Thread: Defender Brake Problem

Have you checked the booster ?

They are notorious for fatigue cracking around the M/C flange as JC suggests.

Get someone to use the brakes hard while stationary and you watch for deflection in the booster near the M/C.

If you want to be dead certain of TDC, pop the rocker cover off, wind the engine over with a socket and ratchet on the crank bolt and watch for No. 4 cyl rockers to be rocking, No. 1 rockers should both be loose, indicating that cylinder is at TDC, compression stroke.

Before doing that I'd just remove the booster hose as JC suggests above and feel for suction first, after thoroughly checking the booster for cracks.

I have to agree with checking the booster before replacing/fixing the vacuum pump. Recently replaced two pumps within 2 months until I learnt about booster problem. Found the cracks just where they said they would be.
Replaced the booster and vacuum pumps and so far all is good

Cheers

Thx guys I really appreciate the help. I'll have a look at the booster tomorrow. Last question, which cylinder is no.1 standing in front of the car facing the front windshield?

The timimg mark for the 300 tdi is located on the timing cover.

Originally Posted by GyroLandy

Thx guys I really appreciate the help. I'll have a look at the booster tomorrow. Last question, which cylinder is no.1 standing in front of the car facing the front windshield?

It will be the one closest you, ie closest to the radiator will be no. 1 cylinder.

Please help, I reached a dead-end.

I checked the booster for cracks but can't find any.

A few questions:

Vacuum pump - I don't have a meter to measure the suction but when I remove the vacuum line at the booster end and press by finger over the front end of the line I can feel there is suction (at engine idling) albeit not very strong. How strong should this suction be (without measuring with a meter)? The suction is continueous and not sporadic, is this correct?

Master cylinder - I have removed this. There are three fittings for brake lines 1 for the rear and 1 for each front wheel.When I compress the shaft with some brakefluid still in the reservoir the brake fluid sprays out the firts hole (rear) but not out of the other two although I can feel air being pushed out. Is this normal?

Is there any way to have a booster tested?

How will I know whether the vacuum pump is correctly installed without removing it?

Lastly, when I removed the master cylinder from the booster with the brake lines etc still in tact I could compress it only about 0.5cm by hand. Is this normal or is it suppose to be able to move a bit more. With the brake lines off and the fluid removed I can compress it all the way

I've had vacuum pumps partially fail whereby they provide some suction but not enough. It's more common for them to fail completely. My mechanic confirmed the pressure was not strong enough as I did not have the gear.

I have a vacuum gauge, and am in Carlingford. If borrowing it would help, pm me :-)