electric vacuum pump

Following on from previous post i have now fitted the Hella Electric Vacuum Pump for the brake servo on my series three. I had poor running and smoke problems and decided to get away from the manifold butterfly set up which i thought was the problem. The pump is Hella ref. U28 and is switched via a relay from the brake light switch, I removed the servo flap/butterfly and the operating rod then used a piece of 6mm threaded rod,rubber washers,plain washers and nyloc nuts to seal off the spindle area. Initial impressions when driving are much smoother running little or no smoke and good servo effect i can easily get the oil light on! I have ordered a vacuum switch as an option to run a minimum level of servo boost in the system but doubt if i will mess about fitting it the brakes are so good.

Sounds a good option and worth knowing. My servo seems to work much better when I come of the brakes and press the pedal again - just much more responsive. There's no air in the system but I assume it's probably servo related.

The modification was done to improve the running but i do think the brakes are better perhaps the electric pump is giving a more consistant vacuum over the manifold set up.