Parking brake - All-wheel drive

My car: Golf IV Variant 4-Motion.

Problem: Due to the all-wheel drive, I experience significant understeer in corners, and I have to drive very slowly to navigate a 180-degree turn. Going uphill, this type of corner isn't a problem – I can control the understeer with precise throttle control, and it goes around the corner without issues. However, going downhill, it's much too fast. When driving a front-wheel drive vehicle, the handbrake is often used.
My problem is that it doesn't work on my car.

Is it now possible to temporarily deactivate the Haldex clutch using the handbrake lever switch? (Then it should be possible to go around corners faster going downhill!)

Hi Solarplexus.

Well, the understeer with the 4motion is understandable, since it's not a 100% all-wheel drive system, but when taking 180° turns uphill, I struggle more with oversteer than with understeer (ESP -> OFF) .
The tendency to oversteer on descents is likely due to the higher weight, not the 4Motion all-wheel drive system. In most cases, it's possible to achieve nice drifts downhill by using careful handbrake application and disabling the ESP (Electronic Stability Program). I've actually considered messing around with the switch on the Haldex control unit myself, but it's not as simple as it seems.
Here's an interesting link, nonetheless:


Best regards,http://www.eiptuning.com/eip/haldex_popup.html{MARKER}

Okay, but the manual anchor isn't working for me.

Going uphill is also tricky: If I approach the curve at a high speed, I tend to understeer, so I have to brake to regain control of the car. Starting from the middle of the curve, the desired oversteer effect will occur.
Because of the understeer, you can only go around corners very slowly.

Haldex tuning would certainly be interesting, but it would need to be tested beforehand!
Is there also a distribution network in Germany or Austria ?

Hi.

'The understeer issue with 4motion is correct, but it doesn't come from the active all-wheel drive system, but rather from the inactive one. So, if you interrupt the Haldex control, the effect will either remain the same or become worse.' Furthermore, I don't believe the control unit will allow such an intervention without 'complaining' or raising an error.

Well, anyway. Why isn't the handbrake working for you?

Best regards,

When I pull the handbrake, you can notice that the car struggles more.
I have never been able to make the rear end oversteer with that method .

Speculation: If I engage the handbrake, there will be a difference in engine speed. The all-wheel drive system will likely interpret this as the front tires slipping and will lock the system completely. That's why I think it's difficult to get the rear tires to lock up with the handbrake. (Or: My handbrake isn't working properly - which, of course, happens sometimes!)


Perhaps I should take a driving skills training course with a focus on 'drifting' .

What is the curb weight of your car ?

Hi.

So, my little golf ball wiggles its little bottom nicely when the muscle power delayer is engaged at the right moment.

[Speculation mode = ON]
I also don't believe it locks when the handbrake is engaged, because the control unit checks that.
[Speculation mode=OFF]

My own weight is approximately 1440 kg, plus or minus a few crushed ones.

Best regards,

Troubleshooter wrote:

But well. Why isn't the handbrake working for you?

Hi,

It all depends on the specific all-wheel-drive system being used.

Intelligent and very expensive/modern all-wheel-drive systems (VW Touareg, Porsche Cayenne, BMW X5, etc.) detect when the rear wheels are braking and disconnect the rear drivetrain from the front. If this doesn't happen, the handbrake can apply unevenly to the front wheels (right rear to left front, and left rear to right front). Therefore, a certain Audi Sport Quattro S1 had two handbrake levers in its competition version. One for the right side and one for the left.
For a long time, a major challenge with all-wheel-drive vehicles was integrating a properly functioning ABS (Anti-lock Braking System), and this was due to the same reasons why it often didn't work correctly.
All-wheel drive vehicles were therefore at a significant disadvantage when braking downhill for a long time.
Today, systems like the Haldex clutch disconnect the rear-wheel drive from the front-wheel drive during braking, and the ABS functions just as well as it does on vehicles with only two-wheel drive.
Whether a handbrake recognition system is available depends entirely on the vehicle manufacturer. It is not normally necessary. In fact, it is often desirable for the handbrake to engage on all four wheels (e.g., when starting on a hill on a slippery surface). Therefore, this function is often omitted.
The same applies to the Golf Synchro.

