mike77

Can anyone confirm if the fuel line that routes over the top of the cam cover (left when facing) down the fender sidewall and along the full length of the car is the one that connects at the front of the rear wheel arch.

It is two lines actually but I think I want to replace both. Struggling to see for sure which one it is. I think it is the second line from the edge of the car in the bank of 4 lines that travel thr length of the car. Not certain though as it like spaghetti junction in the engine bay

mike77

Cars an s4 btw. First line goes from the fule dampner at the front of the engine over the cam cover. Connects at the engine bay sidewall to a long hard line that disappears down under the car.

mike77

Here are some pics. Can't get a good enough view to make my mind up which it is. From the top it looks different from underneath.





This is the start of the hard line in the engine bay on the front left facing the car.





This is possibly where it routs to in the rear wheel arch

mike77

Think I'm looking at the right line. I've wiggled the line from the top and it look like the second in from the side is moving. There is a hard to reach plastic clamp in the engine bay. I can get it off but I doubt I would be able to get it back on.

For the line with the rubber fuel line section in the first picture is there a rebuild option?

Rob Edwards

Here's a schematic of the fuel and vent lines at a couple of places:

FredR

Mike,

There are two fuel lines that run along the underside of the car and into the rear arch area. The fuel delivery line and the line that runs inboard of this is the fuel return line. Both lines route together in a common run just in front of the firewall then drop down behind the heat shield and then run to the back of the car.

Took a look at mine a few minutes ago and whereas there is a union on the return line there is no such item on the delivery line. Whether there is a union under the car I could not see.

Looks like a sod of a job to replace fuel delivery line. Perhaps someone who has done this previously can help you a bit more. I take it you have not been able to free up the damaged union to date.

I am wondering if a repair can be effected using a compression fitting over the bare pipe if the end is cut off. Not saying I recommend this- not without further research/experience. Clearly this is not something to be gambled with but maybe someone on the list may have experience of such approach?

Rgds

Fred

mike77

Thanks for the pics Rob. Pretty sure that is it labelled "Fuel inlet", "Fuel line from external pump" and "Fuel supply hardline". The plastic clamp in the second picture is the one I reckon I can get off but probably not back on again. I can get one hand in at it from underneath.

Fred the union is under the mud guard so unless you have that off you wouldn't be able to see it.

Due to the size and shape of this line it could be tricky or perhaps not possible without moving other stuff.

I've cut the rubber hose on the line in the engine bay. If there is a way to safely replace that hose then I would be interested to hear about it. It seems like it is just a regular piece of fuel hose pushed over a barbed fitting. Could it be that simple?

Another option could be to cut the hard line back a little and add another fitting.

Mike

FredR

Mike,

I replaced my fuel lines with the kit Roger sells [or used to sell?]. To install this you have to cut the factory crimp off and then slide on some fuel hose and then clamp with a worm drive [Jubilee] clamp. There was quite a lot of intense discussion about the wisdom of doing this a while back -suggest you try to find the thread.

I took the view that this is more or less what the factory did and it seemed to me that when the hose has been slid into postion, the grip from the barbs alone would possibly seal the unit- try pulling it off!. I used two clamps over the barbed surface but I did not go bonkers tightening the clamps- just did them up until the surface of the clamp was flush with the tube run- no more- to pinch it into position and [hopefully] avoid damage to the internal surface.

You may be able to do the cut in-situ using a dremel to cut off the current factory crimp. With the hose now cut you may be able to lever the trapped leg into a better position for cutting the crimp but I have not tried this- mine was done off the car in a vice.

Do the other end off the car and finish off by connecting in situ. You have to be careful you do not score the barbed surface with the cutting wheel.

Of course if you go this route it is your decision- my hoses have been in use for 2 to 3 years and no problem to date. The best route is the GB kit but in your case it is not an option at the moment.

Rgds

Fred

mike77

Hi Fred. I don't know if it is different from year to year or perhaps a PO has been at mine already but there are no crimps or clamps on this hose. Looks like a socketless hose that simply pushes over the barbed fitting.

I think I'll attempt a repair. I have a local pirtek so may pay them a visit. Hopefully they will be able to recommend something.

