, I'll have a power brake pump from a 3/4 ton pickup pushing the much bigger brakes on the front D60 from a military 5/4 ton pickup. I'll also have a disc brake conversion for the matching rear 14 bolt. To allow room for the bigger brakes, I'll be running 16.5" beadlock rims.

I'm not so worried about the fact that I'll have a 135:1 crawl ratio because it'll be a manual transmission (SM465 with 6.56:1/D300 w 4:1/5.13 gears) and I won't have it "in gear" when I'm stopped.

Nevertheless, I'll probably be doubling the weight of my rig by the time I'm done. Then I'll be adding a lot of tools, parts, etc. Put that all on a rig with 38.5" tires and there's no way I'd be trying to stop that with anything less than a heavy duty pickup's brake system.

[Wind_Danzer]

Originally posted by Robert J. Yates
For some reason, you never really see much discussion of this on the boards and when you try to talk about it, the morons shout you down.

Why do you think I posted this here and not JU or Q-tec (though I think most on Q-tec would just let this type of ? drop to oblivion ), though I'm kind of interested in seeing responces from them there.

So some of you guys answer me this.

I'm running 31's (hopefully 33's by summer), heavy bumpers front and rear (ARB and YB w/ additional rack), Kilby skid, rocker guards and soon to be 1/4" Steel flat skid. Now before the "turtle" comments or the weight factor.... will upgrading the gears help with my crawl in the auto? I'd like to do all this work on the Jeep but money is always a factor along with knowledge (which I really have none of that would be usable) and parts, which seems like I'd have to change up my front just for better brakes. Would the gear change be an ok bandaid for the future until I win the lottery?

Robert touched on another thing I have seen on some boards and hear about... higher gearing, different TC and autos seem to really put your crawl in jeparody (ie: lack of stopping). I still don't completely understand why (I'm sure it has to do with the way the auto works, I'm just not up on it).

[Robert J. Yates]

If you have the 3:73 gears in your axles, you don't need to do a thing if you are staying on 31's. I ran those gears with 33's and it was ok and then I put in the crawler gear. Frankly after living with it for almost 3 years now, I find I really do not need the 4:1 other than the fact that it allows me to continue running the stock 3:73 gears my Jeep came with and 35" tires off road. Its really not needed with an auto tranny when you have the appropriate axle gears - which in your case, you may already have. If I had deeper axle gears and the Teralow, I wouldn't be able to get my Jeep stopped in alot more situations without having to go to neutral.

[Scott Hill]

Well I was just reading the FSM to figure out this problem and it turns out if we gas it and brake at the same time we may be better off it has to do with enough backpreasure on the clutches to have them open up to stop the engagement.

this seems to be the cause of the problem as far as I can tell but I am no auto tranny expert.



Scott

[Wind_Danzer]

Hmmm... Scott...

I never use my gas on a downhill. I let my engine brake and I just steer. I have 3.73's and sometimes I'll hit the brakes ont he way down but not a lot. I very rarely go gas one foot and brake the other.

Maybe that's why I see some posts on other forums too, because of what blaine touches on and what you mention now in your latest post.

BTW... Robert peaked my curosity. I've decided to post this question on JU.

[Robert J. Yates]

Originally posted by Wind_Danzer
BTW... Robert peaked my curosity. I've decided to post this question on JU.

I saw that and good luck

If anything, I'll get lucky with some uninformed smack talk and can vent some of my frustrations

[truckjohn]

Well, Robert's observation brings up an interesting idea... what about transfer case output brakes like they used on older trucks parking brakes? I know HIgh Angle Driveline and All Pro Offroad makes some, and it would seem like the way to go when not stopping the crawler gears becomes an issue. Most of them use mechanical motorcycle disk brakes, though.

It would be really interesting to figure out how to plumb up another splitter / P-valve line into the rear brakes somewhere and run a hydraulic transfer case output brake to make stopping real easy. I know that those type brakes really do the trick on big trucks.

Best regards

John

[StealthTJ]

I think Blaine and Robert have pretty much answered it. I've experienced it myself.
The increased "crawl ratio" that the torque converter (torque multiplication) supplies is a lot. When I first did the auto tranny conversion, I still had the stock rear drums ('98 TJ). I had 4.56's in the diffs, 35" tires, and, I left the Tera 4:1 in for the first week. In 4wd (or 2wd) low, it was almost impossible to hold the Jeep, in 1st gear, on level ground, with no gas, and standing on the brakes. The torque converter supplies maybe 2 1/2 times torque mulitplication factor at idle (it lessens as the RPM's increase). The punny little rear brakes and now marginal front brakes (because of the extra weight of the Jeep with the armour, and because of the 35's) simply couldn't hold it back.
Remember, unlike a manual with the clutch dis-engaged, the auto tranny, through the torque converter, always is supplying power, even at idle, and, when at idle, it's suppling a hell of a torque multiplication.
I've had to shift into neutral a few times, before the brake upgrade, even after I removed the 4:1, on steep descents.
Once was when trying to back down a very steep, very gnarly, rocky nasty hill, to get back to the person behind me, who had gotten in a bad way, somewhat sideways. We were going to have me strap him a little. Trying to go super, super, super slow, backwards, even in 4wd lo and 1st gear, was just impossible. The Jeep was easily over running the brakes. Putting it in neutral to back down worked fine, just going into gear a couple of times to climb over big rocks (backwards).
A couple of times (before the brake upgrade) going forward, down very steep, rocky, gnarly descents, I've done the same thing for exactly the same reasons.
After the brake upgrade, I haven't had to use neutral, yet.
I certainly need further brake upgrading in the front brakes.

Regarding "crawl ration", with an auto, it's normally not something that you'll ever really think about again. After the auto tranny swap, which has a taller 1st gear than the manual tranny did, and, after ditching the 4:1, I can crawl up stuff, slower, with much more control now, than I could with the manual and the 4:1.
It's all the magic of the torque converter

I think that Blaine's hit it on the head. Most of us have neglected a very important part of our Jeeps, when upgrading, brakes. Auto's simply manifest that weakness a little more often than the manual trannys do.
Most people really don't realize that they've neglected the brakes until they have to e-stop (or try ) on road to avoid an accident.



Fred

[MJR]

As others here have said the stock brakes just barely work on a stock rig with a automatic in gear in low range. Shifting the automatic into neutral is the same as pushing in the clutch on a manual. I can only think of a few people that have a low enough crawl ratio to creep down hills in gear, most will push in the clutch if it starts moving to fast.

Mine was even worse than most of the later vehicles (TJ, ZJ, etc...) as stock my 88 XJ came with a single diaphram brake booster. Switching to a dual diaphram helped but as Blaine said all I did was to increase to force applied to the brakes without regard to the fact that the parts were not designed for this.

I also replaced the rear end with one that had disc brakes with only a slight improvement. I did not choose to remove the seal in the prop valve until I addressed the front brakes. The reasons for this are like what Blaine said. I didn't want the rear brakes to do more work than they should. This would have not helped the bigger problem which is the front brakes.

I ended up doing a complete WJ front knuckle/brake swap (with help from Blaine, Thanks) using 2003 calipers. This finally fixed the braking problem of not being able to stop. I now do not push the shifter into neutral anymore going down hills in low range as the brakes can now stop the vehicle.