Suspension Faults

**101RRS** · 29th January 2019, 01:49 PM

Just a side question - all the "experts" say the relay should also be changed - why? I mean it is a relay to provide power to the compressor - if the relay fails the compresor doesn't run at all - pretty obvious. I have had relays fail occasionally but overall they are pretty reliable. If the compressor relay should be changed on a regular basis why not other relays in the car system.

The relay right next to the compressor relay is exactly the same spec and part number and we do not change it - I did swap them around and it made no difference.

So if the relay is working OK why does it need to be changed?

Oh trying one last thing - have ordered a metal cap for the Hitachi to correct the air leak from the pilot air pipe connector just in case that is the issue - i dont think so but worth a try before I spend big bucks.

Garry

**Graeme** · 29th January 2019, 05:00 PM

What's the current rating on a relay for an Hitachi and one for the AMK? I thought the AMK was rated higher but perhaps by the time a compressor needs replacing the relay contacts are well worn and possibly cooked from the excessive running of an inadequate compressor.

**101RRS** · 3rd March 2019, 01:37 PM

As a last resort I bought the stainless desicant chamber end cap and an exhaust valve rebuild kit to see if they may have been the issue.

Put the cap on today - made absolutely no difference (nice piece of kit though) - fault came back soon after starting. I tried to get the exhaust valve out but just ended up wrecking it

.

As I noticed it is very hard to blow through the felt filters so as the fault I have been getting is C1A20 - pressure increases too slow when filling reservoir I thought that as it is a nice warm, very dry day I would try and run the air compressor without any desicant or felt filters to see if they were the issue - nope faulted straight away.

So I have a new "ring" on the compressor piston, (the cylinder is perfect - still has the hone marks) new desicant, new filters, new end cap and the system still throughs up the C1A20 - pressure increases too slow when filling reservoir - there are no leaks in the compressor system nor elsewhere in the car (drove 1000km on Wed with no compressor running and height was fine).

So - why isn't this compressor not getting enough pressure up - who knows. Is there an issue with the pressure sender in the main valve block - again who knows as there are no specific codes showing for this.

I understand there is a software update for the Hitachi to lower operating pressure but no one seems to know about it.

Time to bite the bullet so i am going to order a knock off AMK kit and see what happens. If I still get the same "C1A20 - pressure increases too slow when filling reservoir" code after I have the AMK clone and its soiftware installed and the I might look at the pressure sensor.

Thanks for all the input

Garry

Ps - the compressor runs fine - just cannot quite get enough pressure (it will lift the car to extended height) - what else can I use this compressor for noting I already have two normal tyre type 12v compressors at home?

**Graeme** · 3rd March 2019, 03:49 PM

Can you monitor the reservoir pressure to see what it starts at and if it is actually increasing?

**PerthDisco** · 3rd March 2019, 04:05 PM

Duckworths, I believe, sells the original Hitachi unit which would have to be easiest R&R without change of pipe connections or software?

**IvanR** · 3rd March 2019, 04:26 PM

Check to see if your air tank as a plug at the front end, if so then you could plumb in a gauge to check pressures.

Ivan

**101RRS** · 3rd March 2019, 04:32 PM

Originally Posted by Graeme

Can you monitor the reservoir pressure to see what it starts at and if it is actually increasing?

I do not have the means of doing that but by inference I know the compressor is filling the tank. If I bleed the tank, the compressor fills it and I am able to go up and down without fault from the compressor (so the tank must be getting full and at a high pressure) - it is (as we discussed before) when I have stopped playing around with heights and just driving along that the fault comes up - your earlier thought that it is just not enough to keep the tank topped up with that bit extra pressure to cover self levelling when driving I suspect is on the money. The reason for this I am not sure.

When playing around with exhaust relief valve system I broke off the hexagon head

. I thought not such an issue as the metal plug with the spring and seal is still in place but air comes out the plug so maybe that is where my pressure loss is - the exhaust relief valve could be leaking.

But it is time to cut my losses on this.

Thanks for your help - much appreciated

**101RRS** · 3rd March 2019, 04:45 PM

Originally Posted by PerthDisco

Duckworths, I believe, sells the original Hitachi unit which would have to be easiest R&R without change of pipe connections or software?

Thanks - nothing comes up on their site using their search function but then if you just type in air compressor nothing comes up either.

**justinc** · 3rd March 2019, 04:53 PM

Garry direct sales to the public places like Airbagman in QLD sell the Dunlop version, can't remember if you get the bracket with them . At least you will get a warranty buying local...
I will put money on it being a dodgy pressure sensor, the one integral with the pump...🤬

**101RRS** · 3rd March 2019, 08:11 PM

Ok time for me to cry wolf again and again

.

I have just been for a 70km drive with no faults.

Today I tried to take out the exhaust valve to put in a new spring and seals.

However everything was stuck and I managed to rip the hex head off it

IMG_20190303_135919.jpg IMG_20190303_135847.jpg

Researching further I found this is quite common. Initially I though it would be Ok as the plug was still in the threaded section but when I ran the compressor and leak tested the area it bubbled up big time. Now as the compressor was under no load, the exhaust valve was closed as it should have been there should have not been any leak.

At this point the light came on - I figured that the exhaust valve was stuck slightly open, dumping some air from the piston out the exhaust rather than into the suspension system - but only open a little as decent pressure was still getting into the sytem.

So I tried to remove the plug by hitting it with a big hammer and a screw driver to turn it - no luck, then a little heat and no luck - so time to order that new compressor which would take a few weeks to arrive.

The old compressor needs to go back in while a new one arrives, so I had to seal the plug so that the compressor would provide at least some air from start to when it faults usually 5 min after start - tops up the tank.

So I super glued

the hex nut back in, and covered the lot with sealant and guess what - it sealed it.

Compressor back in the car (now down to less than 5 mins to get back in). For the usual test drive - normally takes about 10km to fault when the system has been tinkered with. This time after 70km and 90 minutes no faults - no issues raiseing and lowering and no slow rising messages as I had before.

My take is that the area around the exhaust valve is prone to internal corrosion due to humid exhaust air from the system. Corrosion was either holding the valve open a little or preventing it from closing completely. Me bashing the crap out of it had dislodged the valve and it now seals but probably not for long.

I will now order a new exhaust valve housing and drill out the plug that is in there at the moment - a new compressor is on hold for the moment.

Thread: Suspension Faults

Thread Tools

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions