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Read the WELCOME ALL BMWFANATICS post.
discussion HPFP PWG - BMW vs GW
- Thread starter shark111
- Start date
Thanks! The quote is from BMW Midrand, miss that BMW Fanatics discounts though š
freakoid9000
Active member
If you're feeling brave, you can attempt a DIY rebuild on the HPFP. I have done this on mine, and it has been 100% since. The hpfp is filled with hydraulic fluid, which leaks out over time. (usually via the rotary seal) There is a step by step process of refilling the pump, and replacing the seal.
There are obviously a few ways in which these pumps can fail, but most of the time, it is due to the fluid leaking out.
I see that the online guide has now been password protected, but have a look at my post over on spoolstreet, for a rough guide:
https://www.spoolstreet.com/threads/please-review-log-hpfp-failure-or-something-else-solved.9048/
Post #4.
Good luck!
There are obviously a few ways in which these pumps can fail, but most of the time, it is due to the fluid leaking out.
I see that the online guide has now been password protected, but have a look at my post over on spoolstreet, for a rough guide:
https://www.spoolstreet.com/threads/please-review-log-hpfp-failure-or-something-else-solved.9048/
Post #4.
Good luck!
Bugger
///Member
Not sure if you've tried this site? I've ordered from them once or twice, just did a generic search on HPFP though so not sure if yours is in here? Prices on the search return look decent.
Thanks all,
I ended up going with BMW, Goldwagen didn't have stock, and no one else stocks it. Unfortunately as my car is the older PWG type most places don't stock it.
FCP Euro only has the BMW version and a remanufactured version, the reman was $550 before shipping and timing was an issue as was worried about getting stranded.
BMW part installed, also ended up replacing the vaccum pipe they goes over the cam cover as it had a thin crack, definitely an improvement in cold start!
I ended up going with BMW, Goldwagen didn't have stock, and no one else stocks it. Unfortunately as my car is the older PWG type most places don't stock it.
FCP Euro only has the BMW version and a remanufactured version, the reman was $550 before shipping and timing was an issue as was worried about getting stranded.
BMW part installed, also ended up replacing the vaccum pipe they goes over the cam cover as it had a thin crack, definitely an improvement in cold start!
Thanks for this information!
I have been suffering from a failed HPFP as well and have been looking for information on re-building these pumps as an option. If I may ask where did you get a new seal?
*Sorry for hi-jacking this post but I thought gathering more info on this thread will help everyone more rather than starting a new one.
freakoid9000
Active member
I was lucky enough to have one lying around, but most seal companies should stock them.
Here is how I did mine:
The hpfp is filled with hydraulic fluid (CHF11S). This can leak out over time, and cause the pump to not function properly, as it relies on internal oil pressure to function. This was the case with my pump. You can measure the depth of the diaphragm, I believe it should not exceed 20mm to the outer rim. (I went from 27mm to 16mm)
I removed the pump, opened the pump, removed the cam gear from the shaft, and removed the rotary seal on the shaft. Then reassembled, without re-installing the oil seal. You then fill the pump with oil via the shaft. You will need to cycled the pump with a drill or impact in-between filling it, to make sure all the air is out. Once no more bubbles appear, install new oil seal, thread on cam gear, and you should be good to go.
I'm afraid I only took a few pictures while doing this. Be aware, that this is just one of a few possible reasons that your hpfp may fail. If you open the pump, and it is filled with fuel/oil mix, there are o-rings that you will need to replace. A special tool is required to remove these cylinders to get to the o-ring. If one or more of the bellows have split, you will have to replace the pump.
I have driven about 3000km so far on the rebuilt pump, and no issues. My recent logs also show that the pump is performing as it should.
Remove these 3 torx bolts:
Clamp cam gear in vice:
Put screwdriver in this slot, and hit with hammer - counter-clockwise - to loosen cam gear on the shaft
Then remove the cam, and remove the shaft and oil seal. Then reassemble without installing your new oil seal yet.
Once reassembled, apply a small amount of vacuum to the diaphragm - I inserted a tube and then sucked on it, then clamped the tube to hold the vacuum (this allows a little more oil into the pump, and will ensure good internal oil pressure)
Fill through this gap. You can see I threaded a bolt into the shaft, where the cam goes, to enable me to cycle the pump with my drill. Fill with CHF11S, and cycle the pump, fill, cycle, etc etc - It took about 45mins for me to get no more bubbles. Once the bubbles have stopped, remove the bolt, slide on your new seal, and make sure it is seated correctly. Then thread on the cam, remove your vacuum tube, and you should be golden. No need to tighten the cam, the rotation of the engine will do that for you.
Oil seal: (22mm X 10mm X 7mm)
I'm just sharing my experience that worked for me. Good luck!
