Parking Break Off Road 'Trick' Dealio?...

It's no secret. I'm an off-roading nooob - learning and what not. With that said, I'm still a little confused by something...

At last years Zu I was encouraged by several people to lift up gently on my parking break on tougher obstacles when I noticed my wheels slipping (screeching). It worked like a freakin' charm and helped me get up quite a few spots, but I don't quite understand WHY it worked.

Could somebody break this down for me and explain WHY it works, and exactly what applying parking break tension does for our 4x4?

-biju.

You have LSD (Limited slip/posi-traction) in the rear axle. When you apply the parking brake, it provides additional resistance on the clutch packs to engage the posi more effectively on demand. sometimes it works, other times not so much.

thats it in a nutshell.

Before reading his reply, I was about to say the same thing as Keith…
(only nowhere near as succinctly! :smilewink )

So help me understand this a little further... isn't it safe to assume, then, that I should just give the parking brake a pull to a few clicks and just leave it there when in 4L? - Essentially keeping this 'posi' engaged more throughout the trail?

(searching google right now to learn what 'posi-traction' is...)

-biju.

Quote:

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Originally Posted by biju

So help me understand this a little further... isn't it safe to assume, then, that I should just give the parking brake a pull to a few clicks and just leave it there when in 4L? - Essentially keeping this 'posi' engaged more throughout the trail?

(searching google right now to learn what 'posi-traction' is...)

-biju.

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Not so good...you would over heat the parking brake drums. :nogray:

Ldub

good point - understood.

When I do end up using the break again - is there any real danger in using it for that purpose, then? In other words, am I doing any real harm to my rig?

That's about it for my Q's. Thanks, all.

-biju.

Quote:

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Originally Posted by biju

good point - understood.

When I do end up using the break again - is there any real danger in using it for that purpose, then? In other words, am I doing any real harm to my rig?

-biju.

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Its an assumed risk. Jeff Mason snapped an axle on Moab Rim, Z turn obstacle a few years back by doing this in his Amigo. I think it was a freak change that it happened then/there and I havent heard of any prior or sense.

It does add extra resistance to the rear, and you are overpowering the parking brake and adding some extra heat to the rotor drums, and shoes. for the little bit of time to go over an obstacle, I cant see that it would be doing anything major there... ALTHOUGH, it could very well "glaze" the shoes and make them less effective, especially with prolonged driving in that condition of a partially activated parking brake.

Synopsis: Yeah there are risks, but would I use it? You betcha, until I got a locker, see below. I dont think there is anything significantly detrimental to using this method. YMMV

Essentially, when it tightens the clutch packs, it somewhat replicates a locker by allowing both tires to turn simultaneously and "carrying" a wheel through the air while still making forward progress.

Its not 100% and can be fallible, Ive seen it literally do nothing but put extra drag on a rig preventing it from climbing, and the other extreme, watch it act just like a locker.

Except for a lunchbox locker (not available for the 12 bolt axle in the VX), and lincoln locker(welding the spider gears to make it a spool, not recommended for on-road driving), a selectable locker (ARB, available for the 12 bolt) is your best bet to ensure you have the traction needed when you want it.
Leave it off and you have an open dif, engage it and you are fully locked. WIth those lockers, they are typically engaged as you approach an obstacle and disengaged after clearing it.

In my Amigo, I had an LSD OEM, and changed it out to a automatic (lunchbox) locker Powertrax No-Slip. This basically has the ability to lock and unlock depending upon the force transmitted to the dif through the throttle, terrain, etc. Mine pretty much stays locked all the time because my foot is always in it. Unfortunately the D44 has many more choices available than the 12 bolt.

But back to the issue at hand... in my experience in driving with one, spotting people, and generally just being around for the past 6 years... LSD serves it purpose, but dont expect great things from it. I would estimate that it does the job and gets you some assistance 70% of the time, although exhibiting lock type traits are far more rare and should only be expected <20%. Of course a lot of that depends upon the clutch packs, springs, lubrication, etc to be HIGHLY effective. and coming up on several years old, the deterioration also becomes a factor.

My advice, if you plan to wheel it, which it sounds like you do, get an ARB for that rear axle, front too, but more important to be locked in the rear. That way you still have the street and trail ability, best of both worlds.

Thanks for the detailed information, Loco... I appreciate it! See you @ Zu...

-biju.