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I just purchased a used PSE pump (with a bad motor) and was hoping to use my motor that I thought was still operational... turns out it has since died also... so I want to replace the motor itself. My question is, how do I replace the motor? When I take the motor out, there is piece at the end that does not seem to come off... and the replacement motors don't seem to have it... see photos below to see what I'm talking about:
I haven't worked on one but by the look of the shaft in the first picture, that flywheel and clip are just pressed on, and not too tightly either, so you should be able to lever them off and press them back on. That's pretty standard engineering for a motor like that.
The dark grey piece is part of the body of the pump, it is, as you might have noticed, made of graphite and is very fragile, easily damaged. You need to pull the key off the shaft without marking the graphite part, be careful what you lever. Do not grip the key too hard either, if you damage the key you might need a replacement. The key is an interference fit on the shaft, it is fairly tight.
The replacement motor are readily available (made in China) one problem you might encounter is the size of the motor shaft, as noted the key needs to be tight on the shaft. If it is not tight there is quite a challenge to secure it.
For testing, the pump needs to produce minimum 45 psi, 3 bar.
So I was able to get the piece off by prying it up. I made a couple very minor nicks in the piece so I hope that doesn’t matter since I can’t see how I would’ve been able to get anything underneath in order to pry it up.
I put everything back together, but I’m only getting 22 psi. At first I was only getting 15, so I took it apart and screwed it back down and got a few more psi. I don’t know what I need to do to get 45psi out of this thing.
Well. After tinkering a bit more and by just loosening and adjusting the grooves to line up better, I was able to get about 38 to 39 psi. Not sure if I’ll get much better, but there doesn’t seem to be any scientific procedure to get this to output at max. I tighten the screws a bit and then gradually tighten a quarter turn but it’s not going any higher until it gets too tight and bogs down the motor. Motor draws a steady 10 amps.
Well. After tinkering a bit more and by just loosening and adjusting the grooves to line up better, I was able to get about 38 to 39 psi. Not sure if I’ll get much better, but there doesn’t seem to be any scientific procedure to get this to output at max. I tighten the screws a bit and then gradually tighten a quarter turn but it’s not going any higher until it gets too tight and bogs down the motor. Motor draws a steady 10 amps.
Well, you are almost there, but it might not be enough. The pump should produce about 45 psi (3 bar). This is required for correct and sustained operation of the trunk (boot) closing / locking.
To explain this a bit more, when the trunk is closing and locking the pressure is increased to 2.7 bar (40 psi), the PSE then monitors this pressure to make sure it does not drop (as it will if there is a leak in the latch). If the pressure drops (or is not achieved), the PSE sets a fault code, then the PSE repeats this test on the following times that the trunk closes, if the test fails repeatedly, the PSE disables the closing/ locking of the trunk (boot) and sets a code stating that the “air demand” is too high due to a leak. This code is cleared if the power to the PSE is cycled, by removing and replacing Fuse f71, or disconnecting and reconnecting the PSE. The closing / locking then works for a few more cycles before being disabled again.
So you problem is that you are right on the cusp of the required pressure. Perhaps the damage to the sealing faces of the graphite parts is the problem, I did highlight that. When the pump seals correctly it will produce 45 psi and draw about 12 amps (rather than 10).
You might be lucky, and have just enough pressure, if you can monitor the pressure on the HECK line, when the trunk is closing, you will see exactly what is happening.
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