By the way, the Haldex clutch could theoretically function without any electronics, as it is a purely mechanical system. A control valve compensates for the control pressure generated solely by the difference in speed between the inlet and outlet, and forcibly opens the system.


Simpler all-wheel-drive systems, as found in dedicated off-road vehicles (and sometimes in SUVs), either use a manual dog clutch or are permanently driven with an intermediate differential. These systems can be extremely unstable during full braking, within the ABS control range. Body roll and suspension issues are not uncommon. Often, this results in the vehicles "jumping" or "bouncing."

Hello,

Just try disabling the ESP (Electronic Stability Program) and it should work with the tailgate swing function.
By the way, it's also difficult to perform a tail-out maneuver with the handbrake at low speeds on the rear-wheel-drive Golf IV. It works perfectly fine with ESP OFF.

Hi everyone,


By the way, the Haldex clutch could theoretically function without electronics, as it is a purely mechanical system. A control valve takes the control pressure, which is generated solely by the difference in speed between the input and output, and forcibly opens the system.

Theoretically, it could function without electronics, but that would only be the case if you wanted to 'force-deactivate' the all-wheel drive. If you bypass the control system and force the all-wheel drive to be engaged, it would cause stress and strain (I've already tried it). In addition, the 4motion system doesn't just calculate the necessary rear-wheel drive based on the slip of the front wheels, but also takes into account the accelerator pedal position, speed, and steering angle sensor (at least, that's how it was explained to me).

[SpeculationMode = ON]
That's why I also assume that the parking brake is being checked.
[SpeculationMode=OFF]

And as I mentioned, the handbrake turn works well on S3, TT, and 4motion models, provided that ESP is turned off.

Best regards,

Troubleshooter wrote:

.... In addition, the 4motion system doesn't just calculate the necessary rear-wheel drive based on the slip of the front wheels, but also takes into account the accelerator pedal position, speed, and steering angle sensor (at least, that's how it was explained to me).

Sure, the electronics are doing that.
To avoid or reduce stress in the drivetrain, the Haldex system is partially disengaged. You just have to live with the (unnecessary) loss of power on the rear axle.

Quote:

[SpeculationMode = ON] That's why I also assume that the parking brake is being checked. [SpeculationMode=OFF]

"Not with the Golf 4. At least, I once drove one on snow, and it was clear that the front wheels were locking up when the handbrake was engaged." By the way, the vehicle was quite new, and I don't think it's due to a defect.

Hi everyone,

Thankfully, it's snowing where I am right now, because I wasn't sure anymore, and I quickly did a small test run.

Okay:

Situation 1:
'Gas off, brake hard, engage handbrake = rear end breaks off, only the braking rear axle is visible in the tracks.'

Situation 2:
Gas off, brake, handbrake on, gas on = rear end breaks loose, front wheels spin, and when you release the handbrake, you can clearly feel the rear axle engaging = wonderful drift.

My opinion: If the parking brake is engaged, the Haldex clutch should be disengaged.

At least that's how mine does it, and I can rule out a defect.
But since it's snowing almost everywhere right now, hopefully a few more 4motion owners will chime in .

Best regards,

Hello.

According to the SSP 4 Motion in the Golf 4, the Haldex system is disengaged when the handbrake is pulled. As soon as the message "Release parking brake" appears on the display.

Sure, here's the translation:

"MFG" is an abbreviation for "Mit freundlichen Grüßen," which translates to "Sincerely" or "Best regards" in English.

But will those guys still be interested in him after 27 months?

Hello.

it could be

There's nothing to argue against that.

The posts will continue to be read even long after they were originally published.

Things might still change, or someone might have another idea!