Hard brake pedal in reverse

[shack]

So we went for a jaunt today to a sale, had the trailer on which has override cable brakes, nothing strange happened until we are loading up our valuable purchases and I was backing down a hill.

As I was going very slow backwards down the incline I was riding the brake pedal, probably only went 25 metres and the pedal went hard as a rock and wouldn't hold the car,I grabbed drive to stop and it was fine then, the brake pedal went back to normal, so I thought I would test again....Yep the same, so on the way home I tried going downhill forwards, couldn't make it happen.
So what's going on? Vacuum leak? Vac pump on the way out?

Cheers James

[Aaron IIA]

Were you riding the brake pedal at a constant pressure, or repeated on and off?

Aaron

[justinc]

Remove the vac fitting and poke a long zip tie in as a dipstick, I would bet on the booster having oil in it, reduces its capacity by up to 40% at least....

[shack]

Were you riding the brake pedal at a constant pressure, or repeated on and off?

AaronProbably a few jabs, but then riding the pedal and went hard, but I'd have to re check for sure

[shack]

Remove the vac fitting and poke a long zip tie in as a dipstick, I would bet on the booster having oil in it, reduces its capacity by up to 40% at least....Ok I can try, but I thought they had an electric vac pump, so the "oil" would be brake fluid? So the master cylinder would be down on fluid then?

Edit: just checked, it's full to the full mark

[justinc]

Diesel or petrol? Diesel were prone to this issue only.

[shack]

Diesel or petrol? Diesel were prone to this issue only.Diesel

[shack]

But where does the oil come from?

[justinc]

Discovery 3 Brake Booster: TDV6 (https://www.4x4community.co.za/forum/showthread.php/244563-Brake-Booster-TDV6)

[PerthDisco]

Discovery 3 Brake Booster: TDV6 (https://www.4x4community.co.za/forum/showthread.php/244563-Brake-Booster-TDV6)

Does this problem disappear after a certain model year?

[shack]

So I've checked the oil level with a "dipstick", the dipstick got oil on it but very minimal, what's the next move?

[justinc]

Sick it out, tube and large syringe

[Eric SDV6SE]

Justin,

Do you know if this occurs on diesel D4’s as well? If so, can you post a pic of the vacuum hose to disconnect to check?

thanks in advance,

Eric

[Barryp]

There was a recall on diesel D3s. Its engine oil coming up from the vacuum pump. The recall changed the plumbing from the vacuum pump (back of engine driven off the camshaft) to the brake vacuum booster. Shouldn't be an issue on a D4 unless a seal has gone in the vacuum pump.
Regards Barry

[shack]

Diesel or petrol? Diesel were prone to this issue only.So I've just realised that the electric vac pump I bought months ago from a D3 wreck, was obviously a petrol, that's where my confusion started,I couldn't work out how an electric pump would let oil into the booster, of course it can't.

I think the brakes are getting harder,
I'll have to get into the job seriously this week,I found a government recall on the pump, looks like there is a sticky valve that can give problems as well.
Thanks for your advice

Cheers James

[shack]

There was a recall on diesel D3s. Its engine oil coming up from the vacuum pump. The recall changed the plumbing from the vacuum pump (back of engine driven off the camshaft) to the brake vacuum booster. Shouldn't be an issue on a D4 unless a seal has gone in the vacuum pump.
Regards BarrySo is there any evidence now that the updated plumbing between the vac pump and the booster actually fixes the problem?

I've discovered that the issue with ours isn't reduced vacuum capacity in the booster due to it being full of oil, the fault is the booster is leaking quite badly...No doubt due to oil ingression.
I'm thinking it already has the updated plumbing, but that it was fitted AFTER the current booster already had oil in it, so I'm hoping a new booster will fix the problem.

Other than that I guess I would need to also replace the vac pump if it was faulty to stop oil ingression, which I really don't want to do !
But how would I know that it was faulty?

It creates good vacuum, and there appears to be very little oil actually in the booster.

Any thoughts from anyone, I'd love to hear!

[Saitch]

My '08 D3 has started to get a random 'Hard Pedal'. How long does a recall stay in effect? Especially a safety recall.

[loanrangie]

My '08 D3 has started to get a random 'Hard Pedal'. How long does a recall stay in effect? Especially a safety recall.

Has the recall been performed before, is there is a sticker on the door jamb ? It should be still valid if it hasn't had it done but getting a dealer to co-operate is another matter.

[Saitch]

Has the recall been performed before, is there is a sticker on the door jamb ? It should be still valid if it hasn't had it done but getting a dealer to co-operate is another matter.

Only 'Airbag' and VIN plate.

