Technical Bench Test HPFP?
- Thread starter Ben54
- Start date
1) You can measure the depth of the diaphragm from the outer edge. If its anything above ~20mm it has lost its oil. (if it's completely empty it will usually measure 27mm from the outer edge) This is usually caused by the rotary seal on the shaft failing. I have successfully rebuilt mine. You will need a 22mm X 11mm X 7mm high pressure rotary oil seal.
2) If you open the pump, and it is filled with a mixture of oil and fuel, then one of the o-rings on one of the 3 bellows has gone bad. These can also be replaced with a 20.35mm(ID) X 1.78mm o-ring.
3) Another point of failure (rarer) is a split in one of the bellows. Have not been able to source these, but if you have several pumps lying around you could use a good bellows from another donor pump.
There is a bit of a procedure when it comes to refilling the pump, as you need to get all the air out. If you need this info, let me know, and I'll post it below for you.
Pic of how to measure:
Rotary Seal:
2) If you open the pump, and it is filled with a mixture of oil and fuel, then one of the o-rings on one of the 3 bellows has gone bad. These can also be replaced with a 20.35mm(ID) X 1.78mm o-ring.
3) Another point of failure (rarer) is a split in one of the bellows. Have not been able to source these, but if you have several pumps lying around you could use a good bellows from another donor pump.
There is a bit of a procedure when it comes to refilling the pump, as you need to get all the air out. If you need this info, let me know, and I'll post it below for you.
Pic of how to measure:
Rotary Seal:
No problem. This has worked for me.
Firstly you will need to remove the hpfp. Once done, clamp firmly in a vice, taking care not to damage any bits on the pump.
Once clamped, remove these three torx screws. *take note - some fluid will leak out, so have a couple of rags handy.
IMPORTANT - if the fluid coming out of the pump stinks of fuel, one or more of the o-rings on the bellows have failed and will need to be replaced.
Once the pump is apart, clamp the pump like so:
Place a screwdriver in the slot below, and strike counter-clockwise with a hammer until the cam is loose
You should now be left with this:
Push the rotary seal (in red out, and discard)
The other end of the pump will look like this:
Give everything a good clean with some brake cleaner or similar.
Next, reassemble everything in reverse order - but don't install the cam gear or the new rotary seal yet.
Should look like this:
So next, you want to apply some vacuum to the diaphragm. I found some clear hose lying around which fit snuggly into the diaphragms hole, and just sucked on it a few times to create a strong vacuum on it. I then clamped the pipe to hold the vacuum while I refilled the pump. (a mighty vac or similar would probably do a better job, but I didn't have one to hand)
Next, find a suitable bolt that threads into the pump's shaft. Like so:
Once the bolt is installed, start filling the pump down the side of the shaft with CHF11S. (red arrow) Fill it until it is almost overflowing, and then with a drill or an impact, slowly start cycling the pump. You will notice the fluid start disappearing into the pump, and bubbles emerging. Repeat this several times (5-10x) until the pump no longer takes any fluid, and bubbles have stopped coming out.
Now, remove the bolt, and install your new rotary oil seal. (22mm X 11mm X 7mm) Take care installing this seal. It has no seat, and you don't want to push it in too far:
Next, thread that cam gear back in, no need to tighten, engine rotation will do that.
Remove your vacuum, and that's it. Job done. Re-install, and hopefully, rail pressure is back. You can and should remeasure the diaphragm before installation. It should be well below 20mm.
As an additional note. I have found, that on my pump, the pressure in the pump would eventually pop out the rotary seal. I have since had a machine shop cut a groove into the pump to take a circlip, which has solved this problem.
And that's it. Hope it helps.
**some of the pics in this post are not mine, as I didn't photograph every step.
Firstly you will need to remove the hpfp. Once done, clamp firmly in a vice, taking care not to damage any bits on the pump.
Once clamped, remove these three torx screws. *take note - some fluid will leak out, so have a couple of rags handy.
IMPORTANT - if the fluid coming out of the pump stinks of fuel, one or more of the o-rings on the bellows have failed and will need to be replaced.
Once the pump is apart, clamp the pump like so:
Place a screwdriver in the slot below, and strike counter-clockwise with a hammer until the cam is loose
You should now be left with this:
Push the rotary seal (in red out, and discard)
The other end of the pump will look like this:
Give everything a good clean with some brake cleaner or similar.
Next, reassemble everything in reverse order - but don't install the cam gear or the new rotary seal yet.
Should look like this:
So next, you want to apply some vacuum to the diaphragm. I found some clear hose lying around which fit snuggly into the diaphragms hole, and just sucked on it a few times to create a strong vacuum on it. I then clamped the pipe to hold the vacuum while I refilled the pump. (a mighty vac or similar would probably do a better job, but I didn't have one to hand)
Next, find a suitable bolt that threads into the pump's shaft. Like so:
Once the bolt is installed, start filling the pump down the side of the shaft with CHF11S. (red arrow) Fill it until it is almost overflowing, and then with a drill or an impact, slowly start cycling the pump. You will notice the fluid start disappearing into the pump, and bubbles emerging. Repeat this several times (5-10x) until the pump no longer takes any fluid, and bubbles have stopped coming out.
Now, remove the bolt, and install your new rotary oil seal. (22mm X 11mm X 7mm) Take care installing this seal. It has no seat, and you don't want to push it in too far:
Next, thread that cam gear back in, no need to tighten, engine rotation will do that.
Remove your vacuum, and that's it. Job done. Re-install, and hopefully, rail pressure is back. You can and should remeasure the diaphragm before installation. It should be well below 20mm.
As an additional note. I have found, that on my pump, the pressure in the pump would eventually pop out the rotary seal. I have since had a machine shop cut a groove into the pump to take a circlip, which has solved this problem.
And that's it. Hope it helps.
**some of the pics in this post are not mine, as I didn't photograph every step.
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