As far as I can make out from the photos of an upside-down airbox here: https://www.ebay.co.uk/itm/SKODA-FABIA-MK1-TYP-6Y-00-07-1-9-SDI-AIR-FILTER-BOX-6Q0-129-601-AE/253755564121?hash=item3b1502a059:g:GVcAAOSwWV9bTHTz the air pipe you are looking at goes into the top half of the airbox, and as such is probably just a source of filtered atmospheric-pressure air. So I doubt that fixing that hose will affect the crankcase pressure, unfortunately.

Edited 5 November, 20187 yr by Wino

The assumption of excess crankcase pressure may or may not be correct and may not be causative of the leak. Presumably the vacuum unit, bolted to the cylinder head and driven off the cam, also has gasket or O ring between it and the head in the area of the oil leak and these could be the source?

Hot oil is very thin and will find its way through imperfect joints easily by capillary action. I suspect you may be barking up the wrong tree, simply use RTV silicon to seal the new cam cover in place and you should have no further trouble.

The leak seems to be coming from between the cover and the top of the block, rather between the block and the vacuum pump. But, I'll check the vacuum pump area when I collect the car. 

I was hoping fitting a new cover(with gasket) would have solved this, but it hasn't which is annoying.

Thanks for the advice, I'll keep you updated.

I have repaired the hose and added more silicone to the gasket.

On the bolt nearest this end, the thread had gone bad, so I changed this as well. Hopefully, this will finally be the end of this problem.

The broken hose went into the upper part of the airbox (see below)

Since having this all done the brakes have now gone very "hard," they work OK, but I need to push the pedal hard to get them to work.

Could this be because of the repair work to the vacuum hose? What should the mechanic have done differently?

Thanks

You should check that you have a good vacuum between the pump and the servo, a hard brake pedal suggests an air leak somewhere. Remember that the vacuum pump does not need an air supply since it is evacuating air and pumping it back to the air box through the pipe you have repaired, make sure it's not blocked.

Thanks sepulchrave

I'll check the hose from the pump to the servo.

When you said "make sure it's not blocked" at the end of your reply, what were you referring to? the new hose?

 

 

1 minute ago, richardwalker said:

Thanks sepulchrave

I'll check the hose from the pump to the servo.

When you said "make sure it's not blocked" at the end of your reply, what were you referring to? the new hose?

 

 

 

Yes, any blockage will reduce the available vacuum, simply test it by disconnecting the repaired hose and seeing if the brake pedal is better.

How many hoses come off the vacuum pump?

Thanks, 

It's night here now, so I'll check it in the morning, when I can see better.

Yes - just one hose coming off the vacuum pump.

 

So the vacuum pump must exhaust into the cam cover.

Really need to know what that new hose connects into at the airbox, and if that is blocked.

Hard to see in this picture, but this is the only hose coming from the vacuum pump.

Thanks guys, I'll check where on the airbox the hose goes and make sure there a no blockages. 

Am I correct in my understanding - If the brakes were fine before the hose repair, the hard breaks must be caused by a blockage in the new hose or where it connects to the airbox?

 

 

Edited 7 November, 20187 yr by richardwalker

You can see the little flap valve where it exhausts in this photo (stolen off an ebay listing).

 

 

I think your understanding is correct (reply to your edit).

I'm not too sure what the 'pressure converter' does on your car but it wouldn't surprise me if it needed a source of atmospheric pressure air to do its job.

Here's a diagram of the hoses: https://workshop-manuals.com/skoda/fabia-mk1/engine/1.9/47_sdi_engine_fuel_injection/fuel_preparation_system_diesel_injection/exhaust_gas_recirculation_system/piping_diagram_for_exhaust_gas_recirculation/

 

Maybe the EGR delete has had an effect after all, how has it been done?? This N18 valve, what I was calling the 'pressure converter' just now (No.2 on that page) seems to deal with the EGR, and only the EGR, but if it is letting air into the non-return valve (No.5 on that page) when it shouldn't be, that might explain the hard brakes.

21 hours ago, richardwalker said:

Am I correct in my understanding - If the brakes were fine before the hose repair, the hard breaks must be caused by a blockage in the new hose or where it connects to the airbox?

Thinking about this some more, I think this isn't the simplest explanation.

 

More likely is that during the replacement of that hose, the main brake servo hose has been disturbed and a leak created or worsened. You'll soon find out I guess; if detaching the hose from the airbox fixes it, I'm wrong.

I blocked off the EGR by blocking the hose that goes from the Exhaust gas recirculation valve -N18- (number 2) to the Mechanical exhaust gas recirculation valve (number 1)

A friend did this advising me that it would be better for the engine, increase power and MPG.

It is difficult to tell, with the sound of the engine, but there seems to be some hissing coming from the area around the non-return valve (Number 5) and the hose looks a little split, I'll investigate this area further when I get the chance, perhaps this where the problem of the hard brakes is coming from, although it is strange they were fine before. You'd think the mechanic would check everything when they changed the hose, but alas, that is not how thing are done over here

Edited 8 November, 20187 yr by richardwalker
Re-read

23 minutes ago, richardwalker said:

seems to be some hissing coming from the area around the non-return valve (Number 5) and the hose looks a little split

 

See if gaffer tape improves matters?

Get a photo of the splittiness first though.  They're often split worse on the underside, where it's harder to see, but phone cameras come into their own.

 

On a friend's Polo, recently, this one looked OK from above!

Edited 8 November, 20187 yr by Wino

Self amalgamating tape is ideal to repair this kind of split.

 

https://www.toolstation.com/shop/Adhesives+%26+Sealants/d180/Tapes/sd2420/Self+Amalgamating+Repair+Tape/p55262

Thanks - I'll have good look around the non-return valve in the morning and try to fix it with some Self Amalgamating Repair Tape, if needed. 
Would it make sense that a split here wouldn't result in any symptoms (the brakes were fine before)  until the hose from the airbox to the " Exhaust gas recirculation valve -N18-" was repaired? 

When engine rocks fwd/bkwd, the hard walled rigid vacuum pipe, if split, will slip back off the valve opening up the split further, lose vacuum, hard brakes after the servo reservoir exhausted, you might have not noticed previously because the reservoir had enough in hand for a single actuation. Split will be getting longer.

Edited 8 November, 20187 yr by xman

13 minutes ago, richardwalker said:

Would it make sense that a split here wouldn't result in any symptoms (the brakes were fine before)  until the hose from the airbox to the " Exhaust gas recirculation valve -N18-" was repaired? 

Not to me.

I'm still fairly sure (pending you having a looksee inside the airbox lid) that the hose going to the airbox is just a source of filtered air, and it was getting unfiltered before via the disintegrated hose, so no functional difference.  The process of fitting that new hose will be what's made the difference, not the presence of it, I reckon.

Check the PCV, positive crankcase ventilation valve is not blocked, its the big black round plastic thing plugged into the top of the cam cover. That leads to excess pressure in crankcase and leaks.

I recently changed the PCV, and breather tubes, so I presume they will be ok, but I'll check them as well.

I'll open the airbox and see where the new hose connects - hopefully be able rule that out.

 

Could the way I blocked the EGR, simply by blocking the hose that goes from the Exhaust gas recirculation valve -N18-  to the Mechanical exhaust gas recirculation valve, cause any untoward problems?