[BradC]

To be fair ours had the recall performed before it left the UK. The the guys that performed the donk swap after it **** the bed used the un-recalled pipework from the donor, so I have a booster full of oil again (I can hear it bubbling at the lights). I've drained it once. I'll do it again shortly. I ordered a set of new (post recall) pipework. I just need to get around to installing it.

[Saitch]

Well, I've just wasted a fair bit of time, trying to find out if my D3 had been fixed under recall. A dealer, North of Brissie, told me it wasn't subject to recall, but wouldn't look at the ACCC site that I was on, that stated it was subject.

In a fraction of the time spent with the Northern mob, Southport Land Rover has supplied me evidence of the repair and date thereof. (Which means I'll be out of pocket[bigsad])

[BradC]

Part number is LR018673

[discorevy]

Well, I've just wasted a fair bit of time, trying to find out if my D3 had been fixed under recall. A dealer, North of Brissie, told me it wasn't subject to recall, but wouldn't look at the ACCC site that I was on, that stated it was subject.

In a fraction of the time spent with the Northern mob, Southport Land Rover has supplied me evidence of the repair and date thereof. (Which means I'll be out of pocket[bigsad])

If I'm reading this correctly, you'll already have the updated part (LR018673) if so, suck it (booster) and see, it takes quite a while to accumulate, and as long as it hasn't destroyed the diaphragm, it may last a few years yet.

[RANDLOVER]

It's worth changing the one-way/check valve every few years as they fail in the recall pipework.

[PerthDisco]

If you have to change the booster change to the RRS version for extra boost. A simple change over and not overly expensive part if you hunt around.

[DiscoJeffster]

If you have to change the booster change to the RRS version for extra boost. A simple change over and not overly expensive part if you hunt around.

Ewe, not something I’d do. I think the boost level on the car is perfect. I have a Golf GTi with such a sensitive pedal, it take so long to adjust to.

Each to their own I suppose.

[PerthDisco]

[emoji638][emoji6[emoji640][emoji637]][emoji6[emoji640][emoji638]][emoji6[emoji640][emoji637]][emoji[emoji6[emoji640][emoji638]][emoji640][emoji640]][emoji[emoji6[emoji640][emoji638]][emoji640][emoji6[emoji640][emoji638]]]]Ewe, not something I’d do. I think the boost level on the car is perfect. I have a Golf GTi with such a sensitive pedal, it take so long to adjust to.

Each to their own I suppose.

I always felt the non dust Akebono pads lost some of the original bite so this brought it back up again. Also now have SS flex brake lines which assist as well. Definitely not over sensitive just more oooompff when you want it.

[PerthDisco]

Sooo, on the weekend I was reversing a trailer down a boat ramp and got the hard pedal in reverse was quite a shock as ramp was steep and short and not wanting to stop without massive pressure on pedal.

Back to normal city driving and all good again but testing in a car park after a few short stabs of the brake in reverse hard pedal again.

I can sort of remember on last offroad trip getting a hard pedal going down a steep incline as well that was a bit scary. A few stabs and boost was lost. In city driving boost is good on first press.

So today I pulled the vacuum line off the booster and was able to suck out a small amount of oil.

Booster was new RRS spec replaced in 2022 has done about 80 k kms. I have the updated vacuum pipe work.

The previous booster at 14 years old failed to point there was no boost whatsoever but I didn’t notice this hard pedal previously.

In our 1991 80 series LC the brakes failed in the sense the pedal went slowly to floor. Not good when holding on a hill at the lights. Another stab would grab the brakes again. That was solved with a $50 master cylinder kit to replace the rubber cup seals on pistons that grab the fluid.

I’ll see in next few days if booster can hold pressure on multiple stabs with oil removed.

Test your car in a car park by applying a few quick stabs and see if you loose boost assistance by the third press. It may also be a failing vacuum pump potentially.

[BradC]

I’ve had brake loss at the end of a big decline. I’m used to no assist. One of our cars has no assist at all. 2 hands on the wheel and both feet on the pedal kinda stuff. My encounter was like trying to push a pedal into a steel block (click click ****ing click). My gut says I bottomed out the master. So I wonder if mine is a combo of buggered booster and master. I’ve pulled plenty of oil out of the booster twice. Thinking I might fit a new master, booster and electric vacuum pump. No oil to bypass the check valves that way.

[PerthDisco]

I’ve had brake loss at the end of a big decline. I’m used to no assist. One of our cars has no assist at all. 2 hands on the wheel and both feet on the pedal kinda stuff. My encounter was like trying to push a pedal into a steel block (click click ****ing click). My gut says I bottomed out the master. So I wonder if mine is a combo of buggered booster and master. I’ve pulled plenty of oil out of the booster twice. Thinking I might fit a new master, booster and electric vacuum pump. No oil to bypass the check valves that way.

