| Author | Message | ||
     Geoff Wootton Grand Master Username: dounraey Post Number: 1788 Registered: 5-2012 |
I've never seen this type of fuel leak before. My thoughts are this can only be a blocked filter. If it was a sticking float then the fuel would be flowing down the overflow tube. I will investigate tomorrow, but would welcome any suggestions.  | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1789 Registered: 5-2012 |
Thinking about it, if the fuel filter is totally blocked, then shouldn't the pump stop pumping. Is this a fuel pump issue? | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2410 Registered: 6-2009 |
This looks like what must be the SY1 location for the carb fuel filters, but I can't be 100% certain about that. Is it possible that somehow there's been a catastrophic failure of the O-ring that's supposed to keep the fuel "in there"? If that were the case it wouldn't make much difference what the carb was doing since as soon as flow was cut off to the carb there appears to be a place for the fuel to go and for the fuel pumps to keep pumping as a result. This is all a SWAG, as I've never seen a fuel fountain like this on a low pressure system such as the SYs use and that looks like a gusher. Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1790 Registered: 5-2012 |
Hi Brian Thanks for your reply. You are correct in saying these are the carb fuel filters on the SY1/HD8. I think you are also correct in your diagnosis of the problem. I was wondering if the "logic circuit" telling the fuel pump to stop pumping had gone faulty, causing it to run continuously, building up such pressure that the carb seals were blown. It turns out, having read up the really ingenious way the fuel pump regulates pressure that it's virtually failsafe. So, the problem has to be, as you say, a catastrophic failure of the O-ring seal on the filter housing and not a seal failure due to increased fuel pressure. I rebuilt the carbs with a Burlen kit a couple of years ago, so I was expecting the seals to be "modern fuel proof". It will be interesting to see what's inside there when I investigate tomorrow. Geoff | ||
| Martin Taylor Frequent User Username: martin_taylor Post Number: 88 Registered: 7-2013 |
Did you lube he O-ring with atf when you reassembled? Either torn or modern fuel has killed it, looks dangerous! | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1856 Registered: 6-2006 |
I would say the o'ring. Has the car been standing for a long time? I've seen a few like this. The odd thing is that when you go back to it the next day the fuel has made the seals swell again and the leak stops. Seems like they are tolerant of modern fuels but not "no fuel" tolerant! | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1519 Registered: 9-2004 |
Another possibility is air still in the secondary filter outlet pipe to carbs allowing the pumps to pulsate with a higher diaphragm pressure! | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1791 Registered: 5-2012 |
Thanks for your replies. They've all been really useful in helping me decide on the best way forward. Paul - You are right on the money. I have indeed had the car laid up for 3 weeks whilst carrying out a very very leisurely reconditioning of my calipers and replacement of the (probably) 43 year old brake hoses. I'm now on the brake bleeding stage, which is why I started the engine yesterday and discovered the petrol leak. The car is garaged and has been subject to high ambient temperatures of 100F+ on most days, which would certainly aid the drying of the O-ring. I have this morning turned on the ignition and as you predicted, no leak whatsoever. This does of course beg the question, should I replace the O-ring now that it has expanded and sealed the gap? Thanks again everyone. Geoff | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1792 Registered: 5-2012 |
BTW - Martin - Yes, very dangerous. It's lucky I noticed the leak early on. The engine was running and the valley was filling up with neat fuel. The garage still wreaks of petrol this morning, even though I had the garage doors open all yesterday evening. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2411 Registered: 6-2009 |
Geoff, Definitely replace the O-ring. These are not rare items and if you go to your local auto parts store you will find the correct size. It certainly could not hurt to lubricate, and very lightly, the surface that will mate against the body of the filter containment to allow it to slip into place more easily. It should not be necessary to do so on the side that hugs the cap itself and, in fact, could be detrimental to do so since this side would best have a "death grip" on the cap during insertion. Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1793 Registered: 5-2012 |
Hi Brian Thanks for the advice. I will do that, especially as gas leaks are so dangerous, particularly when the gas is pouring out all over the engine and exhaust manifold. I've already done the hard part - removing the U shaped intake duct. I'm having difficulty bleeding the brakes. I open the bleed nipples and nothing comes out - lol. When I start the engine the brake pressure warning lights go out and I've got a piece of wood holding the brake pedal down, but not a drop of fluid emerges from the bleed nipples. Tomorrow I will spend all day on it, coaxing the fluid through. I think it's because all the hoses and caliper bores are completely empty. I guess I somehow need to prime the system. The joys of RR ownership. Geoff | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1857 Registered: 6-2006 |
