300Tdi - no brake pedal pressure

I would try clamping each flexible rubber hose individually (both fronts and rear) and see when clamping one if the pressure comes back. That would isolate a problem.

You could also remove the master cylinder and look inside you’re booster to see if it’s full of oil.(leaking vac pump). If so you could possibly have a faulty booster. Usually this gives a hard to push pedal but I have had once before a very soft pedal from a failed brake booster on a tdi.

Good luck!

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Originally Posted by johntins

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Don't blame you. I was merely trying to point out a way to eliminate the m/cyl from your fault finding process. Those tests can be carried out in the car, bearing in mind the effect brake fluid can have on paint....

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Thanks again Johntins. I may we’ll end up having to pull it all out so will bear that in mind. The paint work is not a major concern as this is my project vehicle and is fairly rough on the outside. Painting it may be on the list in the distant future... mechanical is fine, except the brakes :-)

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Originally Posted by Sivvy130

I would try clamping each flexible rubber hose individually (both fronts and rear) and see when clamping one if the pressure comes back. That would isolate a problem.

You could also remove the master cylinder and look inside you’re booster to see if it’s full of oil.(leaking vac pump). If so you could possibly have a faulty booster. Usually this gives a hard to push pedal but I have had once before a very soft pedal from a failed brake booster on a tdi.

Good luck!

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Hi sivvy130, I had a look at the booster when I pulled the m/c out and appeared ok, pedal travel is smooth. Silly thing is it was working fine until I decided to flush the system as part of replacing all the fluids as I had no knowledge of when it was last done. Now I have problems:-)

Wilwood supply with a new master cyl 2 plastic barb fittings and 2 short pieces of clear plastic tube .You fit these to the MC fill with fluid and pump by hand till no more bubbles fit the MC,remove tubes .If this procedure is not followed it is very hard to bleed the system

AM

When you release the pedal, does it come back up by itself?

When you try and bleed, does the fluid level change?

When you say "no resistance", is that all the way to the floor?

Have you tried 'drip bleeding'?

Basic stuff, but did you bleed from the longest to the shortest pipe run?

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Originally Posted by johntins

When you release the pedal, does it come back up by itself?
Yes it does

When you try and bleed, does the fluid level change?
Yes, the front brakes at least (no discernible change with the rears)

When you say "no resistance", is that all the way to the floor?
Correct, but this was after bleeding done, or as much as I could get done. When bleeding each corner there was pressure. It was when I went to move the vehicle (and down a hill) that I discovered there where no brakes at all.

Have you tried 'drip bleeding'?
No, ran out of time yesterday as I had to wait for my peddle pusher to get home from work and then a storm came through and this vehicle is too high to get into the shed (or the shed is too low I guess) so it was beer o'clock.

Basic stuff, but did you bleed from the longest to the shortest pipe run?
Front left first (per Haynes Manual/Land Rover Workshop TV)
Front Right
Rear Left
Rear right

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Not going to have much opportunity to do anything until next weekend now and the temps are supposed to be mid 40's so maybe nothing is going to get done. I have ordered a replacement flexible hose for the rear from Mario so should be here soon. Will swap that out and try again. Will also get a break hose clamp from Supercheap and isolate each wheel per the above suggestion from Sivvy130. Oh better get some more brake fluid too :-)

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Originally Posted by travelrover

I was having trouble getting brake peddle pressure as I had decided to flush the system last year. I had some on the second pump which was sort of ok. I bleed the system three times and no change, but rego is coming up so on advice of a few I replaced the master cylinder. The replacement was the genuine item.

When bleeding got plenty of pressure and fluid through the front brakes, but bleeding the rear brakes very very little fluid came through but there was peddle pressure. But then when I went to test the vehicle there was zero pressure, no resistance at all.

I will re-bleed during the week weather permitting but was wondering what else it may be? No leaks, everything looks fine. Can’t help thinking the new master cylinder..???

Any clues?

Also does anyone know what this is, mounted next to the master cylinder. It has three wires (all cut) red white and black and couple of tubes plugged into it.
Attachment 134882

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Do not discount the possibility that the "new" master cylinder is U/S.
I went through two "new" ones before I worked that out.

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Originally Posted by scanfor

Do not discount the possibility that the "new" master cylinder is U/S.
I went through two "new" ones before I worked that out.

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Pretty much where I'm leaning.

Last year I replaced the MC on a disco series 1 (I also run a RRC) and went through all of this, and the new MC was a dudd MC (still waiting for my $400 back). The pedal went straight to the floor with the usual squishing noise. Now a new MC does not bleed easily just by itself. You may need to brake the lines at the MC and make sure all that nasty air is gone. Just break them and have a cup of tea. If you then get a teeny amount of pedal pressure you are in business. I know nothing of defenders, but I have little faith in pressure bleeding as such. for the traditionalists, having the missus pump up the brakes while you bleed is a path to divorce and should be treated accordingly. All I do is hang a reservoir 10 feet higher the the car, join the tube from it to the nipple, open it and break every connector under the bonnet, and leave it for a couple of hours. Seems to work. The theory being that if the fluid can seep everywhere you don't want then surely ..... As to the crook MC I eventually swallowed my pride and took it to a great bunch of guys who run a shop. They confirmed the dudd MC and rang the spare parts shop to add some gravitas. $50 well spent. And to get the second opinion, I went to their shop on handbrake and in LR. Finally (and it is easy to say) Don't let the frustration of it all get you down.

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Originally Posted by hydronaut

Last year I replaced the MC on a disco series 1 (I also run a RRC) and went through all of this, and the new MC was a dudd MC (still waiting for my $400 back). The pedal went straight to the floor with the usual squishing noise. Now a new MC does not bleed easily just by itself. You may need to brake the lines at the MC and make sure all that nasty air is gone. Just break them and have a cup of tea. If you then get a teeny amount of pedal pressure you are in business. I know nothing of defenders, but I have little faith in pressure bleeding as such. for the traditionalists, having the missus pump up the brakes while you bleed is a path to divorce and should be treated accordingly. All I do is hang a reservoir 10 feet higher the the car, join the tube from it to the nipple, open it and break every connector under the bonnet, and leave it for a couple of hours. Seems to work. The theory being that if the fluid can seep everywhere you don't want then surely ..... As to the crook MC I eventually swallowed my pride and took it to a great bunch of guys who run a shop. They confirmed the dudd MC and rang the spare parts shop to add some gravitas. $50 well spent. And to get the second opinion, I went to their shop on handbrake and in LR. Finally (and it is easy to say) Don't let the frustration of it all get you down.

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Funny, ain't it. Back in the dark ages, I was taught to bleed the m/cyl before I fitted it. This was on mil spec IIas. Not sure it helped, but it is a practise I have continued.