[Spencer2362]

Hey everyone, so I have a 81 rabbit pickup with the 1.6D ever since I bought the truck I've had trouble with air in the fuel lines, it's only when the truck isn't running the fuel rushes back to the tank, when it's running it's fine, I have pressure tested the system and I found no fuel leaking upto 15psi. I'm kind of out of ideas on what the problem could be. Has anyone else experienced anything like this or have any ideas?

 

[Spencer2362]

I'm wondering if, I noticed it does use coolant, nothing insane but a noticeable amount, but it doesn't overheat at all, could it possibly have a blown head gasket and be allowing air in?

 

[ORCoaster]

... it's only when the truck isn't running the fuel rushes back to the tank, when it's running it's fine,

I have pressure tested the system and I found no fuel leaking up to 15psi. Has anyone else experienced anything like this or have any ideas?

Spencer2362, What you have going is the classic seal leak that is letting the air in and the fuel goes back to the tank under a siphon effect. Air leaks can be hard t find and because it is a vacuum on the inside of the IP it is different than pressure in the line going in.

So where to look? Biggest suspect is at the front seal just behind the pulley on input shaft. If at sometime in the past or maybe even currently you or someone had the timing belt too tight, belt should flex to a 45 degree angle when correct, then it puts pressure on the seal and wears it out. Not a big deal to change it out and the part can be found easily at the VW online parts places.

There are other less prone areas. But if you recently removed the inlet or outlet banjo fittings you probably noticed a copper washer between the pump and the fitting. These compress to make a seal and they can get a memory that needs to be erased and there is an easy way to do that. There are also some on the lines going to the fuel filter so if you did maintenance there it is another place to look.

For resetting the copper washers I use a bit of very fine say 360 or 400 wet rub, and I place the washer on the paper with a bit of WD 40 and make sure the paper is on a very flat surface. Then I take my finger and place it on the washer and do figure 8's on the paper and count the numbers. 8-1, 8-2 … I start with 8-8 and then back it down as I look at the surface for fine lines showing. I don't try to remove them all. Because once you sand on them you get to fire up a propane torch and heat the snot out of them. Make them turn blue then let them cool. Annealing them is what you are doing.

Now reinstall them and don't be shy about using that 17 or 19 mm wrench and tighten them down.

Other leaky places are at the seals of the cold start lever. It is against the engine side of the IP and I wouldn't try to work on it unless you pull the pump. That requires a retiming so IF you don't have the experience for that find someone that does. Bentley manuals help for service on these cars but the timing method is something I wish I had been taught by another and not had stumble through all the problems associated with doing the process.

The back seal also is known to leak at the line between the distribution head, that gizmo with the four lines connected to it and the IP. Getting that seal off then back on can be done on the vehicle but is kind of tricky and you risk having the whole thing come apart in your hands, if you are lucky. All over the gravel driveway if you have my luck. But there is a process that just needs to be followed to get a new seal, easily purchased online, back on there. But you should be seeing or finding fuel with a dry paper towel if it was leaking there. Same with the Cold start and front seal.

Hope that gives you some ideas. There may be more but this will get you started with the majority of them. The other one I should mention is the top of the IP itself. That one can be a bugger so best left to the last if at all.

 

[Spencer2362]

... it's only when the truck isn't running the fuel rushes back to the tank, when it's running it's fine,

I have pressure tested the system and I found no fuel leaking up to 15psi. Has anyone else experienced anything like this or have any ideas?

Spencer2362, What you have going is the classic seal leak that is letting the air in and the fuel goes back to the tank under a siphon effect. Air leaks can be hard t find and because it is a vacuum on the inside of the IP it is different than pressure in the line going in.

So where to look? Biggest suspect is at the front seal just behind the pulley on input shaft. If at sometime in the past or maybe even currently you or someone had the timing belt too tight, belt should flex to a 45 degree angle when correct, then it puts pressure on the seal and wears it out. Not a big deal to change it out and the part can be found easily at the VW online parts places.