Any idea what sort of psi and temperature this hose needs to deal with?

jpitman2

I had occasion to replace the delivery line on my 83 S a few years ago. Note this is a CIS ROW car, so pipes will be different, but read on. Without a hoist it would be VERY hard to replace the return line, as it is laced between the body and the main crossmember, so I didnt do that. I could not lace the complete delivery line into the rear wheel well arch and up into engine bay. In the end I cut the line ~ 1ft back from where it bends up into the engine bay, and fitted a joiner. This also enabled me to get the rubber hose tightened onto the new pipe, which would have been a real PITA otherwise. Have had no leaks in years from the joiner, and seeing an identical unit in a picture above cheers me up somewhat. As long as you can source a correct joiner (mine was from a Pirtek dealer), I would have no hesitation recommending one, as lone as you leak test it! The short return hose from the steel line to the tank gauge head pulled off the steel line with great ease, so I fixed a new hose on with a jubilee clip, also never leaked.
If the issue is the leak at the joiner in the rear wheel arch, I would replace it, checking the pipe ends for clean and burr free. Are the tube nuts tight on that joiner?
jp 83 Euro S AT 56k

FredR

Mike,

I had to cut crimps off some of my hoses- cannot remember specifically what the score was with that particular piece. I have some photos somewhere if I can find them. Either way it should be easier to cut the hose off the barbs but be careful to avoid scratching the surface- not that you are likely to create a leak path.

As I understand the maximum pressure the fuel delivery system can reach is about 3.8 barg so a design pressure of 5 barg would be reasonable. Not sure what temperature the hose can be exposed to but I suspect my engine bay will see temps in the region of 80C- maybe more. In the UK I expect you can take about 15C off that number but that is a wild *** professional guess.

Rgds

Fred

mike77

Ok I took the line down to Pirtek and the guy measured it and said 10mm and came back with 9.5mm internal diameter hose. It slides on and off very easily and I was expecting that the hose should stretch over the barbs. The guy said use clamps. The next size down he had in stock is 8mm internal. This will slide on tightly. However I've read somewhere that 10% stretch is ideal and too much stretch will cause failure. So the 8mm would be 20% stretch. Too much?

Also I had a closer look at my hose when I removed the remaining piece from the line. There were no crimps on it. The line is made of a rubber outer layer which can be cut off easily and then a plastic line which is smaller internal diameter than even the 8mm line I have. Looks like it has been heat shrunk onto the barb. I removed the line fairly easily with a soldering iron rather than trying to cut it.

jcorenman

As mentioned, I think replacing the hardlines would be way more trouble than it is worth unless they are damaged or corroded. The concerns are typically the hose sections in the engine bay, because of the heat and potential for fire.

There is a disconnect shown in your pic, near the jump-post on the car's right side, between the body hardline and the combination hose/hardline that crosses the right-side cam cover to the front damper. This would allow the front line to be replaced or repaired separately.

Here's the two pages from PET. The first shows the hardlines from fuel-pump (7) to filter (11) to engine-bay (lines 20, 21, 22):



This view shows the combination hose/hardline (#8 here) that connects from line 22 in the previous illustration to the front damper (#5 here).




Correct, the original hose was was designed to be pressed onto special (sharp) barbs without clamps or crimps. It is a two-layer hose as you noted, a rubber protective layer over plastic (nylon I believe). It is very durable, and if the outer layer is in good condition (e.g. not cracked) then personally I would leave it alone.

There is a similar hose between the pressure regular and damper behind the engine, under the MAF. This one is more troublesome simply because it is out of sight without removing the airbox and MAF, so typically goes uninspected for long periods.

Much has been written here about the advisability of crimping rubber hose over the sharp barbs designed for plastic hose, it is a risk that I will not take.

Greg Brown can supply replacements for that fuel line in two flavors, shown on his website at http://www.precisionmtrwerks.com/products/products.htm:

'OEM-Style' 87-95 Front fuel supply hardline 928 110 367 15N




'Replacement' Style 87-95 Front fuel supply line 928 110 367 15RD



The "OEM-style" hose routes the same way as stock, over the right-side cam cover, and replaces the pressed-on mylon/rubber hose with hi-tech braided hose and proper metric fittings.

The second deletes the hardline section and routes fire-sleeved hose around the front of the engine directly to the damper. This is a better choice in my opinion but doesn't look "stock" if that is an issue.

ROG100

We stock the GB fuel hoses 8>)

mike77

Unfortunately my problem is that the disconnect at the jump post is frozen and the bolt on the hard line side is rounded off. So I had to cut the rubber/plastic section of the hose. So for the moment at least I'm needing to repair the hose in situ. Using a replacement would require that I either change the hard line or cut the bolt off and put a new fitting on.