Groan - Rear Suspension Collapsed Again

[mikesands]

Must be the 5th time for me. And several hundred pounds each time to fix. Lexus you should be ashamed of yourselves.

Last time it went they said it was because a lug had snapped, so I asked them for the sensor that they replaced at the same time.

I'm going to ask my friendly technician to see if this one will fit. So I have been cleaning it up and noticed the really bad state of the contacts. (Lexus told me that it's usually the contacts that corrode and necessitate a new one). But this raises a couple of questions for me

1. Couldn't they be assembled using some kind of conductive grease like you use on a car Battery terminals

2. If the male prongs on the removed sensor are in a bad way, surely the female prongs on the car's loom are going to be just as bad - but they don't change that part of the connector do they?

Mike

[cruisermark]

mike I feel for you and admire you patience - with me usually the second time I have a minor problem I start looking for a new car - incidently someone was mentioning a couple of days ago here that you had sold your 430? this is obviously not the case

[brendangeorge]

Hi Mike

I am surprised you have had 5 problems with the sensors - I have a 2002 and have had none yet! One of my pals has a face lift model and he has had to rplace his rrear ride height sensors. If you had a bracket failure then why did the sensor need replacing? From you comment you seem to be saying it is the connector that has corroded - this will have been caused by water getting in so did they fit the previous sensor properly. I don't play about under miy car but if the connectors are exposed they need to be water proofed or will fail. The protection of cables and connectors is a big topic but keeping the water out with a boot will be the best bet.

Also I am not sure what conductive grease is - people often cover their Battery terminals to prevent corrosion but you do not want anything other than a clean metal on metal contact at the terminal or you will cause problems.

Bren

[mikesands]

Because I can'tmove the car from my drive my engineer came to me last night and we spent two hours trying to fix the problem. I had a spare, only slightly suspect sensor with arm, and we thought we would be able to make this work even if it was the other arm/sensor that was faulty. We couldn't, so take note.

Anyway during the process we stripped a sensor open. I had assumed it was some kind of solid state miracle (I mean it does cost £300). In actual fact it's two copper tracks on a circuit board, and two copper brushes, and that's it. Probably about £3 to make, and it's obvious to me who is not an engineer all the places this thing can go wrong (seals, seizing ball joints, seizing centre shaft, corroding copper contacts etc). Not very clever at all.

Anyway he's coming back tomorrow with his diagnostic kit (which he forgot). and we'll check which sensor it is then fork out another £300. At least the bracket on the arm is still OK.

Mike

[ipwn]

Can I have your old knackered one if you plan to bin it? I'd like to take a peek inside and see what actually goes wrong. Seems like a common issue, if it's just some circuit wizardry then maybe I can do something?! Ideally would like to prep myself for this :D

[mikesands]

I'll take some pics. To be honest the tracks and brushes look fine, maybe I will put a mul'timeter to check for continuity, but my bet is on the connection between the cars loom and the sensor.

It's pretty obvious how the lug snaps off on the control arm. The sensor comes mounted on its own jointed arm that looks a bit like a bat's wing and has two small ball joints which have small delicate rubber boots on them (the one fitted by Lexus 5 months ago has already got a torn boot). So if these ball joints seize up, then it puts stress on the mounting bracket. Also one of the sensors had a semi-seized central spindle (which rotates the brushes along the twin circular tracks). This again would put stress back to the bat wing's mounting bracket on the control arm.

All of these things are potentially fixable if they go wrong but as we discovered last night you can waste several hours trying to get things working and find it's wasted. So easier for the dealer just to order new very overpriced parts.

Mike

[mikesands]

Well - that didn't work. The diagnostic machine told us the RR ride height sensor was faulty, so I bought a new one from Lexus £330 :arrrggg-matey: . Now the machine is telling us there are no faults but the back is still down on its haunches. We ran the engine for a while but nothing, we've tried disconnecting the Battery for 5 minutes but no luck. the two rear sensors are showing about -90mm and the front ones about +30mm. If we jack the rear up the sensor readings on those go to about +70mm, so they are definitely sending the right signals.

What device tells the system to pump air to particular struts, because to me it looks like that is what's faulty? (we can hear the compressor and the front struts are pumped up so it's doubtful it's the compressor at fault)

Any ideas anyone?

Thanks

Mike

[Malc]

Mike, I feel for you hugely with all your LS430 troubles.

Us oldies with LS400s are, I guess like me, simply scared to death of trading from our beloved LS400s to a LS430.

I don't know how I would cope facing the trauma you have these past months, especially knowing that the comparatively simple LS400 has given me a decade or more of fantastic, reliable and simply totally cost effective motoring ... and will hopefully continue to do so for many years to come

Malc

[brendangeorge]

Well - that didn't work. The diagnostic machine told us the RR ride height sensor was faulty, so I bought a new one from Lexus £330 :arrrggg-matey: . Now the machine is telling us there are no faults but the back is still down on its haunches. We ran the engine for a while but nothing, we've tried disconnecting the battery for 5 minutes but no luck. the two rear sensors are showing about -90mm and the front ones about +30mm. If we jack the rear up the sensor readings on those go to about +70mm, so they are definitely sending the right signals.

