angelfj Posted October 12, 2012 Report Share Posted October 12, 2012 With less than 1000 miles on the clock, both carbs on the Grey Lady are leaking badly! The leak is at the point where the banjo bolt joins the float bowl to the carb body. See below. The washers identified as No. 64 & 65 on my carbs look different than what is shown here. Mine look more like a top hat, one on top and the other on the bottom of the banjo bolt joint. Upon close examination my washers look swollen and bulging out. The rear set are actually torn and hanging below the banjo bolt head. Our first thought was the ethanol has attacked the rubber. However, the carb rebuild kits were sourced within the past 2 - 3 years. I would have thought that new carb seals and washers would be resistant to ethanol. So, has anyone else had this problem? Could there be another cause for these seals failing? Thanks, Frank Quote Link to post Share on other sites
Menno van Rij Posted October 12, 2012 Report Share Posted October 12, 2012 (edited) I've sent you an email containing an address on your side of the pond. Menno Edited October 12, 2012 by Menno van Rij Quote Link to post Share on other sites
Don Elliott Posted October 12, 2012 Report Share Posted October 12, 2012 Frank - Make sure you use a lot of old dry rags to absorb the dripping petrol or else the Grey Lady will start to lose her paint where the drips collect. Quote Link to post Share on other sites
vivdownunder Posted October 13, 2012 Report Share Posted October 13, 2012 Hi Frank, That's a notorious spot for leaks. I've made up bottom shims so the banjo bolt better compresses the 2 x top hat washers. Also, perhaps you have old stock top hat washers that won't cope with e blends. Maybe try Joe Curto for better quality (nitrile) washers, or Burlens the UK SU people. The other thing that causes leaks there is the earlier carbies with banjo bolt fuel bowl fittings. When tightening these it's essential to hold the bowl still so it can't twist and distort the top hat washers. Regards, Viv. Quote Link to post Share on other sites
Icarus60 Posted October 13, 2012 Report Share Posted October 13, 2012 Frank I rebuilt my H6 carbs using Burlen full overhaul kits. These kits didn't come with the top hat washers so I contacted Burlen who sent them to me FOC. They told me they would be revising kit contents to include them in the future. Product Name Grommet Part Number AUC 1534 Category Float Bowl Chamber Adaptors Price £1.03 (£1.24 inc. VAT) Click image to enlarge Image copyright The SU Carburetter Co. Description Grommet Austin Healey Sprite Mk1 MGA 1500 MGA Twin Cam Triumph TR2, TR3, TR4 I think this is what you require. Regards Rog Quote Link to post Share on other sites
Richardtr3a Posted October 13, 2012 Report Share Posted October 13, 2012 I had this same problem and discovered that when the new cars were exported to African countries, these top hat washer were notorious for leaking. Standard Triumph's answer was to include a replacement set with each new car ! Why didn't they design the fault away? I fitted mine with a lot of liquid sealer and a copper washer which compresses them a bit harder. They have stopped leaking but I will avoid undoing them in the future. Why do the float chambers have to be mounted on rubber and not just have a copper or fibre washer set up like the supply pipes to the float chambers? Good luck. Quote Link to post Share on other sites
Fireman049 Posted October 13, 2012 Report Share Posted October 13, 2012 Did anyone see my recent article in TRaction regarding modifying my SU carburettors to stop them leaking? I'll try and dig up the magazine and let you have the issue number. I think I've got the original photo's on my PC? Tom. Quote Link to post Share on other sites
MikeTR-6 Posted October 13, 2012 Report Share Posted October 13, 2012 Had new seals on my carbs , started leaking in no time . I think the slightest movement of the float bowel when working on the engine damages the seals Mike Quote Link to post Share on other sites
Chris59 Posted October 13, 2012 Report Share Posted October 13, 2012 Did anyone see my recent article in TRaction regarding modifying my SU carburettors to stop them leaking? I'll try and dig up the magazine and let you have the issue number. I think I've got the original photo's on my PC? Tom. Tom, sure we did (I'm certainly not the only one !), but would you please tell us where the seals/o'rings you used can be found, thanks ? Quote Link to post Share on other sites
JeffR Posted October 14, 2012 Report Share Posted October 14, 2012 Frank, I had the exact same problem happen with my '3' this summer towards the end of a 1,000 mile trip around Devon and Cornwall. We pulled into a pub for lunch and when the car stopped there was a strong smell of petrol coming from the engine compartment.. I opened the bonnet and saw drip, drip, drip from the bottom of the float chamber. When I undid the banjho bolt and stripped the selas out (after lunch and a pint or two of course) I found a chunk of rubber had been torn from one side of the top 'top hat' seal. The bottom seal was fine. As luck would have it - over the road from the pub was a DIY shop! and a few minutes later I came out armed with a pack of two rubber seals designed to replace the seals from the screw tops of hot water bottles. To my amazement it worked a treat! The only downside was that in the car park where I made the repair, parked opposite where two MGBs, who's owners couldn't resist coming over after they'd finished their lunches to make encouraging comments and to sympathise with a poor TR owner! As this stop was the last before home I experinced no further problems. A few days later I checked the rear float chamber rubbers as they also seemed