Dash Binnacle vacuum pipes

[spock505]

This car is always one to surprise me, hope someone can help with this.

Since owned there has been a loud wine from cold which eventually fades, its more pronounced when cornering but has so far alluded me, until now.

I think it could be the speedo cable so removed the binnacle to check, move around which made some difference. Tried adding oil into the cable end but may have been too thick, will try again a bit later - what puzzles me is the two ends of vacuum pipes sitting at the base.

No vacuum being pulled while running, no obvious connections left unconnected, ignition switch has both still attached - any ideas?

Plugged both with golf tees and put binnacle back loose,

Going to pull cable from the bottom tomorrow and renew or refit if able to lube properly.

..ta.

[babymog]

What color is the tubing that runs to these rubber hoses? I'm assuming this is the 124, is your leveling switch for the headlamps still hooked up?

[spock505]

Hello Jeff, it didnt come out very well in the pics but one has a blue strip, I think the smaller of the two but can check.

Headlamp self level works fine, very strong vacuum under hood when checking auto box but might be a different circuit.

Both are too short to reach back of instrument cluster unless something missing?

edit, yes, sorry 124

[babymog]

If I were to guess: a vent. Hopefully someone here will know.

Usually the rubber ends are pushed onto a smaller plastic line, the plastic line is color-coded.

[Zulfiqar]

The vent for your vacuum system is a plastic pipe that just hangs about 2 inches in the cabin from the rubber grommet behind the brake booster.

Trace this out - if you smoke cigarettes you can pull a puff and blow in it and get someone to identify where its shooting out from.

[spock505]

Bit of an update, the plastic tubing of both pipes is black, however the smaller one of the two has a blue strip.

I have unplugged both lines then off for a test drive, no difference at all, everything seems to work too?

Tracing both lines through the bulks head, they look to turn left (right for LHD) under the main rear bulkhead, not sure what happens then.

This whistling noise is driving me crazy (ier) tried following the speedo down into the box but unsure if the orange cable is the other end, if it is then that's going to need the box dropping to get access, difficult enough taking a piccy.

PLUS, not sure it's that anyway.

It sound like the cabin fan burnt out but turning on/off makes no difference, car has been on axle stands running in gear, no noise aggghh..







Is this the speedo cable in orange?

[spock505]

Still checking vacuum system for potential problems before removing modulator early next spring.

I have spent a bit of time locating various pipes which correlate to the service manual layout, the two mentioned above as someone mentioned could be cabin vents.

The diagram lists four pipes in total, one for key switch, second 'other consumer' and the remaining two 'air admission to vehicle'.

One of these pipes joins to the bottom of injection pump while the other comes off the two manifold valves which control resonance flaps.

Any idea what their purpose is?

[tyl604]

You should have two rubber hoses connected to two nipples on the switchover valve and one nipple open. Do you have that? Seems like one hose goes from switchover valve to ALDA near the injection pump; short, about 18 inches long. The other goes over the valve cover and to the back of the turbo where there is another nipple; maybe 36 inches long. Maybe one of your questioned hoses goes to the switchover valve?

If it is not connected to your switchover valve properly, you should be having pickup problems.

[spock505]

Not sure if this is connected to the above, but when depressing the throttle say more than a third you can hear the 'draw' or suction being created. It might correlate with the butterfly flaps opening inside cross over/manifold, not sure but similar throttle positions.

Is this normal or something out of place?

[spock505]

Removed the dash binnacle to trace pipes, the two main brown pipes appear to connect to the ignition switch - I can be 100% sure as going by feel only, but there's nothing else around that area needing a vacuum.

Is it usual to have two pipes connecting the ignition switch?

The other two marked 'a' in the diagram just sit behind the binnacle itself, the spare 'c' appears to be as above, hooked up to the ignition.

The vacuum noise above - doh! moment, as the hood pad has been removed allowing a big gap between the bulkhead and hood allowing engine noise into fan duct, or at least I hope that's what it is - everything gets amplified through that horn ..

[BWhitmore]

Yes, the two brown vacuum tubes attach to the ignition switch. These 2 tubes allow vacuum which is controlled by a vacuum switch on the ignition switch to operate the injection pump shut down valve to turn the engine off.

[spock505]

Thanks, so that's all four pipes accounted for in that bundle, there are others but I think they forma another vacuum circuit not shown above in relation to head lamp tilt, door locks and so on.

There's also something in the ceiling light area which needs a vacuum, I remember unplugging this when refurbishing sunroof.