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406 HDI vacuum issue?

Posted: Sun Jan 10, 2016 7:25 am
by senate
Hey guys!

Having some issues with my 2001 HDI Wagon:
For the last two weeks I had been intermittently hearing what I assumed to be a sticky break calliper coming from the passenger side of the car (the sound would go away when I would brake, and then resume), but yesterday I noticed quite a drop in power (usual boost is 18-20psi, it now only reads 0.5-1psi) and a very faint feeling brake pedal, but the brakes still work to a degree - I just need to make sure I'm paying attention! So my thinking is that what I thought was a sticky brake calliper was air escaping from somewhere!

I've check the solenoids on the firewall and all three are working, I then connected a vacuum gauge to the line going to the turbo, it holds a steady -2psi vacuum until braking, where with a fully pressed brake pedal it draws up to around -22psi, but no variation in vacuum pressure otherwise. There are no audible signs of a leak currently, and all lines running to and from the solenoids are fine.

I haven't had the engine light come on, and there haven't been any antipolution warnings either.

I'm at a bit of a loss as to where to turn next and thought I would ask here to see if anyone has experienced anything similar before getting a mechanic to chase the problem down.

EDIT: Since doing some more reading I'm starting to think it might be something as simple as the vacuum pump itself, as -2psi doesn't appear to be anywhere near enough vacuum produced, I believe it should be around 10psi? Plus the fact that everything it feeds is now not working at full capacity.

Any help is greatly appreciated!

Cheers, Tim.

Re: 406 HDI vacuum issue?

Posted: Sun Jan 17, 2016 3:15 pm
by lozz
Are the brakes ' spongey?.

Have you checked the caliper?.

Re: 406 HDI vacuum issue?

Posted: Fri Jan 22, 2016 11:29 pm
by gumby6371
Could be a loss of vacuum anywhere in the circuit, cheapest option first would be change the hoses and see if it cures it. Shouldn't be any more than £5 for the pipe from a motor factors.

Re: 406 HDI vacuum issue?

Posted: Sat Jan 23, 2016 7:39 pm
by Milesh
Start with the pump as they should provide a fair bit more than that, Sounds like similar issues to me as the pump had been changed by the previous owner, Just do one thing at a time, I'm getting there slowly, bloody things

Re: 406 HDI vacuum issue?

Posted: Sat Jan 23, 2016 8:30 pm
by GingerMagic
Hi, my vac pump is just under 1bar when idling, which is about 15psi.

If you have access to a vacuum gauge you can test all your vac pipes in and out of the solenoids etc to see if there are any issues....