Sprung a Leak....Help!

Sunroof · 07-12-2005, 04:42 AM

I need to replace those fuel hoses (rubber only) that run from the end of the tunnel to the pump and back. This is the second time now I found fuel on the garage floor and the second time I tried to clamp them down tight. They are the old hoses that need refreshing.

Having never done this, I do not want to screw anything up! I do see that the hoses come off the metal fittings that come slightly out the back of the tunnel and run up and around the tranny and thru the firewall to the pump. Its obvious you just thread them thru; however, their are always tricks of the trade and I am seeking any advise to make the job safe and effective, especially threading hose thru and around.

Jacking up the rear will keep the gas in the tank so I would think even a half-tank (where I never let it go lower) is okay.

Any feedback is welcome.

Thanks
Bob
73.5T - CIS (2.4)

Jim Sims · 05:24 AM

Two of the lowere fuel lines are a combination of metal and rubber hose with the hose swaged onto the metal portion with a permanant ferule (clamp). One can either order new lines (if they are still available) or carefully remove the ferule, replace the hose and resecure with a hose clamp or new swaged on ferule. It would be best to remove the metal/hose lines and do this on a work bench. To remove the lines: disconnect one at the fuel pump outlet (on the side if it is an OEM Bosch pump) and the other at the tunnel. Then slip the rubber hose portions of these lines out through the metal straps (shown yellow in the below images). Next pull both lines downward, sliding the metal portions downward; one of the metal prtions goes through the body and is protected by rubber bushings at either end as it passes through the body. Don't lose these bushings as they will be needed upon reinstallation. The third line consists of only hose and runs from the tunnel to the pump inlet. Fourth and fifth lines (larger ones) are vapor vent lines running forward to the vapor cannister in the front trunk. Label everything as you take it apart, wear eye protection (a eye full of gasoline is not good!), do this away from open flames (outside in the open air is best), disconnect the battery ground(s) and have a fire extinguisher on hand. Removing the DS rear wheel will provide more working room and access. Jim

Oh No, fuel on the garage floor!!

911pcars · 07-12-2005, 06:13 AM

Not sure who originally posted this pic, but thanks. It's illustrates where the lines go through the tunnel. Note; the POV shown is from underneath the vehicle; rear is to your left.

If I'm not mistaken, the fuel line runs through the housing labeled, "driver side conduit".

Hope this helps,
Sherwood

Zeke · 07-12-2005, 08:17 AM

Which ever way you do it, you will use some hose clamps. As Grady says, always use proper fuel injection hose clamps which do not show threads to the rubber. The OEM clamps are called NORMA or Norma-Scheling (sp?). Newer versions of the Norma clamps can be found here on Pelican, at the dealer or BMW and Mecedes dealers. There is another compnay that makes almost the same thing called ABA and they own, I think, about 2/3 of the world's clamp manufacturing companies.

http://www.ultimategarage.com/abaprice.html
or, email this guy: UKPTS@EARTHLINK.NET (an independent in CA) Just tell him what you need.

Sunroof · 07-12-2005, 11:31 AM

Thanks everyone. This is a worst case scenario for me as I realized I have a tank over 7/8th full and no means for draining. With a full tank of gas I just might try to tighten down those clamps one more time and make my way to the mechanic.
I do not have any desire to work under the car with an almost full tank of gas tackling these lines, so here is where the expert will do the job.

I talked to my mechanic and labor is 2-hours to R&R all the lines. Reasonable to me considering benzene is not my friend in little more then a confined space! Of course unless I go to "Level B" if you all know what I am referring to.

Bob

Jim Sims · 07-12-2005, 12:16 PM

Do you still want the hose sizes? Two hours is a very good price if the mechanic sticks to it. I hope he understands that two of the fuel line rubber hoses are swaged onto metal lines. Cheers. Jim

Sunroof · 07-12-2005, 01:00 PM

Jim.
Please send them on.
The mechanic claims that it all can de done so its sounds reasonable. I have been researching a new fule tank so catch my thread on that one for the 73.5T. Please advise if you can lend any info. on this subect. Since I plan on completing the restoration I prefer to go with a new tank then what so many have done and that it is the boil and coat process. If the tank I describe is truely the one to fit this car I can get it for much less here, which makes it worthwhile.

Greatly appreciate the help here.

Bob

911pcars · 07-12-2005, 01:06 PM

I find it hard to believe you can't find someone to transfer 14+ gallons of 94 octane from your car into their tank. If you lived a little closer, I'd do it for free.

Or ask the mechanic to credit you for the gas he transfers into his car.

Sherwood

chrisp · 07-12-2005, 01:32 PM

If you can get new lines put in the tunnel for 2 hrs labor then go for it. Just getting the line grommets in will take you and hour and every bit of foul language you can muster. It also is easier with two people...so you'll need a friend.

FYI, you can pinch off the line coming out of the tank (into the pump) disconnect the pump and it'll hold the 7/8ths.

Jim Sims · 07-12-2005, 01:54 PM

"FYI, you can pinch off the line coming out of the tank (into the pump) disconnect the pump and it'll hold the 7/8ths."

