Banjo bolt on SU H6 small leak

[Richardtr3a]

I have two H6 SU carbs on my 3A and after a short use this week both carbs have a small leak at the banjo bolt.  I tried to make them tighter but there was very little movement

In my SU box I have new washers but I am not sure which to use. 

1. 2 x Red fibre
2. 2 x.  Black fibre
3. 4  x Solid copper
4. Tin of Heldite sealer ,not ethanol resistant

I am close to one of the few filling stations in Sussex which are ethanol free, but I am planning journeys to France and visits to friends and family. This sealer was working well last year and I really need a long term answer.

Please advise

Richard & B

[JochemsTR]

if using copper, try to heat them till red, cool them down and re-install.

[Richardtr3a]

Thanks for the advice. The copper ones are a good fit but small profile. I need the car for a show this week end so I will try the black Heldite with the copper and see if that last for a short drive there and back.

But I am going to Classic Le Mans so it must have a long term repair soon. What do other owners use?

Thanks Richard & B

[stuart]

Ive not had a problem using the red fibre ones which is what Burlen supply.

Stuart.

[BlueTR3A-5EKT]

+1 for fibre washers.

What spanner are you using to tighten the banjo bolt?    I have always used a ring spanner, rather than an open ended or adjustable.

[FatJon]

Heldite and copper for all the high pressure banjos on my EFI. Not had any leaks. Copper lubricated with heldite seems much less inclined to get “ragged up” while tightening than fibre in my experience.

[Richardtr3a]

My Heldtitd has failed today, and I am now looking at fibre washers with Loctitc 290 thread locker. Do the fibre washers need any attention before use. Has anyone used a quality sealer which works.

Thanks for the advice so far.

Richard & B

[Waldi]

Fibre washers should not need any sealant, but it will not hurt.

Do a trial fit without the washers first (only finger tight), to check that the thread is not seized or there is a chest on the bolt that is restricting compression.

Waldi

[BlueTR3A-5EKT]

Richard,

Are you using new AUC2141 fibre washers or something you found in the plumbing drawer that sort of looks OK?

See  https://mgbhive.co.uk/product/16-auc2141-mgb-fuel-fibre-washers-set-of-4/

Failing that have you rung Burlen and asked for their advice?  01722 412500

 

In the years of having banjo fuel connections I only ever had leaks if I did not tighten correctly, causing the fibre washer to not be seated or use new fibre washers of the correct size that seat in the banjo mating face.  I never had to use any sealants or additives to get a fuel tight connection.  Loctite may not be a sensible product to use as it could lock the banjo bolt in the float lid stopping you from removing or tightening in the future.  Remember the best way to break the Loctite grip is to get it hot with a flame.  I doubt the leak is from the thread but is by the insufficient sealing of the fibre washer.

As Waldi has suggested it, and I second it, you should try the banjo bolt in the float lid without the banjo fitted to be sure the things screws in smoothly by finger pressure only.  If they don't you may have cross threaded the things or damaged the thread in the float lids.

 

Cheers

Peter W

 

Edited July 15, 2022 by BlueTR3A-5EKT

[Richardtr3a]

Thanks for the help. I am ordering new washers on Monday as long as they are in stock. The bolts screw in by hand so I think that the thread is ok. 

Have been advised to soak the washers in water for an hour before fitting. Is this a good plan ??

Perfect day for driving the car , if it was working ??

Thanks Richard & B.

[Waldi]

Hi Richard,

I never needed to use sealant for these fibre washers on carburettors.

I once was a trainee with a gasket manufacturer and worked on a warranty case where a client experienced leakage from “our”gaskets (no, we did not respond with “we have never had complaints before”).

 It appeared during investigation that the thinner based solvent in their sealant attacked the gasket material. But it is common practice to use a bit of silicone sealant or similar on gaskets in our cars.  But I would do without sealant first. Sometimes they need a bit more tightening, if they sweat  but that’s it.

