Steering rack leak?
 

Hello!
I hope you are all well.
I haven’t been on the forum for a while, lots of things going on in my life.

Just wondering, is it possible for the steering rack to leak from the body of the rack?
A couple of days ago just as I got back from a short drive i heard a slightly increased steering noise at full lock. Then as I stopped there was smoke from the left hand wheel well/bonnet.
It was the steering fluid, level very low, and leaking onto the drive.
I checked the delivery pipes, and the reservoir, all appear to be dry. Even the bolts where they connect to the steering rack seem dry.
I guess Im going to need a new rack.
Never expected it to leak from the body of the rack.

Normally smoke from the left hand side is the pressure feed pipe rusted through where it runs in the wheel well, even on LHD cars.

However, there are two hardlines running along the body of the rack which connect the valve block to the piston. I've seen one instance (Mike's T8) where one of these lines rusted out and leaked fluid.

Other places it could leak from are the valve block itself, although thats highly unlikely, or the seal at the end of the piston which is relatively common, but that would be on the right on your car and it tends to go everywhere as it drips out of the rubber boot.

If its definitely not the pressure feed pipe then I'd say one or both of the hard lines. They're not service items unfortunately so you can't buy them separately, (and they're almost certainly different to the RHD pipes I have on the shelf) so you'd still need a replacement rack. At least it's slightly easier to change on a LHD manual...

Hi Mikki!
Thanks for the detailed reply. Looks like I’m going to have to crawl in there and take a better look.
I replaced the delivery pipe recently so it hopefully isn’t that.
The dripping was happening more or less in line with the steering wheel.
I’m not sure I am confident enough to tackle rack replacement myself.
Am I right in thinking its undriveable in this condition? The power steering pump will start sucking air and get damaged?

Personally I wouldn't drive it if it's smoking as it's dripping on the exhaust. With a flash point of 160C that would make me very nervous. And yes, if the pump runs dry it will shred itself very quickly.

Is it servotronic? Concievably it could leak from the servotronic solenoid, as that is basically a pressure control valve and is right in line with the steering column. I don't have enough experience of servotronic racks to say whether that is a common fault or not though. I also don't know if the rack still has to come out to change the solenoid, but I can ask.

Thanks Mikki! You know so much about these cars +++
Its servotronic. I removed the relay from the footwell when it failed.
If it is a leak from the rack somewhere I’ll get a new non servotronic rack. I prefer the heavier feel of the standard rack anyway.

Hi Mikki,

Can I ask for your advice please. Would this work?
To connect the output of the power steering pump back to the reservoir so that I can drive the car to the mechanic without having to pay for a flat bed truck?
I havent really thought about what kind of pipe to use that would even fit.
Thanks in advance!

I think that would be very difficult tbh - the output of the pump is 130bar / 1800psi. With no restriction on it I suspect it would be almost impossible to restrain the hose to keep it in the reservoir. More likely it would spray fluid everywhere.

How far is the mechanic? I would be more inclined to remove the aux belt if its not very far. You'll lose the alternator, but they'll run for a short time on a fully charged battery. Depends how far you have to go really.

Thanks for replying so fast!
Haha I can just picture it, that would be very funny.
Ok thats a terrible idea.
Great idea about just taking the belt off.
Its only a 30Ah battery I hope it will make it.

Oh yeah I forgot you have a lithium pack don't you? 30Ah won't run an 8 for very long, and bad things happen to the electronics when the battery runs out of jiuce.

Can you borrow a bigger battery and hook it up with jump leads maybe? I've never measured how long an 8 will run with no alternator - only dealt with the aftermath.
Maybe charge the battery, take the belt off and run it for a bit with a voltmeter on the battery and see how long it takes to get down to 12.2 - 12.3V? (or whatever safety not-discharged-to-death voltage it is for lithium)

Oh no, that sounds very bad! what happens to the electronics when the voltage gets low? Thanks for telling me that could have been bad.
This lithium battery has some sort of low voltage cut off to preserve around 10% of the charge in case the car is left sitting too long. Maybe that will protect the electronics? But maybe I should just pay for the truck and not take any risks. Losing all power on the road suddenly is not going to be very safe.

