P38A Adding a valve to manually fill EAS tank and why did my pump fail again?

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Montyjohn

Montyjohn

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Location
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I think I've blown my EAS pump again. Repaired it about 6 months ago, and EAS worked perfectly, but today it refuses to raise.
It was working perfectly the other day, and I drove with the tailgate open. EAS was therefore disabled. About 15 minutes into the journey EAS fault message pops up. Thought this was weird as the EAS shouldn't have been trying to do anything.

Cleared it with the Nanocom, it just said invalid error, then pump was running continuously, getting very hot, rear valves open, but not raising. So assume the pump is toast again.

What's strange is the car barely lowers when left for a couple of days, and after repairing the pump 6 months ago, the EAS was operational almost immediately on start-up, so it seemed to be holding pressure. I've not found any problems using soapy water.

Before I do anything I want to add a Schrader valve to fill the tank, get the car to the right level so I can use it, and monitor the tank pressure to see if it's holding decent pressure.

Couple of questions.
Which pipe am I best attaching my 8mm/8mm/6mm t-piece to?
I was thinking to the one that I think is heading to the dryer. Would this fill the tank with the engine off?

Screenshot 2024-09-10 095901.jpg
 
Yes valve should be in the 6mm tank line (port-6 on diagram below), but after fitting & pressurising do the soapy water tests on the tee & valve with cap off.

FYI, the lower 8mm line (port-7) is the pump feed to the dryer when filling. Dry air then returns via Port-5, through the NRV1 and out port-6 to the tank. When lowering the car, air comes from the bags via exhaust valve & NRV3 out Port-5 and backwards through the dryer to the exhaust. This extracts moisture from the dryer to the exhaust.


1725965738724.png
 
Montyjohn said:
I think I've blown my EAS pump again. Repaired it about 6 months ago, and EAS worked perfectly, but today it refuses to raise.
It was working perfectly the other day, and I drove with the tailgate open. EAS was therefore disabled. About 15 minutes into the journey EAS fault message pops up. Thought this was weird as the EAS shouldn't have been trying to do anything.

Cleared it with the Nanocom, it just said invalid error, then pump was running continuously, getting very hot, rear valves open, but not raising. So assume the pump is toast again.

What's strange is the car barely lowers when left for a couple of days, and after repairing the pump 6 months ago, the EAS was operational almost immediately on start-up, so it seemed to be holding pressure. I've not found any problems using soapy water.

Before I do anything I want to add a Schrader valve to fill the tank, get the car to the right level so I can use it, and monitor the tank pressure to see if it's holding decent pressure.

Couple of questions.
Which pipe am I best attaching my 8mm/8mm/6mm t-piece to?
I was thinking to the one that I think is heading to the dryer. Would this fill the tank with the engine off?

View attachment 325700
Click to expand...
Sounds like the pump is feeing a leak somewhere.
 
I did some testing today, with a T and a Schrader valve on the 6mm pipe direct to the tank.

I filled it to 110psi and I was able to raise it straight to the high setting with no fuss.
Left a door open, and measured all four corners and let it sit for 4.5 hours.

Front and Rear passenger side = Zero drop Measured form top of rim to arch, to the nearest mm)
Front and Rear driver side = raised by 2mm.That's a strange one. Maybe that side of the car warmed up. Either way, no apparent leak.
Tank pressure, dropped form 85 psi to 76 psi. So at that pressure about 2psi per hour.

Is that loss enough to kill an AES pump rebuilt 6 months ago, only using it on the weekends?
Doesn't sound right to me. If so, these EAS pumps are very fragile. If this is typical I think I'd light to fit an LED internal to tell me when the pump is running so I can spot it earlier.

I think the next step is to put the valve on the tank and pipe only and see if it looses any pressure over night.
I'd like to solve this before repairing the pump again.

If the tank and pipe on it's own hold pressure, I assume it's a seal in the valve block. Do I just go an change all the o-rings, or is there something more targeted I need to check?
 
Montyjohn said:
I did some testing today, with a T and a Schrader valve on the 6mm pipe direct to the tank.

I filled it to 110psi and I was able to raise it straight to the high setting with no fuss.
Left a door open, and measured all four corners and let it sit for 4.5 hours.

