Failed 3 NCT's, 3 mechanics later...

kennethk

hi all, just looking for some advice. I have a 02 VW Golf MK4, which failed the NCT for a frayed brake cable, which was replaced. However the brake pedal is still spongy - the NCT tester called it a ''deathtrap''. I had a mobile mechanic then bleed the brakes - thinking the previous mechanic had not fully bleed the brakes.

However after the second bleeding of the brakes they are still spongy! Dont want to bring it back to the first mechanic, and VW want €130 for a diagnostic test alone.

Can air get into the master cylinder if the brake fluid was not kept topped up when bleeding the first time, and could this trapped air be responsible for the spongy feeling?

Any help at all would be greatly appreciated!

Voodoomelon

I went through something similar with a 728i recently. No matter what I couldn't get to the bottom of a soft brake pedal.

Bled the system about 4 times, including activating of the ABS/DSC pump, no change. Swapped out the master cylinder for a new one and little to no change.

I reckon it was sticking front calipers as the pads were ferociously difficult to push back in on changing. Considering the age of your car, it could be something similar.

rex-x

Mk4 golf has a bleed nipple right on the master cylinder itself. Quite common for that to cause your symptoms if not bled properly

jca

kennethk wrote: »

hi all, just looking for some advice. I have a 02 VW Golf MK4, which failed the NCT for a frayed brake cable, which was replaced. However the brake pedal is still spongy - the NCT tester called it a ''deathtrap''. I had a mobile mechanic then bleed the brakes - thinking the previous mechanic had not fully bleed the brakes.

However after the second bleeding of the brakes they are still spongy! Dont want to bring it back to the first mechanic, and VW want €130 for a diagnostic test alone.

Can air get into the master cylinder if the brake fluid was not kept topped up when bleeding the first time, and could this trapped air be responsible for the spongy feeling?

Any help at all would be greatly appreciated!

Did they actually do the brake test? What are the figures? Sticking calipers will give a springy pedal and heart attack brakes. I'd get the pads, discs and calipers looked at and cleaned up thoroughly to eliminate them from the equation. New pads on badly worn discs will give the same symptoms.

George Dalton

rex-x wrote: »

Mk4 golf has a bleed nipple right on the master cylinder itself. Quite common for that to cause your symptoms if not bled properly

This is almost certainly the cause of your problem OP.

kennethk

NCT no 1


NCT no 2


NCT no 3

Trasna1

Jaysus, that heap was left get in an awful state before it's first NCT. I really hope the OP wasn't driving it before it's test.

People complain about the NCT, that it's a money spinner. But when you see fail sheets like the one above you can see the absolute necessity for it.

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Alanstrainor

rex-x wrote: »

Mk4 golf has a bleed nipple right on the master cylinder itself. Quite common for that to cause your symptoms if not bled properly

Prisoner 6753 wrote: »

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But given the above probable solution, that should be a quick and cheap fix. If that sorts it then test it and drive on imo. No point junking it if is otherwise driving fine.

kadman

Early ABS systems can be tricky, some recommend pressure bleeding,

http://www.stoptech.com/technical-support/technical-white-papers/bleeding-abs-brake-systems

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Prisoner 6753

Prisoner 6753 wrote: »

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Everything was fixed apart from the spongy brake pedal