Getting a working Bosch High Pressure Diesel Pump


With Peter’s help, we attempted to start the car, but nothing happened. The engine turned over but nothing further. We checked the glow plugs and while some were dead the car should start. It turned out after some investigation that the High Pressure Diesel Pump was not working.

Bleeding the pump

There are two screw at the top of the pump (to the left and right of the Bosch label) to bleed any air from within the pump. There’s also a pump action handle on the side of the pump to prime it with Diesel.

I took photos of the part number (shown above) it’s PES4A50B410RS144. This was useful as I could search for it later on the internet to see how/where I could get it fixed.

There is another label on the pump, it’s the regulator (Regler) and on mine it was EP MZ 60A 93 d.

I googled these numbers and found a few hits on ebay, most were ‘non working’ or ‘unknown condition’ pumps, but after further searchind I found a seller who sells many different pumps that he acquired from a business that went bankrupt. The business was a pump refurbish-er. The pump he had for sale was a few hundred euros cheaper than what I was quoted for a repair of my own pump and his was certified by Bosch in January 2017.

The pump clearly looked awesome but it had a slightly different regulator part number 94d versus 93d. I asked a diesel pump specialist here in Sweden if it would work and he said it would.

Fingers crossed he’s right !

I’ve made a short video of un-boxing the new pump here.