Octavia 1.4tsi 2012

Hello. I’m on my third break servo as two have failed on me now in the last year. There is oil visible in the failed servos and in the air line coming from the servo. Seems it’s getting oil into it from the engine somehow and so the vacuum seal is failing. Very dangerous indeed for the break peddle to turn into a brick when you suddenly loose the vacuum assist when breaking at speed ! I was very lucky not to die or kill somebody the first time.

I’m on here now to see if anyone can think of what may be the culprit in the engine that’s letting the oil get into the servo. I’m aware there have an oil matrix instead of a valve on these Tsi engines. But I’ve no idea what I’m visually looking for in the engine.

Will the issue be my master cylinder do you think ?

Edited 14 March14 Mar by MCB

Might it be brake fluid rather than engine oil?

Hello. Thanks. Yeah maybe, but the break fluid level doesn’t go down.

I can’t afford to replace the master cylinder to find out. But then maybe I’d better as i don’t want it to happen again on a motorway sliproad like the first time.

Edited 14 March14 Mar by MCB

Breezy_Pete , should I replace the master cylinder do you think ?

Could it be a failing vacuum pump thats letting oil in? Trace back the servo hose.

Alasdair

Thank you for replying. There is a black tube coming from the servo and looking at the servo from the front of the car it runs to the left and connects to the engine. There’s a one way valve on that black hose which seems to be working if I blow and suck into it, but there is also oil in that section of hose before it reaches the valve. I’m not sure which hose you are referring too ? Where is the vacuum pump ?

Edited 15 March15 Mar by MCB

I think the inlet manifold is your vacuum source. Only diesels have tandem pumps as far as I know.

I think since the only gas flow here is from servo towards engine, the oil must be brake fluid. Source of that must be master cylinder I reckon.

5 minutes ago, Breezy_Pete said:

I think the inlet manifold is your vacuum source. Only diesels have tandem pumps as far as I know.

I think since the only gas flow here is from servo towards engine, the oil must be brake fluid. Source of that must be master cylinder I reckon.

Thank you Pete. I’ll check it out tomorrow. I guess they’re will be ‘fluid’ in the servo now though it is working properly for the time being. So I’ll need another one again as it’ll fail again before too long. I’ve been having used ones put on. They work fine till they get attached to my car 😆

Any advice on testing to see if it is the master cylinder letting fluid into the servo would be much appreciated indeed.

Pumping the break pendle with the cap off the break fluid reservoir ?

Thank you for your help.

Maybe I’ll get a garage to test n sort it. But I can’t afford them these days at £80 am hr. So knowing exactly what I need them to do is best for me.

If replacing the master cylinder is something I can do myself then I’ll do that.

Not sure on yours as mine is MK2 diesel 1.9tdi and 1.6tdi with mechanical pumps but a quick google on skodaparts.com and found this for 1.4tsi caxa

The above is electrically operated and dont think lubricated by engine oil so sorry I may be wrong as to where the oil is coming from if it is oil. The only other source of oil I can think of is bad pcv valve.

I don't recommend this at all but over the years of working on cars have found brake fluid tastes different to engine oil and tends to have a sweet chemical odour and numbs tongue. They are both toxic!! and taste awful so not really advised.

Alasdair

😆 yum yum !

Thank you for your time investigating and replying Alasdair. The tsi has no pcv valve. Instead it has a matrix the oil has to travel through apparently.

I’m going to try to determine if it is coming through the servo. I guess it must be. So hopefully replacing that will fix it.

It’s a very scary and dangerous thing for it to suddenly fail while driving and I must solve this.

Thank you

As said not advised taste wise but hope you get to the bottom of it. Havent heard of a matrix system before but you learn every day. Unless its a small amount of brake fluid I cant see why the level isnt dropping. A long shot but maybe a problem with matrix itself As said hope you get it sorted.

Alasdair