quite damp.. Exactly the same had happened - the rubber of the top 'top hat' was torn in exactly the same place (where it lies under the supporting arm of the float chamber..The bottom seal, as before, was in pristine condition. Thinking about it since - I have an inkling the problem is likely due to the vibration in the float chamber arm when the engine is running causing the rubber to fatigue and tear over time. It's intereating to note that the botton 'top hats' on both float chambers were still in good condition which I think is due to the fact that they are each supported by dished steel washers. This probably provides more stability. I've since repaired both carbs with new sets of 'top hat' washers but have also put a steel dished washer (the same size as the bottom steel washer) between the bottom of the float chamber and the top 'top hat'. This is in the hope it reduces the direct pressure of the float chamber support arm on the rubber thereby reducing the tendency for the rubber to fatigue.. Seems to be working so far. Finally, in my research on this subject I discovered that the rubber 'top hats' are described as an upgrade from the fibre washer set as in your diagram. These were originally used on the TR2. So, just as a precaution I now keep two repair seals for hot water bottle tops and two sets of fibre washers in my spares kit - for the next time I meet up with two MGBs! Regards, JeffR Quote Link to post Share on other sites
Richardtr3a Posted October 14, 2012 Report Share Posted October 14, 2012 Well done Quote Link to post Share on other sites
angelfj Posted October 14, 2012 Author Report Share Posted October 14, 2012 Frank, I had the exact same problem happen with my '3' this summer towards the end of a 1,000 mile trip around Devon and Cornwall. We pulled into a pub for lunch and when the car stopped there was a strong smell of petrol coming from the engine compartment.. I opened the bonnet and saw drip, drip, drip from the bottom of the float chamber. When I undid the banjho bolt and stripped the selas out (after lunch and a pint or two of course) I found a chunk of rubber had been torn from one side of the top 'top hat' seal. The bottom seal was fine. As luck would have it - over the road from the pub was a DIY shop! and a few minutes later I came out armed with a pack of two rubber seals designed to replace the seals from the screw tops of hot water bottles. To my amazement it worked a treat! The only downside was that in the car park where I made the repair, parked opposite where two MGBs, who's owners couldn't resist coming over after they'd finished their lunches to make encouraging comments and to sympathise with a poor TR owner! As this stop was the last before home I experinced no further problems. A few days later I checked the rear float chamber rubbers as they also seemed quite damp.. Exactly the same had happened - the rubber of the top 'top hat' was torn in exactly the same place (where it lies under the supporting arm of the float chamber..The bottom seal, as before, was in pristine condition. Thinking about it since - I have an inkling the problem is likely due to the vibration in the float chamber arm when the engine is running causing the rubber to fatigue and tear over time. It's intereating to note that the botton 'top hats' on both float chambers were still in good condition which I think is due to the fact that they are each supported by dished steel washers. This probably provides more stability. I've since repaired both carbs with new sets of 'top hat' washers but have also put a steel dished washer (the same size as the bottom steel washer) between the bottom of the float chamber and the top 'top hat'. This is in the hope it reduces the direct pressure of the float chamber support arm on the rubber thereby reducing the tendency for the rubber to fatigue.. Seems to be working so far. Finally, in my research on this subject I discovered that the rubber 'top hats' are described as an upgrade from the fibre washer set as in your diagram. These were originally used on the TR2. So, just as a precaution I now keep two repair seals for hot water bottle tops and two sets of fibre washers in my spares kit - for the next time I meet up with two MGBs! Regards, JeffR Jeff: Many thanks for sharing your experience. Perhaps our theory regarding ethanol blend petrol is a dead end! frank Quote Link to post Share on other sites
Fireman049 Posted October 16, 2012 Report Share Posted October 16, 2012 (edited) Chris - sorry for the delay in answering. I Googled up Neoprene 'O' rings. Check with any supplier that their 'O' rings are compatible with oil and petrol. My carburettors are still leakproof since I fitted the modifications. Tom. Edited October 16, 2012 by Fireman049 Quote Link to post Share on other sites
JeffR Posted October 16, 2012 Report Share Posted October 16, 2012 Tom, Just for information, the 'O' rings I took off my carbs during the repair I described above where 16 years old having been installed at the time my '3' was rebuilt. Apart from what I consider to be 'fatigue' tears in the upper 'O' rings, the bottom ones are still in as new condition.which suggests at least the seals of this aera are not affected by the new fuel formulations. I'd be interested to hear how you get on both from a 'fatigue' and chemical perspective. Regards, JeffR Quote Link to post Share on other sites
Fireman049 Posted October 16, 2012 Report Share Posted October 16, 2012 (edited) JeffR - My car has been off the road for some time owing to an ongoing rebuild (she's now ready for painting!). I have been running the engine on a regular basis to attain full operating temperature so the carb. seals have been put to the test over a very long period. Tom. Edited October 16, 2012 by Fireman049 Quote Link to post Share on other sites
