Hi all,

This subject has been messaged to death, so ive read up and am just wanting a pointer.

I have a 200tdi, so no abs and ive been changing pipes, essentially all the ones outside the engine bay as a result of a MOT advisory. I thought if the couple they mentioned were going, then how long till the rest! Anyway, ive got through about 2litres of brake fluid in the process, so there if theres air i should still have a pedal. However, I dont. The brakes operated fine before but the vehicle has been standing for 2 years so im wondering if the, apparently corroded, master cylinder would produce these symptoms due to a bit of full travel abuse during bleeding? I cant see any leaks, i have had to tighten a few unions though during the process. The pedal has a little consistent resistance all the way to the floor. Any other thoughts before i go and get a master cylinder?

Thanks in advance

Pete

Look in the M/C while someone pumps the pedal, any splashback ?

That's a common issue with classic cars, when flooring the pedal with a piston with some corrosion on it goes into uncharted territory, as it were, and destroys the seal.
I always just press the pedal halfway now, as I can't get on with these easy bleed systems, that's old school for you, but I do use the one man bit of hose with a ball valve in the end..

Hi guys,

Theres no one else around at the minute Speckydude, that said i can see movement in the reservoir level when i push it. What does that signify? a buggered seal?

Yeah discocol, i read about the halfway thing to late. Anyway a new master is £45 and to be honest, it looks a bit corroded from the outside so cant be a bad thing to replace.

Cheers

You may find your defunct master cylinder is repairable all you need along with a bit of refurbishment is a new seal kit, something you may wish to do so u have a spare master cylinder, but at £45 for a replacement It may not be worth the trouble.

discool said:

You may find your defunct master cylinder is repairable all you need along with a bit of refurbishment is a new seal kit, something you may wish to do so u have a spare master cylinder, but at £45 for a replacement It may not be worth the trouble.

Click to expand...

Yeah i thought that, but a) i want it to be mobile asap b) its not that expensive. that said i might have a go at cleaning it up and putting a seal kit in just to learn how to do it!

After you've fitted the new or refurbished MC, fill the reservoir to top with new fluid and begin to bleed the system by simply opening first the rear LH caliper bleed nipple, should be no need to pump, wait, make sure the bleed port is opening properly, not clogged with dirt, fluid will start to flow out of the bleed nipple, (it takes a bit of time), be sure to keep the fluid reservoir level topped at all times. once fluid with no obvious air bubbles is flowing from LR, lock off nipple, then repeat process on right rear repeat process making sure to keep the reservoir full, the theory being you start furthest away from the MC and work to closest. Once fluid flowing clear of bubbles at RR lock off, move to left front, repeat, then move to right front, repeat. Do not let the MC res level get low or you may have to start over. Remember only one bleed nipple open at a time.
It takes a bit more time than pressure bleeding but I use this method when replacing pads or caliper seals etc on older cars, it saves the MC from the problem that Discool has pointed out, that being destroying the piston seals in a crusty bit of the bore.

Agree .