I had another silly idea thats probably more trouble than its worth.
I have an old pump somewhere, maybe I could chop out the part that compresses the fluid and leave it as a freely rotating pulley?
But then I have to remove the new pump and fit this franken pump, its gonna be a lot of pointless hassle.

It would work, but you'd have to pull the front end to change the pump, and trying to drive a D2 with no power steering in traffic is not going to be easy. At that point, just get a tow truck ;)

The running the battery flat example I have seen killed its fuel pump as the voltage was dropping, which is about the worst electrical doodad to change in the whole car! I'm sure something else failed as well, but can't remember what.

A flatbed is looking like the best option tbh.

have you got any AA/RAC/breakdown cover - if so use that, as they will tow you to a garage for repair+++

If not, maybe now is the time to take some cover out ;)

I definitely dont want the fuel pump to fail!
Although I do need to change it soon preventatively. Its still on the original pump.

I have RAC but its the cover where you have to break down away from home to call them out. I didn’t want to pay extra for the home cover as I didnt expect to break down at home :ROFL:
How wrong I was

It already broke down at home a few years ago, clutch failed and stuck. I guess I should have learned my lesson lol!
It seems to inly break down at home on the drive lol!
I can see the advantage of that, but it is annoying.

Well I had a good look today from both wheel wells, with a torch and a usb camera too.
The pipes from pump to reservoir to rack are all dry.
The whole rack looks dry along its whole length, as do the pipes on the rack.
The only part I couldn't see properly is the servotronic box and the connection to the steering wheel coupling.
The exhaust below the rack is wet with oil so it must be leaking from somewhere. I was expecting at least some wetting of the rack from so much oil, but I cant see any oil on it at all.
Its a mystery!
I'll have to take it to the local mechanic to diagnose before I order anything.

By the way, I rang Audi, they no longer have any LHD racks, so it has to be a re-manufactured unit. I don't know if its the same case for RHD racks.

I charged up the battery, only got 7Ah into it which is a bit worrying, considering the voltage before I charged it was 13.18V which should be around 50% capacity.

I removed the aux belt, and started the car with battery only. The idling current draw was 25A. I got my mum to keep the revs just above 2000rpm and the current was still steady at 25A, measured with a good clamp meter at the negative cable.

I hope its not going to draw more when actually moving?
I was expecting it to draw more as rpm increases but this doesn't seem to be the case.

Its a 20 minute, 5.6 mile drive to the mechanic. Looks like I could make it.
Even if the capacity is only 14Ah, that should give me just over 30mins in theory.

Tomorrow is the day of reckoning :)

Good luck! +++

Make sure the AC is in econ mode (or just turned off) - that'll keep the compressor from engaging while stationary and also stop the rad fan coming on.

Thanks Mikki! I was hoping you would read this post.
Do you think there is any reason for the car to draw more amps when actually moving in traffic? That's my main worry which would throw my time estimates off.
Oh yes the damn electric rad fan! Completely forgot about that. Hopefully its cold enough outside so its not triggered by the engine.
Thanks!

Not in a manual. An auto would have some solenoids active in the valve body, but you are free of that scourge :D Injector duty cycle may increase, but I doubt that will make much difference.

I doubt the electrical rad fan will even get a look in at this current temperature so if the AC isn't telling it to run it shouldn't come on at all. The visco fan should be more than enough.

Do you still have SAI on yours? That blower uses a bunch of amps. Maybe just pull the fuse for that, or possibly warm the engine up while still on the battery charger?

I can't think of anything else.

Thanks Mikki! That's reassuring. I'll make sure I don't go anywhere near the aircon button.
Luckily I had the SAI blower removed, I had no idea it pulled a lot of amps. What a relief! that could have been a show stopper.

Well on top of everything else, range estimate was at 0 so I did a test run to get some fuel. On the plus side I made it back home.
However, the unassisted steering is soooo heavy I barely made it out of the drive :ROFL:
The whole adventure took around 12 minutes and it kept running, so maybe it can make it?

