TR4A strong petrol smell in garage

[IanPatterson]

There is a strong petrol smell coming from my TR4A when its in the garage.

I have checked what I can underneath, and the connections to the carburettor but can't see any obvious leaks. 

Can anyone suggest where I can look for the leak?

I put 20 litres of petrol in the other day, and the smell in the garage was stronger afterwards.

Thank you.

[stuart]

Check the filler neck rubber pipe is correctly fitted and the seal under the tank sender , take the rear boot panel off and have a good look around where it sits on the boot floor for any signs of seepage, talcum powder dusted around will show you any very slight weeps of fuel. Check your hoses too as the ethanol in modern fuels can permeate through older type rubber, you need the latest R14 type hose to cope properly with it.

Stuart.

[IanPatterson]

Stuart, thanks. Good advice. As a newbie to the TR, which hoses are you referring to?

[rcreweread]

Ian - Stuart is referring to the hose between the cap and top of tank - bit awkward to see as it's underneath the rear deck.

What sort of tank have you got? Is it an original steel tank or a replacement in either alloy or steel - if its an original steel tank, it will now be over 50 years old so it could easily have minor perforations - if you think you may need a new tank, I can help you- just PM ( personal message - see top RH corner of page with envelope icon) your contact details to me

Cheers Rich

[IanPatterson]

Rich, I will have a look this afternoon (nothing much else going on...)

What should I look for to determine if the tank is new or old apart from rust :-)

[IanPatterson]

OK, I have had a good look at the tank and hose to filler cap.

The tank looks as new. The car was renovated before I bought it. The hose connecting the tank to the filler cap is sound and I can't find any sign of leakage from around the hose. Also there is no strong petrol smell inside the boot.

So its sounds like its from the tank onwards. From the boot I can't see where the feed pipe goes from the tank to the carbs. As I said earlier I can't see leakage at the carbs so its between the tank and the bonnet somewhere, 

[Nigel Triumph]

Is the smell only noticeable when you put the car in the garage with the engine hot, after a run?

Pretty well all TRs (except PI) will smell of petrol if parked in a confined space when hot, because the carbs sit above the hot exhaust manifold and some of the petrol in the float chambers evaporates. I always try to leave the garage door open for a few hours after parking a hot Triumph.

If the smell is still strong when the car's stone cold the next morning then it's likely to be a leak from one of the places mentioned in the previous posts.

Nigel

[IanPatterson]

The smell is there permanently. It gets stronger if the car is left for a while and unused. 

[stuart]

On a 4a the fuel pipe should go out of the tank with a hard pipe down to where it joins a short section of rubber pipe to the chassis pipe that then goes forwards along the tunnel and then along the chassis to a section of rubber pipe up to a short section of solid pipe into the pump (Check the pump for weeping around the body where the diaphragm is screwed down) then it goes hard line round the front of the engine to a short section of rubber pipe to first carb and then from front carb to rear carb with rubber/solid line.Any one of those sections of rubber could be at fault.

Stuart.

[ChrisR-4A]

Duplicate post

Edited April 22, 2020 by ChrisR-4A

[IanPatterson]

I have checked all joints from the pipe coming in to the engine compartment to the pump to the carbs. I can't feel any seepage although I could tighten the nut on the pump exit pipe a bit. How do I get to check the exit pipe from the tank to check that union?

[stuart]

18 minutes ago, IanPatterson said:

I have checked all joints from the pipe coming in to the engine compartment to the pump to the carbs. I can't feel any seepage although I could tighten the nut on the pump exit pipe a bit. How do I get to check the exit pipe from the tank to check that union?

You`ll have to get underneath to see that, as stated earlier dust all the joints and rubber pipes with Talc it will show up even the slightest permeation.

Stuart.

[Rob Salisbury]

Hi,

           the pipe exits the tank just in front of the rear diff cross member on the nearside, so get the car securely raised so you can get underneath and check the pipe union joint (brass nut plus olive round the tube) nearside rear wheel off also helps.    It could also be the union base hard soldered to the tank, ....repair here is a job for experts as the tank needs to be completly free of all petrol vapour for obvious reasons ....(though light the blue touch paper and run works for the foolhardy with a lot of space around),  but my guess would be the first rubber pipe joint just by the start of the diff tunnel.

Cheers Rob 

[IanPatterson]

OK, thanks both. That's tomorrow sorted then.

[trchris]

Hi 

You may also get a slight wiff of fumes from the vented filler cap especially on a hot day and closed garage

Chris 

[IanPatterson]

That's a good point. However I have had the issue over the winter so I think its maybe a small leak somewhere.

[rcreweread]

Ian - the fact that this problem became a lot more noticeable when you put 20 litres of petrol in must be significant - any leak in the pipe system, to my mind, can be largely ruled out as the pipes would normally be full,even with a small amount of petrol in the tank.

What could be relevant is the higher level will expose parts of the system not normally "in the Petrol" - so look at the joints and connections ( eg to the fuel pump) which are now full of fuel and may not have been before - I had a similar issue which I eventually traced to a weeping joint on the fuel pump which I just couldn't cure, so I replaced the pump and problem solved.

Also, originally, there was a type of hairy underfelt stuck across the back of the fuel tank in the boot which was great at harbouring damp, and this can cause pinholes in your tank around it's waist - I know you say the tank looks really good but is it a steel or alloy tank - if the former, they can look good on the outside but corrosion can go unnoticed in the underfelt - whats the inside of the tank look like? 

Cheers  Rich

[IanPatterson]

Hi all and thanks for the suggestions. The TR was in my local garage last couple of days for something else & I asked them to check all the fuel linkages etc. under the car.

The pipes coming out of the bottom of the tank were OK.

However they said that the hose from the filler cap to the tank needed tightening - and they did that. The smell has nearly gone away, so although I had checked the hose just by running a finger round the joints, this would seem to be the reason. Also fits in with the stronger smell after filling.

Thanks again.

[Bleednipple]

4 minutes ago, IanPatterson said:

Hi all and thanks for the suggestions. The TR was in my local garage last couple of days for something else & I asked them to check all the fuel linkages etc. under the car.

The pipes coming out of the bottom of the tank were OK.

However they said that the hose from the filler cap to the tank needed tightening - and they did that. The smell has nearly gone away, so although I had checked the hose just by running a finger round the joints, this would seem to be the reason. Also fits in with the stronger smell after filling.

Thanks again.

Thanks for feeding back Ian. It's always really helpful when folks post an update on what solved a problem they reported. Hope you're enjoying your 4A.

Nigel