There are other less prone areas. But if you recently removed the inlet or outlet banjo fittings you probably noticed a copper washer between the pump and the fitting. These compress to make a seal and they can get a memory that needs to be erased and there is an easy way to do that. There are also some on the lines going to the fuel filter so if you did maintenance there it is another place to look.

For resetting the copper washers I use a bit of very fine say 360 or 400 wet rub, and I place the washer on the paper with a bit of WD 40 and make sure the paper is on a very flat surface. Then I take my finger and place it on the washer and do figure 8's on the paper and count the numbers. 8-1, 8-2 … I start with 8-8 and then back it down as I look at the surface for fine lines showing. I don't try to remove them all. Because once you sand on them you get to fire up a propane torch and heat the snot out of them. Make them turn blue then let them cool. Annealing them is what you are doing.

Now reinstall them and don't be shy about using that 17 or 19 mm wrench and tighten them down.

Other leaky places are at the seals of the cold start lever. It is against the engine side of the IP and I wouldn't try to work on it unless you pull the pump. That requires a retiming so IF you don't have the experience for that find someone that does. Bentley manuals help for service on these cars but the timing method is something I wish I had been taught by another and not had stumble through all the problems associated with doing the process.

The back seal also is known to leak at the line between the distribution head, that gizmo with the four lines connected to it and the IP. Getting that seal off then back on can be done on the vehicle but is kind of tricky and you risk having the whole thing come apart in your hands, if you are lucky. All over the gravel driveway if you have my luck. But there is a process that just needs to be followed to get a new seal, easily purchased online, back on there. But you should be seeing or finding fuel with a dry paper towel if it was leaking there. Same with the Cold start and front seal.

Hope that gives you some ideas. There may be more but this will get you started with the majority of them. The other one I should mention is the top of the IP itself. That one can be a bugger so best left to the last if at all.

Thank you very much sir, the input shaft seal would make the most sense, I can hardly even pull the belt up at all much less 45 degrees?? i have noticed some oxidation build up on the rear of the block. I will start with replacing the seal

 

[briano1234]

Getting that seal off then back on can be done on the vehicle but is kind of tricky and you risk having the whole thing come apart in your hands, if you are lucky. All over the gravel driveway if you have my luck.

Been there not on a VW, but a Valve body on a Tranny, lost one of the restrictors... Ended up remaking it out of Brass Stock a Nail to Punch a hole and a lot of filing.

Thank you very much sir, the input shaft seal would make the most sense, I can hardly even pull the belt up at all much less 45 degrees?? i have noticed some oxidation build up on the rear of the block. I will start with replacing the seal

Belt tension is one of those Gimme's on the Dubs too tight and you wear out parts ie: WP, IP, Crank or Cam seals. That 1/2 twist is the key as well as Singing
of the belt...

The Advent of the Clear Line is the ability to tell you where the direction air is coming from tank/filter to IP or Ip to Return....

Good site to Book Mark for IP repairs:
http://vwdiesel.net/forum/index.php/topic,4353.0.html

If you are Leary or Debatable on your Skill set, you can find a local IP rebuilder to have them install a rebuild kit, IIRC it was only about 200 when I had to rebuild mine back in the 90's years before the interweb and forums. The rebuild kits are relatively cheap. The "Special" tools for the Tri-square nuts, and things can be easily sourced. Replacing the Belt if you do that will require the Locking tools, and you might as well replace the motor mount, and tensioner while you are at it.

Be Warned that the Crank bolt torque has different Values depending on the style of Bolt Hex(6pt) or Double-hex (12pt).

 

[Spencer2362]

Could it be possible that if the seal is bad it's allowing air into the coolant system? When I had it running I did notice steam coming from the reservoir at a large rate.

 

[Spencer2362]

That would be amazing if I could find anyone near me? I kind of live in no where. I did put a clear line on the inlet to the ip and can see the gas is rapidly sucked back as soon as the vehicle is shut off.

 

[briano1234]

Posting your General Vicinity in your profile clues us all where in world you are located ie: Chicago (upper Illinois) PNW Pacific North West (Seattle, Portland), Upper NY (Anderondiks, Buffalo....)

