Distributor vacuum unit 1 237 121 373

Hi
I have a 1972 w108 280SE 3.5L

The vacuum advance unit on the distributor is faulty (Part no 000 158 18 18) - can you help with a source or repair?

regards Hans

Hi Hans,

I can tell you Bosch no 1 237 121 373 . But I do not know of a current source. I once tried to repair the 1 237 121 927. It is extremely difficult.

Hi
I have bought a Bosch SVDA 034 and modified it to fit.

The arc has been enlarged and the lever has been lengthened to match the original unit.

It fits perfectly and cost only £16
regards
Hans

Hi Hans,

curious as I am I checked for Bosch SVDA 034. But I only found a vacuum unit from Powerspark for a small Bosch distributor. Bending the arc to make it fit an 8-cylinder distribtuor and lengtheing the bar is one thing. I could not find its advance data anywhere. So which vacuum advance in °on main shaft or cam shaft do you now have at which vacuum being applied? It is not just a matter of mechanically fitting, advance data must also fit.

Hi
The length of the arm has been adjusted to match the original and the movement is the same so the advance should also be the same.

Hans

Hi Hans,

sorry to disagree. All those vacuum units differentiate. not only between arc of distributor and left or right hand. they also have a pressure where they start to move and where they end. And slope of advance is determined by a spring. So it would be surprising if that fits your desired vacuum unit 1 237 121 373. Unfortunately Powerspark does not specify the advance curve of their unit. Otherwise I could compare. But I am doubtful it would fit.