Vacuum system for brake booster on 80 series (1 Viewer)

[sunrk]

I've been removing some aftermarket antenna stuff (am/fm and uhf cb) from my 80 today and got curious about the vacuum setup that is used with the brake booster (no clutch booster on Oz 80's).

I've never seen any sort of warning light show up or any sort of buzzer making a noise, so I'm not sure what the vacuum warning switch does.

But I was wondering how it works and why a vaccum pump on the motor, plus a very small reservoir, is needed for the brake booster to operate?

I've never had the vacuum pump or the 'tank' or the brake booster itself out.

The hoses for the vacuum setup look like they need replacing as they seem to have cracking.

The rubber boot for the vacuum warning switch is coming apart.

Is the vacuum pump a generic 1hz motor component (not specific just to 80's)?

 

[mudgudgeon]

The vacuum pump and accumulstor/reservoir is something you'll find in some form on a lot of diesel engines.

Typically a diesel has no throttle plate in the intake. The intake tract and manifold is always fully open. Diesel engine speed and power is regulated by controlling fuel flow, not by controlling airflow into the engine with a throttle like a petrol engine.

As a result of not having a throttle plate, diesels don't pull much vacuum. They don't reliably pull enough vacuum to boost the brakes etc.

The work around for this is to have a vacuum pump and reservoir. Some diesels have a vacuum pump built into the alternator. 1HZ has one driven from the timing gears. Others use electric pumps.

The vacuum pump is generic to 1HZ, 1hd-t, 1hd-ft, 1hd-ft as they are the same engine family.
Fairly good chance Toyota would have used the same pump on other diesels around the same era

 

[Ragnaroek]

I've never seen any sort of warning light show up or any sort of buzzer making a noise, so I'm not sure what the vacuum warning switch does.

If i remember correctly, the vacuum warning switch triggers the brake warning light in the dash when activated.

My vacuum tank rusted through a few years ago, and i think the light came on when it failed.