Leaking fuel pump repair BMC 1.5

[Monkey 1]

My Fuel pump had been leaking for a while now, steadily getting worse, so I decided to have a go at fixing it. A quick look through the forums & it seems my problem is quite a common, but I couldn't find any information on repairing it so I thought it might be helpful if I post how I did it for the cost of around a fiver & an hours work

 

The fuel appeared to be leaking from the top of the pump through the gasket below the part the throttle & the engine stop are fitted to. Bellow is a picture of it removed... I will refer to it as the unit.

 

 

To remove this you need to remove the throttle cable & the stop cable, I just removed the split pins holding them. To undo the two retaining bolts Ideally you need a splined socket but I used a 6mm ring spanner. Its fiddly but manageable.

Once undone the unit can be lifted off & removed. Be careful as there is a piston that fits into the pump inside. as shown below...

 

 

It turned out the Gasket wasn't the problem, diesel was leaking from the engine stop levers shaft. The stop leavers shaft can be carefully pulled out of the unit, you may need to push the piston in a little to free it.

Make sure you note which way round it sits as it needs to go back in the same way. Once out you will see the black rubber O ring on the shaft as seen in the picture below... (pic shows the shaft with the stop leaver removed)

 

 

Now I can't tell you the exact size of this O ring sorry! I just matched one up from a box full I have. It is a simple job to just flick the old ring off & pop a new one over the end then just push the shaft back into the hole it came from, making sure it is in the same way it came out.

 

Because the unit had been removed ideally it needed a new gasket. I figured it might be a bit tricky to find an original so I used silicone instant gasket & it has sealed fine.

All that is left to do is put it back together. This is as simple as removal but is a bit fiddly getting the piston back down into the pump without disturbing the silicone sealant.

You may need to bleed the pump before starting the engine. This is done by undoing the screw on the side of the pump, shown below... (Pic shows pump with unit removed for clarity. The bleed screw is the 8mm bolt just above where the unit sits & below the red wire)

 

 

Once the bleed screw is undone a few turns, wind the engine over until you get a good squirt of diesel out of the bleed screw, then tighten it back up.

Thats it! Hopefully you should now have a leak free pump.

[Speedwell]

Brilliant post. I think this is just what Jimfin needs

Arthur

[jimfin]

Just what I needed. Thanks to Speedwell for telling me about this. Also thanks to Monkey 1 for the posting. Most of the mud has cleared and I can now see where I am going.

[Monkey 1]

Glad it's been useful

[Chris Pink]

My Fuel pump had been leaking for a while now, steadily getting worse, so I decided to have a go at fixing it. A quick look through the forums & it seems my problem is quite a common, but I couldn't find any information on repairing it so I thought it might be helpful if I post how I did it for the cost of around a fiver & an hours work

 

 

Good post, great pictures....

 

but... (could you hear it coming?)

 

 

1/4" and 5/16" purlease....

[Monkey 1]

My tool kit doesn't go back that far. I have on occasion rummaged through the rusty old spanners I inherited with the boat, but only as a last resort. I like my spanners shiny.

Edited November 21, 2012 by Monkey 1

[alan_fincher]

Great post, it is really very helpful & knowledgeable. Thanks for sharing this.

You are a spammer, aren't you "greentechtown"?

 

User reported.

[Tony Brooks]

I have no wish to criticise the OP but would like to make three points.

 

1. I "piston" is in fact the hydraulic governor that is finely balanced between fuel pressure and spring pressure. Evan a glob of water here can stop it working so extreme cleanliness is essential, as is making sure any rags/paper used for the purpose do not shed fibres.

 

2. I think that you will find that the securing bolts stop the control spools being pulled out so unlike the photo may have to be removed - not 100% sure on this.

 

3. This is related to 1 above. Be exceptionally careful if you are to use any form of gasket sealer in case it gets squeezed into the governor mechanism.

 

One more thing. If you are going to this trouble rather than use any O ring it may be prudent to try to make sure it is not subject to attack from hydrocarbons and more importantly Bio-diesel. The older DPA pumps are one of the models that are likely to suffer gradual attack by any bio content of the fuel.

 

Finally a tip I picked up from someone else on here. Make sure the cables are adjusted so when the levers hit their tops no more strain is put on the lever because this can also cause such leaks.

 

Well done, and I have done that job with a hammer, screwdriver and pair of water pump pliers but that was to remove water from the housing so I could drive the boat back to easy access.

[Monkey 1]

Good points Tony. Yes, it does help to remove the securing bolts completely as it is tight access with all the fuel lines in position, & as you say, you can't withdraw the shaft with them in place.

 

I just gave everything a wipe round with kitchen roll! I was careful not to disturb the piston. But as you say, it is wise to keep everything as clean as possible, especially where fuel pumps are concerned.

 

That is a very good point re the sealant. I used a new tube with a very small hole made in the nozzle, keeping the sealant to the very edge of the fitting so as not to cause a blockage.

I wonder if the original gasket can be bought? I remember making my own back in college all those years ago!

[Tony Brooks]

Good points Tony. Yes, it does help to remove the securing bolts completely as it is tight access with all the fuel lines in position, & as you say, you can't withdraw the shaft with them in place.

 

I just gave everything a wipe round with kitchen roll! I was careful not to disturb the piston. But as you say, it is wise to keep everything as clean as possible, especially where fuel pumps are concerned.

 

That is a very good point re the sealant. I used a new tube with a very small hole made in the nozzle, keeping the sealant to the very edge of the fitting so as not to cause a blockage.

I wonder if the original gasket can be bought? I remember making my own back in college all those years ago!

 

 

I would expect any half decent Fuel Injection Specialists to be able to supply the gaskets because those pumps are used on far more than BMCs. For a start the Perkins 4-10x series and some six cylinder engines as well. I think that sort of part will be common across the range.

[jake_crew]

Quote "I just matched one up from a box full I have".

 

What material was the O ring made of ? There are dozens of types of rubber and hundreds different grades.

 

Some will be OK in a given fluid, others will go rock hard and some will dissolve into goo.

 

The change from mineral to bio containing fuels has caused even more compatibility problems, with older rubbers that worked OK, now failing.

 

I hope your repair works well but do beware, just 'cos the new one's black doesn't mean its the same as the old one.

[Monkey 1]

I'm not too concerned about the O ring. It's an easy job to change it & I have a dozen more in the box.

[olegmenshov]

Hi monkey1. Could you please to repost pics)))? I read carefully your smart post but you pics was deleted on this post. Is it possible to repost them )))? 

[pete.i]

this thread is donkey's years old and I don't think the OP posts here any more. I have reproduced the pictures on your original thread.