Although I am so worried hitting stuff because of the heavy steering, I may just order a flatbed truck.

Now I know why those 80's truck drivers had such huge arms

Just for info, I charged the battery back to full again, using a smart charger which displays capacity that went back in.
It put 4.8Ah back in. It seems to add up, at 25A draw, that's 11.5 minutes
Looks like I could have made it to the mechanic, if it wasn't for the heavy steering, especially at slow speed. It wasn't worth the stress. RAC charged me only £33 to upgrade to home start.

These little RC chargers are great! I was worried I didn't have a charger that can charge LiFePo4, as it turns out this little charger I already had for RC planes can do it!
Charges at 4A current.

Well the new (remanufactured) rack is in. Its not a cheap job, 7.5 hours labour!
I have to say I made a mistake! I ordered a non-servotronic rack on purpose, but I forgot how those feel. I have been driving around with a non-working servotronic rack for years and really liked the heavier steering at slower speeds which made the steering feel more precise in my opinion and gave the car a lot of character. It felt like a big car. It felt more sporty.
Now the new rack is in the steering feels so light! I dont like it at all.
I may have to swap a remanufactured servotronic rack back in when I have time/money to blow :ROFL:

So a broken servotronic rack is heavier than a non-servotronic? Is it any different while moving? I really dislike how light working servotronic is at low speeds - it feels like driving on ice.

What was leaking on the old rack?

I honestly never noticed that on my PF S8 which had it, it was brilliant!
I particularly liked the way it firmed up at "higher" speeds, it was rock solid at 140-150mph. :rolleyes:

Though I did once have a real "driving on ice" effect from the power steering on a Rover 800 that failed in a very unusual way.
Basically it lost all road feedback, so if you were stationary you could spin the wheel and it would turn to the limit and "bounce" back to the other side, probably cycling 4 or 5 times before the bounces reduced to nothing.
It was actually just like driving a big old American car so it wasn't as tricky as you'd imagine, but very very weird at first. :D

I really disliked how light the servotronic rack was at slower speeds too. I only found out how different it is on my old S8 when the servotronic relay failed. At first I thought it felt too heavy at slow speeds but I quickly got used to it. So when I bought my current S8 which had a working servotronic rack, the first thing I did was pull out the relay :)
It felt great, much more precise because a bit if extra effort was needed, and it just felt right for the size of the car, like you could feel what the car is doing.
I was hoping the non servotronic rack would be a bit heavier than the servotronic, but it seems just as light as a working servotronic.
Just pull the relay if you want to try it for a few days.
They gave me the old rack back, he said it was one of the hard lines on the rack. I’ll have a look and let you know.

I just had a thought it could be because the manual car is less heavy? Its hard to remember exactly, I think that the auto felt heavier with the relay pulled. The manual feels just right. And with the standard rack it feels too light. Maybe the standard rack feels better on a auto car?

Sorry to rant even more :p
I drove my father in law’s Citroen, I think its a C3?
The steering felt heavier than on my D2!
That is just depressing :ROFL:

In theory it should be possible to tune the servotronic to be weighted just how you like, anywhere between broken and max assist. Its just a PWM signal on the solenoid, with a ratio of speed to pulse width controlled by the module. Either fiddle with the speed signal in to the module, or drive the PWM directly with something like an Arduino and you can have whatever configuration you like.

If it was just one of the pressure lines failed on your servotronic rack thats a pretty simple fix using stainless braided hose and banjo fittings. HEL (who are 6 miles from me and do stainless brake lines) could make those up easily enough, then you could reinstate the servotronic with custom settings. I have three D2s with servotronic now so its something I want to investigate.

Servotronic on my S4 feels like it's either on at very slow speed or off once you get moving. I have not noticed any gradual increase or decrease in assistance.

I think it may need to be fully rebuilt. It had play in it, I got several warnings during MOTs
When I save up some cash Im going to get it rebuilt. I dont like the feel of this non-servotronic rack.