Wooden brake pedal at very slow speeds

Hi I have 2003 Freelander TD4 Auto.

I have a brake problem. At very slow speeds the brake pedal is wooden and not assisted at all. Normal driving is fine. I have done the test pumping up the brake pedal when the ignition is off and then holding the pedal down when starting. The pedal then goes down a bit as expected.

I have replaced any of the vacuum hoses that look a bit long in the tooth but still the same. When I remove the vacuum hose from the EGR at idle the vacuum is definitely less than at 2000 RPM. I haven't put a vacuum gauge on it but if I did then what results would I expect to see.

Everything else is working fine and the Millers Auto box oil is fantastic!

Before I start replacing parts anyone got any suggestions?

Thanks

The Vacuum pump is driven by the camshaft, so is related to engine speed, if you don't have vacuum brake assistance at low engine, and therefore pump speeds it would suggest yuu have a vacuum leak somewhere. I'd suggest buying a roll of ~5m of 4mm silicone vacuum hose and fo over the entire system. There's vacuum lines all over the engine, don't forget the long mofo that runs to the vacuum actuator solenoid valve on the turbo charger or the EGR at the front, but my favourites would be the two lines coming off the vacuum reservoir.

Thanks for your reply. Is that the vacuum accumulator under the brake servo? I have some silicone tubing (nice and red so I can tell what I have changed)! But I have not changed the ones going to the accumulator. I shall try it tomorrow.

Have a read of this, I had the same. Start by testing the vacuum pump, figures given, then test it with the piping connected in logical chunks.


https://www.landyzone.co.uk/land-rover/td4-black-smoke-puff-and-p1e30-solved.374126/

Hi

The link doesn't appear to work. Can you try posting again or PM me?

Thanks

Fixed the link for you:
https://www.landyzone.co.uk/land-rover/td4-black-smoke-puff-and-p1e30-solved.374126/

Thanks for the link. I might just go all out and replace all the vacuum hoses. Any idea what the round plastic item just before the servo with the 3 hoses on it does?

chasn said:

Any idea what the round plastic item just before the servo with the 3 hoses on it does?

Click to expand...

If it's a ribbed plastic tank, then it's vacuum accumulator, which is there to maintain a reasonably constant vacuum in the system.

chasn said:

Thanks for the link. I might just go all out and replace all the vacuum hoses. Any idea what the round plastic item just before the servo with the 3 hoses on it does?

Click to expand...

The vacuum hosing is so cheap you are as well to do it all in a oner, apart from anything else, all the hoses are the same age, so it's likely that if one has failed, the others will follow suit in short order.

Thanks. It was the small plastic item about the size of a penny washer with 3 vacuum pipes going to it that I am bemused what it does?

chasn said:

Thanks. It was the small plastic item about the size of a penny washer with 3 vacuum pipes going to it that I am bemused what it does?

Click to expand...

Got a picture of it?

I'/m guessing he means the little check valve on the rigid vacuum line going to the servo, which is located after the tee for the EGR vacuum supply and just above the vacuum reservoir?

That's the one. What does it do?

I believe it's a check valve, also known as a non return valve, it's locaiton would allow the vacuum pump to evacuate the air out of the servo, but not permit air to go back through the pipe to refill the vacuum chamber on the brake servo in the event of a vacuum failure such as a split hose or a failed pump. Where had it failed, was it the red hose coming off the side of it that had failed and since been repaced, or was it elsewhere?

Thanks. That makes sense. Also if the engine cuts out then would be enough accumulated vacuum to allow you to stop with some assistance. I replaced some of the flexible hoses with red ones recently. I chose red as I could then see easily which ones I had already replaced. I didn't do the hoses at the back of the engine so I shall do these sometime this week.

Does anyone have a diagram of the vacuum system?

Hi
Found a split in the vacuum pipe that goes from the accumulator along the top of the engine. Back to good brakes again.

Thanks everyone for your help.