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What I was trying to say was that my '78 appears to have had the two external pumps from the start, in reply to the comment that the '78-79 would have had an internal pump.
Mine has an external under the tank, and then another next to the filler neck portion of the tank, behind the right rear wheel.
The second external pump you speak of is known as the "fender mounted" secondary pump. Cars that have this pump would not have had the in-tank pump originally. Early cars that do not have the fender mounted pump WILL have the in-tank pump. All '78-'79 928s had two pumps originally.
Apart from 78 all the tanks are the same.
Early tanks had a different sized thread sleeve for the in-tank pump/strainer. 36mm v 37mm from 79 onward. Also the bracket at the filler neck was not used on early cars but does not hamper fitment of late to early.
Cracks can be welded as long as you weld with the exact same material the original tank is made from. However not easy to do.
New tanks are readily available again for $1700.
We now have an insert to replace the threaded sleeve that often pulls out of the tank.
The OP didn't say if he had a US or Euro 1980. This car could be CIS or Motronic. The CIS tanks have a smaller indentation in the pump area, as the filter is located in the right quarter panel with the accumulator. The motronic tanks can be used in the CIS car, not vise versa, there is not enough room in the CIS tank indentation for the motronic pump/ filter setup located back there. Beware of interchanging tank cradles with different tank designs too, it doesn't work. Its best to get the tank style that matches yours.
Originally Posted by Kiln_Red
....Early cars that do not have the fender mounted pump WILL have the in-tank pump. All '78-'79 928s had two pumps originally.
Respectfully, this is incorrect. All of the early cars were wired for an in tank pump (all the way back to #1) but many many cars did not have it installed. I don't know how many, but i've seen dozens of them over the years with the same factory petrified cloth black tape rapped around the wire connector. My observations indicate that MOST early cars had one electric pump, SOME have two external electric pumps, and the rarest combination is an electric in tank pump and one external electric pump. These observations apply to my sampling of 77-79 cars only.
The original issue of a cracked tank at the bottom strap as described by the OP is often caused by improper installation of the tank. it is easy to get these tanks in just a little bit cockeyed, and many installers use the cradle bolts to pull the tank onto place putting undue strain on the tank in THE EXACT SAME SPOT on the bottom of those tanks, then they crack in the exact same place every time (as described by the OP) A quick telltale of crooked tank syndrome is the position of the filler cap in the quarter panel hole..the filler grommet and cap should all fit perfectly centered in the hole. Another is an un-natural "dent" in the bottom of the tank near the cradle base when the bolts are tight. Be ready to futz with the positioning. If you've never changed a tank also make sure you check out how that overflow/ vent hose goes THROUGH the chassis and presents a challenge you may not be aware of as well. Good luck!
78/79 cars all came with 2 pumps as Greg stated.
1) In-tank pump plus external pump mounted on the outside of the tank
2) External pump on the outside of the tank plus another pump mounted in the fender of the right rear tire. Opposite side to the filter/accumulator.
drooman,
This has been recently contested. Both above posts are from earlier this year and in response to the suggestion that early cars could have 1 or 2 pumps, originally. I do not agree. AFAIK all early cars had some combination of 2 out of 3 available fuel pump types. All of them had an external main pump. AFAIK the 017 pump was the first to be used in a single pump configuration. I have never seen either the 984 or 967 pump installed by itself in an originally equipped 928. Are you saying that you have?
I was so sure of myself I posted it it twice! (not sure how that happened)
Anyway, yes I know what the PET says about the double pump installations in 78-79, its just that I've seen so many with a single pump. The cars with 2 external pumps have this weird cloth-turned to petrified goo tape covering the in tank pump wire connector. It is quite consistent on the cars with 2 external pumps. I just keep running into single external pump cars with the internal pump wires taped up the same way. Its pretty easy to tell if the rest of the single external pump installation parts (line over to the accumulator) are original. In fairness I have no observational recorded data of which part number the single external pumps were in those cars.... also there's been so many of them changed by now with the wrong ones. I suppose there are also many cars that had in tank pumps that people pulled out and replaced with a strainer.
I know that Greg and Roger are correct in interpreting the PET, but the earlier the car the more likely one sees variations from PET on some things. Most of the cars I mess with are 77-78 Euros so that could be effecting my observations as well. I suspect that these earliest cars are outliers in production consistency and its effecting my view. I should have thought about all of this before I posted that you were incorrect.
PET reads that the internal fuel pump was used from 79 RoW S/N 0334 & 79 US S/N 0014 >>
I suspect the fuel tank threaded sleeve diameter changed from 36 to 37mm in preparation to accomodate the forthcoming internal pump.
PET reads that fuel pump 2 (in wheel well) was used to >> 78 RoW S/N 0375 & 79 US S/N 0013
For US cars, this makes sense. For RoW cars, this has to be incorrect.
I suspect Porsche MAY have started adding fuel pump 2 from 78 RoW S/N 0375 >>
Before that, intermediate piece (item 25a) P/N 92835661700 was used in the same location as fuel pump 2.
Anecdotally, I've seen a few later-78 RoW with this intermediate piece (RoW S/N 0579, for instance).
So I don't know exactly when the change occurred.
