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I have a 1985 which has started leaking fuel at the rear. I removed the cap to get to the pump, filter and hoses and here are some pics. You will see the two pics which show the rubber boot being wet after just one day, so I suspect it's leaking from that area. The banjo bolt above seems tight and dry at the touch !
Is this something where I need to replace the fuel pump or new crush washers and possibly new metal tube to be sure ?
The hose on the other side of the pump is dry and also the hose coming from the tank is dry, even though my hose clamp has rotted out and broke in half !
On this picture you can see the drip at the end of the pump before I dried it up to see if still leaking and it's not coming from there ! Broken clamp at the tank All dry, but yes dirty This is after one day Same thing here. it was all dry yesterday.
All I know is those dam banjo bolts need to be stupid tight (or they weep/leak). Took me a couple attempts on my 86.5.
I assume that you weren't trying to re-use the copper washers? That never works. Fresh washers, and only moderately tight... cracked fittings tend to leak.
As Jim suggested always use new sealing washers
if this is your first time touching the pump and filter you would be ahead of the game if you bought a new check valve it comes with 3 new sealing washers
a new rubber tank to pump line
Note their are two different rubber lines one for a strainer and one for intank pump
and a new short metal line
use some PTFE sealant on the threads ov the new check valve to pump make this tight
the use anti seize on the cap nut don’t make this super tight as you will bend the bulb area and then it will crush to out of flush and it will leak making the cap nut tighter will only make the leak worse
As Jim suggested always use new sealing washers
if this is your first time touching the pump and filter you would be ahead of the game if you bought a new check valve it comes with 3 new sealing washers
a new rubber tank to pump line
Note their are two different rubber lines one for a strainer and one for intank pump
and a new short metal line
use some PTFE sealant on the threads ov the new check valve to pump make this tight
the use anti seize on the cap nut don’t make this super tight as you will bend the bulb area and then it will crush to out of flush and it will leak making the cap nut tighter will only make the leak worse
Thank you Stan. Yes it's the first time that I am in this area. My goal is to purchase new crush washers. Does the check valve go on the center connection of the fuel pump ?
When you talk about PTFE, will Teflon white tape do ? When you say make this tight, I have been known to over tighten stuff and it breaks !
I gather to change the rubber hose from the tank to the pump I will have to empty the tank ?
While there, I would change the strainer, the hose from strainer to pump, the metal tube, the check valve (including the crush washers) and the filter.
And like Jpitman2 said, remove the entire assembly and work on a bench.
If, for some reason, you cannot get you hands on new crush washers, you can sometimes get by with sanding the old ones flat with 800 grit or finer.
Yes, sometimes. The problem is that they are crush-washers, and work-harden when crushed.
I'll just leave this here: https://www.mcmaster.com/97725a550 ... $10.43 for a package of 25.
While there, I would change the strainer, the hose from strainer to pump, the metal tube, the check valve (including the crush washers) and the filter.
And like Jpitman2 said, remove the entire assembly and work on a bench.
Yes, sometimes. The problem is that they are crush-washers, and work-harden when crushed.
I'll just leave this here: https://www.mcmaster.com/97725a550 ... $10.43 for a package of 25.
Long-time lurker, first-time poster to this thread...
The second picture in the first post tells a lot. Fuel is pretty good about honoring the laws of gravity, and the film on the tank tells me that the gasket at the tank fitting is possibly leaking. There's a split at the fuel hose between the tank and the pump, showing right there near the tank fitting. The plated steel clamp failed due to corrosion, leaving the possibility that the hose going on to the fitting nipple is also leaking. So three possible leaks, any of which might cause the fuel film on the tank. The good news is that those pieces are easily changed together. That hose is one of only three pieces of fuel hose on the car with a soft low-pressure core, by the way, meaning it needs non-barbed fittings. And will leak if the clamps are loose or have failed. (others are the FPR-to-fuel cooler return hose, and the fuel return hose into the top of the tank)
Unless there is a clear indication that the pump fittings are leaking, consider leaving them intact rather than disturbing them. There are actual torque specs for the fitting pieces, suitable for fitting new crush washers and such, and provided you haven't distorted the S pipe while disassembling. Trying to get the torque correct with the pump and filter mounted is a chore at best. Small misalignments mean leaks that show up on first test, and get worse when you try and add just that tiny extra bit of torque to the banjo fittings to try and get them to seal. Instead, the washers gall and/or the hollow bolt starts to stretch and distort... and the leak gets worse. Moral: do any surgery like this on the bench please, with proper tools. Especially the disassembly part. Consider a counterhold on the banjo to prevent twisting the S pipe into a funnier-looking pretzel as you disassemble. Use PTFE thread sealing paste on the threads, and also on the washer faces to minimize galling. Regular anti-seize isn't fuel proof while the PTFE paste is, so it will be there next time you want to change a pump or fuel filter. You can reduce your assembly torque by 10% or so and maintain the same clamping force with the lubricated threads vs. dry.
FWIW, I've never seen a plugged fuel filter in a 928 that's been driven regularly and/or stored well. Changing fuel filters "just because" doesn't buy you much beyond a chance to have more leaks. They don't wear, and new or old they will only plug when particle contamination blocks the filter media inside. I'm sure that others have seen filters that deserved replacement due to tank contamination or dry storage. So far though, I've only played with 928's that were able to drive to clinics. If they drove in, they could drive out with the same filter in place.
12-15-2019, 08:04 PM
Is my fuel pump done for ?
