Sender unit sealing

[pageste]

I was hoping to take the Herald to Santa Pod this weekend so decided to take her for a good shake down run to sort out any issues. I have to say she went pretty well so after a 30 mile run I made it back home, in fact al the way to my house bar 30 feet when she cut out and refused to restart. Another benefit of the Herald is I can push it on my own so managed to get her back on the drive where I quickly deduced it was a lack of fuel. Strange as I should have had plenty but having had the same issue before I double checked the sender unit on the tank and sure enough it seems I had lost a large part of it out the sender unit. I have recently replaced the seal ( twice) and put a new locking ring on but still I have a serious leak. I tried some hylomar on the seal this time and again Ive got a leak. Is there a secret to getting these sealing rings on, I'm turning it as far as I possibly can before it pops back out again ?  I'm thinking there may be something wrong with the lip on the actual tank ? Any suggestions before I fork out for a new tank ( I might go for the screw type sender ) On the attached photo you can see why I didn't know my fuel situation the Earth tag has come off the sender.

 

 

[Guest]

I have the same sender unit set-up on my Alpine and on turning the sealing ring clockwise it locks down and cannot be moved any further, this ensures a tight air / liquid seal.

 

So I think your problem, as suggested, is that the tank flange is not flat / incorrect / damaged and this of course prevents a liquid tight seal. I imagine you are able to smell fuel all the time in the boot area ?? 

 

You will certainly need to clean up all the gunge around the sender aperture in order to determine the state of the flange the sealing ring locks down on to.

 

I take it your sealing ring also has a separate rubber seal which needs to be in place, I doubt it will be a metal to metal fitment.

 

Once you have done the above it will be a case of ensuring the tank sender unit flange seat is flat / level otherwise the sealing ring is not going to seat properly.

 

Any additional photos may assist.

 

Hope that makes sense and helps ??

 

Regards.

 

Richard.

[Guest]

You should have something as shown with the 2x attached photos

[Darren Groves]

I agree with Richard, turning the lock ring it's normally pretty solid and can't be turned through the locked position as you can, doesn't sound right. Do you definitely have the rubber seal fitted?

 

I wouldn't have thought hylomar is fuel proof (though I might be wrong), Wellseal is and would work better.

 

Darren

[pageste]

Thanks for the replies all, I bought the seals and ring from Paddocks but Ive also tried another ring I had. If you tighten the ring it gets tighter and tighter then just rides out of the flange. Ive cleaned up the mating face and tried it with just the rubber ring and I tried it with Hylomar ( it is petrol safe). I also tried another sender I had and the ring still comes out. Looks like there is something amiss with the tank flange. Worryingly I cant smell the petrol either but there isn't a section on the forum for Schnozzle trouble.

[dougbgt6]

Actually there was a thread on here acouple of days ago about a horn manufacturer called Clearhooter. You must have missed it!

 

Sounds like the flange has got bent upwards, probably not a good idea to try and bend it back, you wont get it uniform. A thicker rubber ring? Or pack the metal ring against the flange?

[Pete Lewis]

Looking at your pictue the tank ring is badly formed there should be three well defined lugs that let the dimples in the loose ring fit so when you fit and rotate then ring the bayonet idea rides down the ramp and clamps the sender in place up against its seal its popping out indicates the lugs are not kept in place , the ring looks smaller than the tank rim .....all a bit past its best

On the line there would be a three pronged claw to twist the ring equally, all we can do is tap it tomthe end of the ramps, but then it pops out !! The tank looks to be your problem

so the tank rim needs some rework, no sparks though

[pageste]

No Pete don't give me the most expensive answer !!!!    I think you may be right, this has "sweated" a bit for some time but is now too worn to work affectively. So you don't suggest welding the sender in situ then ? I could kick myself for not looking at this sooner as it looks like Im attending Santa Pod in a Citroen................................oh the ignominy of it all.  As an aside how does a non moving item like this get worn ? Its like my wallet wearing out - should be impossible.

[Guest]

It's possible that the seating rim on the tank was not 100% during production and over a period of time has deteriorated or a PO may have damaged it whilst carrying out some work; it does not take much for that to occur.

