Its brassing me off!

[TheOriginalMrP]

Putting my tank back together after cleaning. Can't get the sender cap to screw down for love nor money... It's like the tank has shrunk over the winter and isn't deep enough to take the sender... Any suggestions before I set fire to it? ;-)

[stunned_monkey]

Make sure the filler hose is fully seated as it can push down on the top of the tank enough to prevent the tank sender from dropping all the way in.

I've been where you are now scratching my head and wondering what the hell was going on. This was the cause.

[TheOriginalMrP]

It's not as clear cut as that and I'm done with moving the unnecessary! The problem is the cap. I can jam things in the tank so the sender sits nice but the cap won't screw on straight with the sender in place. Threads seem ok but when I get it to start, there's always a gap on one size as if it's cross threaded. It's seriously doing my nutnow lol. The baffle etc was a live of cake but I think this is going to be an issue. My tank always leaked when brimmed so it could well have been cross threaded before.

Darn thing!

[stunned_monkey]

Trust me, if you took the tank out, it'd fit fine. If it's a DMCH sender, you may find it's a function of the little tab not lining up with the notch, an the way the thing looks straight when it isn't.

Also you an take the pump out and use the hole to lift the top of the tank up a bit.

[TheOriginalMrP]

Pump already out, not taking the tank out. Is it more likely to go straight in if it's full of fuel? Surely the weight would push down to a degree.

I'm going around in circles as every time I think it's started, it ends up with a gap one side, and like you said not straight in the tank.

It came out easy enough!

[stunned_monkey]

WHat happens when you take the sender out - can you install the ring then?

[TheOriginalMrP]

Yes. Ring fits flush without sender, with just the seal and with just the sender and no seal. But when sender and seal are in the equation, it won't dog down flush at all. It clamps down one side and leaves a gap the other side.

The thickness of the seal/lack of thread on the cap seems the problem.

It's tightened down now but it's not right. Tempted to fiill the tank to the brim and see if that helps. If not I might try the seal in boiling water to soften it.

There is a notch cut out Martin and it fits snug enough until you start screwing the cap down. Then it twists it out of the notch and that's probably what's causing it to lose its snugness and cross thread. I've got an inkling this is how it came apart hence the fuel smell and leak when tanked up.

Obviously caused spratty a headache so he did what I've done possibly, and just lived with it....

[TheOriginalMrP]

I have also read that the early DMCH senders are longer than the later ones, I have a feeling it's an early one. There are two domed screws on the bottom... Could these be replaced for countersunk ones?

Another tip from archives on the net suggest removing the tank plate to allow more flex in the bottom of the tank. This is an option if it's true.

I also noticed you can buy a standard sealing ring which may be flatter but there is nothing wrong with the sender seal itself. Could I use an older generation seal if it's flatter even though it has no lip that snugs into the later senders?

Either way it's totally piddled me off today. It took 30 mins to clean the tank and assemble everything in the tank nice which is all new, and 4 hours trying every method to get the sender unit part right - a part there was no issue with. Never again! My right hand still has cramp and had remained numb from leaning in the compartment anxious to sort it... As is said it's back together but a new approach is needed. I'm sure she will run fine now though!

MrP
Ps Cheers Martin for the quick replies... Could have done with you here today really!

[Chris Williams]

Hope you get it sorted, begining to regret ordering a new sender unit to replace mine now! if it's this much hassle.
Chris

[TheOriginalMrP]

The whole shape of a plastic fuel tank changes as does a plastic can when they are full.

I have a hunch if you ain't draining your tank and it's about half full, your sender should drop in without issue. And if you have the later sender coming then it's shorter anyway...

I kind of wish I'd have gone for the all in one pump and sender now as you just blank the existing sender hole up with a piece of stainless and a seal.

Yet it's not all rosy as most of the people who have fitted these units have problems refitting the access panel due to the extra height of the assembly.

Why isn't nothing straight forward?

Reminds me of the frustration as a kid having 10 airfix models for Christmas, and no polystyrene cement in the box plus no model shops open till new year!

[stunned_monkey]

I definitely had this issue on my car and I had one of the very first of the new senders from DMCH. If it screws down fine without the seal, then the problem isn't the sender butting up against the bottom of the tank.

Now you mention it, I do vagulely recall having to hang onto the cable to stop the thing spinning when you do the ring up.

I'm not a million miles from you in Chippenham BTW. Taking a trip across the bridge at the weekend too...

[TheOriginalMrP]

Well if it's not too far out of your way I would certainly appreciate it!

I'm sure if I'd have had someone there with me yesterday to assist I would have cracked it, I just couldn't hold enough stuff at once!

The notch in the tank is pointless really with these type of senders. It just causes a problem.. Maybe if I grind the notch off it will seat better and it don't matther if it spins then!

I also see so reason why it won't seal as is because the seal is pushed onto the tank flange hard enough cross threaded or not.

Let me know roughly what day and what time on the weekend and I can try and mentally prepare!

Even with the job of having my heater box out, nothing consumed so much time for something so trivial!

Ben

[stunned_monkey]

I'm more and more convinced it's got something to do with the way the cable coming from the sender forces the ring to sit at an angle when you try and do the bleeder up. I remember this battle, just not exactly how I solved it!

We're looking at a Smart in Wales so could be Sat or Sun. assuming it doesn't go on ebay before then!

[TheOriginalMrP]

Ok buddy I will send you a pm nearer the time. Failing that, my numbers on my signature.

The wire itself has an oblong block on top which I tried holding with a mole grips.

The sender does hit the bottom of the tank without the seal in place yet it will screw up not cross threaded.

Like I said I jammed a ring spanner in the tank sideways by the filler to flare it out a bit... No avail!

[TheOriginalMrP]

Hopefully now I can draw a close to this.

I can confirm that Martin was right in as much as the existing tank sender seal was too fat, thus preventing the cap to screw on properly. Even removing the screws from the bottom made no difference. In fact, I think the cap may have been cross threaded when I removed it.

Anyhow I got some 1.5mm cork sheet and cut around the old seal. When refitting the cap, unlike before it wasn't turning the whole unit unlocating from the lug continuously.

Now the cap is snug tight with no cross thread. I'm convinced it won't leak liquid or fumes now.

Just fresh petrol now to see if the whole job has been a success.

It wouldn't usually have taken 6 months to do a job of this integrity. If all the bits were to hand it's probably a few hours work.

Cheers Martin, and for everyone else's input.

I will update my other post in this section if the sputtering is rectified!

Ben