Draining a fuel pump BMC 1.5

[Markymark]

Hi all, I need to drain my fuel pump on a BMC 1.5 as I need to apply thread lock on the ideal pin that has a slight leak, any help would be greatly appreciated.

[philjw]

Is this the lift pump or the injector pump?

[Markymark]

1 minute ago, philjw said:

Is this the lift pump or the injector pump?

lift pump, I think I've worked it out. turned off fuel tap run engine until fuel out and engine stop then soaked up fuel from pump outlet with tissue.

[RLWP]

40 minutes ago, Markymark said:

lift pump, I think I've worked it out. turned off fuel tap run engine until fuel out and engine stop then soaked up fuel from pump outlet with tissue.

Sorry, you turned off the fuel then ran the engine until it stopped?

Richard

[bizzard]

Whats an ideal pin? If you mean the pin that the lever rocks on and is leaking fuel the pumps diaphram must be holed, in which case fuel will trickle into the engine sump. First don't run the engine!. Try the lift pump hand lever to feel that it has pump resistance, if not tun the engine by hand a little to get the pumps lever on the back of its driving cam in the engine. Then turn the fuel tap off at the tank. Find a little tapered bung to push into the fuel pipe. Remove pumps outlet fuel pipe, bung it up quickly so it doesn't drip fuel with the lttle bung. Remove inlet pipe and unbolt and remove pump. Refitting. Bolt on pump, connect inlet pipe, turn on fuel tap at tank. Use the pumps hand lever to pump up fuel to fill the pump until fuel gushes out of its outlet port, quickly un bung the oulet pipe and connect it.  You should have only have allowed a tiny bit of air in by doing it like this and could save you a lengthy bleeding proceedure when you refit it and try to start the engine. Just a little bleed at the injector pump and injectors might be necessary.

[Flyboy]

3 hours ago, Markymark said:

lift pump, I think I've worked it out. turned off fuel tap run engine until fuel out and engine stop then soaked up fuel from pump outlet with tissue.

I can't think of a better way to damage the lift pump.

[pete.i]

And now there is a better than evens chance that you will have to bleed the engine. Not difficult BUT! There are some Youtube videos if you have to do this.

[Tony Brooks]

1 hour ago, Flyboy said:

I can't think of a better way to damage the lift pump.

Why, its a diaphragm pump with no fuel lubricated parts.

I could understand if you said injector pump but even then I think there would still be sufficient residual fuel in the body to prevent damage.

 

Markymark. Please clarify what you are talking about, it makes little sense to me. I you apply thread lock to what I fear you may be talking about on the INJECTOR pump you are likely to ruin it. Photos, better description, or diagram please.

[Flyboy]

40 minutes ago, Tony Brooks said:

Why, its a diaphragm pump with no fuel lubricated parts.

I could understand if you said injector pump but even then I think there would still be sufficient residual fuel in the body to prevent damage.

 

 

Because with the fuel cock turned off it will be trying to pull a vacuum which will possibly damage the diaphram. Nothing to do with lubrication.

[RLWP]

8 minutes ago, Flyboy said:

Because with the fuel cock turned off it will be trying to pull a vacuum which will possibly damage the diaphram. Nothing to do with lubrication.

The diaphragm will just stay up in the chamber

[Flyboy]

39 minutes ago, RLWP said:

The diaphragm will just stay up in the chamber

And the pull rod will be trying to pull it down.

Edited January 13, 2018 by Flyboy

[Tony Brooks]

1 hour ago, Flyboy said:

Because with the fuel cock turned off it will be trying to pull a vacuum which will possibly damage the diaphram. Nothing to do with lubrication.

If you think so but remember it can never be subject to more than atmospheric pressure on its underside - about 15psi. I doubt it will ever get to that level because it is more than likely that air will be drawn through a less secure part of the system like a filter seal, taper fuel cock, fuel tap O ring etc.