Wheels off ground = No hand brake

[10G]

I've come across this the last 2 times I've had the Patrol up on stands.

If the rear wheels are off the ground, the hand brake does nothing. Car in neutral, hand brake on hard, I can still turn the rear wheels. Is that normal? I've never come across that before.

[dom14]

I've come across this the last 2 times I've had the Patrol up on stands.

If the rear wheels are off the ground, the hand brake does nothing. Car in neutral, hand brake on hard, I can still turn the rear wheels. Is that normal? I've never come across that before.

Are you saying if the rearwheels are on the ground then the handbrake works fine?

Handbrake drum is in between the rear driveshaft & gearbox.

If there is no handbrake at all, you should immediately address it by adjusting the handbrake.

Even with the LSD arrangement it makes no sense. Once the rear driveshaft is locked by handbrake, the pinion gear can't move and then the crownwheel can't move. That means wheels can't move regardless of what spider gears can do. This is true regardless of whether you lift one wheel or both rear wheels up.

What I dunno is whether GUs have the handbrake arrangement somewhere else other than the above location between the driveshaft & gearbox. But, I seriously doubt that makes any difference at all.
Or whether it has some clever arrangement to cancel the handbrake when rear wheels are off the ground and transfer the handbrake to front wheels. That would be something I would love to see.

[sooty_10]

The handbrake is on the transfer case, not the rear wheels directly. The rear diff is still between the brake and wheels. Do both wheels spin together? Or opposite directions?

Sent from my SM-G950F using Tapatalk

[10G]

The handbrake is on the transfer case, not the rear wheels directly. The rear diff is still between the brake and wheels. Do both wheels spin together? Or opposite directions?

Sent from my SM-G950F using Tapatalk

I didn't look. I was putting the wheels back on on the weekend and went to tighten the nuts a bit and the thing span around. I went into the cabin, yanked on the handbrake and it was full on. I just parked on a mound at lunch today, the handbrake works well, no problem.

I would think that if the handbrake is on, it's on, weird.

[dom14]

Apologies. This post was meant to be a new thread. Somehow ended up accidentally posting on this thread.

Mods, pls delete this post.

[dom14]

The handbrake is on the transfer case, not the rear wheels directly. The rear diff is still between the brake and wheels. Do both wheels spin together? Or opposite directions?

Sent from my SM-G950F using Tapatalk

Yeah, but once the rear driveshaft is locked, we shouldn't be able to turn the wheels, right?
That's what the handbrake effectively does, right?
And if the 4WD engaged and auto/manual hubs engaged, we effectively have four wheel handbrake, right?
In other words, handbrakes are still effective even if the rear wheels are lifted when the 4WD+front auto/manual hubs engaged, right?
Or am I confused?

[10G]

You're correct.

Once you pull the handbrake up, the wheels whichever wheels, shouldn't spin irregardless of how the handbrake mechanism works.

[Tip12345]

well the wheels will still spin one forward and one backwards with the tailshaft locked . me thinks ....

[10G]

I don't think I understand all this?

How would the wheels become 'disconnected' from the drivetrain if they are lifted off the ground? There's a hole in my knowledge I think.

[sooty_10]

Potentially the free spinning effect of an LSD, especially a worn no limiting one? One wheel forward one backwards. The driveshaft sits still. Someone more diff knowledge then me would know. Simple way is to put car in 4x4 and leave it in gear. Front wheels will keep everything from spinning.

Sent from my SM-G950F using Tapatalk

[Tip12345]

Yes 4 we is only 2wd take two wheels off the ground is one front and one back . It's stopped ..unless doff locks of some sort .. the doff drives the wheel with the least resistance.

[10G]

Don't have an LSD, it's open diff with a factory locker fitted.

Think I'll look for that Spanish bloke, Manual!

[garett]

Don't have an LSD, it's open diff with a factory locker fitted.

Think I'll look for that Spanish bloke, Manual!

lock the diff then see if it still happens

[the evil twin]

Don't have an LSD, it's open diff with a factory locker fitted.

Think I'll look for that Spanish bloke, Manual!

Engage the Locker and I reckon you won't still be able to spin the wheels.

An open diff means any two shafts can turn whilst a third is stationary

[10G]

You guys all seem to be talking about the same thing which is great, but I still don't understand how the hand brake works???

Can someone please explain it to me???

Thanks heaps.

[mudski]

You guys all seem to be talking about the same thing which is great, but I still don't understand how the hand brake works???

Can someone please explain it to me???

Thanks heaps.

