Defender300tdi brakes very heavy

Hello All,
Got a bit of a problem with me old girl, ive fitted new discs and callipers all round, bleed it all clear. haven't touched the servo or vac pump,,, The brakes work okish but they feel very heavy like the servo aint working. Now ive checked the servo by pumping up the brakes then with the pedal held down starting the motor, pedal falls a small amount, brakes not pulling or throbbing. One thing I did notice is the plastic elbow and seal on the servo seem to be " a soft fit" as in you can wag it about with easy. could this be killing the vacuum, working on my own its hard to have my head under the bonnet and press the pedal at the same time. So any tips, ideas or know how would be very helpful.. Thanks All..... Tom

pull the vac hose off servo see it pedal hardness and travel alters put your finger over the hose with engine running to feel if theres a strong vac check hose and t pieces etc are sealed causing loss of vac

Cheers James, ill go try it now

Ok ive check all the pipework as best I can without removing it. the vacuum on the servo pipe was there but I wouldn't call it a strong one,, ( risking all the jokes ) I could put more vacuum there by sucking the pipe, rechecked the pedal fall again and it was very slow, felt more like it was leaking pressure not dumping it, the sort of feeling you get when you pump brakes that need bleeding then hold them on,,,kinda slowly died away if that makes sense.. next step to try driving and braking with the pipe on and then with it off, see what happens

sounds like a leak in the vac pipe system or poor vac pump

That makes sense,,,, Just out of interest is there a better way to test the servo,,, the pedal idea seems a bit hit and miss

what kind of vacuum should one expect from the vacuum pump, just out of curiosity. I do have a vacuum gauge and i'd like to measure mine.

The test you describe, pumping the pedal with the engine off to use up stored vacuum and then starting the engine with the pedal depressed, is the accepted way of checking the operation of the servo. If the pedal dips on start-up as yours does, then all is OK.
If you have new discs and pads I suspect that the brakes just need to bed in, it is normal for them to feel a little numb for the first few applications.
I would be inclined to take the Land Rover to a quiet stretch of road and give it a few firm applications of the brakes and things should improve quickly.
When things don't work, you have to ask yourself what has changed since the last time they worked, i.e. discs and pads.

Hello RR,dont think its bedding,,, the whole story. I changed all four corners as matter of course, the two rear callipers were seized and the front discs well worn,, now having replaced all that the pedal and the braking is still the same as before I changed everything,,,, I tried slapping the buggers on and still cant lock any of the wheels at any speed, all four corners are working and it stops in a straight line but swopping new for old hasn't improved the brakes.
ps. the new parts have been on for around 400/500 miles.
pps. something I did try was the vacuum with the engine ticking over and with it reving, there wasn't much difference in the amount of suction

Your servo is suspect IMHO. It's a fair age by now if it's the original.

Remington rolling block said:

Hello RR,dont think its bedding,,, the whole story. I changed all four corners as matter of course, the two rear callipers were seized and the front discs well worn,, now having replaced all that the pedal and the braking is still the same as before I changed everything,,,, I tried slapping the buggers on and still cant lock any of the wheels at any speed, all four corners are working and it stops in a straight line but swopping new for old hasn't improved the brakes.
ps. the new parts have been on for around 400/500 miles.
pps. something I did try was the vacuum with the engine ticking over and with it reving, there wasn't much difference in the amount of suction

Click to expand...

you should feel a fair vac if not theres a leak in pipe system or pumps poor

Basic check for the vac pump. With engine on tick over remove vac pipe from servo and place your thumb over the end. Should stay put even with your thumb held up some.

Hi tottot, James,,
Very hard the judge without a manometer but ill try and describe best I can....... At tickover with the pipe off the servo,,, if I put my thumb over the hole you can feel the suction, but the slightest break in the seal and its gone, if I rev the motor and do the same theres is a small increase in vacuum but not much, same again smallest loss of seal the the section has gone, one thing I did try but was a bit tongue in cheek was to hold a cigarette about 6" from the pipe at tick over it did not pull the smoke,,,, this is like asking someone to describe the colour red lol we all see it somewhat different. Anyway im grateful for the time and effort from you chaps, thanky kindly..... later today im going to pull all the pipes off for a proper look

Hi Zeaphod, You may have a point matey, she's a 96 with 148,000 on the clock and as far as I know the only things that have been changed apart from discs calipers are the chassis and exhaust so I guess the wear bug could have a hand in this

Does seem the vac pump is not up to much. 300 one's are a common problem.