On a '73.5 CIS, the pump is at the rear and its rubber feed line from the tunnel is one of the lines being replaced. The rubber hoses at the front between the tank and the hard lines into the tunnel in theory could be clamped flat to seal but given their age (32 years) it is my experience that they will crack and then also require replacement. I would pump down the tank through the filler neck or fuel level sender hole (Oklahoma gas credit card method) and then unscrew the drain plug to remove the last bit in the bottom. Jim

Sunroof · 07-12-2005, 03:42 PM

Easier said then done fellas. I do not have the capacity in empty tanks in my garage either they be for the lawn mower, outboard motor or the chain saw to store 12+ gallons. If you want the gas which is probably full of fine rust particles, you can have it! I agree that pinching off the front old hoses is not an option. My garage stinks of gas and is permeating into the house, so for now I will try to tighten those clamps at the hard line and limp over to my mechanic for the repair. When asked if he needs to drain the tank, his answer was no.

Personnally I am fed up with this old fuel line from the fuel pump forward, 33+ year old tank and changing my fuel filter every 3K to protect my system components down stream. I am looking at buying a new tank and getting the system back to like new condition.

Appreciate all the responses.

Bob

Jim Sims · 06:49 PM

The suction hose between the metal supply line at back of tunnel and the 73.5 CIS rear fuel pump intake is 9 mm ID x 15mm OD; the '72-73 parts catalog lists this as PN 911.356.073.00; Pelican shows they can get this line for $26.29. I simply bought braided fuel hose (VH-9-14) by the ft. from Pelican. If you are concerned about fuel debris left in the metal lines and elsewhere you may consider adding an additional fuel filter in the middle of this suction line. In my son's '73.5 we used a NAPA Gold #3033 fuel filter (has a metal housing) which is basically set up to work with 3/8" ID hose which worked with the 9 mm ID OEM hose size. There were no problems with fuel pump suction cavitation or pressure drop.

Other relevant 73.5 rear fuel line part numbers:

Pressure line (combined metal and rubber hose line) from fuel pump to accumulator: 911.356.066.30 (superceded to 91.356.066.31) Pelican shows they can get it for $31.41. Looking at an old 73.5 pressure line of this type I have on hand: the rubber hose section appears to be 8 mm ID by 13 mm OD x about 20" long (length is an estimate as the line was cut to install an extra fuel filter).

Return fuel line (combined metal and rubber hose line) from engine CIS to rear tunnel metal line: 911.356.064.30 Pelican shows they can get it for $24.46. Looking at an old '73.5 return line of this type I have on hand: the rubber hose section appears to be 7 mm ID by 12 mm OD x about 28" long.

If you want to replace all the rubber fuel hoses then below is additional 73.5 CIS engine fuel/vacuum line information including rubber hoses from fuel tank to metal lines at front of tunnel:

Units are in millimeters unless noted otherwise.

Fuel distributor to cold start valve: C7.5 x 13.5 x 410 (16-1/8") maps to Pelican VH-7-12.

Fuel distributor to double T fitting (reducing socket in the 1973 Porsche lexicon): C7.5 x 13.5 x 630 (24-13/16") maps to Pelican VH-7-12.

Double T fitting to return line to fuel tank: C7.5 x 13.5 x 330 (13") maps to Pelican VH-7-12.

Throttle valve to double T fitting: C4.5 x 10.5 x 360 (14-3/16") maps to Pelican VH-5-10.

WUR to double T fitting: C4.5 x 10.5 x 300 (11-3/16") maps to Pelican VH-5-10.

Throttle body to top of pneumatic valve (de-acceleration valve): C4.5 x 9.5 x 230 (9-1/16") maps to Pelican VH-5-10.

Throttle body to pneumatic valve: C9 x 15 x 190 (7-1/2") - 2 pieces this length are needed; maps to Pelican VH-9-14.

Throttle body to distributor: C3 x 6.5 x 650 (25-5/8") maps to VH-3.5-7.5.

Several of the above sizes also replace the rubber fuel lines that "jumper" between the metal lines at the front of the tunnel to the fuel tanK. These are worth replacing too, given their location and likely age and condition.

Suction line (tank to metal fuel pump suction line in tunnle): C9 x 15x 330 (13") maps to Pelican VH-9-14.

Return line to tank: C7 x 12 x 350 (13.78") maps to Pelican VH-7-12.

You may want to check my sums but I ordered the following to do this engine and front tank (doesn't include rear fuel pump related hose) "rehose" job:

3 feet of VH-3.5-7.5
3 feet of VH-5-10
6 feet of VH-7-12
3 feet of VH-9-14

More than you probably wanted to know. Jim

Sunroof · 07-13-2005, 04:27 AM

Wow! Thanks Jim.

I appreciate the parts list. I was under the car last night and retightened the clamp which was loose and may have solved the problem for now but not cured the symptom. I tried to trace everything out, but the transmission mount was in the way to get a good picture of what was going on. The two hoses for vapor recovery were in the way. I thought I saw the two fuel hoses, but the one that was leaking appeared to be a third that was a smaller hose (cloth covered). Strange! Or the hose was once cut and placed over the metal line with only one clamp that does not seem to want to hold for a long time.

I think realistically if I tackled this myself it would be a mess. Your great photos showed the tranny out and everything accessible. I wish I had that advantage. The car is in the air is the best place to perform this work.

Since you have a 73.5T do you know anything about the fuel tanks? When I replaced my fuel filter a few weeks ago the gas that leaked out was rusty. Its time for some action on the tank. Have you replaced yours?

Thanks Again
Bob