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[Diamond Black Geezer]

Cheers!! That's much appreciated 

Once again, stuck at work, when I'd rather be at home tinkering   

[05omegav6]

Double check the main vac line from plenum to brake servo... it can chafe where it crosses the aircon plumbing, causing an almost invisible leak... a couple of wraps with insulation tape is a quick fix

[Diamond Black Geezer]

Will definitely double check. This main pipe has been replaced as of last night (with one, interestingly, with insulating tape round it, where it crosses the aircon plumbing!  )

[Webby the Bear]

Hypothosising again...

If that brake servo pipe had a vac leak from rubbing against the A/C or whatever. Could this 'rob' the multirams of the AMOUNT of vacuum required to operate them?

[Diamond Black Geezer]

It could, one supposes. Though not sure if my issues are caused my the Multirams not working. I'd have thought the hunting etc.. is more down to for instance, the ICV not getting the proper 'oomph' - which I appreciate, would be the same root cause you mention.

I will pop off the man vac pipe, and try and give it a blow, maybe trying the old leaky bike tyre trick - soapy water on it, look for bubbles? That might work on other pipes, too, actually.

The more I think about it, though, I seem to remember the Multiram didn't want to go on very well due to the plethora of vac pipes all over the place - in fact there was a pipe that popped off, as I seem to remember - just spotted it before putting it on proper, after a 'dry run' maybe find that, check it's not leaking a little air...

[Marks DTM Calib]

Disconnect the servo pipe to plenum connection and blank the plenum hole over....then try.

This eliminates all the vac piping, if it now runs fine you can add section back in one by one to narrow the fault down.

Certainly don't go willy nilly replacing bits as all you do is add more unknowns 

[Webby the Bear]

Disconnect the servo pipe to plenum connection and blank the plenum hole over....then try.

This eliminates all the vac piping, if it now runs fine you can add section back in one by one to narrow the fault down.

Certainly don't go willy nilly replacing bits as all you do is add more unknowns 

Thats a really good point, i never thought of that!

Presumably a bolt will fit?

[Diamond Black Geezer]

Ahhh, thanks Mark DTM!

See I would have reasoned by doing that she'd run rough too, as the pipework isn't all connected as it wants to be... But as you say, blank the plenum hole off, which makes sense.

Also, as I have my suspicions, that the multiram plenum isn't mated quite right, or an o-ring's slipped or something, if the problem persists, then it's a strong contender that it's this.

Much appreciated! God, I can't wait to get back to giving advice to members, not taking. I'm never comfortable borrowing even a quid off someone, and taking free advice off people comes into that category. I always try and give back where I've taken 

[Webby the Bear]

DTM charges £400 a response. His bill will be PM'd at the end of the tax year 

[Diamond Black Geezer]

DTM charges £400 a response. His bill will be PM'd at the end of the tax year 

 

If I blank off, as the £400-a-time response ( ) suggests, will this kill all vaccuum, including the thin vac pipes? A bit like cutting an electrical wire, it kills the 'circuit' Or will blocking the plenum and main servo vac pipe thereby narrow down the leak to one of these thinner pipes?

Sorry, this is a question I could answer by just doing it, but I'm not going to get chance to look at her until Wednesday, and the suspense kills!!! 

[Webby the Bear]

You wont be killing intake vacuum... by bunging the brake servo entry point youve simply cut off the vacuum going to the brake booster and the multirams (none of which are needed as the cars sitting in park on your drive).

if you find that the idle smooths out you know that the vac leak is somewhere in those vac lines (brake servo pipe, multiram lines etc.)

[Marks DTM Calib]

It will remove the VAC feed to all vac operated devices e.g. multirams, brake servo, heater system, air injection valve.

To block, I usually use very well secured tape (needs to be well secured or it will get sucked in) or I have a bolt of smaller diameter then the hole with 2-orings around it, this fits snugly inside the hole.

[Diamond Black Geezer]

Much appreciated. Already looking in the warehouse at work for any stray O-rings that might fall into my pocket   

[Webby the Bear]

i bought an o ring set from hellfrauds. only couple of quid and all the o ring sizes you could need

[Webby the Bear]

just to reiterate.

defo make sure the hole is sealed. for one, your testing will obviously be pointless if youve replaced a vacuum leak...with another.

but most importantly (and i dont know if anyonse done this)... i stupidly started my car with the brake servo pipe disconnected and i can only describe it as an explosion out of the hole  nearly poo'd myself