Replace, I was thinking months minimum to dry out. Perhaps let Burlen know as well. Have you bled the accumulators? Run for a few mins. turn off engine. bleed accumulators. should get 1/4 pint or more fluid out of each. Bleed accumulators again if you are getting aerated fluid out. I can't tell whether you have a master cylinder on your car (I can see it has points so probably) but I would start by bleeding that first. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1794 Registered: 5-2012 |
Hi Paul I will be far more methodical tomorrow and follow your advice - bleed the accumulators first. My car does have the master cylinder. I was able to bleed the left hand low pressure circuit with a vacuum pump. However, I had no success with the right hand circuit. I'm going to try bleeding this circuit in the conventional way i.e. pumping the brake pedal, but have to wait for my helper (my long suffering wife) to return from a business trip in the UK. In the meantime, I thought I'd get the high pressure circuit working. Geoff | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1858 Registered: 6-2006 |
you should be able to bleed the high pressure before the master cylinder, but you will need to wedge the pedal much harder. Is the pedal going to the floor? Is your master cylinder failure emergency stop working? | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1520 Registered: 9-2004 |
Not forgetting the bleeding of the self levelling system! | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2412 Registered: 6-2009 |
Geoff, If you have fluid making it to the pumps all else should take care of itself (with the exception of the master cylinder and downstream, perhaps) as far as getting fluid pushed out to the endpoints of the system if the bleed screws are open to allow same. I have seen reports of air locking in the gravity feed hoses, so the first thing I'd check is whether you're getting fluid feeding into the pumps and then whether you're getting fluid to the accumulators, which you can check with the bleed screw on each (knowing the stuff really shoots out from those screws, so attach a piece of vinyl hose and have your catch bottle at the ready). Brian | ||
| gordon le feuvre Prolific User Username: triumph Post Number: 205 Registered: 7-2012 |
Don't forget to make sure gauzes in reservoir (s) are not slimed up stopping fluid going down pipes. if res. top has not been off in long time remove and look. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1796 Registered: 5-2012 |
Hi Folks Gordon - I did remove the lid of the reservoir and removed all the fluid. It was surprisingly clean after 4 years. The first time I did this the reservoir was full of green gunge. Given how clean it was after 4 years I suspect the fluid had not been replaced for at least 10 years before that. I've checked and the filters are clear. Patrick - height control is next on the agenda. Brian - I noted your comments on potential air lock in the gravity feed hoses. Fortunately all was ok. Paul - One interesting thing is I had to shorten the piece of wood I am using to push the brake pedal to the floor. Even though the low pressure circuit is spongy and needs further bleeding, the pedal no longer goes right down to the floor. Current state of play is I've "filled" all the various circuits and am about to go round a final time to make sure all the air is out of the system before road testing. So far, No Leaks  However, I still have a problem with the rear right low pressure circuit. I can pull brake fluid through, but only a little at a time with the vacuum pump I'm using. Since my helper (wife) is not due back from the UK until next Friday I cannot use the obvious way forward of pumping the brake pedal. I believe the reason my vacuum pump is not pulling the brake fluid through is because of vacuum leakage through the thread of the bleed nipple. I'm thinking of using plumbers teflon tape on this thread to effect a seal. There are conflicting opinions on the web. My current view is that as long as the tape is used only on the thread and kept well away from sealing surfaces of the valve, then there will be no problem. I'm asking for views on whether I should take this course of action. Geoff | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 833 Registered: 4-2012 |
Geoff someone on this forum has changed the master cylinder for a much larger one fitted to a land rover, I think it may have been suggested by Paul Yorke. Richard. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2417 Registered: 6-2009 |
Teflon sealing tape, so long as you don't cover anything but the threads, should remain very well away from the sealing surface of the caliper body and bleed screw. It's worth a shot and should have no negative effect at all if applied only to the bleed screw threads. Brian, who is thankful that both my cars are "post master cylinder" models | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1797 Registered: 5-2012 |
Thanks Brian. Since you concurred with my view on this, I went ahead and it worked like a dream. The brake fluid came through as normal straight away. I should be back on the road tomorrow. 3 weeks to recon the calipers and replace the hoses. 2 days to bleed the system. If Paul or Jim need an ace mechanic, they only need to call me. Re: who is thankful that both my cars are "post master cylinder" models True, but you will never experience the joy of seeing brake fluid finally emerge from a master cylinder model. |