What device tells the system to pump air to particular struts, because to me it looks like that is what's faulty? (we can hear the compressor and the front struts are pumped up so it's doubtful it's the compressor at fault)

Any ideas anyone?

Thanks

Mike

Are you using a suspension specialist Mike - my local indi got somebody in to check mine out when my compressor became a little noisey. I did not see the testing but my suspenion is fine - the rear is a little slower to react than the fron but within spec (LPG tank I expect). The guy used a specialist piece of kit.

You say it is down on it haunches - have you got it parked on a slope?

Bren

[ROYT]

Any air leaks preventing the rear to pump up?

[bigjap]

sometimes even thou you can hear compressor working, is it pumping out enough air,the ones on range rovers used to sound like they were working but worn out inside you could repair those,i don't know about the lexus,obviously on yours it sounds like no airs getting to rear

[Bluesman]

You were certainly at the back of the que when good luck was given out. Hope you sort it soon. Mike

[mikesands]

Yeah I'm beginning to suspect that the compressor is working but not well enough. A couple of years ago it began making some awful noises and Lexus wanted £1200 to change it. After posts on here (quoting a Russian forum), I persuaded the dealer to strip the compressor and clean the seals. It's been fine until now, but probably needs a new one.

Mike

[brendangeorge]

Hi Mike

How did your saga finish - did you get the beast sorted out in the end?

Bren

[mikesands]

Progress - but I could really do with some creative thinking from people on here. My guy has taken the compressor off and found it works. He has also found a little air distribution box/regulator close to the compressor, which has two solenoids (he thinks to control air to front and back). If he disconnects both solenoids the compressor pumps up the front suspension with no problem but the back stays down.

Any ideas?

Mike

PS Good job I didn't order a new compressor which Lexus Teesside have quoted me £1850 for

[Bluesman]

Progress - but I could really do with some creative thinking from people on here. My guy has taken the compressor off and found it works. He has also found a little air distribution box/regulator close to the compressor, which has two solenoids (he thinks to control air to front and back). If he disconnects both solenoids the compressor pumps up the front suspension with no problem but the back stays down.

Any ideas?

Mike

PS Good job I didn't order a new compressor which Lexus Teesside have quoted me £1850 for

I wish I had a magic wand to wave over your car. Mike

[brendangeorge]

Hi Mike

As I am about to attack my Nav DVD I looked out my workshop data disk - I may be an electronics engineer but I am not an auto electrician. However there are front and rear control valves for the system so I suppose there may be a fault in one of them.

Here are 4 pages from the service CD - wiring diagram and system outline that tells you how it works. You may already have the disk or if you want PDFs (even with my core skills I cound not work out how to post files :) ) PM me and I can email them.

http://s1336.photobucket.com/user/snarler45/media/emas-r-page-001_zps9337bd6d.jpg.html?sort=3&o=3

http://s1336.photobucket.com/user/snarler45/media/emas-routline-page-001_zps75c617cb.jpg.html?sort=3&o=2

http://s1336.photobucket.com/user/snarler45/media/emas-routline-page-002_zpsfa6ede1f.jpg.html?sort=3&o=1

http://s1336.photobucket.com/user/snarler45/media/emas-routline-page-003_zpsd77b9857.jpg.html?sort=3&o=0

430 Nav system or mow the lawn? Decisions decisons.

Good luck

Bren

[mikesands]

Thanks Bren

I will pass this on to my guy and see if they make sense to him. Seems logical that it's a rear control valve that has failed doesn't it?

Thanks

Mike

[ROYT]

Although none of this may be relevent to your 430, as you are struggling, here is some info from an Ls 400

#1 ht. control relay appears to be for the front and #2 ht.control relay for the rear.

On my picture #2 looks like it's on the right hand side of the boot.

the #2 ht control valve and relief valve are together next to rear damper.[looks like drivers side rear on the pic.assuming RHD pic.]

Rear ht. control sensors are at the bottom of each damper.

check for air leakage with soapy water at pipe joints.

In problem charts uneven ht. indicates 'ht. control valves/ exhaust valve circuit'

As you might expect there is about 30 pages of diagrams etc.

[mikesands]

Thanks Roy,

Hopefully Chris - the engineer who is trying to fix things for me - will pick this up as I have given him the link to the thread. He had said he believed the culprit could be lurking near the right rear wheel arch

Mike

[39buss]

Have you given up on the 430 and traded it for an RX400 instead.?

[mikesands]

'fraid so Jim. SORN'd the LS although my engineer still thinks he can fix it. He has an LS430 and is swapping everything from his to mine until he finds what the trouble is. I left him about to swap the air suspension ecu.

Mike

[Bluesman]

'fraid so Jim. SORN'd the LS although my engineer still thinks he can fix it. He has an LS430 and is swapping everything from his to mine until he finds what the trouble is. I left him about to swap the air suspension ecu.

Mike

Swopping everything, and I bet its the very last thing he tries. Good luck with it. You have had some really bad luck with that car. Mike

[willskoda]

Did you try putting the suspension into the high mode after fettling with it?

[mikesands]

Yes

Mike