The wheels need on ground contact for the handbrake to work (for open diffs or rooted LSDs only) because its operating via the tail shaft. Same applies for open diffs if you are in motion and one wheel lifts off the ground. Lock the diff locker in and this doesn't matter.

[GQtdauto]

Looks like someone else just worked out most of our four wheel drives are actually two wheel drives , I felt so cheated !

[10G]

Yeah, nah yeah, I understand all that open diff, power goes to the wheel with least resistance stuff, I'm just trying to work out how the hand brake works and so on.

There's something that hasn't clicked. The brake is applied to the tailshaft. The brake stops the tailshaft spinning, is that correct?. The tailshaft connects to the diff. The diff to the axles & the axles to the wheels. Is that correct?

If that is correct I can undertstand how the hand brake would work. But what is it that disconnects or whatever when the wheels are lifted off the ground??

I didn't think to look and it's gonna be 2 weeks until I can look again, but when I spin the rear wheels in the air, does the tailshaft spin??

Ever had that feeling that you know there's a bit of info you don't know, but you think you should know it and it drives you crazy, that's this.

Is there something in the diff that disengages?? I'm no mechanical wizard as you've probably guessed.

Thanks for any help.

[the evil twin]

With an open diff if one wheel can spin one direction and the other wheel is free to spin the opposite direction the input shaft can potentially remain stationary.

If either wheel has resistance then the Input shaft has to turn as well (if one wheel is held stationary the input shaft and other wheel will spin at the diff ratio).

Sooo... when the handbrake locks the input shaft it will therefore only be effective when the wheels aren't hangin in mid air.

Nothing is mechanicaly disconnected... what is 'disconnected' is the wheels from the ground... 'connect' one wheel to the ground or lock the diff so it can't 'differentiate' any longer and then the brake works as advertised

https://www.google.com.au/imgres?imgurl=https://i.ytimg.com/vi/SOgoejxzF8c/maxresdefault.jpg&imgrefurl=https://www.youtube.com/watch?v%3DSOgoejxzF8c&h=720&w=1280&tbnid=vailucECfq2mvM:&tbnh=118&tbnw=211&usg=__jJRwFGQl_za_Oj1NY9nelYZWtM4%3D&vet=10ahUKEwjP5q_hv47ZAhUEtJQKHYGOAjIQ9QEIKzAA..i&docid=iBFoCGcm8LJ2jM&client=firefox-b&sa=X&ved=0ahUKEwjP5q_hv47ZAhUEtJQKHYGOAjIQ9QEIKzAA

In the image if you turn one light blue shaft, the two orange gears rotate in opposite directions to each other and turn the other light blue shaft the opposite way.
The Crown Wheel the orange gears are attached too doesn't need to move and therefore the dark blue shaft (Input Shaft) doesn't move at all

[10G]

AHHHH. So it's the tailshaft that is locked / braked and not the wheels and it's the tailshaft being held stationary that holds the wheels stationary UNTIL they are lifted off the ground, so the hand brake doesn't act on the wheels at all, just the tailshaft.

Thanks ET, I owe you another beer. Awesome I've learnt something.

[the evil twin]

AHHHH. So it's the tailshaft that is locked / braked and not the wheels and it's the tailshaft being held stationary that holds the wheels stationary UNTIL they are lifted off the ground, so the hand brake doesn't act on the wheels at all, just the tailshaft.

Thanks ET, I owe you another beer. Awesome I've learnt something.


Nailed it dude ^^^^ ... (in fairness others said similar but I'll still take the Beer) :cheers:

[dom14]

well the wheels will still spin one forward and one backwards with the tailshaft locked . me thinks ....

Hmmmmm....... that can't be correct...me thinks mate, 'cos what the handbrake effectively does in a GQ(dunno about a GU) is to lock the rear driveshaft from spinning. For example lift the rear wheels and shove a screw driver, tyre lever of something through the uni joint and try to spin either one of the wheels. You won't be able to do that. Don't damage the uni joint by putting too much force on the wheels though. :)

[dom14]

AHHHH. So it's the tailshaft that is locked / braked and not the wheels and it's the tailshaft being held stationary that holds the wheels stationary UNTIL they are lifted off the ground, so the hand brake doesn't act on the wheels at all, just the tailshaft.

Thanks ET, I owe you another beer. Awesome I've learnt something.

Yeah, but it works fine as long as the wheels on the ground. With my stock real LSD, it works off the ground as well(not it that helps :) )

[10G]

(in fairness others said similar but I'll still take the Beer) :cheers:

Yeah nah. Yeah, thanks to all that helped.