At Idle when I push the brakes the engine drops revs

[Sirlancealot_alot]

Hi everyone, at idle when I push down on the brake pedal the engine drops revs, when I let the pedal out the revs come back up. I'm working mostly on my own so I struggle to be at the front end and in the drivers seat at the same time, what should I start checking. Thanks.

[Jordi]

Not a lot, presuming it has servo assisted brakes and isn't even noticable when driving?

It's pretty normal on older cars for this to happen.

[Sirlancealot_alot]

Thanks, I had an older car when I was younger, now my memory has faded.

[Sirlancealot_alot]

While your there, what if it becomes noticeable when driving?, which should be hard to spot as the rev's always drop off when I'm braking.

[Darrell]

My rpm does not drop off when brakes applied.
Is it possible the servo is leaking air ??

[RickUK]

Not sure what the problem could be really,possibly something to do with the vacuam if it does have servo assited that is,then that could be a possible cause.

One thing i am certain about and that is when i apply my brakes the speedo drops down by a massive amount