 

You are correct to think that non-moving parts should not wear - hence my 2x opinions above.

 

Do you run with the small Herald tank or the Vitesse size unit ??

 

May be worth seeking out a decent 2nd hand replacement before going down the ££££ route.

 

Good luck.

 

Richard.

[Guest]

"Spitfiregraveyard" has what appears to be a decent Vitesse size tank. including the sender unit and securing ring etc.

 

http://www.ebay.co.uk/itm/TRIUMPH-HERALD-VITESSE-PETROL-FUEL-TANK-SENDER-UNIT-SALOON-COUPE-CONVERTIBLE-/182618099864?hash=item2a84e31098:g:QjAAAOSwDrNZPtj0

 

His stuff is spot-on, so you can buy with confidence in my experience and also comes with free p&p.

 

A possible solution and he may be going to TriumFest - worth an enquiry direct I would say. 

 

Regards.

 

Richard.

[JohnD]

I've just used some Flange Sealant, LocTite 5922, to seal the access hatch on my custom wheel well fuel tank, after adding tank foam.   It's a silicone based mastic, said to be suitable for all automotive fluids, and ". It may also be used for repair of damaged pre-cut gaskets"   (Loctite TDS: http://tds.henkel.com/tds5/Studio/ShowPDF/MR%205922-EN?pid=MR%205922&format=MTR&subformat=REAC&language=EN&plant=WERCS )

 

Previously, I had used Red Hematite, but I only had a stub of the tube left, and none at the shop.

 

John

[Pete Lewis]

on the SGY tank you can see  the three well defined  lugs.  yours seems lost/ hidden /disappeared/Over used   

 

can you re form them with moles, club hammer,  boy scout scouts penknife ,  or  whatever  ???

 

it should bend a bit to improve what you have 

 

and the aftermarket rubber rings are not fit fr purpose  the grow in petrol, so whilst they look like a ring they dont have the specifications on the drawings same problems as TRE boots cylinder rubbers antirolls , pedal rubbers  etc 

 

so what do modern car builders use  they get it right,  down to volume and being cheap or better profit

would  classic  jag and aston owners have these  crap rubber parts   anyone know ???

 

just off to solve Gully's professional rebuilt gearbox OD pumping oil on the road gearbox .

its been back twice ...exspurts  again     ex..... the unknowing and...........   spurt   a drip under pressure 

 

well the suns out and good for Triumfest     sorry cant be there   have a good day 

[dougbgt6]

John, I think this is radio spares, same logo.

 

http://uk.rs-online.com/web/p/pipe-thread-sealants/0691814/

 

However, Hylomar Universal blue sealant is widely available and highly regarded. I've used it, it's like Red Hermatite, only blue.

 

http://hylomarsealant.com/

 

So, blue is the new red.

[JohnD]

I don't think Red is completely inactive in the face of fuel.   In a wide joint it's OK, and it's "non-hardening" , but it seems to get very soft and squidgy where it meets the fuel.

 

A rubber ring should be made of Viton rubber to resist fuel, especially modern, no-lead, some alcohol fuel.

It's available in small sheets on eBay, so you can cut out your own.

 

John

[dougbgt6]

John, that would be my choice also, a thicker gasket, rather than start wielding the "Big Persuader". Certainly worth trying before take steps that can't be reversed. 

[pageste]

Thanks for the support guys, I have all but emptied the tank so may try and improve the situation with the lugs using non metallic tools methinks. If something has a seal I prefer not to use any sealants but as Pete says some replacements are pretty poor. Unfortunately stuck at work today and tomorrow so probably a limit to what Im going to get done. As Im taking the kids with me Sunday if there is any issue with it she will have to stay home. I remember seeing a bloke cutting a fuel tank out of an MG once with ox/acetylene, to be fair the ambulance was there very quickly.  Once again thanks for the suggestions

[Colin Lindsay]

I remember seeing a bloke cutting a fuel tank out of an MG once with ox/acetylene, to be fair the ambulance was there very quickly. 