angelfj Posted October 26, 2012 Author Report Share Posted October 26, 2012 UPDATE We got new Viton® washers from Joe Curto and installed them on both SU carbs. No leaks, but you can be sure that this is something that will be checked often. The original washers shown below were installed about 2 years ago, that is they were exposed to E10 gasoline for that long. However, since the car was finished in June there are only about 1000 miles on the clock. If you have ANY doubts check your car before you put it in storage over the winter. Most experts recommend a full tank of fuel to avoid condensation in the tank. However you don't want a failed rubber washer to cause a serious fuel leak and possible failure. I installed an in line shut off valve (locking type) which I will close and then run the engine until the lines and fuel bowls are empty. Cheers, Frank Quote Link to post Share on other sites
angelfj Posted October 27, 2012 Author Report Share Posted October 27, 2012 UPDATE We worked late last night preparing for our 1600 mile trip to Galveston, TX. Would you believe the BLOODY CARBS ARE LEAKING AGAIN - ARRRRRRRRGH1 Don't know what to do at this point. Brian has a theory. He believes that the cup washer is spinning as we turn the banjo bolt and that perhaps this may be distorting the washer thus causing the leak. Your suggestions are welcome and we will be off for Texas early Sunday morning. Cheers, Frank Quote Link to post Share on other sites
Menno van Rij Posted October 27, 2012 Report Share Posted October 27, 2012 (edited) Frank, I've just read your two postings; somehow, I'm under the impression that the cracks in the washers aren't caused by the quality of the fuel. I would think that the 'top hat' part of the washer (= thinnest part of the washer) would have suffered most - or show signs of it. To me it looks more 'mechanical': both are snapped at the same position (on the flange) and the 'route' of the crack is more or less similar (curved) and both have almost the same length. After reading your second post, I tend to go with Brian: as if the washer is tortioned or twisted! Menno Edit: I'm using a lot of ' ' because I don't know the proper English terms for it. Edited October 27, 2012 by Menno van Rij Quote Link to post Share on other sites
stuart Posted October 27, 2012 Report Share Posted October 27, 2012 It does look as if the washers are being distorted to the point where they are being cut through.Personally I would be inclined to ditch them and go back to fibre or copper washers as per the earlier installations. The Jag HD6 /HD8 types used them with no detriment as long as you have the Phenolic blocks between the carbs and the manifolds. Stuart. Quote Link to post Share on other sites
vivdownunder Posted October 28, 2012 Report Share Posted October 28, 2012 Frank, that's why SU changed from the banjo bolt to a stud permanently attached to the carby body. Not uncommon for the banjo bolt to twist the top hat rubbers and cause damage. I'm not sure you can go to H4 solid fibre bowl mounts without matching shorter banjo bolts. Maybe user flat washers as packers beneath the fibre washers. Hope you get a result - long gallop down to Galveston and don't want to be petrol sniffing all the way, let alone dripping down onto the generator, starter and exhaust. Regards, Viv. Quote Link to post Share on other sites
angelfj Posted November 4, 2012 Author Report Share Posted November 4, 2012 Viv, et al: Back from Galveston. Carbs were dry throughout the week including some spirited driving! Quote Link to post Share on other sites
Menno van Rij Posted November 4, 2012 Report Share Posted November 4, 2012 Viv, et al: Back from Galveston. Carbs were dry throughout the week including some spirited driving! Great you're back safe! More important perhaps: how's your home after Sandy!? Menno Quote Link to post Share on other sites
Fireman049 Posted November 4, 2012 Report Share Posted November 4, 2012 (edited) Frank - Why not try lubricating the washers with rubber grease. This would allow the washer to turn with the banjo bolt and not to snag because of dry friction. Worth a try? Tom. Edited November 4, 2012 by Fireman049 Quote Link to post Share on other sites
vivdownunder Posted November 5, 2012 Report Share Posted November 5, 2012 Great news Frank that she ran well and now safely back home. Hope you didn't get any property damage from Sandy, unlike our relative's home a while back, oddly enough in Galveston !. Regards, Viv. Quote Link to post Share on other sites
angelfj Posted November 5, 2012 Author Report Share Posted November 5, 2012 Thank you to everyone who expressed their concern. We were very fortunate because we are approx. 100 miles inland. It was mainly the coastal areas that took the worse hit with many homes flooded. Some families are just beginning to return to their communities. We do have one small hole in our roof where a medium sized branch speared its way through the shingles and plywood underlayment. That's something I need to repair today as we expect rain later in the week. Just a note, during the 1600 mile trip to Texas , last Sunday & Monday, we must have counted well over 100 bucket trucks heading North and at least another 50 - 60 large mobile engine-generator sets. This spirit of helping left us with a good feeling. Cooperation like this is typical as electric utility companies share resources during times of crisis. My local electric company sent 50 linemen to New Orleans Louisiana during the infamous hurricane Katrina disaster and most of them stayed for over one month. Quote Link to post Share on other sites
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