Does 4 wheel drive = 4 wheel brakes?

[RoyJackson]

I respectfully disagree. Many larger tractors with electronics involved in the engagement of the four wheel drive, some if not all new 6xxx Deere's, the M Kubota with cabs, ect; lock the tractor in four wheel drive when you apply both brakes. If not to aide in braking functions then why else?

Well, I don't have a large Utility like that...just a CUT.

My 4400 acts more more like gwdixon's tractor...hit the steering brakes, no effect on the fronts.
I think most CUTs are more similar to my 4400 then larger UTs.

 

[DK35vince]

Well, I don't have a large Utility like that...just a CUT.

My 4400 acts more more like gwdixon's tractor...hit the steering brakes, no effect on the fronts.
I think most CUTs are more similar to my 4400 then larger UTs.

This has already been explained.
By hitting only one brake the other rear wheel and the driveline to the front wheels are still driving. So there will be no braking effect to the front.
Brake both rear wheels and the front wheels will be braking because the front and rear are linked together by the driveline.

 

[RoyJackson]

This has already been explained.
By hitting only one brake the other rear wheel and the driveline to the front wheels are still driving. So there will be no braking effect to the front.
Brake both rear wheels and the front wheels will be braking because the front and rear are linked together by the driveline.

All you're actually doing is putting more contact patch to the ground...not really "braking" anymore then engine braking slows the tractor.
I see what you're describing...I guess that's never been what I considered using the brakes.
Frankly, I've always used engine braking (in 2WD or 4WD) much more then using the tractor's brakes.

 

[DK35vince]

Example.
If I am going down a muddy hill, slam on (both) my rear brakes locking up and sliding both rear tires at least one front tire will also slide because is locked to the rear by the driveline

 

[DT86]

Example.
If I am going down a muddy hill, slam on (both) my rear brakes locking up and sliding both rear tires at least one front tire will also slide because is locked to the rear by the driveline

Yes , my thoughts exactly! :thumbsup: Or hopefully provide enough surface area or "contact patch" (I think we mean the same thing?) to stop the sliding!!

 

[DK35vince]

I have read in a thread when applying the brakes when in 4WD you are in theory applying brakes to the front and rear wheels since they are locked together by the drive shaft. Does this only apply as long as you are using the engine also for braking? So if you apply the clutch then apply the brakes are you disengaging the front from the rear and therefore only have essentially the rear brakes?

When in 4 wheel drive the front and rear are still locked together by the driveline whether the clutch is engaged or disengaged.
So the braking to front front wheels still applies with the clutch disengaged.

 

[edrobyn]

I was on a hill the other day in 4WD doing some mowing and applied the brakes and was amazed at how well it stopped. I was thinking I just had some good rear brakes now I know why it stopped so well.

 

[Jay4200]

I have read in a thread when applying the brakes when in 4WD you are in theory applying brakes to the front and rear wheels since they are locked together by the drive shaft. Does this only apply as long as you are using the engine also for braking? So if you apply the clutch then apply the brakes are you disengaging the front from the rear and therefore only have essentially the rear brakes?

Yes. AAMOF, my 4x4 ATV has a warning sticker on it to that effect.

JayC

 

[LD1]

TO the OP:

YES, in a MECHANICAL 4wd tractor you have 4wheel braking IF in 4wd, regardless of clutch pedal position.

Example.
If I am going down a muddy hill, slam on (both) my rear brakes locking up and sliding both rear tires at least one front tire will also slide because is locked to the rear by the driveline

THIS^^^ is wrong.

Remember the rules of a differential. They are very simple.

There is ONLY 3 ways a differential can work. (standard open diff) And 3 parts, 2 axles, and 1 driveshaft.

1. Everything is turning
2. Everything is STOPPED
3. Two things are turning. This can be a drive shaft + one axle (one wheel peelers). OR it can be BOTH tires and the driveshaft is stopped. BUT, the tires will rotate opposite directions (unless something is broken)

BUT, why you (DK35vince) are wrong, is that it IF the rears are locked up, that means the DS feeding the front will ALSO be locked up. So based on the rules above, Either you tires will be spinning opposite directions (one forward one reverse) OR the most likely....they are also locked up.:thumbsup:

And these rules are EXACTALLY why stepping on only ONE brake does nothing. Because again, TWO things have to be turning, OR everything has to be stopped. It is easier for the engine to continue turning the other tire AND the driveshaft feeding the front vs the alternative of either stalling or smoking your clutch.

And to those who say "yea, but there are no breaks on the front tires".

Well, there are actually no brakes on the rear tires either. Or even the wheels for that matter. Most of our CUT's have inboard brakes, so they are actually NOT braking the wheel, rather they are braking the axle, which is coupled to the wheel. Same thing for the fronts, IF in 4wd, those SAME brakes are mechanically connected to the front wheels. It just has to go through a few more gears and shafts first, thats all. Think of it as one big system, all inter-connected. It dont matter where the brakes are.

Another example I like to use is the old 2.5T military axles (for those mudder guys). Those dont even have brakes on the axles. They have brakes in the Pinion:confused2:

Sorry to be long winded. Hope this clears things up for some. Have a happy Turkey day

 

[k0ua]

TO the OP:

YES, in a MECHANICAL 4wd tractor you have 4wheel braking IF in 4wd, regardless of clutch pedal position.



THIS^^^ is wrong.

Remember the rules of a differential. They are very simple.

There is ONLY 3 ways a differential can work. (standard open diff) And 3 parts, 2 axles, and 1 driveshaft.

1. Everything is turning
2. Everything is STOPPED
3. Two things are turning. This can be a drive shaft + one axle (one wheel peelers). OR it can be BOTH tires and the driveshaft is stopped. BUT, the tires will rotate opposite directions (unless something is broken)

BUT, why you (DK35vince) are wrong, is that it IF the rears are locked up, that means the DS feeding the front will ALSO be locked up. So based on the rules above, Either you tires will be spinning opposite directions (one forward one reverse) OR the most likely....they are also locked up.:thumbsup:

And these rules are EXACTALLY why stepping on only ONE brake does nothing. Because again, TWO things have to be turning, OR everything has to be stopped. It is easier for the engine to continue turning the other tire AND the driveshaft feeding the front vs the alternative of either stalling or smoking your clutch.

And to those who say "yea, but there are no breaks on the front tires".

Well, there are actually no brakes on the rear tires either. Or even the wheels for that matter. Most of our CUT's have inboard brakes, so they are actually NOT braking the wheel, rather they are braking the axle, which is coupled to the wheel. Same thing for the fronts, IF in 4wd, those SAME brakes are mechanically connected to the front wheels. It just has to go through a few more gears and shafts first, thats all. Think of it as one big system, all inter-connected. It dont matter where the brakes are.

Another example I like to use is the old 2.5T military axles (for those mudder guys). Those dont even have brakes on the axles. They have brakes in the Pinion:confused2:

Sorry to be long winded. Hope this clears things up for some. Have a happy Turkey day

Excellent explanation, I hope this puts the question to bed once and for all.

James K0UA