A couple of e39 questions

stephenperry wrote: turn the stalk to position 1 and click the thumbwheel on the stalk up to maximum (as high as it will go) now go outside the car, leave the engine running, and spray some water at the sensor does it work now?

No. All it does in position 1 is run intermitantly regardless of whether the sensor is drenched or bone dry.

The headlight washers work fine, although the windscreen washers are a little bit lacklustre.

looks like the sensor is at fault:

It sounds like the rain sensor has failed as it just doesn't work at all. I also wonder if it's connected to thumbwheel not working i.e changing the frequency of the intermittant wipers.

I might just wait until the cars next a service so the dealer can have a look at it. Do you have any idea how much a new rain sensor costs?

The washer jets are feeble on both the normal window wash and the quick power wash. I'll have a look tomorrow weather permitting.

Well I thought I would contact the guy who sold me the car before I went any further and I was the right thing to do. He didn't know the car had auto wipers fitted until he had the windscreen replaced. When the screen was replaced the rain sensor was turned off and in order for it to work again I need to switch it on via a small switch on the unit itself. Or at least that's what he was told. Unfrotunately this also means that he doesn't know if they work as they should, but it does explain why they are not functioing at all.

I will have a look tonight after work.

Any chance of instructions on how to remove the rear view mirror?

Thanks Stephen.

Could it be more complicated?

Now I'm worried about breaking the mirror, sensor and the screen!

Right, I had a little look just now and made some progress. I removed the end caps and noticed that although there was no switch as such on the sensor, the electrical plug had not been pushed in properly. So I pushed it in and then tired to turn on the auto wipers. I set the ignition to position 1 and clicked the stalk up to position 1. Sure enough the wiper did one sweep and then stopped. So some thing is now working since yesterday they just stayed on intermittant. Unfortuantely I don't have any water to test them so i'll try that when I get home. Fingers crossed everything works. I just wonder if it was disconnected because the thumb wheel isn't working so the sensitivity can not be adjusted. Well No doubt I'll find out soon.

Thanks again Stephen

Well I poured some water over the sensor and they cam on and continued running till the screen was clear. Excellent. Of course the real test will be when I am driving and it starts to rain.

Oh and guess who stood in the wrong place when he poured the water down the screen. I realised as the wipers flicked water all over me. Doh!

You can't jack up an E39s rear end and then support it on axle stands as the only place you can position the axle stands is directly under the jacking point......And you can't jack the rear end up anywhere else other than the jacking points.

Hmmmmmm

Needless to say Haynes don't tell you how to get round this one!  they just helpfully say "jack up rear of vehicle and support"

I asked a BMW tech (at an open day visit at a dealer) where I could sit an axle stand under the rear of my E39 and he couldn't answer me as he didn't know!

You would have to drive it up on ramps but that will possibly make draining the oil difficult.  The car ideally needs to be on a lifting table.

The rear suspension of an E39 is quite delicate in terms of what each component is designed to do.  All the vertical load at the rear end is taken by the rear shock/strut assembly.  In theory you could place an axle stand under the rear shock/strut assembly but suspension arms will get in the way. 

The rear sub frame where the diff and suspension arms are bolted to is only designed or rather its mountings are only designed to resist lateral sideways loading from cornering and a small amount of vertical loading imposed by the torque reaction from the diff.  Not vertical loading from lifting the rear end!

Tell you what, you can fit a towbar to the back end then you can jack up the rear end from the towbar, I mean that's what Kwik Fit do

Disclaimer! that last paragraph was a joke but I have seen a Vauxhall Omega jacked up at the rear end by using the towbar while getting two new rear tyres at a local Kwik Fit!

Andrew