The rock hard pressing steel is run out of boost which to be fair all cars do if you continually pump the pedal but on a 4wd it’s hard to use engine braking when reversing a boat and trailer down the boat ramp.

Maybe it’s just a natural quirk. When our last booster failed it when to full time pressing steel feeling.

[BradC]

The rock hard pressing steel is run out of boost which to be fair all cars do if you continually pump the pedal but on a 4wd it’s hard to use engine braking when reversing a boat and trailer down the boat ramp.

Maybe it’s just a natural quirk. When our last booster failed it when to full time pressing steel feeling.

Yes and no. When the booster fails (or runs out of vacuum) the pedal piston connects with the master cylinder piston. At that point you are pushing directly on the MC and with enough force you can still activate the brakes (both feet on the pedal and pulling on the steering wheel kind of force). In this instance there was nothing left. I know I can still brake the car when the vacuum is exhausted as I've tried it when I was going through the HPFP issues. This was different. With the benefit of hindsight I should have hit the EPB because at the speed I was going it would have fired up the pump to brake rather than tried to apply the hand-brake shoes.

I'm budgeting for a booster and master cylinder. The first time I drained the booster I reckon there was enough oil in there to have contaminated the seals on the MC.

The issue as I see it is the vapor pressure of the oil. When there is significant vacuum, the oil will travel past the non-return valves even when pulling from the booster to the pump. That oil will then condense in the booster. They tried to fix it with an additional NRV, but I don't think there's a way around it. I thought about a "catch can", but the problem is the oil vapor under vacuum. It'd just pass through the bottle. An electric vacuum pump is the final answer, but coming up with a solution that is affordable and available is another story entirely.

[PerthDisco]

Yes and no. When the booster fails (or runs out of vacuum) the pedal piston connects with the master cylinder piston. At that point you are pushing directly on the MC and with enough force you can still activate the brakes (both feet on the pedal and pulling on the steering wheel kind of force). In this instance there was nothing left. I know I can still brake the car when the vacuum is exhausted as I've tried it when I was going through the HPFP issues. This was different. With the benefit of hindsight I should have hit the EPB because at the speed I was going it would have fired up the pump to brake rather than tried to apply the hand-brake shoes.

I'm budgeting for a booster and master cylinder. The first time I drained the booster I reckon there was enough oil in there to have contaminated the seals on the MC.

The issue as I see it is the vapor pressure of the oil. When there is significant vacuum, the oil will travel past the non-return valves even when pulling from the booster to the pump. That oil will then condense in the booster. They tried to fix it with an additional NRV, but I don't think there's a way around it. I thought about a "catch can", but the problem is the oil vapor under vacuum. It'd just pass through the bottle. An electric vacuum pump is the final answer, but coming up with a solution that is affordable and available is another story entirely.

I agree on the vapour as there is no appreciable oil in the pipes when you undo the quick disconnect

[PerthDisco]

Yes and no. When the booster fails (or runs out of vacuum) the pedal piston connects with the master cylinder piston. At that point you are pushing directly on the MC and with enough force you can still activate the brakes (both feet on the pedal and pulling on the steering wheel kind of force). In this instance there was nothing left. I know I can still brake the car when the vacuum is exhausted as I've tried it when I was going through the HPFP issues. This was different. With the benefit of hindsight I should have hit the EPB because at the speed I was going it would have fired up the pump to brake rather than tried to apply the hand-brake shoes.

I'm budgeting for a booster and master cylinder. The first time I drained the booster I reckon there was enough oil in there to have contaminated the seals on the MC.

The issue as I see it is the vapor pressure of the oil. When there is significant vacuum, the oil will travel past the non-return valves even when pulling from the booster to the pump. That oil will then condense in the booster. They tried to fix it with an additional NRV, but I don't think there's a way around it. I thought about a "catch can", but the problem is the oil vapor under vacuum. It'd just pass through the bottle. An electric vacuum pump is the final answer, but coming up with a solution that is affordable and available is another story entirely.

This issue has now caught me out on the boat ramp a few times. Holding the weight of car and boat with foot on the brake all of a sudden there's no assist and you are braking Fred Flinstone style with massive foot pressure. Also happened to me on a very very steep driveway reversing down barely able to hold just the car's weight with reverse gear selected. In forward normal driving plenty of stopping power on the road and you don't notice stopped level at the lights. Booster was replaced a few years ago when the original completely died and would hold no boost. Did have a small amount of oil in it which I removed. Very annoying. The reversing on a hill phenomenen has been reported globally.