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Discussion Starter #1
Took the beast out over the weekend and had a great drive.

After I returned home I parked on the driveway whilst I was let the missus into the house. I then moved the beast into the garage.

In the morning I found a damp patch of oil like substance on the driveway and a few spots leading up to it in the path that I reversed down. Guessing from where the car was when I let the missus in the house I don't think this is coming from the engine.

I checked under the car in the garage and no further liquid has leaked overnight.

From my estimation it would put the rear diff in that sort of area? Any ideas about what could be leaking? The liquid was quite black and didn't have much of a smell.
 

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Jon Baker said:
Took the beast out over the weekend and had a great drive.

After I returned home I parked on the driveway whilst I was let the missus into the house. I then moved the beast into the garage.

In the morning I found a damp patch of oil like substance on the driveway and a few spots leading up to it in the path that I reversed down. Guessing from where the car was when I let the missus in the house I don't think this is coming from the engine.

I checked under the car in the garage and no further liquid has leaked overnight.

From my estimation it would put the rear diff in that sort of area? Any ideas about what could be leaking? The liquid was quite black and didn't have much of a smell.
Jon
The differential on these cars are virtually bomb proof. They do weep slightly from the fill /drain bolt, but I have never seen one drip.
This would mean a leak from the input shaft lip seal or the output shaft seals.
They only leak if the diff has overheated, & I mean seriously overheated.
To carburise a seal made from Viton or flourocarbon would require bulk oil
temps over 160 C on a regular basis.

Could I suggset jacking the rear of the car up & cleaning the differential.
Whilst you are there, look above the diff & see if the self levelling accumilator or the pipework to & from it is leaking.
These things rot & dump hydraulic fluid all over the diff.
They do go after about 10 yrs.

If it is not this then at least the diff is clean & you can then run the car & trace the leakage.

Regards
Farrell
 

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Discussion Starter #3
Could I suggset jacking the rear of the car up & cleaning the differential.
Whilst you are there, look above the diff & see if the self levelling accumilator or the pipework to & from it is leaking.
These things rot & dump hydraulic fluid all over the diff.
They do go after about 10 yrs.

If it is not this then at least the diff is clean & you can then run the car & trace the leakage.

Regards
Farrell[/QUOTE]
Cheers for the advice. I will take a look next weekend - the car is not a daily driver.

I have a feeling it could be another one of the self levelling accumilator pipes, one of these went just before I bought the car about 16 months ago. The reason it was found was that an MOT tester thought that the brakes were leaking and refused to pass it.

If this is the case are they easy to source and fit? Cost?
 

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I had the same symtoms earlier this year.

As a clue, in my case it was the self levelling valve which had to be replaced. It is a small part but over £200 IIRC.
To compound matters the pipework would not let go of the valve and a couple of new sections of pipe were needed as well. The old sections of pipe were a ***** to get out cleanly.
Best of luck.
cherrsagai
Brian
 

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Brian M5 said:
I had the same symtoms earlier this year.

As a clue, in my case it was the self levelling valve which had to be replaced. It is a small part but over £200 IIRC.
To compound matters the pipework would not let go of the valve and a couple of new sections of pipe were needed as well. The old sections of pipe were a ***** to get out cleanly.
Best of luck.
cherrsagai
Brian
Yes
Would completely agree. You cant get the other pipes out of the valve.
I replaced most of the hydraulic pipes due the amount of corrosion as well.

Farrell
 

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Discussion Starter #6
farrell said:
Yes
Would completely agree. You cant get the other pipes out of the valve.
I replaced most of the hydraulic pipes due the amount of corrosion as well.

Farrell
Is there a resevoir where I can check the hydraulic fluid level? That would be a good indicator of whether it was the hydraulic pipes or not.
 

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Jon Baker said:
Is there a resevoir where I can check the hydraulic fluid level? That would be a good indicator of whether it was the hydraulic pipes or not.
Jon
This check should be carried out on the level with a cold engine.
Pop the hood. Go to n/s front of engine compartment. Just next to the air box there is a black metal reservoir with a fastening wheel which is marked chf111s
This is the reservior for the pas, EDC & self levelling system.
unscrew & remove lid. remove mesh filter using 10mm spanner.
The level should be just under the filter.
If significantly lower or an empty reservior, should give indication to heavy leakage but not conclusive.

The visual check under the vehicle is the best option.

OK.

Farrell
 

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A couple of years ago, the diff in my car started leaking, but it never dripped oil on the ground like you describe. It would make an oil-film on the rear end of the car, everytime i drove the Autobahns with great velocity.

A couple of new gaskets and it was ok again..
 

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Donati said:
A couple of years ago, the diff in my car started leaking, but it never dripped oil on the ground like you describe. It would make an oil-film on the rear end of the car, everytime i drove the Autobahns with great velocity.

A couple of new gaskets and it was ok again..

I recently changed all the seal on my diff. It had had a slight leak for nearly 3 years before that. It would leave the odd drop after a long drive, but nothing that caused a noticeable drop in oil level. It's not an uncommon failure on E34s in general.
 

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AlexA said:
I recently changed all the seal on my diff. It had had a slight leak for nearly 3 years before that. It would leave the odd drop after a long drive, but nothing that caused a noticeable drop in oil level. It's not an uncommon failure on E34s in general.
Mine does the same, i have a slight drip from the rear diff, which BMW said is not coming from the oil seals but may be the speedo sender. How hard is it to loosen the diff for inspection?
I assume you can lower it slightly with the driveshafts still in place?
 

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madm5 said:
Mine does the same, i have a slight drip from the rear diff, which BMW said is not coming from the oil seals but may be the speedo sender. How hard is it to loosen the diff for inspection?
I assume you can lower it slightly with the driveshafts still in place?
I got someone to do the work for me, since I don't have a lift, but the sender o-ring is also supposed to be a fairly common failure. I think it's a lot easier to change than the seals.
 
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