Bleeding brakes.....(in both senses)

[N00b]

The story so far. my 2006 ZTT failed its MOT on a few issues, a corroded/leaking offside rear brake pipe. The MOT work is all complete now except for the fact that my mechanic cannot get any fluid through the new pipe he fitted.
After speaking to him yesterday I now know the following.

The pedal depresses fully to the floor.
The fluid level in the reservoir doesn't drop, nor does it leak any fluid.
He thinks one of the master cylinder seals may have been pushed inside out but after doing some reading in here the T4 system seems to get mentioned often, so my questions are:-

A) do the informed minds in here have an opinion on what can be done?
B) Is it likely that I need a new master cylinder and
C) can this job be done without access to a T4 system?

It's the only thing that's stopping me from getting the car back on the road and to say it's frustrating the life out of me doesn't even come close. If I haven't given enough info on the problem please ask.
All help NEEDED welcome.
Thanks in advance.

[drewbie]

I've always used Eezi Bleed in the conventional manner, at no more than 20 psi without any problems.

[T-Cut]

The MGR Workshop Manual doesn't mention T4 in the section on brake bleeding. However, some forum members say it's the only way to purge air from the servo unit. I guess if any air has somehow gotten into the servo, then presumably so. Most brake bleeding (I'd suggest over 95%) will be done without a T4.

As to your specific problem, if the fluid level in the reservoir remains constant, after repeated full stroke pumpings, the master cylinder must be faulty. There's no other logical explanation.
TC

[N00b]

Thanks for your collective advice so far. Does anyone know if the brake master cylinders are all the same part? I've found one for sale described as part SJC000080. FYI the car is a 2 litre 115bhp diesel.
What would be the way to handle this problem? Try to get it plugged into a T4 first then if that doesn't cure it replace the master cylinder?
Based on what's been said above am I correct that if the master cylinder is replaced it will definitely need to be plugged into a T4?

[itcaptainslow]

Sounds like some air has somehow got into the ABS block-the only way to bleed this effectively and properly is using T4 or PScan to perform a “power bleed” function.

[N00b]

Can someone PM me Dave Johnsons number? He serviced my car at the back end of last year but I cannot for the life of me find his number.
Thanks again for all your help.

[Arctic]

Hi David.
have a read of the link below take note of Jules method

https://www.the75andztclub.co.uk/for...ad.php?t=63314

[SD1too]

Originally Posted by N00b

... my mechanic cannot get any fluid through the new pipe he fitted.

Hello David,

Fitting a new length of brake pipe and bleeding the system is a straightforward task. If your brakes were working normally before this work was attempted then any problems have to be down to your mechanic I'm sorry to say. It's not normal for a brake master cylinder seal to be "pushed inside out" by normal brake pedal operation.

To answer your questions in reverse order:

Originally Posted by N00b

C) can this job be done without access to a T4 system?

Yes. When the brakes are bled (with the engine not running) all the valves in the ABS modulator are in their default position. This is effectively the same as a length of plain brake pipe. There is therefore no necessity to drive the modulator using T4 for normal bleeding operations. If the modulator has been replaced then it may be a different story.

Originally Posted by N00b

B) Is it likely that I need a new master cylinder

You need a considered and accurate diagnosis David. What you have at the moment is a guess involving speculative replacement of parts at your expense.

Originally Posted by N00b

A) do the informed minds in here have an opinion on what can be done?

If this problem has occurred whilst your car was in the care of your mechanic, he is responsible for rectifying it free of charge to you.

Originally Posted by N00b

... am I correct that if the master cylinder is replaced it will definitely need to be plugged into a T4?

No it won't definitely need to be plugged into a T4.

Is he saying that he cannot obtain a flow of fluid from all four bleed nipples or just the one supplied by the pipe he's replaced?

Did he start the engine at any time after the repair work had begun (this may trigger modulator activity)?

Has he used Eezi Bleed as suggested by drewbie? If not, he should.

Good luck!

Simon

[dave lincs]

Ok a simple thought on this the brake must have worked before replacing the pipe or the car would have failed the brake performance test, so it must be something he has done ?

Disconnect new brake pipe at front end see if fluid comes through then same at rear if it does

Ps if fluid gets to low then it will need to go on T4 to bleed the system correctly

Dave

[N00b]

Update. My guy has used an air powered bleed tool and told me today that he cannot get any fluid from the other three corners. The pipe he replaced was either damaged or corroded through as it was leaking fluid.