Since you are in the UK, I would order from Burlen. And order a spare set, they are cheap.

Good luck 

Waldi

[Dic Doretti]

          I had a leaking banjo at Malvern last year but did not have the big 1" ring spanner in my tool kit. Searched the autojumble and found one for a £1, nipped up the banjo and haven't touched it since. Fibre washers and no sealant.

          Cheers

          Richard

[Richardtr3a]

Hi Waldi,

You know a lot about this subject. What do you think about soaking the washers in water for one hour before fitting.? This was recommended to me by a friend. Please let me know what you think.

Richard & B

[Waldi]

Hi Richard,

well, know a lot… that’s too much credit. I never soaked them, and would not do it, it may get soft.

Waldi

[Lebro]

If I was going to soak them in anything, it would be petrol not water. But I probably would not soak in anything.

Bob

[RobH]

The hard red fibre washers are vulcanised (or should be) and are pretty much resistant to fluids at least in the short term, so soaking isn't going to do anything.  The material is also widely used as an electrical insulator - it would be pretty useless for that if it readily soaked up moisture. 

 

 

 

Edited July 17, 2022 by RobH

[Richardtr3a]

It looks as if the new washers will have to be fitted dry. Unless anyone has used Blue Hylomer or similar. My new washers should be here on Thursday. It looks like no sealant. Luckily I have an American socket set and one fits the bolts very well. It is a 13/16 " This gives me a 10" long handle which should be enough to clamp up the new washers.

But I would like to stop worrying about potential leaks and use some brand of sealer. I can't be the only TR3A owner with this sort of problem. Every time that I open the bonnet I check the Banjo bolts. However things could be worse !!!

The hot afternoon has made the house back door frame shrink by 1/16" and the lock. will not turn. The latch is still OK.

Any help or advice would be useful, Thanks

Richard & B

[Richardtr3a]

23 hours ago, Waldi said:

Hi Richard,

well, know a lot… that’s too much credit. I never soaked them, and would not do it, it may get soft.

Waldi

Thanks Waldi, very useful

[Richardtr3a]

After receiving advice from some professional people I am planning new washers with Hylomar M light as a backup when fitting.

Has anyone ha any problems with adding Hylomar to the new washers??

Thanks Richard & B

[stuart]

You shouldnt need anything with those fibre washers. I always fit them dry, run it up for a bit and carefully nip the banjo up if required.

Stuart.

[mike ellis]

+1 and never had a problem in 50 years

Mike

[Richardtr3a]

Fitted the new washers and used Hylomar Blue to help seal the Banjo. I left it untested for a couple of days and this morning went for a test start up. 

Ir started well after a manual prime and the new sealed washers are all dry. So that is a success so far. But I noticed a very slight stain on the float chamber.I took the top off and the float was too high so the petrol was right at the top.  I found the pliers and bent the lever so that the fuel coming from the viton valve would cut off earlier. This has worked well but I must have bent it too far because now the engine will not run smoothly.

Is there a special technique or is it trial and error. 

Thanks Richard & B.

[foster461]

Float height is important as it sets the fuel level in the carb.

 

[Richardtr3a]

Thanks very much. I was hoping that there was a new more clever way to get this right.

I will try the drill bit tomorrow.

Richard & B.

[Richardtr3a]

A very useful morning on the carbs. I found my set of drill bits and the 7/16" one was useful.  I adjusted both carbs and cleaned out the float chambers which had some deposit of grey dust inside. It was awkward to get the floats out but a small length of wire helped. I put it all back together and after a start up it ran well in the driveway.

Both carbs are now dry and I am hoping for more m.p.g. I am planning to leave the banjo bolts and new washers untouched until next spring. I may have to check the glass bowl on the fuel pump. But I remember having a lot of trouble in sealing the glass where it touches the pump last time that It was cleaned.

What is the best way to seal it ??

Thanks Richard & B.