EAS! Compressor/pump

Hi. Newbie to this, but been referring to the forum a lot over the last few months. The joys of P38 ownership has meant this summer I've; changed head gaskets (after a failed thermostat cooked me very quickly), new coil pack and leads, waterpump, fan coupling etc etc.
Now I've got some air suspension work (oh joy). Air bags were replaced a couple of years ago, but over the last few months the compressor has been taking longer and longer to pump me up from access height. Went all over with my soapy water sprayer and couldn't find any leaks. Then last week she wouldn't pump up at all. Ahha! Compressor me thinks. So did the Wammers 'how to check'. Had suction from inlet, but air out of blue outlet pipe was poor (could hold my thumb over it).
So, took compressor to bits and the piston seal was wearing down, so fitted new seal/liner kit. Looks great, all cleaned up and tight fitting seal. Alas, when refitted (not connected to output pipe) I could still put my thumb over outlet. If anything it was making less air; and as I did this I could hear the pump motor slowing down.
What do you think guys? Bad electrics, worn bushes?
Thought I'd better ask in case I'm missing the bleeding obvious (not the first time), and before I raid the wallet again and buy a new compressor.

Did you check and reset the inlet and outlet reeds. Exhaust reed sits on an O ring if that is not sealing properly it will never pump anything up. But sounds like the compressor is tired.

Hi Wammers. Thanks for quick reply. yes checked the reeds and refitted a new small o ring (came with kit), all looks good. I'm sure your right. Tired compressor. Time to order a new one I reckon.

kevwill said:

Hi Wammers. Thanks for quick reply. yes checked the reeds and refitted a new small o ring (came with kit), all looks good. I'm sure your right. Tired compressor. Time to order a new one I reckon.

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If both valves are working and motor is good it should burn your thumb with the air being forced past it if you press too hard.

Double checked the valves and they looked good to me. I opened the motor end and was greeted with lots of small black carbon/metal bits. Didn't delve any further. So I guess motor is dying. Hardly any air and when I put my thumb over outlet can hear and feel the motor slowing down.

Rear bearing has been known to start to seize. Hopefully you didn't use the Dutch seal kit?

where are you located? i might have a spare pump.

Hi Datatek. No, didn't use the Dutch seal (checked the forum first). Got the teflon seal kit from Symlisep38parts on ebay. Came with 2 new o rings and inlet filters - not bad at about £15 - but hasn't helped my old compressor. He sells recon ones for just under £90 with the p&p. Might go for one of those.

kevwill said:

Hi Datatek. No, didn't use the Dutch seal (checked the forum first). Got the teflon seal kit from Symlisep38parts on ebay. Came with 2 new o rings and inlet filters - not bad at about £15 - but hasn't helped my old compressor. He sells recon ones for just under £90 with the p&p. Might go for one of those.

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That's probably your best bet unless you feel like dismantling the motor to get at the rear bearing.

Hi sas1810. Thanks for kind offer. I'm in Hastings, so a bit too far away from you. Petrol and beer tokens would clean out the Christmas fund. I wonder if the wife would like a new compressor for Xmas?

Datatek said:

That's probably your best bet unless you feel like dismantling the motor to get at the rear bearing.

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Yer right. And no, I dont fancy dismantling the motor. I'll end up starting a fire! He gives 6 months warranty on the recon comp, by which time I'll probably be doing the head gaskets again!

New compressor arrived today. Fitted it (left output unconnected), and same result as my old one; hardly any air coming out. Not sure where I should look next. Any ideas greatly appreciated.

kevwill said:

New compressor arrived today. Fitted it (left output unconnected), and same result as my old one; hardly any air coming out. Not sure where I should look next. Any ideas greatly appreciated.

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Send it back and get one that works.

Datatek said:

Send it back and get one that works.

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Is it as simple as that? Seems a bit of a coincidence that new compressor runs exactly same as my old one. Is there something that powers the compressor I should be checking. Fuses are all ok and I've swapped the relay, but still hardly enough air to blow up a party balloon.

kevwill said:

New compressor arrived today. Fitted it (left output unconnected), and same result as my old one; hardly any air coming out. Not sure where I should look next. Any ideas greatly appreciated.

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I have had a brand new compressor from Island 4x4 with the exhaust backing plate set far too far away from the reed valve. That caused the O ring to fall out of it's seat. O ring should be stuck in place with a little silicone sealant to prevent this and backing plate set only a couple of mm above reed at nose.

wammers said:

I have had a brand new compressor from Island 4x4 with the exhaust backing plate set far too far away from the reed valve. That caused the O ring to fall out of it's seat. O ring should be stuck in place with a little silicone sealant to prevent this and backing plate set only a couple of mm above reed at nose.

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Hi wammers. I checked all this. Cleaned reeds and fitted oring with tiny smear of silicone. Just seems as if my compressor (and new one) is not getting enough power to it.

I hate to teach mother how to suck eggs, but are you doing the test with the engine running and is your alt providing enough power to keep the battery topped up? If yes, you could test the compressor off the vehicle, full battery and some cables to provide power to the motor. Although ideally a universal transformer so you could make sure it was getting the right power to it would be ideal. If it still isn't producing air then the new comp is knackered.

Bix said:

I hate to teach mother how to suck eggs, but are you doing the test with the engine running and is your alt providing enough power to keep the battery topped up? If yes, you could test the compressor off the vehicle, full battery and some cables to provide power to the motor. Although ideally a universal transformer so you could make sure it was getting the right power to it would be ideal. If it still isn't producing air then the new comp is knackered.

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The compressor will not run on the car unless the engine is running unless you jury rig it.

Yes guys. Had the car running (alternator good, 4 months old). I connected the new recon comp up to the blue pipe; sat with the engine running/door open for 10 minutes. Closed the door and up she came. So thats good. Spoke to Simon at at symlisep38 who rebuilds them, and he told me they test them on 2 different vehicles with a 10psi gauge. This doesnt sound much to me. What psi should these pumps be producing. I was expecting a good one to blow me half the way down the street (maybe I've got a strong thumb). Anyway, 10 mins to fill up the system from completely empty seems ok to me.

wammers said:

The compressor will not run on the car unless the engine is running unless you jury rig it.

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Really? Yikes, glad I didn't buy the other Rangie the dealer had then, that one would happily kick in the compressor just on the battery.