Front and Rear passenger side = Zero drop Measured form top of rim to arch, to the nearest mm)
Front and Rear driver side = raised by 2mm.That's a strange one. Maybe that side of the car warmed up. Either way, no apparent leak.
Tank pressure, dropped form 85 psi to 76 psi. So at that pressure about 2psi per hour.

Is that loss enough to kill an AES pump rebuilt 6 months ago, only using it on the weekends?
Doesn't sound right to me. If so, these EAS pumps are very fragile. If this is typical I think I'd light to fit an LED internal to tell me when the pump is running so I can spot it earlier.

I think the next step is to put the valve on the tank and pipe only and see if it looses any pressure over night.
I'd like to solve this before repairing the pump again.

If the tank and pipe on it's own hold pressure, I assume it's a seal in the valve block. Do I just go an change all the o-rings, or is there something more targeted I need to check?
Click to expand...
Rust pin holes in the tank are not unknown. A leaking exhaust can also melt the plastic pipes.
2psi per hour pressure loss, = 48psi per day so tank empty in 2 or 3 days which is going to make the pump run for 15 or 20 minutes at least every weekend which is not going to do it a lot of good.
If there are no external leaks, it sounds like a valve block overhaul is due.
 
Soapy water first. Check the tee fitting & schrader valve (with the cap off). Then get under the car & check the tank fitting, plus cover the tank in soapy water for any pin-holes.

The tank pipe (usually) runs along the left chassis rail & then over the rear cross-member & forwards to the tank. Check the pipe for leaks due to heat damage from the exhaust.

It could also be a slight leak on NRV-1 inside the valve block.
 
Montyjohn said:
I did some testing today, with a T and a Schrader valve on the 6mm pipe direct to the tank.

I filled it to 110psi and I was able to raise it straight to the high setting with no fuss.
Left a door open, and measured all four corners and let it sit for 4.5 hours.

Front and Rear passenger side = Zero drop Measured form top of rim to arch, to the nearest mm)
Front and Rear driver side = raised by 2mm.That's a strange one. Maybe that side of the car warmed up. Either way, no apparent leak.
Tank pressure, dropped form 85 psi to 76 psi. So at that pressure about 2psi per hour.

Is that loss enough to kill an AES pump rebuilt 6 months ago, only using it on the weekends?
Doesn't sound right to me. If so, these EAS pumps are very fragile. If this is typical I think I'd light to fit an LED internal to tell me when the pump is running so I can spot it earlier.

I think the next step is to put the valve on the tank and pipe only and see if it looses any pressure over night.
I'd like to solve this before repairing the pump again.

If the tank and pipe on it's own hold pressure, I assume it's a seal in the valve block. Do I just go an change all the o-rings, or is there something more targeted I need to check?
Click to expand...

Doubt it would have warmed that much. I'd check PaulsP38A website. Could be the tips of the solendoids aren't sealing properly or one of the NRVs is leaking. It certainly shouldn't raise itself when off!
 
Grrrrrr said:
Doubt it would have warmed that much. I'd check PaulsP38A website. Could be the tips of the solendoids aren't sealing properly or one of the NRVs is leaking. It certainly shouldn't raise itself when off!
Click to expand...
Mine often rises a bit overnight when weather is warm. Usually at the back. Valve tips do weep. In winter it drops a bit.
 
pwood999 said:
Soapy water first. Check the tee fitting & schrader valve (with the cap off). Then get under the car & check the tank fitting, plus cover the tank in soapy water for any pin-holes.

The tank pipe (usually) runs along the left chassis rail & then over the rear cross-member & forwards to the tank. Check the pipe for leaks due to heat damage from the exhaust.

It could also be a slight leak on NRV-1 inside the valve block.
Click to expand...
I fitted a Schrader valve to the pipe to the tank, filled the tank, left it 24 hours and it only lost about 3 psi.
Since the garage compressor is filling it with warm air, 3 psi sounds like the pipe and tanks are not the issue. So I'm going to skip the pin hole check on the tank.

So that just leaves the valve block.

When you say NRV1 it it usual to replace the valve, or is it just an o-ring? Can't seem to find the valves sold separately.

Any other likely culprits whilst I have it apart?
 
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