Thanks for the details @freakoid9000
For those who want to do the same - I ordered my seals from Seal Galore in Jet Park.
I got the Quad or X ring seals as well to change them at the same time.
Parts needed for one pump:
For those who want to do the same - I ordered my seals from Seal Galore in Jet Park.
I got the Quad or X ring seals as well to change them at the same time.
Parts needed for one pump:
- 3-off 1.78x20.35mm Quad ring
- 1-off 22x10x7mm Oil seal
Guys, some feedback from me.
I have two non functioning HPFP's which is used to try and rebuild. And in summary - don't waste your time, buy an original from BMW.
I tried rebuilding these pumps a few times over with different methods and could not get them to work. For a number of reasons I can mentions below:
Its a very messy job and I gave up and got the right part from BMW.
I still have these two failed pumps that I might have another crack on with some other o-ring sizes to see if I can get it to work but in the mean time this was a failed attempt.
I have two non functioning HPFP's which is used to try and rebuild. And in summary - don't waste your time, buy an original from BMW.
I tried rebuilding these pumps a few times over with different methods and could not get them to work. For a number of reasons I can mentions below:
- The o-rings I believe are not the correct size. No matter what I tried the o-rings would get pinched when installing them and that would result in them not sealing obviously. I tried different lubes. I tried turning them in slowly. I tried turning them in quick. I tried heating the housing and freezing the bellows. All of this did not work.
- I even tried a few similarly sized o-rings from BMG and could not get them to seal.
- The shaft oil seal should actually be 22x11x7mm and not 10mm. This seal works fine but the issue is sealing the unit with oil after wards.
- I tried both Freakoids method of filling with oil while applying vacuum to the diaphram and even submerging the whole unit in oil and bolting it together.
- It all looks promising at first - the diaphragm showing showing 16mm vs 27mm - but after rotating the shaft a few times the oil starts coming out the high pressure fuel side and the diaphragm quickly returns to 27mm indicating failed o-rings.
Its a very messy job and I gave up and got the right part from BMW.
I still have these two failed pumps that I might have another crack on with some other o-ring sizes to see if I can get it to work but in the mean time this was a failed attempt.
Thanks for the heads up, sucks it's not a simpler solution as it would have been alot more popular especially as these have, gotten rarer to come by
freakoid9000
Active member
ah man, sorry to hear that. I guess I was lucky enough to not have to change the internal o-rings that seal the bellows!
Yeah man it could be a really nice DIY solution to an expensive problem.
Jip seems the main issue are those bellows o-rings!! I did some measuring of the bellows and followed a proper o-ring selection guide which indicates quite a different size. So when I have some time I will try these and see if that makes it any better.
freakoid9000
Active member
Reviving this, with a bit more info, and a bit more personal experience.
A while back my rail pressure was starting to falter again at WOT. After measuring at the diaphragm, I was back to 27mm. After I removed the pump, I noticed that the new rotary seal had been completely pushed out by the internal pressure of the pump. I had a local engineering company machine a slot/groove to take a circlip, which now firmly holds the seal in place. Almost 1000km later, and rail pressure is perfect.
PDBoosted is indeed correct, the shaft seal is 22x11x7mm. Regarding the seals for the bellows, it seem(after some more research) that X-rings are not the way to go, as the seals get pinched while re-installing, and that causes further leaks. A standard O-ring is the way to go.
Size: 20.35mm(ID) X 1.78mm - It's worth noting, that the usual failure point is the rotary seal. So if you have no fuel inside the pump, there is no need to replace the seals for the bellows. If it ain't broke, don't fix it.
Rail pressure is now happily at 2550-2700psi at WOT.
*I tried to upload a pic of the pump with it's new circlip, but for some reason, the site is not letting me do that today.
A while back my rail pressure was starting to falter again at WOT. After measuring at the diaphragm, I was back to 27mm. After I removed the pump, I noticed that the new rotary seal had been completely pushed out by the internal pressure of the pump. I had a local engineering company machine a slot/groove to take a circlip, which now firmly holds the seal in place. Almost 1000km later, and rail pressure is perfect.
PDBoosted is indeed correct, the shaft seal is 22x11x7mm. Regarding the seals for the bellows, it seem(after some more research) that X-rings are not the way to go, as the seals get pinched while re-installing, and that causes further leaks. A standard O-ring is the way to go.
Size: 20.35mm(ID) X 1.78mm - It's worth noting, that the usual failure point is the rotary seal. So if you have no fuel inside the pump, there is no need to replace the seals for the bellows. If it ain't broke, don't fix it.
Rail pressure is now happily at 2550-2700psi at WOT.
*I tried to upload a pic of the pump with it's new circlip, but for some reason, the site is not letting me do that today.
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