MHT Posted May 24, 2022 Report Share Posted May 24, 2022 Hi, I have a Spitfire Mk3 with I think a leaking fuel pump. I'm no mechanic so following my Haynes manual I wanted to open the fuel pump and perhaps change any washers etc. that could be the cause. I start to unscrew the top but every time I do fuel starts to flow out of the top. The manual doesn't say anything about this so what am I doing wrong? Would this be just the fuel coming back down the pipe that leads to the carburettors and so would soon stop flowing or should I be doing something else? Link to comment Share on other sites More sharing options...
johny Posted May 24, 2022 Report Share Posted May 24, 2022 It shouldnt come back from the carb side as theres a non return valve in the pump to stop that so the flow you have is probably coming from the fuel tank under syphonic action. Isnt there a rubber pipe connection on the tank line just before the pump inlet which you can disconnect and quickly plug or even clamp? Link to comment Share on other sites More sharing options...
MHT Posted May 24, 2022 Author Report Share Posted May 24, 2022 Thanks johny. Yes, there is a rubber pipe, and I did wonder if clamping it might be what's needed, but the pipe looks quite old and it is quite stiff, and I was worried that clamping it could damage it. But maybe that's what I need to try. Link to comment Share on other sites More sharing options...
Mjit Posted May 24, 2022 Report Share Posted May 24, 2022 If the pipe's seen better days your first step is probably to hit the club shop and order some new E10 safe tube and replace it. With or without that you do tend to get a syphon as the pick-up end of the pipe is submerged, the pipe full, and the outlet end lower than the pick-up. I'm not personally a fan of clamping off any hoses and instead go with the slight of hand of; pulling the pipe off, shoving a bolt in the end of the pipe, ifnecessary tightening the fule hose clip on the bolt. I think it's a 1/4" bolt you need for the fuel pipe. Having an inline fuel filter in that piece of pipe helps too - in this case as it will generally have an air bubble in it that helps stop the syphon but generally to stop some of the drud making it over to the carbs. 1 Link to comment Share on other sites More sharing options...
MHT Posted May 24, 2022 Author Report Share Posted May 24, 2022 Thanks Mjit. Might be wise to replace the tube. I'll have to refer to my manual again for that! Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 24, 2022 Report Share Posted May 24, 2022 clamping will destroy the integrity of the hose , cant see it the way to treat any hose use a bolt or shank of the drill to plug the hose is far better anything smooth remember any messing with hose you can make the dreaded rubber slivers from inserting the metal pipes , they can really mess you up , crafty little sods decent hose helps a lot , do not buy fake junk of the market place +1 for club shop Pete Link to comment Share on other sites More sharing options...
johny Posted May 24, 2022 Report Share Posted May 24, 2022 Reckon if it cant take a light clamping its not safe to use on the car😁 Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 24, 2022 Report Share Posted May 24, 2022 well there's clamping and .....clamping what it does to the reinforced structure you cant see like i would not want anyone clamping my brake hoses either its not the best wayto do this . plug it or cap it but crush it has no appeal Pete Link to comment Share on other sites More sharing options...
johny Posted May 24, 2022 Report Share Posted May 24, 2022 Hmmm the Triumph WSM says theres no problem using a hose clamp on brake hoses so I cant believe its too bad for fuel pipe either.... Link to comment Share on other sites More sharing options...
Wagger Posted May 24, 2022 Report Share Posted May 24, 2022 Not sure how easy this is on a Spitfire, but on a Herald or Vitesse it is really easy to remove the hose from the top of the tank. You then only have to catch what is in the pipe from the rear when you unscrew the pump. I have a glass bowl pump, easy to check the non return valves on that. If this is impossible, block the tube with bolt or even a tapered punch and jubilee clip. I never ever clamp hoses. I have seen brakes lock on, clutches permanently disengaged, and cracks in fuel lines where this has been done. Hoses are meant to be round tubes, not squashed. Only in an emergency have I ever squashed a tube flat by folding it. This even works on copper mains pipe if a joint bursts. Sorry, but squashing tubes is a 'Bodge' and that it pretty dire coming from somebody who is famous for such measures. Link to comment Share on other sites More sharing options...
johny Posted May 24, 2022 Report Share Posted May 24, 2022 I really think any pipe that cant take a clamp isnt fit for purpose and shouldnt be in use which, as I say, is what Triumph indicate in their manual. However it is of course only one of various options👍 Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 24, 2022 Report Share Posted May 24, 2022 you wouldnt clamp a braided hose and ideas from 50 years ago dont always work out well with years on warranty dealing with AP /Girling of the day any hose with clamp marks they just rejected any other part of a warranty claim pete Link to comment Share on other sites More sharing options...
