Hi

3.9 Classic Hard Dash Non ABS 1993.

Found a small pinhole leak in the vertical brake line running down from the master cylinder to the flexi hose so replaced it, also replaced all the bleed nipples on the car as some were looking like they were going to be challenging to remove in the future..

Refilled and bleed the whole system and it took a long time to get the pedal to a stiff press but we did manage it eventually, with total resistance at about half travel. The issue is that after starting the engine virtually all resistance on the brake pedal is lost. There are no leaks on the garage floor at all anywhere and this is confusing me.

Could this be a faulty master cylinder? I replaced the servo with a brand new one about 6 months ago and I have no reason to suspect the pedal linkage etc.

I did notice that when bleeding and topping up the reservoir that as I pressed the pedal there was what I can described as a small 'eruption' of fluid at the top of the reservoir level - like some air was pushing up some of the fluid from beneath but it did not look like it was air 'popping' out of the fluid - more like the after effects of dropping a small stone into a puddle.

I'm not sure if that is normal. I'm confused cuz if there is no leak I can only assume no air is getting in so why loose resistance after the engine is started.

Any suggesting welcomed.

Cheers

Ade 405 AB exec seats Baltic and Cirrus
93 RR Classic efi

Remember it's easier to get forgiveness than permission!

Gone in order:
4.4 TDV8 SE - gone to a good home
93 Classic hard dash Plymouth Blue
03 L322 Oslo Blue
2000 Disco TD5 ES Epsom Green
98 P38 Rioja Red
89 Classic Cairngorm Brown

Ade,
Deep down in my grey matter from many moons ago, I remember something very similar.
Although you say you recently replaced the servo.... I definitely remember it eventually proved to be cured by replacing my servo.
Once the engine is running and the vacuum built up it was leaking within the servo unit and then somehow recirculating.

I vaguely remember stripping it down and fitting a new diaphragm.

Best wishes
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

You may have already done this, but when I had similar I found the only way to successfully bleed the brakes was using a power bleed system - I had one where it replaced the cap on the matter cylinder with a special one which had a valve and pipe which you connected to the spare wheel.

This pressurised the reservoir and pushed the fluid and any air right through to the bleed nipples.

It wasn't expensive and made a difficult job simple.

From memory, the master cylinder has a hole drilled just forward of the rubber seal to allow residual fluid pressure to return to the reservoir when the brakes are released. When the pedal is initially pressed, a small amount of fluid may be ejected back into the reservoir until the hole becomes covered/passed by the rubber seal. This may be the small 'squirt' you can see.
The fully retracted position of the master cylinder piston/seal, and hence keeping the distance to the hole to a minimum, is controlled by the pre-set nose of the servo shaft.
The pre-set position can be adjusted with care BUT BEWARE:
Over adjustment will result in the brakes jamming on when the fluid temperature rises as the expanded volume cannot return to the reservoir when the pedal is released.

Post script. In my experience, early Range Rovers do not have the 'solid' pedal feel of later ABS types, even when bled correctly. Forty years of progress. 1972-2012

I would agree with that. The feel is much more linear compared to modern cars (even when bled properly).

It may just be that you have air trapped somewhere and you need to keep flushing through ... the easiest being a power-bleed setup as described above. V8 or else ...