LagondaNet

[JohanB]

I'm reconnecting the various vacuum hoses between the programmer, the controller and the ac/heater unit. Parts had been disconnected and also some alternative vacuum piping had been installed by a previous owner.
The 2 pipes (Vacuum feed and heater valve control) that run between the engine bay and the cabin had perished and mostly disappeared. My question is: where do they pass through the bulkhead, I didn't see any obvious grommet or the like to pass them through. It is an LHD car.
Second question is that the AC maintenance document describes a restrictor fitted to the rear of vacuum valve 2. There is nothing fitted there now and didn't come across anything in the various bits and pieces that came with the car. What is it? A piece of pipe with a calibrated hole restricting the airflow?

[DonaldNZ]

Hi Johan

Did you manage to figure this out as I m in a similar pickly

Kind regards Donald

[JohanB]

Hi Donald,

It turned out that they go through the bulkhead on the side of the steering wheel. There is a hole with a rubber seal a bit inside of the brake booster. In my case it was obscured by the windscreen wiper motor.
The restrictor I was referring to seems not to be fitted in practise or at least no one recalls having seen one fitted.
If you search the forum you'll find more info on the vacuum tubing for the heater system.

Regards,

Johan

[DonaldNZ]

Thanks Johan

on #32 I found the diagram someone has written got flaps, a/c and heater tap all cycling, such a relief. I used a festo compressed air vacuum generator and a power supply so I could spend a couple of days working through the four plumbing options. The vac generator made 25" vacuum, the engine at idle was about 10" with the slider valve obviously leaking. The airflow changed from floor vents and demist with ac pump and heater changing duty cycle and temperature with knob changes, at 10" vacuum.

My guess is the restrictor is to slow therefore quiet the flap changes, yet retain the flap power.
25" to 10" vacuum added maybe 2 seconds to airflow changes with virtually inaudible flap changes.
With the added bonus that if the heater vacuum falls off / leaks to full open cab side of the restriction the air leak back into the inlet manifold is minimal so minimal engine tune change.


you'll get a restrictor from a japanese car wreckers late 80 early 90' around the carb. pick several different suck resistances.

a better option is an ebay 6mm pneumatic valve & 1m of tube, then the restriction is adjustable. use silicone for the tube to pneumatic. joiner.

I used 4mm pneumatic tube and silicone for the ends to re plumb, worked a treat.