Oil Leak at Fuel Pump

[BarryHarding]

I have overcome most of the major oil leaks, on my CC Bradford, but this one has got me beat.
Oil leaks from the fuel pump body around the pivot pin and where the primer lever pivots, it is not leaking around the gasket where it mounts to the crankcase.
I had a thought that the diaphragm may be creating suction and drawing oil up from the crankcase, and on inspecting the pump it appears to me that it would be possible for this to happen especially if the rod from the camshaft was a very neat fit in the crankcase hole which might allow it to act as a sort of non return valve.
The crankcase runs at a negative pressure and there are no major oil leaks elsewhere on the motor.
I wonder if anybody else has had this problem and if so how they overcame it.
Regards
Barry

[Keith Clements]

Barry,
You have done well to reduce down to just one oil leak.
I will ask around the local Bradford owners.

[AlanBartlett]

A small oil leak that is pretty good going!

I would have a check of the breather valve, see if the pipe is possibly blocked or the vanes damaged or shut and covering the holes. You should be able toe feel it blowing when the engine is running. New ones are available from club spares.

As I recall its just a push rod from the cam through the crankcase is the only way out for oil to the petrol pump area, is it a nice fit inside its hole?

[PAUL BEAUMONT]

There is an oil return hole below the push rod. This must not be covered by the gasket or blocked with gunge or sealant. Sorry I don’t have an accessible bare crankcase to photograph at present

[BarryHarding]

Thanks Paul,
That could explain it, I will look into it in the next few days and let you know how it goes.
Regards
Barry

[Keith Clements]

As a CC Bradford owner I have not experienced the pump oil leak described. I would check.
1. Is breather valve actually achieving the vac. quoted by Jowett at 12 inch on Redex filled manometer hot at tickover, reducing with increased engine speed.?
2. My recollection is that there is a small breather hole in the lower pump body, which should be clear.

Incidentally, on the subject of engine oil leaks on CC, does anyone have experience of seal area repair sleeve (eg SKF) for rear crank seal ?
On this model, unlike Jav/Jupiter the lip of the seal bears not on the rear of the shaft but on a projection on the front side of the flywheel. Is this amenable to fitting a SS sleeve ?

Observations welcome. Sorry I cannot attend meetings at present as a result of health matters.
Best wishes, Ian Martin.

[PAUL BEAUMONT]

Jowett seem to have played around with the crankshaft rear seal. There are at least 3 different seal arrangements. I see no reason why a stainless repair sleeve should not be fitted to the flywheel, though these are quite expensive - especially in 3" sizes

[Keith Clements]

An alternative is to use double lip seals which are only a little bit more expensive....sorry we have gone off topic, Barry!

[BarryHarding]

I have the pump off the car at the moment, I can find no hole in the crank case other than the pushrod hole.
My pump has no breather hole.
When testing the crankcase vacuum I have 11inches of upper cylinder lube (I used Flashlube, an Australian product I believe) at 2000rpm, as I understand it 10 to 12 inches is recommended.
There are a couple of very minor leaks but the only one of concern is the fuel pump.
I set my pump up on a plate with a fitting on the back attached to a vacuum gauge and operated the primer lever, this shows 2 psi of pressure with the lever pressed and a similar amount of vacuum when it is released.
If I remove the screw nearest the crankcase (this is one of the screws holding the 2 halves of the pump together) this gives me a vent to the base of the pump and the gauge has no reading when the primer lever is operated.
What I have done is drilled a 2mm hole through the screw and with it replaced on the pump the gauge still has no reading when the lever is operated.
I have not refitted it to the vehicle yet, but I wonder what a breather like that will do for the oil leak and the crankcase vacuum, guess I can only try it and see.

Barry

[PAUL BEAUMONT]

There is an oil return hole below the push rod. This must not be covered by the gasket or blocked with gunge or sealant. Sorry I don’t have an accessible bare crankcase to photograph at present

I may have misled you here. Only one of my crank cases has the drain hole I referred to. It appears that the only method of oil control is the closeness of the plunger push rod in the crankcase. The pump is identical to the Javelin pump but the push rod is more than twice as long. I would expect this to be a problem on the Javelin if it is on the Bradford. My CC does not appear to leak oil from the pump

[BarryHarding]

Success!
I have been distracted with other things, but this weekend I have travelled around 190 miles with no sign of an oil leak at the fuel pump.
Now I can park it anywhere without leaving a pond of oil, however it still occasionally leaves a spot about 25mm dia. on the ground, looks like a slight leak from the rear main seal, at this stage I think I have got it about as good as it is going to be.
Thanks everyone for your input.

[Keith Clements]

Well done but what fixed it?

[BarryHarding]

As per my previous post, I drilled a breather hole through one of the screws which prevents the back side of the diaphragm acting as a pump drawing oil out of the crankcase then putting it under pressure and squeezing it out of every crevice in the base of the fuel pump, this appears to be 100% successful, no sign of it leaking now.
Nobody else that I have spoken to has ever had the problem of the fuel pump leaking this way, this was a major oil leak, so I don't know what is different with my engine.