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760 hpfp diy

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diy hpfp
106K views 218 replies 60 participants last post by  Big N Fast 
#1 · (Edited)
original post with a lot more info(if your in to that kind of thing :) ): http://www.bimmerfest.com/forums/showthread.php?t=681883

Do not respond if someone says they can rebuild your pump for 800$ 1200$ or 1600$ all there doing is whats listed in this guide. noone has any proof that they can obtain anything othere than a non-factory diaphram

This guide will show you how to replace the high pressure fuel pump diaphragm

Before you begin I would recommend that you visit MWS's youtube page and look thru the videos about the HPFP
it contains valuable info on how the top part of the pump comes apart and if you have any issues afterwards

(like not removing the pump before opening it up !).

https://www.youtube.com/user/slkttop/videos <<< MWS on youtube
http://s288.photobucket.com/user/usdrake1fallen/story << my Photo bucket

Before attempting this procedure you need to be sure that your hpfp is the culprit and that you don't have any other parts in your fuel system that could be causing similar problems.

This should take no more than 30-45 minutes per side. Drivers side is the hardest becase of all the tubes/wires/tanks/engine stuff

Parts / tools:

2 Magna fuel diaphram's part# MP-9400-03 one for each side. 16.97 each + shipping from Summit racing http://www.summitracing.com/parts/mrf-mp-9400-03

Needle nose vic-grips

Sharp razor.

Paper towels to soak up fuel.

flathead screwdriver.

Now on to the actual repair:
1. Remove black vent hose by pushing in on the black piece circled in the photo.
2. Put some towels down under the pump to collect any fuel that might drip out of the vent lines !
3. Loosen screw connecting the vent pipe on the top of HPFP or remove it from the pump. It might be on there really good so make sure the
clamp is loose enough for it to freely more around the tube then give it a good pull it should come off without too much effort.



4. Remove all four screws on the outside of the pump with your vic-grips and make sure you can move it around and that is loose from the engine
THIS IS A MUST DO NOT SKIP THIS !!!



5. Now it is time to remove the cap on our HPFP. Loosen each bolt just a little bit each pass until they are all out. Be Careful once all the screws
are out under the cap there are a SPRING, METAL RING, BLUE O-RING AND A CIRCULAR BLACK CAP to remove.



parts removed



6. Now that those item's are out of the way we need to remove the ring that holds the diaphragm in place. Use your fingers in the center of the ring
to pull it out of the pump. USE LIGHT PRESSURE UPWARDS ON THE PUMP MAKING SURE IT DOESN'T GET COCKED INSIDE OF THE PUMP AND GET STUCK ! You can also use a socket that fits snug inside the hole and pull it out with light pressure



7. Now it's time for the tricky part removing the diaphragm. Yours might be stuck to the metal ring we just took out. It might be stuck inside the pump or it might be loose inside the pump. If it is loose inside the pump just use your nails to get the edge up and pull it out. If it is stuck inside the pump you can poke a hole in the middle of it and use something like a small electronics screwdriver to get it out. What even you do do not scratch the inner surfaces of the pump !

8. Now its time to cut our new diaphram. place the larger thicker metal ring inside the magnafuel diaphram and then very carfully go around and trim the excess material off on the outside.







9. Compare it to the old diaphram and make sure it is the same size.



10. Place the new diaphram inside the pump and make sure it fits nice and there isnt any gap that could let fuel get by.



11. Place the metal ring back inside the pump nice and evenly making sure not to angle it so it doesn't get stuck



12. Replace black circular plastic piece and the blue oring. The oring is kinda tricky but it has a groove that it goes in and once you get it back in
it will stay there for the rest of the assembly.

13. Now replace the thinner metal circle with the high part facing up and the spring back on the pump with the top cap. You will need to compress the top cap and hand tighten the screws. If you have a inch pund torque wrench tighten the bolts to 69 INCH-POUNDS.

14. now insert the four long bolts that secure the pump to the engine. You might need to push the pump down to get the bolts started. Make them snug Then
tighten them a little more than that.

15. Reattach vent hose to the nipple on the top of the pump.

16. attach the 2nd vent line by pushing the two line's together till you hear or feel it click together Then give it a little tug to make sure its
together

17. Now we need to get fuel back into the fuel lines and pum. Turn the ignition on to position 2. Foot off the brake and push the start button.
Repeat this about 5 times then start the car and let it run. because the fuel system was open the engine may not start immediately there may be a
2-3 second delay.

17. YOUR DONE !!! GO GET YOUR SELF A BEER !
 
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#98 · (Edited)
Just go to contitech web page, you can search the product manager for diaphragms in your country. Eg in germany the gentlemans name is very appropriately mr. Sieben :)

The thing is that I did my research work out of sheer interest without any profit in mind. Therefore I dont mind sharing all the info I have with others. I dont want to see another bmwallroundwhateverthatguyis who is charging atrocities and claiming to develop high-end-materials himself.
 
#103 ·
took a pump off the car today to check as it was pissing out fuel from the cap.the ring inside the pump just above the diaphragms was stuck i prised it up by getting screwdriver underneath ,now the ring drops back in very loosely ,has any experienced this brass outer part it sits in now looks slightly oval.should the silver ring be push fit tight or loose
 
#105 ·
Repairing the hpfp on my 2004 bmw 760i I am looking for the parts to rebuild the pump

Hello everybody this is my first post and I hope I get it right. I am repairing the hpfp on my 204 bmw 760i I am looking for the parts to rebuild the pumps. Any help will be appreciated. I don't know who I can order the kit from or where to send the pumps out to have them repaired. Help
 
#110 ·


Hello everyone,
Long time lurker first time poster.
I wanted to show a possible reason some of us are having more difficulties than others with the HPFP diaphragm repairs.
I did mine with the MP 9400-3 diaphragm from Magna Flow but after just a few miles they failed again.
I saw a post about diaphragm shrinkage. Man you gotta hate shrinkage.
Here's the thing. No pun intended.
Look at the two pictures. If you don't clean out those micro grooves you will be just like I was mad because the cheap fix didn't work. Also look at that bevel on the spacer it's beveled halfway across. If you cut the diaphragms the exact size and they shrink just a little you're outta gas.... Pun intended that time.
So to recap. Cut diaphragm a little oversized and make sure to clean out the micro grooves on both sides.
Good luck.

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#112 ·
@RonHall512
Thanks for the tips about the grooves. Has the magna flows lasted after you cleaned the grooves or did you go with something else for the diaphragm? I had cut the Magna Flow diaphragms slightly oversize, but they still failed in less than 100 miles. Just pulled the driver side again and found this
 

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#113 ·
Yes they still failed.
I think some of the guys used two per side.
My car is not my daily driver so I can experiment.
I have a sheet of Viton coming today from Amazon. I ordered the 1/16 thick with 1000psi burst pressure. I plan to double it and see what happens.
I'll post the results.

I also have a test sheet of some special order material that I came up with the specs for coming next week.
I'm pretty sure we can double it and it will hold.
If the stuff I came up with works I'l be on the hook for a few yards of the material.
I'll divide the cost by 6x6 pieces and sell it at cost plus shipping for anyone that wants some.
I think if the cost estimate works out a 6inch by 6 inch square will end up costing about 12.00 plus shipping.
I'll post here when I know more.


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