Fuel pump expert needed !

[no 6]

I'm struggling a bit here, and could use some help from an expert. Please be patient with my ramble, in case any of it helps.

I've got an oil leak on my standard 1584, which appears to be coming from the pin on the fuel pump.

When I'm driving, it will dump a load of oil. If I stop and clean it up, it will be OK for ages, but if I leave it, it just leaks and blows smoke everywhere (apologies to anybody travelling from Vanfest to Swindon yesterday). Maybe cleaning it up pushes the pin back in to a place where it doesn't leak ?

Anyway, did the obvious thing, and bought a new fuel pump. However, when reading up how to fit it, the manuals say to put a load of grease in the base of the pump. So if the base of the pump is supposed to be full of grease, how am I getting oil out of that pin ? Is the problem with the gasket, which is letting oil up into the base of the pump ? But then, how is a paper gasket supposed to hold the oil back under pressure ? Do I have a crankcase pressure problem ? (the breather seems OK, but I haven't checked the relief valves)

Tried to get the fuel pump off, but it seems to be a right *** getting to the nut at the back, so I would like to understand as much as possible so I know what to do and can get any extra bits etc before I tackle it again.

 

[Snakey]

Deffo won't claim to be an expert, but it sounds as if the plastic flange which is the guide for the fuel pump pushrod may be worn. Or the pushrod itself.

I think the grease is only packed in for the pushrod to pump mating faces...

http://www.vwheritage.com/vwh/VW-Camper-Van-Parts/Bus-Parts-1968-79/Engines-1600cc/Fuel-Carb-Manifold/?templateID=vwh

Might be worth fitting new flange and pushrod if you are going to replace the pump as well.

 

[no 6]

Deffo won't claim to be an expert, but it sounds as if the plastic flange which is the guide for the fuel pump pushrod may be worn. Or the pushrod itself.

I think the grease is only packed in for the pushrod to pump mating faces...

http://www.vwheritage.com/vwh/VW-Camper-Van-Parts/Bus-Parts-1968-79/Engines-1600cc/Fuel-Carb-Manifold/?templateID=vwh

Might be worth fitting new flange and pushrod if you are going to replace the pump as well.

Thanks for the reply. Got a pushrod anyway, but a new flange might be a good idea (as long as I can fit it without making things worse).

 

[chubbub2005]

Sorry not any help but I've got the same problem but mine is not the original pump. It's an angled Brosol for an alternator and I,m running a dynamo. So will be watching this thread with interest.

 

[no 6]

I'll try to get over to GSF in the next couple of days and get a flange (or pedestal as they seem to call it), and then have a look. I'll keep you informed, or if you are anywhere near Swindon, come and join in !

 

[Rita '71]

No 6,

See Bentley, Chapter 3, Fuel System, pages 7-9. Fig. 4-3 shows a nice picture of everything. The bore in your flange may be worn, allowing oil to come up to the top and leak out of the gaskets that seal the pump to the flange, or through the flange base gasket. Or, your flange could be broken, they're made of plastic ya know. Worst case would be that the flange has snapped in half down inside the case and only the top part comes out. Very precarious removing the rest of what's left if that's the deal. Flanges become brittle over time, like if it's the original one in your engine, just be careful removing it. Once it's out, check to see how loosely the pump rod goes up and down through it.
It's also a good time to check your fuel pressure. A lot of the aftermarket pumps can push up to 7 lbs. of pressure despite using the correct pump rod. Best way to figure this is to put a temporary fuel gauge between your pump and carb. You can either stack gaskets below the pump to raise it higher to reduce pressure, or grind your rod down at the top, but the gasket thing is more preferrable. It all depends on what carb you are using and what kind of pressure it likes.
Hope this helps.

Charlie

 

[no 6]

Charlie,

Thanks for the comments. I don't have Bentley - should add it to my collection.

I tried swapping pumps this afternoon, but the fuel inlet pipe on the new one ('dynamo' version from VWH) rubs up against my TP manifold so I thought that a bit dangerous with a fuel pipe.

So I've now got a new flange and gaskets installed (the flange loooked OK, but the top gasket was pretty shot) with the original pump and rod, and will see if that makes any difference. If not, I'll have to try and bend the inlet pipe without crushing it and then try that.

 

[Rita '71]

No6,

Definately add Bentley to your collection. Sounds like the new pump, if out of whack, it's best not used. Don't bother trying to bend the pipes on it. Take it back and get your $ back and tell them it fits too close to your manifold. I don't know what a dynamo VHW fuel pump is. Is it Brazilian, Mexican, Chinese??? Keep in mind I'm in the US, never heard of that one.
Keep posting on your progress........

 

[chubbub2005]

I,m running the alternator pump on mine i.e.
The pumps angled over to the left hand side to clear the larger diameter of the alternator but have generator fitted, will this give you more clearance?
Must be ok as long as you use matching push rod.
Mine works ok except for oil leak as per yours, but not as bad.
Bit worried about disturbing flange now

 

[oldporridge]

There's a special crescent shaped spanner available from any quality tool shop that makes it easy to remove the rear nut - it's called an 'obstruction' spanner, or something like that.

 

[no 6]

Sorry not any help but I've got the same problem but mine is not the original pump. It's an angled Brosol for an alternator and I,m running a dynamo. So will be watching this thread with interest.

Well, I did 50 miles yesterday, including some hard motorway miles, and so far it looks OK (touch wood). My gut feel is that it was the gasket on top of the flange which made the difference, but the flange itself may have halped. I'd say it's worth changing both, and see how you get on.

 

[chubbub2005]

Thanks for the info. Ill do as you suggest and change gasket and flange first.

 

[no 6]

I'll get some more miles in this week, to build my confidence. If we both get a result, I'll be even happier.

 

[no 6]

Update - pi$$ed oil all down the M4 to Picnic in the Park yesterday. Looks like a fuel pump is needed after all !

 

[Rita '71]

No 6,

Sounds like this is an ongoing problem. That is after a few miles you start developing an oil leak from the fuel pump mounting location. Your fuel pump itself is not causing the leak, but rather how it is fastened down to the case studs. Sounds like it may be loosening up after driving your Bus around for a while. I would try some of those 13mm nuts that have the nylon inserts in them, or at least use the curved washers or some lock washers if you're not. Nuts should be torqued to 2.5 mkg, or 18 lbs.