I’ve a problem with fuel leaking from the fuel pump outlet (to the carbs). I tighten the pipe and all is fine for a bit and then it works itself loose and starts leaking again. I have the braided type hose. Last time I had it apart I put some Blue Hylomar on the threads (inlet and outlet) and the pipe from the tank is fine, just the other side comes loose and leaks. I also have a problem with the domed cover on the pump (it’s an all metal replacement type pump, rather than the original glass bowl type), which also come loose and leaks.
Can anyone recommend a threadlocking sealant I could use to fix this?
I’m considering replacing the pump incase it’s the threads that are damaged (seems to tighten up ok though) but if anyone could give me some tips to try beforehand I’d be most grateful.
I question as to whether or not the threads are supposed to seal the connection. I had a similar problem with mine using regular metal fuel line. The end was flaired and the nut was supposed to tighten the flair on to the pump creating a seal. I finally figured out that the flair was not the correct connection and what I needed was a compression olive that fit around the metal fuel line. That did the trick as the nut compressed the olive around the fuel line and up against the pump. Is it possible that your braided hose actually has an internal connection that requires the use of a compression olive?
Hello Robbie,
You need to check the following. On the feed pipe to the carbs there should be an olive type fitting where the pipe enters the pump. The nut which screws into the pump compresses the olive onto the outlet pipe and also forms a seal with the pump. This is easily overtightened. Does the nut (Fitting) seam to screw right into the pump and ‘bottom out’ the shoulder of the fitting onto the pump? This means that the ‘olive’ which is a barrel shaped brass ring normally, has been compressed to its maximum. Tightning the ‘bottomed out’ nut further will not clamp the olive and you have a leak. The answer is to cut off the olive and fit a new one over a new section of the pipe. Make sure you fit a new nut also. If it still leaks then the pump seat where the olive seals is goosed and replacement is the answer.
You say the filter cover also leaks? This could be just the gasket needing replaced or a fault in the actual cover. Needs examined. Could it be just the cover leaking and making it look like the pipe also?
Anyway.. Hope you find it ok. I would remove the pump to the workshop for examination. These usually work well with no leakages.
Looks like I need to check out the olive (if there is one). The backnut doesn’t bottom out and I’m wondering if it’s not been tightened enough to compress the olive. I’m very wary of over tightening into the Alloy body of the pump, what kind of torque should I be putting on here?
Also, what size is the olive and where’s the best place to get one. Plumbers merchants?
I think they are 1/4’’ dia Robbie. Try an engineering supply company. 1/4 might be a bit small for the plumbers.
If you get stuck I will have a looksee if I have a few I can let you have.
No 6mm will not do it. 1/4’’ and 6mm are different sizes.
Good if you can get them at the plumbers. Hardware store is a good idea! never gave them a thought. let me know if you have difficulty, which I doubt. They are easy to obtain.
A quick search on plumbers supply merchants was fruitless but I found these on ebay after I read a previous post on here. Which ones would be suitable?
Been a while but I finally found time to tackle the hose connections.
Quick question: When tightening a new oilve (on the spigot of the braided carb hose) do I do as one would do with a household compression fitting and tighten a full turn from finger tight?
I don’t want to ‘neck’ the tube by over tightening
Hi Robbie,
That’s way too tight even for a household fitting as you put it - you will crush the pipe. Make sure the olive slides freely on the pipe before you assemble it, finger tighten the nut then just nip it with a spanner. Check for leaks and nip it up a bit more if necessary. If you do overtightened it there is no way back.
I ploughed ahead before I read your reply Roger. I ended up doing a full turn with the spanner . It was however not tight until then and I don’t think I swung on it excessively. It did feel like I’d just nipped it up.
I’m hoping it’ll be ok, there are no leaks at the moment after running in the garage for 5 mins or so but then it would take a few miles of use before it leaked before. I’ll have to wait and see.
Hi Robbie,
I don’t think your 1 turn will be over the top. If its now not leaking leave it alone. Any future leakage will be taken care of with just 1 ‘flat’ max turn on the nut.
Hi Robbie,
Sorry if I caused you to worry unnecessarily but I had visions of you winding on a full turn after it got tight and crushing the olive completely. As Alex says don’t worry about it…if you just nipped it up as you say and it’s not leaking it will be fine.
All the best.