E280 cdi - Leak on high-pressure pump

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johnsco

MB Enthusiast
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Nov 22, 2008
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Location
Leeds, West Yorkshire
Car
E280CDI SPORTS ESTATE and C200 KOMPRESSOR SE Coupe Auto (1.8 lit petrol)
For a couple of days I've been smelling a diesel leak.
Sure-enough ... One of the connections to the HP pump was leaking.
[ Bosch pump ... Bosch part nr: 0445 0101 45 ]
See yellow arrow.

I thought it was the clip - Replaced it with new jubilee clip - Still leaking.
I then thought it was a split in the end of the flexible pipe - Cut back 12mm - Refitted - Still leaking.
On closer examination, the leak appears not to be coming from the connection, but from the base of the hexagonal nut at the end of the yellow arrow.

I am going to try to unscrew this nut with the connection on.
Looking at some adverts for recon pumps (£350 !! ... ) you can see some yellow sealant at this point.
I am guessing that this seals the threads and is resistant to attack from diesel fuel.

Does anyone have similar experience ?
I am assuming the connector can be unscrewed and refitted with sealant.
Can anyone recommend the best sealant to use.

Thanks in advance.
John
 

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Polite bump.
Any thoughts, guys ???
 
or .... perhaps it seals onto a copper washer.
Haven't looked yet !
 
Are you sure that's part of the pump body?
I only have the earlier CP1 pump for comparison.

The only yellow sealant I've seen on MB fasteners is pre-applied thread lock on the injector hold down bolts.
 
Hi,
I have not experienced any leaks yet, but always it is a fate waiting to happen. I rather doubt that sealant is ever used on HP Diesel lines, generally it is just rubber ( Viton? ) O rings, copper washers and cleanliness !
I have had a search on google and there are a couple of pump strip downs referenced from other Forum sites, which may help you, but I rather think that they are an earlier pump.
Also usefully from your favourite auction site there is a fuel pump repair kit for £7-55 (plus postage) which is cheaper than a used fuel pump @ £62 ish also on there. The pump repair kit seems a useful item to keep for a rainy day.

Steve
 
Thanks guys.
The pump is a Bosch unit ... Bosch part nr: 0445 0101 45.
It was fitted new only about 6 months ago.
Somewhat disappointing that this should happen so soon.

Had a word with my mentor at Rodley Motors in Bradford ... always good for help and support.
He suggested that the connection point probably screwed into the body of the pump using a taper thread with no copper washer and no sealant.
We agreed that I would try the obvious fix - Just pinch it up a bit and hope it cures the problem..
Care needed --- aluminium threads are the usual nightmare.

It was very tight, but I got a ring spanner on it and pinched it up as much as I dared (which was not much).
Replaced the rubber pipe and clip.
BINGO ... It appears to have done the trick.
Ryan at Rodley Motors told me that they do have some specialist sealant which they sometimes use on diesel connections, and this would have been our next try.
However - It appears to be OK.
:D
 

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