StratfordShark

After several days of the penetrating oil - soak overnight - wrench routine I've given up on trying to loosen the nut attaching fuel line to fuel filter outlet. Have tried the tip where you put the counter-hold wrench and the fuel line wrench in a 'V' and squeeze, but it just feels like the nut I want to loosen is rounding (the flare wrench moves moves round and slips).

Shame as I have nice new filter ready, and a new check valve on the way to see if it fixed warm start problem (I should do a full fuel system diagnosis, but the new check valve is much cheaper than just buying a pressure gauge and adapter for the fuel rail so I thought I'd try it while I was changing the filter).

Have checked for fuel leaks while running then replaced the pump cover.

I was thinking that if I can't shift the nut, then I could replace the fuel line which has the stuck nut at the end by undoing the connection in rear wheel well where it joins to line running to engine. But this section of line runs under a plastic cover back to the filter, which is clamped under the cradle holding the tank. This cradle is horribly rusty on my car anyway so I'd like to renew it if possible.

So if I go this route are there any tips/watch outs for changing the cradle? Presumably the fuel tank has to be supported while the cradle is off? Oh and is the connection in the wheel well between the fuel lines likely to be easier to undo than the one between filter and fuel line, or will I just have the same problem?

I'm also curious. If I took my car to a shop and asked them to change the fuel filter, then what magic tool would they have access to that would help them solve a problem they must frequently come across. Is it just that they'd have the car on a lift so would have better access to the stuck nut? Is there some kind of impact tool that can go round a line? I've jacked up the rear to give me a little better access but obviously didn't succeed!

Adrian

Fabio421

I have had this problem on my 78. It was a b!tch to remove. If your flare nut wrench is rounding or slipping then that means that it is spreading under load. Get a higher quality flare nut wrench. Snap on make a type of open end wrench called "Flank Drive" that actually hold better that a craftsman flare nut wrench. These are expensive but maybe you can borrow one from a mechanic friend.

Good Luck

Fogey1

Maybe try a different penetrating oil?

There are those who swear by "KROIL" by Kano Labs. Not readily available at your local FLAPS, but many sources when googled.

I have no experience with it but more than one here have said it blows the doors off PB Blaster, which is generally well-regarded and is in your FLAPS stock.

Tom928

Would a line wrench help?

BTW - Some gun shops carry Kroil.

Edgy01

'


A line wrench and a flair nut wrench are one and the same. (I think of them as line wrenches, too).

StratfordShark

Yes I wondered about the quality of the flare wrench - I will look for something better.

I've also been looking for different penetrating oil but here in the UK Kroil and PB Blaster are brands I haven't seen on shelf, but I admit I haven't googled for them. I'm going to follow up both suggestions this evening.

Thanks,

Adrian

ZEUS+

There is a fitting that screws into the filter that the line attaches to. Have you tried removing the fitting from filter ?

inactiveuser1228

Heat it with a torch!

StratfordShark

That's interesting. Presumably this fitting has the hex flange on it that you have to counterhold? I'm going to look at the new filter.

Thanks,

Adrian

StratfordShark

Is that OK on a fuel line right under the tank?

If it is safe then I might try the 'hot socket' idea I've seen, where you heat the end of the wrench before putting it on the nut. Again I haven't tried it up till now because of the obvious safety issues.

If you don't see any more posts from me then we'll all know you were joking!

Adrian

Imo000

I know this sounds simple but were you squeezing the two wrenches in the right direction? For example, the top one needs to rotate in counter clockwise direction and the botton clockwise. So if the filter is lets say in the vertical position, then the top wrench has to be on the left side and the bottom on the right side. Then when you squeez them, the forces will go in the proper direction. I made this mistake a couple times over the years and thought maybe this is what you are experiencing.

StratfordShark

Yes I'm pretty sure I'm doing it right. The filter outlet is to the right. I'm counter-wrenching the inner nut (on the filter) clockwise, and the nut on the fuel line counter-clockwise.

Reading the write-ups of changing the filter it seemed like a 10 minute job, and I didn't see any mention of problems loosening the nuts. I seem to have bad luck where this kind of thing is concerned!

Thanks anyway for your suggestion

StratfordShark

Thanks for the tip Fabio - I've found a few ebay auctions for snap on flank drive wrenches including 19mm so will try to pick one up there first. I have heard some great things about the flank drives so will be handy to have a set anyway for future jobs. This wasn't the first and no doubt won't be the last seized nut on my S4!

Jay W

I would say the torch idea is a joke. Sure it would get it apart but then you would have to find the filter and the line about a mile away

StratfordShark

Hmm on the new filter the flanges at each end of the filter are screwed in pretty tight. Holding the filter by hand I can't make any impression on them with a box wrench.