The Gas being Sucked back as in which way? If the Bubbles are coming from the IP to the Fuel Filter, then you are looking at a Seal leak on the ip or a Hose connection between the Tank and the IP. Coming from the Filter to the IP says that it is on the feed line, or connections to the ip.

Did you re-use the copper washers or buy new? If you re-used them you needed to Sand them smooth as in removing ridges, then hold over a open flame till they change color from shiny to dull, this re-conditions them and increases the seal. Even New washers should be cleaned and heated in case there is a preventative coating on them.

 

[Spencer2362]

That was it ORcoaster! Thank you very much sir, I had the pump resealed and the guy said there was almost no seal left on the input shaft seal.

... it's only when the truck isn't running the fuel rushes back to the tank, when it's running it's fine,

I have pressure tested the system and I found no fuel leaking up to 15psi. Has anyone else experienced anything like this or have any ideas?

Spencer2362, What you have going is the classic seal leak that is letting the air in and the fuel goes back to the tank under a siphon effect. Air leaks can be hard t find and because it is a vacuum on the inside of the IP it is different than pressure in the line going in.

So where to look? Biggest suspect is at the front seal just behind the pulley on input shaft. If at sometime in the past or maybe even currently you or someone had the timing belt too tight, belt should flex to a 45 degree angle when correct, then it puts pressure on the seal and wears it out. Not a big deal to change it out and the part can be found easily at the VW online parts places.

There are other less prone areas. But if you recently removed the inlet or outlet banjo fittings you probably noticed a copper washer between the pump and the fitting. These compress to make a seal and they can get a memory that needs to be erased and there is an easy way to do that. There are also some on the lines going to the fuel filter so if you did maintenance there it is another place to look.

For resetting the copper washers I use a bit of very fine say 360 or 400 wet rub, and I place the washer on the paper with a bit of WD 40 and make sure the paper is on a very flat surface. Then I take my finger and place it on the washer and do figure 8's on the paper and count the numbers. 8-1, 8-2 … I start with 8-8 and then back it down as I look at the surface for fine lines showing. I don't try to remove them all. Because once you sand on them you get to fire up a propane torch and heat the snot out of them. Make them turn blue then let them cool. Annealing them is what you are doing.

Now reinstall them and don't be shy about using that 17 or 19 mm wrench and tighten them down.

Other leaky places are at the seals of the cold start lever. It is against the engine side of the IP and I wouldn't try to work on it unless you pull the pump. That requires a retiming so IF you don't have the experience for that find someone that does. Bentley manuals help for service on these cars but the timing method is something I wish I had been taught by another and not had stumble through all the problems associated with doing the process.

The back seal also is known to leak at the line between the distribution head, that gizmo with the four lines connected to it and the IP. Getting that seal off then back on can be done on the vehicle but is kind of tricky and you risk having the whole thing come apart in your hands, if you are lucky. All over the gravel driveway if you have my luck. But there is a process that just needs to be followed to get a new seal, easily purchased online, back on there. But you should be seeing or finding fuel with a dry paper towel if it was leaking there. Same with the Cold start and front seal.

Hope that gives you some ideas. There may be more but this will get you started with the majority of them. The other one I should mention is the top of the IP itself. That one can be a bugger so best left to the last if at all.

 

[Spencer2362]

I'm from Sioux Falls, SD I am unable to find any classic Dub owners even remotely close?

Posting your General Vicinity in your profile clues us all where in world you are located ie: Chicago (upper Illinois) PNW Pacific North West (Seattle, Portland), Upper NY (Anderondiks, Buffalo....)

The Gas being Sucked back as in which way? If the Bubbles are coming from the IP to the Fuel Filter, then you are looking at a Seal leak on the ip or a Hose connection between the Tank and the IP. Coming from the Filter to the IP says that it is on the feed line, or connections to the ip.

Did you re-use the copper washers or buy new? If you re-used them you needed to Sand them smooth as in removing ridges, then hold over a open flame till they change color from shiny to dull, this re-conditions them and increases the seal. Even New washers should be cleaned and heated in case there is a preventative coating on them.