Replacing fuel hard lines; drop rear subframe?
 

I've got two "small" leaks in my fuel hard lines; one is in the return and one is in the feed. They don't leak a lot but I figure it is enough to either 1) Cause running issues or 2) Blow me up. So I'd rather go ahead and fix it and fix it the right way.

I'm trying to look at it and see a way to where you don't have to drop the subframe but between reading posts here, surprisingly few, and eye-balling it... It looks like you'd have to drop it. I have/had two fractured vertebrae and the idea of trying to put it all back together is frightening so I was hoping that maybe somebody here has an idea that I haven't had.

(Paying someone isn't an option as nobody else gets to touch her. I also have no friends here so I can't even enlist help.)

I had one hell of a time when I constructed some lines so I just got fed up and ran soft HI pressure lines and used the old bracketry as holders for that line.
Then once the line was clear I used hard line.

Forgive me if what you wrote was easy to understand and I'm just missing it; I just pulled my car in to the garage, with no ventilation, and I'm a tad light headed.

You are saying that you ran soft line from the pump to where it clears the sub frame and then just ran hard line from there, right?

That would be much easier but have you had any trouble with leaks or anything? Granted, I plan on re-doing everything in six months to a year when my settlement finishes. I just don't want to risk getting blown up by a fuel leak over the exhaust. :D

speaking as someone who just about replaced all his hard lines, you would need to drop the sub-frame to get them back into the car. I dropped mine planning to use the old ones as a template, but then realized I could get them cleaned with black magic vs bending new.

Misterstyx69 plan sounds interesting enough however.

I found this post of yours on a different thread. I'm assuming this is what you are talking about. I might end up trying this out. I guess I have some time to think about it. I'm not really in a rush either way. Working on this car is my therapy right now.

If you have the time and enjoy the work, why do you even hesitate to drop the subframe, which indeed, is necessary to replace the hardlines?
It ain't that hard.

Two fractured vertebrae and heart issues. I'm just hesitant about getting in to something and then not being able to man-handle it back in.

But yeah, I already bought some PBlaster or PB blaster; anyway, I'm soaking everything overnight and then tomorrow I'm going to start on it for some birthday fun!

Figured I'd upload a few pictures of the lines. They looked fine up until right before they bend up towards the tank. All of it is rusted. I opened up the access panel to see what the rubber hoses there looked like and the top of the tank has 2 inches of dirt/dust. The PO used to have to travel a gravel road to get home so I assume that's what caused the fuel line problems. Just dust and gravel over a few years.

With two floor jacks, there's not much muscle work involved.
Two floor jacks and two people make it cake.

I've never messed with the rear subframe, sorry. So does the differential not come out too? Or can you leave a jack on it and drop the subframe around it?

I pulled them together.

If the car is your therapy then the Doctor will say do not Rush things!
The Rear subframe is a piece of cake to drop,..even better with 2 people( I usually am left to do it alone..SO I make do.).Drop with the diff.
I think I posted a reply on it,so If you found my other reply about when I did the fuel lines you may find the reply for the diff.(maybe in Cdn Main section..awhile back..about a year or so)

Alright, I'll look for it. I'm mostly worried about messing up the axles when dropping the diff. I replaced a transmission in a civic hatch a few years ago, but I was rushing, and managed to break an axle some how.

You'll be golden with 2 jacks. I've re-installed it with one jack before - and I'll never do it again.

When you pull the diff and subframe together, the axles don't move anywhere.

-Undo the shock bottom

- Unbolt calipers and hang from shock

-Unbolt driveshaft and swaybar end links

-Undo subframe and diff mounts (six bolts total?) and drop the whole thing as a unit

While you have it down, check the front diff mount for damage (I'd just get a Mazdacomp mount ahead of time) and consider putting in a pinion snubber...it'll never be easier.
This would also be the easiest time to change diff oil.

actually as long as you're in there, look at the brake line too, its right next to the fuel lines.

secondly, if you're actually doing car repair right, you shouldn't have to work that hard. with the rear subframe, you really shouldn't have to do much more than balance it, or pivot the whole mess onto the jack. the jack should be doing the work :)

replace the brake and fuel lines, they will both either be rotted or close to being rotted

brake lines are still available from mazda, pretty cheap too not worth trying to bend them yourself, fuel line was NLA

you dont mention what model car you have but if its a turbo I would take the opportunity now to run fuel lines that give you room to grow should you aim for more HP

Alright, I've got everything removed other than the subframe and diff mounts. The exhaust was actually pretty tough to break loose. It was all rusted but I'm going to end up getting rid of it and moving to a single pipe. I spent a lot of time today draining the fuel tank and trying to clean up the garage.

I had been parking outside and I guess it was leaking more than I thought. I had a decent size puddle of gas and the whole garage smelled of fuel. Since the water heater is just on the other side of the wall I figured it'd be smart to make sure I didn't have fuel pooling around.

Also, the brake lines are in good shape, I think they were replaced recently. I just finished fixing the parking brake and that's when I noticed the fuel leak.

If you decide to go with stainless fuel hard lines, just be aware that you need a lot of patience and effort to bend them if you don't have a hydraulic bender. Just went through this with my Cosmo. Through great effort, lots of cursing and much manly flexing of muscle I was able to bend the 3/8" lines by hand with the assistance of the bending die from a small hand held tubing bender mounted in my vice. But seriously, an hydraulic bender for the purpose is needed.

Mild steel lines bend easily with the hand held tool.

I'm going to consider my options. I plan on doing a turbo swap once I my settlement finishes up; this is mostly busy work to be honest.

Thanks for all your help, it took about an hour to finish dropping the sub frame. I did find a few alarming things. Well, two, the sub frame mounts had rusted through and I'm really not sure what to do with that now. I didn't think the car was that rusty when I bought it but I guess it rusted in all the wrong, hard to see places.

I'll post some pictures of it later and see what everyone thinks.

Alright, I had a lapse of judgement that I blame on not eating all morning. What is rusted through is the 14mm bolt in this picture.
http://i30.photobucket.com/albums/c3...e/DSC01728.jpg

Is my thinking right that I can still bolt the subframe on and just leave that part danging? It looks like it is just there to help stabilize it maybe?

14mm has to be the socket that fits size. Bolts are measured by the OD of the thread.

Hahaha, Yeah, it is. I didn't go through the trouble of clarifying since that isn't what is the problem.

Here are a few pictures of the rust situation underneath the car. I think I'll probably try to clean up the differential just because I'll have ?a week? before the front diff. mount will be here. It had a decent size crack in the rubber that you can see in the picture.

So, does anyone know why there would be this much rust in the rear of the car but almost none on the rest of the frame/body.

Where was it parked? Previous owner live near saltwater?
My car was outside over half its life and wasnt nearly that bad. Im pretty sure the original owner drove it in the snow a few times but not since i own it had it been through the snow.
Im in the middle of a suspension resto now it gets tedious and can really start to add up once you want to replace, paint, and powdercoat everything

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