[Brakes] Brake issues

[Silverberlingo]

After some grinding on the way to work this week I removed the rear drums today. Still a couple of mm left of the linings but would require changing within a few weeks. Reassembled new shoes ordered and cylinder as one was weeping slightly. Debris removed no grinding drives fine, trip to Euro parts all pagid stuff so decent kit. Strip down changed all shoes and new cylinder. Bleed brakes top up reservoir bleed again no air bubbles but brake pedal hits the floor!!! I then look at forums and see about eezibleed so borrow one from neighbour who assists with cracking bleed screws etc. Again pedal gains pressure but short lived and no brakes. So after what had taken an hour and half it's no nearly 4 hours with no joy from bleeding. I will now have to wait until I get time to try and resolve. I will now chock the front to elevate the reservoir and look at the loading valve on axle (any images to assist in correct position etc). Any further advice welcome and I will update as soon as I have had another attempt. 

[Lighty]

Try clamping off each flexi hose, this will eliminate each wheel from the equation, you should be able to find out which one is causing your issue.
If the pedal,sinks with all 4 clamped you either have a large leak or the master cylinder has failed.

[oilyrag]

Sounds like, as Lighty says, the master cylinder has failed - maybe some muck has moved when the bleeding took place or a seal issue when the pedal was taken to its full travel. The Eezibleed can also cause problems if the pressure in the tyre you use is more than the 10psi or so recommended. Garages use a vacuum system I believe, which pulls the fluid via the bleed nipples.
Check that a flexi isn't ballooning - you'll need someone underneath to watch.
Cheers
Joe

[Gravity]

CAUTION

Sometimes, as suggested above, clamping brake flexihoses is the quickest way to pinpoint a brake problem.
There are downsides to this practice though, so clamp with the utmost care and caution.
Any garage owner will have seen a car where a flexihose has a deformity, or even a swelling, somewhere along its length - and you can guarantee that this was originally caused by clamping the hose, sometimes many months before the damage showed up.

It might be argued that the hose is therefore tired and needs to be replaced, or that the clamp used (often a sharp-jawed mole wrench) was wrong, but whatever the cause it illustrates that clamping a hose can weaken it. Flexihoses were not designed to be crushed, and even if they seem undamaged afterwards, a weakness can show up later in their life.

If you must clamp a flexihose, then buy the tool for the job and use it with care. 

You can tell I'm not biased here!

Gravity

[ffrenchie]

I've been repairing my own and family cars for 45 years and clamped flexy hoses all that time but never saw one damaged other than by perishing due to old age. We used an Eazibleed on an Astra belonging to my brother in law and managed to blow the lip on the seal in the master cylinder with it. Did you follow the instructions and only use low pressure air source they only need about 15psi. We just connected it to the spare and killed the master cylinder with 30+psi.

[Gravity]

I've been repairing my own and family cars for 45 years and clamped flexy hoses all that time but never saw one damaged other than by perishing due to old age.

I agree that you seldom see a damaged flexihose due to clamping. But many garage owners and others have. No doubt you're a careful home mechanic who uses the correct tool for the job and would never grab the nearest mole wrench. Only the foolish would do that, when there are purpose-made tools with smooth contoured profiles to minimise damage.

The fact remains that crushing flexi hoses is an additional future failure risk that, most of the time, does not need to be taken. Maybe I'm sensitive to this issue as I have had a total loss of brakes due to a ballooning hose - caused by a previous owner or mechanic damaging it as described.

Gravity

[Silverberlingo]

I won't get chance to try to bleed the system again until Wednesday. From reading all the various failings of the design system I will take all the other updates people have posted on board and update you all to see what Wednesdays outcome is. Hopefully a full flush with new fluid will sort it.

[polar]

If the vehicle is leaning even slightly forward this can tilt the reservoir forward and stop brake fluid getting over the baffle causing air to get into the system.

As lighty says clamping the hoses will give you an idea if where the air is - use a brake hose clamping tool and you will get no damage to the hoses - when not when i was on the tools anyway - now retired!

[brodfather11]

The load limiting valve on the back axle can cause a lot of the problems with bleeding the rear brakes. Another problem if no fluid is getting through is that the flexihoses insides breaking up and blocking the pipe , seem to work alright until the large amount of fluid tries to go through it then it seems to choke.

A1 as Polar says about the brake pipe clamps.

[Silverberlingo]

Well today where to start!! Go outside and it won't start flat battery or so I thought. Go and get booster pack and it's flat. Jump leads at mates so have to nick the Mrs car and get them to jump start the berlingo. Get back positive terminal sliding around not tight when jumping it. Get it started and daft design to secure terminal adjusted with mole grips battery tested and it's fine. See how it is tomorrow morning in the frost !! Brakes now, eezibleed all set again 19psi in tyre, bottle full new fluid, van parked with front slightly raised, handbrake off fluid reservoir level and topped up. Old milk bottle and length of flexi for bleed nipples. nsr done first osr 2nd nsf 3rd osf last. Lots of air coming through all as they were bled. I think the issues was the reservoir and the tilt even using the eezibleed, the slight dip was restricting the fluid passing over the baffle. Brakes now better than they were before, all the new fluid has made a massive difference. Thanks for advice everyone.