Thread: No driving through the brakes on a D4?

It's not an important driving technique in a modern 4wd like the Discovery 3/4/RRS.

Many of the teachings of these associations are still dealing with older technology and older techniques which is fine in a 2004 Patrol etc.

They still do hill stall starts in Autos for goodness sake!

Left foot braking the D3/D4 sends conflicting signals from the brake switch to the ECU along with an throttle input which reduces the systems effectiveness.

Some of the old guard need to learn the new tech and teach accordingly - which many don't.

nice reply tombie, 100% agreed
in my '13 defender if you put your foot on the brake while accelerating, it kills the throttle until you lift off the brake.

I thought I'd consult Robbert Pepper on this one. Here's what he says.

Not a black and white answer. With its low gearing and now good HDC the latest Discoverys have less and less need of LFB to descent hills, as is the case with most modern cars. In fact, the LC200 is better off with its crawl control, as is the Jeep GC. This is in contrast to say 4-speed Patrol GUs and Discovery 2s! Also worth nothing the latest D4s are much advanced over the early D3s in all their electronic aids.

However, LFB still has a place even with modern cars. Crawling over rocks so you lower a wheel off a rock is one. Hill starting is another, as hill start assists are not to be trusted. It is still a good skill to learn, but not needed very often. So I don't agree it's a complete no-no, but neither do I agree (or teach) it should be used all the time, everywhere, it's just not necessary and can confuse the computers, even if they let you do it. Some cars have rev limits for LFB.

I never touch either the brakes or the clutch on my GQ Patrol with 6.5 Chev diesel. Engine braking and torque at idle speed are all that is required on extreme rock climbs etc.


Rock Crawl in the D4 applies some braking to achieve the effect you are after to maintain good throttle control up hill, without touching the brakes. I don't like hill decent and usually engine braking while idling along is enough for down hill with occasional brakes on very extreme slopes. I treat the D4 like my Patrol in that regard and the D4 auto is brilliant at controlling everything in low range. Even my son's D1 TDI 300 auto has full engine braking on the steepest slopes when in first gear low range and he doesn't need to brake. LR have done well.


I've never once used left foot braking, except on one or two occasions in the Patrol, before I fitted a front locker, to get the LSD to activate better and pull it through a really crossed up section.

ahh the old RAAF 110 steep hill in reverse low range hit starter and crawl backwards.

Instructor had a big stick and if a foot went near the brake peddle he wacked you with it.

Contact instruction

As I said in the other thread, I drive through my brake (LF regularly at very low speed (less than 1km/h) on an extremely steep driveway. The choice is do it or hit the car in front (or something else) ... auto trans, no hill holder ... it's the only way to properly control the vehicle in this circumstance.

Similarly, when reversing my van up the steep driveway into its very narrow garage, it is a choice of be pushed forward and out of line by the van or left foot brake.

Personally I think that the system copes with it fine providing it is done in limited circumstances and at very low speeds. I've been doing it for years, it does not cause a problem with my grandpa D3, not sure how later models take it, but it would surprise me if the system did not cater to some degree for what is a known (bad) driving style.

My 2c worth

Originally Posted by Tombie

Some of the old guard need to learn the new tech and teach accordingly - which many don't.

That's it in a nutshell. With a D4 (and D3) you pretty much need to re-think the way you do everything.

Left foot braking is a good technique in the right circumstances, but there is just no need for it in a D4. I am no fan of HDC and rarely use it, preferring to feather the brakes with my right foot. However I have found on the D4 it can hold your speed at a constant 1 km/h on very steep and rough tracks. I really can't do any better than that.

I still don't use it much and there are situations where you do need to control the brakes yourself, but it is actually very good now.

Cheers,
Jon

I love doing hill stall recovery in our fire tanker. Frightens hell out of new recruits because you have to start the engine with the truck hanging on the gearbox and the engine. The first two second after the engine fires the truck moves quickly until the engine braking takes over