Wagger Posted May 24, 2022 Report Share Posted May 24, 2022 Clamping a soft fuel pipe is one thing. Doing it to a braided brake pipe is a no no!. Would you sllde the protective spring up a flexible pipe and clamp it? I would not! It is sometimes easier to use an alternative method, so why bother? Link to comment Share on other sites More sharing options...
johny Posted May 24, 2022 Report Share Posted May 24, 2022 Ha, the Triumph manual doesnt mention braided hoses in its instruction and obviously theyre a different case because of the risk of damaging the metal sheath. However with conventional types clamping as, for example, a means of identifying where a brake problem lies, is very useful and I cant think of any other way to do it.... Link to comment Share on other sites More sharing options...
Wagger Posted May 24, 2022 Report Share Posted May 24, 2022 OK, leaks are not obvious unless they are extreme. I take drums off and use a strong G clamp to hold the slave pistons in. Pump pedals and observe. Calipers I observe with wheels off with the pedal jammed down with a post between it and the driver's seat. Air is more difficult. However, if you wedge the pedal down overnight and bleed all in the morning most of it will be dissolved and purged. If you describe what problems you have encountered, maybe we can assist. My experience of clamping with my lifelong mechanic pal has been rubber pipes allowing fluid to pass under pedal pressure but then not releasing this pressure when the pedal retracts. Callpers stuck on, and clutches disengaged because the pipes have acted as valves. This happened even using clamps with gentle radii. On my Vitesse, I bleed the rears with high axle stands at the rear. Fronts I do with pipe and funnel connected to the caliper bleed screws. Funnel supported above the master reservoir. Wait for all bubbles to dissipate after pumping. Solo bleed usually works on the front brakes. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted May 25, 2022 Report Share Posted May 25, 2022 I don't clamp, either brakes or fuel, but a golf tee works for plugging the fuel pipe (won't work on brakes due to the metal ends!) Re the initial problem - MHT, do you know where the fuel is leaking from, ie body of the pump or pipe connections? Link to comment Share on other sites More sharing options...
Wagger Posted May 25, 2022 Report Share Posted May 25, 2022 Thanks Colin for bringing us back on topic. Is the pump a glass bowl or the later entirely metal one? The glass ones are rare now but easy to fix. Can be retro fitted too as I have one on a 2500TC engine. I have used golf tees, but don't leave in for weeks as some may dissolve in the fuel or fuse to the rubber. Like the 'O' rings in my plastic drawers all stuck to the bottom! Old Fairy Liquid caps used to fit over some brake pipe ends. They dissolve in brake fluid after a few days too. Link to comment Share on other sites More sharing options...
MHT Posted May 25, 2022 Author Report Share Posted May 25, 2022 Thanks for all the comments everyone, I didn't realise it would spark such a lot of comments about clamping! But from has been said I think I will avoid clamping. The pump is a metal one. I'm pretty sure the leak is from the pump rather than the pipe connections. It leaks even when the engine isn't running. I've just taken a photo of it and tried to indicate where it gets wet with fuel, it's all around the base. Hopefully the photo will be attached. Link to comment Share on other sites More sharing options...
johny Posted May 25, 2022 Report Share Posted May 25, 2022 There should be a gasket under that top cover and the most likely is that it has harden up/shrunk over time so fuel leaks down to the area youve arrowed. Once you have stopped fuel coming through from the tank by your chosen method👍you should be able to remove the cover with minimal spillage to check said gasket and clean the gauze screen... Link to comment Share on other sites More sharing options...
Wagger Posted May 25, 2022 Report Share Posted May 25, 2022 Are any of the gaskets cork? One on the glass bowl type is and shrinks when dry. Sometimes it will not recover. The replacement in my kit was rubber, but it works. Link to comment Share on other sites More sharing options...
MHT Posted May 25, 2022 Author Report Share Posted May 25, 2022 I don't know what the gaskets are made of, no doubt I'll find out when I get chance to try and remove the cover. I assume I can just buy the appropriate gaskets & washers separately? Link to comment Share on other sites More sharing options...
johny Posted May 25, 2022 Report Share Posted May 25, 2022 Mine was rubber but hard and shrunk. It comes in the kit but as theyre normally not far short of the cost of a new pump I'll be cutting my own from neoprene sheet... Link to comment Share on other sites More sharing options...
Wagger Posted May 25, 2022 Report Share Posted May 25, 2022 There is an exploded diagram on Canley's site. Just failed to copy it, but may be work a look. Link to comment Share on other sites More sharing options...
NonMember Posted May 25, 2022 Report Share Posted May 25, 2022 Take care removing (and refitting) that top cover. The setscrew goes directly into the alloy body and it's quite easy to strip the thread. Link to comment Share on other sites More sharing options...
68vitesse Posted May 25, 2022 Report Share Posted May 25, 2022 1 hour ago, johny said: Mine was rubber but hard and shrunk. It comes in the kit but as theyre normally not far short of the cost of a new pump I'll be cutting my own from neoprene sheet... Been a lot of comments on this forum about new pumps generating to much pressure. I rebuilt the pump for my Vitesse with a kit and so far so good. Regards Paul. Link to comment Share on other sites More sharing options...
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