TorontoTim Posted June 15, 2015 Report Share Posted June 15, 2015 Hello wise folk... I have finally got around to stripping my leaking fuel pump (replaced last year) to diagnose the problem. Well, I've found the problem... The lower half of the body of the pump is not flat around the flange where the diaphragm is clamped between top and bottom - I'd say that the six screws have pulled the flange out of shape so that it's "wavy" and is, therefore, far from fuel-tight. if the body is deformed like this, is it U/S or do you reckon it's saveable? It's an old original type with the hand pump etc., so I'm loath to toss it if it can be machined back to life... Thoughts? Thanks, Tim Quote Link to post Share on other sites
Ian Vincent Posted June 15, 2015 Report Share Posted June 15, 2015 Use a sheet of glass and valve grinding paste. It can't make it worse. Rgds Ian Quote Link to post Share on other sites
Lebro Posted June 15, 2015 Report Share Posted June 15, 2015 Or a large flat fine tooth file, working around the circle as you go. Bob. Quote Link to post Share on other sites
Don H. Posted June 15, 2015 Report Share Posted June 15, 2015 I've "refaced" pump castings several times over the years, Tim. None were so bad I'd have called them "wavy", but enough to knock down high spots near the screw holes. Seems to have worked just fine. Piece of cake. I wouldn't hesitate to do it on your housing. The way I've done it is with a reference flat surface and a grinding medium. As Ian suggests I too used a glass plate, but I used a wet 400 (or so) grit paper on the glass. Simple orbital movement of the mating faces took them nice and smooth. Quote Link to post Share on other sites
TorontoTim Posted June 16, 2015 Author Report Share Posted June 16, 2015 Thanks guys - think mine's a bit worse than a gentle grind will fix, but I'll check clearance with feeler gauges tomorrow and report back (I'm watching the Canadian women's soccer/football team right now...). If it's a lot, I'll post a photo. I'm thinking that I can use gentle persuasion with a body hammer, but I'm wondering if it will just bend again as soon as it's reassembled. Anyway, more tomorrow. Thanks again. Quote Link to post Share on other sites
Lebro Posted June 16, 2015 Report Share Posted June 16, 2015 If it is as bad as you suggest, better have it skimmed on a lathe. Hammering may well crack the alloy. Bob. Quote Link to post Share on other sites
Dave Larnder Posted June 20, 2015 Report Share Posted June 20, 2015 Tim If you have no luck, you could always contact David Davis in U.K. he is the A.C. mech. pump prof and has a lot of spares. He rebuilt one for me after my Chinese one disintegrated while in France for the same price you pay for one at the likes of Moss etc.which will still only be a repro not genuine, unlike the one he supplied me with, the real macoy. Dave Quote Link to post Share on other sites
AlanT Posted June 20, 2015 Report Share Posted June 20, 2015 First thing is DO NOT do any hammering, this stuff will crack. The difficulty in machining this kind of thing is finding a way to hold it. This is why the flat-plate lapping method is much preferred. You would probably mount this on an angle-block using the face that mates to the engine. Be easy if the wavy-face is perpendicuar to the engine-face. May be better on a milling-maching where you can adjust for tilt. Quote Link to post Share on other sites
TorontoTim Posted June 20, 2015 Author Report Share Posted June 20, 2015 (edited) Thanks guys - sorry for my delay in getting back. There's no question that it's pretty wavy - certainly visible to the naked eye (I still haven't done a feeler-gauge thing, but you probably get the idea from my description). The good news is that I have a perfectly good one on the car right now so this is far from urgent. The bad news is that this damaged one is a nice original AC. I think it's time to send this off to an expert so, Dave, thanks for the heads-up on David Davies - any contact info for him? Edited June 20, 2015 by TorontoTim Quote Link to post Share on other sites
Alec Pringle Posted June 20, 2015 Report Share Posted June 20, 2015 Tim, see PM Cheers Alec Quote Link to post Share on other sites
RogerH Posted June 20, 2015 Report Share Posted June 20, 2015 Hi Tim, if the wavy surface is a bit too much for the grinding paste then the same sheet of glass with some 800/1200 grit W&D. Roger Quote Link to post Share on other sites
TorontoTim Posted June 20, 2015 Author Report Share Posted June 20, 2015 Cheers, Alec - I'll give him a call. Thanks, Roger. I fear it may be too much for that too but worth noting. I really WILL measure it and report back ;-) Quote Link to post Share on other sites
Dave Larnder Posted June 22, 2015 Report Share Posted June 22, 2015 Tim Maybe Alec has already given you his address etc, I have his phone number if you still need it, but no e mail address. Dave Quote Link to post Share on other sites
TorontoTim Posted June 22, 2015 Author Report Share Posted June 22, 2015 ok, measured. with a straight-edge across two adjacent screw holes, there is room for a .009" feeler gauge between the flange and the straight-edge. I'll give Dave a call to see what he thinks. Quote Link to post Share on other sites
AlanT Posted June 22, 2015 Report Share Posted June 22, 2015 This will lap out quite quickly. Quote Link to post Share on other sites
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