 

I saw one in Kesh Co. Fermanagh in the early 1990s, the guy met the ambulance half way, flying at speed in the opposite direction. He had a rally car rolled on its' side and was trying to weld an uprated fuel pipe to the tank in situ. Such a bang! An immensely dangerous thing to do without proper preparation. 

[JohnD]

Fuel tank + Welding = Immediate Darwin Award candidate.

 

This guy failed the interview: http://darwinawards.com/stupid/stupid2004-07.html

 

John

[pageste]

I used to tow my cousin to various short circuit racing events around the country, at scrutineering at one track it was pointed out the fire extinguisher was not easily accessible to the driver. I quickly moved it using two self tappers. Post race I thought my cousin looked a little unhappy as he removed his helmet and he lost no time in pointing out that I had screwed the extinguisher into the fuel tank and that he had done half the race with his feet sploshing around in fuel. Meanwhile I have had a better look at the Herald tank and it seems it needs changing out. I found a rimmer brothers set of seals and ring in my stores and I even tried an old stanpart original ring. It seems the actual flange is too worn to retain the ring properly and you cant tighten it sufficiently. As the forecast is 30' + this weekend Im not going to risk leaving a fuel trail everywhere. Who knows I may spot something in the autojumble and be bought it as a Fathers day pressie instead of the usual socks. Once again thanks for your help everyone

[pageste]

Me again Im afraid, I decided to push the boat out and replace the tank and sender unit with new. However nothing is ever straight forward with classics is it. The sender unit supplied is apparently the standard replacement now (reputable supplier) and apart from having three contacts instead of my two it has an open plastic body unit. My issue is that when inserted into the tank (it will only go in one way because of the two retaining lugs) the MAXIMUM travel of the arm is to about half way up  the tank. My first thought was it had been assembled wrongly but I spoke to the supplier who says I need to bend the arm ? Does that sound right? Ive seen a few earlier posts that actually said if you need to bend the arm you've got the wrong unit. Anybody got experience with these "new" units ? The attached pictures show the unit as it would go into the tank.  On a brighter note the tank looks great just deciding whether to leave it in Lady Ga Ga pink or spray it black.

[Pete Lewis]

this is pic care of james paddocks

presume the note on bending is from rimmers, ?

why not use your old one ???

 

with 3 terminals is one  for low level lamp warning or do you need to earth it to complete the resistance circuit

the earth on the pate is for when the tank is insulated so you may need both these connected ???

 

 

[pageste]

Pete , My old one is disintegrating it has lost its earth tag and makes nasty noises when you operate it. Its difficult to tell from the paddocks photo but in my pic that is the end of the travel so if you look the plastic bottle is still level/lower than the sender unit so would only be about half tank full ? I read on another forum that the additional wire is indeed for a low level light, possibly this is used on TR7 or something ?

[Guest]

Hello.

 

Unless I have missed it, you have not said what type of Herald you have during this thread - so I will assume you have a 1200 variant.

 

Looking at your photos and comparing them to the attached Canley tech drawing I think your sender unit is incorrect; in so much the arm is angled differently.

 

I agree the new unit has an angle at the electric end but NOT at the float end, which the Canley sketch shows.

 

IMHO the angle has to be in the correct place to allow the float optimum travel which in turn gives the correct fuel gauge reading.

 

Who did you get the sender arm from ??

 

Regards.

 

Richard.

[Gully]

There does seem to be a bit of a 'one size fits all' approach to sender units. My GT6 one is perfectly accurate over 3/4 of the gauge (full to 1/4 full), but then stops at 1/4. The tank is 1/4 full at this point, but the float is at the bottom of its travel and so is supended in space for the next 40-50 miles until I know (from experience!) I need to fill up. One of these days I'll work out what resistor I need to add into the circuit to make it accurate over the lower 3/4 of the gauge, which would be much more useful!

 

As for sealing the sender gasket, I add a smear of Vaseline which seem to work. However, being positioned on the top of the tank on the GT6 it only really encounters splashing when the tank is really full, never immersion.

 

Gully

[dougbgt6]

Gully, bend the wire. You know you want to!