Spare Parts

Over 65,000 part numbers and reference numbers at our disposal


Over 45 years experience

Pumps &

Fully equipped in-house workshop

Injector & Glow Plug Removal

Full range of specialised and universal tools

Diaphragms for Lift Pumps

Showing 1 - 5 of 5 items
Showing 1 - 5 of 5 items

The diaphragm is an important component in your engine's fuel lift pump system.

The diaphragm not only draws the fuel from the tank, but it prevents engine oil from being contaminated with diesel fuel and stops air getting into the system.

Typically, the coatings used on the diaphragms of lift pumps are neoprene and PTFE. Diesel fuel is continually in contact with the diaphragm so the coating has to be resistant to corrosion from the diesel fuel. The coating obviously also needs to be very flexible and to be able to cope with the continual movement that is associated with its use.

If the oil level is rising mysteriously this can be a sign that the lift pump diaphragm has failed and needs to be replaced immediately. Another sign of failure is fuel mixed in with the engine oil, this is very likely the reason why the oil level has been rising. One option is to replace the lift pump entirely, but this may not always be necessary. To save this expense, and if you have the necessary skills of a mechanic available to you, you could replace the lift pump diaphragm unit.

This involves disassembling the pump replacing the diaphragm and rebuilding the pump. It’s a skilled job and Mechanics often need a small 'C' clamp to squeeze the diaphragm and plunger together when reassembling the unit.

At Darwen Diesels we have an excellent range of both single and double U, V, VP and Y type diaphragms covering almost every type of lift pump out there. If, however, you do have a problem finding the lift pump diaphragm you need, then please do not hesitate to call our sales and service team. Our technical advisors will be happy to help you source the part in question if they can.

Can't find what you are looking for?

Please try searching our database using the search below

Still not found what you are looking for?

Call Darwen Diesels on +44 (0)1254 53545

We can source virtually any diesel part!

Or send us a message via our contact form and we will get back to you

  • We hold vast stocks of OE and quality replacement parts
  • We can source virtually any diesel part
  • The largest UK independent distributor of Diesel Fuel Injection components
  • We export our products to worldwide destinations
  • Next day delivery

Please contact me

Special Offer!


10mm reinforced rubber fuel injection hose

View Offer


Darwen Diesels / Firad Heavy Duty Machines catalogue

Click here to view

Featured Products