Leak from fuel pump

27 posts / 0 new
Last post
TomB
Offline
Last seen: 24 min 23 sec ago
Joined: 17/04/2014
Leak from fuel pump
Im getting really fed up with my fuel leak now. Today Ive refitted the pump (K series injection), with a James Whiting rubber gasket, blue hylomar on all surfaces, Loctite 242 (medium strength) on the screws onto the tank, then left it in the sun for all the sealers & loctite to go off. Early evening I put a couple of litres of fuel in the tank and propped it up to tip the fuel around the pump to inspect for any leaks before it goes back in the car. Its still leaking - its is dribbling from the bottom most fastener (6o'clock position) and from the hole that is in pump plate for the original Rover gasket locating dowel. This is the position from where it leaked a fortnight ago causing me to remove the tank. What can be causing this? The face on the tank doesn't appear distorted - Ive used the short edge of a steel ruler along and across the face in this area and it looks flat. The blind rivnut doesn't appear to be loose - I tightened a screw into it until it stopped and the rivet wasn't turning. Im struggling for what to try now. Im wondering about trying a new gasket - JW and maybe the Rover one. The JW one is now heavily coated with Hylomar after two failed attempts to seal it. I could replace the bottom rivnut and help seal in with Epoxy. At least my cracked on the filler neck has been welded now. Edited for typos! Edited by - TomB on 27 May 2012 21:49:08
TomB
Offline
Last seen: 24 min 23 sec ago
Joined: 17/04/2014

Thread resurrection! 

Ive replaced my pump, and now I need to get it all sealed up again.  I've used a James Whiting gasket with hylomar as James recommended. However  fuel is pouring from the holes in the pump flange where the original gasket locating dowels are located again.

Last time this happened I ended up using silicone rather than hylomar and I made it fuel tight. The silicone oozed out of the dowel holes and I gobbed plenty on the dowel holes, and it's stayed fuel tight. However,  upon removing the pump recently I found all the silicone dissolved and in the bottom of the tank. As such I think I need to use something that is thicker and more of a sealant than hylomar, but doesn't dissolve in petrol like silicone  Loctite / Bondloc 574 appears in the archives, who. I've used previous for joints in the engine like the sump.  

I am also wondering if the threads on the rivnuts or bolts are worn. Does anyone know what size/ type of rivnuts are used for the fuel pump? 

7 wonders of th...
Offline
Last seen: 3 hours 44 min ago
Joined: 17/04/2014

rivnuts on the early tanks were hollow, later ones i believe had blind rivnuts fitted - you could get these retro fitted.

SM25T
SM25T's picture
Offline
Last seen: 4 hours 13 min ago
Joined: 17/04/2014
If it is coming through the rivnuts ... can you put Hylomar Blue on the bolt threads. Do I recall the flange is thin ... so important not to overtighten the bolts ? Or is that the sender flange maybe.
TomB
Offline
Last seen: 24 min 23 sec ago
Joined: 17/04/2014

I think I've got blind rivnuts, and the fuel is coming through the dowel holes. So the fuel must be coming through a tiny gap  between the pump flange and gasket, or the tank side and gasket, then out of the dowel holes.  When I put the hylomar on, I squirted it on the faces, then thinned it out with a scraper to make a thin film on each side of the gasket. Maybe I should take it off again and gob more on and not spread it as thin.   

 

 

SM25T
SM25T's picture
Offline
Last seen: 4 hours 13 min ago
Joined: 17/04/2014
Worth a try.
Lotus Boy
Offline
Last seen: 2 months 3 weeks ago
Joined: 17/04/2014

When I replaced my fuel pump gasket with a JW version, I put mine on dry.  No silicone or hylomar.

I was over-cautious when tightening not to distort the tank so when I put some petrol in, it started to leak through so I tightened up the screws a bit more and leaking stopped. 

I'm guessing this doesn't necessarily help you other than to say that just using the gasket alone should work...unless I have been really lucky!?

Cheers

David

 

TomB
Offline
Last seen: 24 min 23 sec ago
Joined: 17/04/2014

I stripped it all apart last night.  Ive cleaned out the rivnut threads with a new bolt modified with a Dremel to make a tap to clean all the old nutlock out.  Ive fitted some new dome headed caphead bolts to help spread the loads more and now the bolts feel more secure now as the threads are not covered with multiple applications of thread lock.  Finally, Ive put loads more hylomar on the tank prior to placing the gasket on, and on the gasket outside face prior to mouning the pump.  Given how that sealer has oozed out of the interfaces on the outside of the pump, I more hopeful that Ive got a good seal this time.  

Not tested it yet with fuel, so fingers crossed! 

TomB
Offline
Last seen: 24 min 23 sec ago
Joined: 17/04/2014

Seems ok so far, I've had 5 litres in the tank and it's been propped up for the last 6 hours with the pump fully submerged and no leaks for hints off leaks at all. Phew! I just hope the hylomar and gasket don't get eaten by bioethanol in fuels. Super unleaded for me now. 

SM25T
SM25T's picture
Offline
Last seen: 4 hours 13 min ago
Joined: 17/04/2014
So far so good.
TomB
Offline
Last seen: 24 min 23 sec ago
Joined: 17/04/2014

Well, I’ll resurrect my own thread! I’ve put fuel in today, nearing the end of my rebuild. The engines all works, so that good, but I’ve got a fuel leak from the same place! So it’s tank out again, but how to cure it? 

I guess I need to inspect the gasket and see if it’s been dissolved by bioethanol. Maybe a new tank or pump cradle.