Hi everyone,

Replaced my brake pipes last weekend, bled all of the brakes through getting no bubbles, tried the pedal was rock solid after about an inch of travel, drove it home and all of a sudden the brake pedal went down rather far, not to the floor and the brakes still functioned but it went down a long way, when back at home put my foot hard on the pedal and it hit the floor... pumped it a few times exactly the same, turned the engine off pumped the pedal and got a solid pedal again

bled them again tonight definitely no air coming out, but exactly the same thing solid pedal when engine off, hits the floor when the engine is running...

any one got any ideas?

Has the fluid gone down?

I suspect a leak somewhere.

Might be something in here that might help.

http://www.fullfatrr.com/forum/topic20532....=purge+abs

This guy was having a similar issue, not sure what the outcome was though.

http://www.fullfatrr.com/forum/topic27669.html?highlight=clane

Did you empty your ABS modulator when you change the pipes? It may need "re-jiggling". Some say you can sort of make it do it using the HDC. Don't believe even the IIDTool can do a rejiggle has to be a Testbook or Dealer jobbie. .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

The fluid hadn't dropped over 3 days of good use, would have expected it to have gone down noticeably considering the movement in the pedal, a friend of mine spoke to a garage today and suggested power bleeding it as old fashioned bleeding doesn't seem to overcome the technicalities of modern systems, have tried activating HDC a few times pedal feels a bit stiffer when its on but not much.

the ABS unit wasn't emptied to my knowledge unless it flowed out of the pipes when i disconnected them in the wheel arch so that could be it, will try power bleeding it and let you know the result!

thanks for the replies

I uesd one of these to flush/replace all the brake fluid on my other car :-
http://www.ebay.co.uk/itm/Gunson-Eezibleed...xyLm9TGaIC

A spare wheel is required (not a FF one naturally), something like a old mini wheel with the pressure let down to 10psi.
The idea is the low air pressure forces new fluid into the system so when you open a bleed nipple it runs out.

Pumping the brake pedal when bleeding brakes is not a good idea as the master cylinder piston moves futher along the bore and could encounter any wear ridges created in the bore resulting in the seal lip possibly damaging / inverting and failing.

Hope you get it sorted

The other issue may be that air worked its way back into the master cylinder, this is a bit of a problem to resolve.... .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Common issue with older cars, before you did any work the piston in the master cylinder was moving a very small amount of it's travel distance to make the brakes work, the last 80% of travel never got used, brake fluid is hygroscopic and absorbs moisture this can corrode the last 80% of the piston bore, when you bled the system you pushed the rubber seal down the rusty bore and damaged them, now fluid is making it's way past the seals and letting the pedal hit the floor...

Not saying it's defo that but if you give it a good bleed and it still happens it's a distinct possibility....  Pete

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Soft vs hard brake peddle. When the car is running, you have power brakes. Once the car is off, you have enough assist built up for one or two brake pressing, then the peddle will firm up a lot. That's why the peddle firms up. As to it going scary low, other posters have some good suggestions. It might be an idea to have an expert sort it. Brakes are important. I had a drive a few years ago with only one wheel braking after a catastrophic failure off-road. It's a trip I wouldn't like to repeat. Others have mentioned previously, if all else fails, the electronic hand brake may sound awful, but it will stop the car in an emergency.

All good suggestions and quite possible, have bled it all through today after using HDC down a steep hill near by in the hope of emptying air out of the ABS block, good news is HDC works great! but even using the eezi bleed and going through 1.5 litres of brake fluid which flushed all of the old red fluid out and no bubbles at all I still have the exact same issue with absolutely no change.

With this result I believe I have done all I can my self and will be taking it to a garage next week, either its air in the ABS that I cant get out or the master cylinder that's nackered, maybe it needs the Test book software running to cycle the ABS while bleeding?

Annoying as I can't say if it was a problem or not before changing the brake pipes as they were leaking and quite possibly giving the same sort of issue masking what ever the problem is now.

Thanks all the same!