3.1TD Bighorn vacum help

[muddy]

I have a 3.1 diesel Isuzu Bighorn. The brakes did a sudden fade, which I traced to loss of vacum assist. Spoke to the local garage mechanic who suggested most likely failed vacum pump - needing new alternator complete at around $800. He did suggest I have a close look at the vacum lines first to check for leaks, but thought that was unlikely. Boy was I pleased to find that nearly all the vacum hoses were perished & split. So I've replaced the main vacum hose from the pump to the brake booster, & just plugged off the other hose from the vacum pump, since it headed into a maze of joiners, switches & diaphrams, which would require pulling the radiator, fan & alternator just to get access to them all.

My question is whether any of them are important? The truck seems to run fine with them plugged, so I suspect they just run the emission control stuff. Am I right?

Thanx

[mud_slinger]

i think 1 ot 2 go the the injector pump but dont qoute me on that one but i guess if everythin works fine it should be sweet. anyone got any other thoughts and ideas?

[dazza85]

You are mostly right - If is like my 2.8 ( don't see why it would not be) the tube that feeds to the other side of the motor feeds the emission control except for one line which goes via a control solenoid to a servo on the diesel injector pump to lift the revs when you turn on the Air con.
If you have removed the Air con, you don't need any of it.

[muddy]

Thanks for the comments. I have noticed the engine revs don't increase with the air-con on, but it's not even close to stalling it either, so I guess it's just that the air-con will be less effective at idle. I can live with that rather than try to replace all the vacuum lines!

[dazza85]

I found that at times the motor runs really rough and can stall at inappropriate moments.
Have you riped all the tubes out or have you left them there but not connected to the vacuum pump ?
If they are still there I believe that we can get you up and running very easily.

[muddy]

The tubes are all there - but not connected to the vacuum pump, although some have come off the various connectors as they are perished & split. I could probably match them up - it's just that they are really awkward to get at...

[dazza85]

The only tube that matters is the one from the injector pump to the control solenoid , this will let you identify which is the correct solenoid then you only need to replace this line and run a replacement line from the vacuum pump to the other side of this solenoid and you can rip out the rest.