But it's apparent there were several early 78 RoW's running around with a single pump.
I should have thought about all of this before I posted that you were incorrect.
Meh.. I'm not a softy. If you knew something that I didn't, by all means...
This subject matter actually unravels about 15 years of knowledge that I THOUGHT I had. Amazingly, I can't tell that any prior RL threads have covered this in great detail.
Originally Posted by Jadz928
PET reads that the internal fuel pump was used from 79 RoW S/N 0334 & 79 US S/N 0014 >>
I suspect the fuel tank threaded sleeve diameter changed from 36 to 37mm in preparation to accomodate the forthcoming internal pump.
PET also lists 2 different internal pumps for '78-'79 as it does with the strainers. 928 608 013 00 includes the application note "-79". If it were only applicable to MY79, then it should simply read "79".
I suspect that PET is in error about its suggested S/N applications for 928 608 013 00. I don't think 928 608 013 01 should have been interchangeable, so S/N notes should be unique for each part number.
Or is the 928 community prepared to say that there were no factory installed in-tank pumps for MY78?
Originally Posted by Jadz928
PET reads that fuel pump 2 (in wheel well) was used to >> 78 RoW S/N 0375 & 79 US S/N 0013
For US cars, this makes sense. For RoW cars, this has to be incorrect.
I suspect Porsche MAY have started adding fuel pump 2 from 78 RoW S/N 0375 >>
This doesn't make sense, in my opinion. If 0579 used a single fuel pump originally, then why would 0375 need 2 external pumps when both cars are RoW-spec'd? It's hard to conceptualize that Porsche determined a need for 2 pumps at one earlier point in production, then shelved the downstream in-line pump for these RoW market cars. Then, fitted the same upstream in-tank pump in RoW cars that they installed in US-spec cars for the next model year.
Originally Posted by Jadz928
Anecdotally, I've seen a few later-78 RoW with this intermediate piece (RoW S/N 0579, for instance).
Are you 100% certain that 0579 doesn't / didn't have an in-tank pump originally? If so, are you just as sure that the intermediate piece was not formerly a fender mounted pump?
Meh.. I'm not a softy. If you knew something that I didn't, by all means...
This subject matter actually unravels about 15 years of knowledge that I THOUGHT I had. Amazingly, I can't tell that any prior RL threads have covered this in great detail.
PET also lists 2 different internal pumps for '78-'79 as it does with the strainers. 928 608 013 00 includes the application note "-79". If it were only applicable to MY79, then it should simply read "79".
I suspect that PET is in error about its suggested S/N applications for 928 608 013 00. I don't think 928 608 013 01 should have been interchangeable, so S/N notes should be unique for each part number.
Or is the 928 community prepared to say that there were no factory installed in-tank pumps for MY78?
This doesn't make sense, in my opinion. If 0579 used a single fuel pump originally, then why would 0375 need 2 external pumps when both cars are RoW-spec'd? It's hard to conceptualize that Porsche determined a need for 2 pumps at one earlier point in production, then shelved the downstream in-line pump for these RoW market cars. Then, fitted the same upstream in-tank pump in RoW cars that they installed in US-spec cars for the next model year.
Are you 100% certain that 0579 doesn't / didn't have an in-tank pump originally? If so, are you just as sure that the intermediate piece was not formerly a fender mounted pump?
I forgot about that second external pump bypass tube Jim pointed out. That makes a total of 5 variations of pump related equipment on early cars:
Single external pump, with single line going to accumulator
internal and external pump, with single line going to accumulator
two external pumps, with split line going to accumulator
single external pump, with split line going to accumulator, and second external pump bypass
internal and external pump, with split line going to accumulator, and second pump bypass?
I,m not even counting really early cars where the strainers, pump attachments, lines, accumulator, accumulator lines, filter, and attachment brackets are ALL different.
I read somewhere (can’t find it now) that the second external pump came into being as an attempt to deal with hot start issues some cars experienced very early on...and that different pump configurations were put into different delivery markets for some time in 77-79. Are there any TSBs about this? Or information on the “un-advertised free updates if you complain about hot starts” (like the S spoiler installation offered to those who complained of high speed lift)
No direct info on repair of the plastic is provided though it does state that it is a polyethylene, various grades are low or high density. If someone were of a mind to repair, it is at least a starting point for finding a matching plastic chemistry.
After removing the tank welding it is not an option. It's trash. Quick question, how important is the year for fuel tanks? Seems they separated into 1978-82 and then 1983 and newer. Basically, would a 1987 tank fit in a 1980?
Yes, I have a used tank from an '97 s4 in my '85 Euro
They can be rewelded with some success. For the process you must use the exact same material. So use material from a scrap tank.
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
I have looked in the classifieds and such but no luck. The car is a 1980, no internal fuel pump just the strainer. The PO had swapped the fuel tank since the first one cracked and the car is currently on fuel tank #2. It was a used tank from 928Intl but within a few hundred miles, it developed a hairline (I mean hairline) crack that was leaking from the very bottom where the strap/support goes under the tank. I rubbed a bar of soap in the crack and that stopped it overnight and the next day I fixed it with some QuickSteel plastic tank repair. It has held for about 8 months until today. It seems to be leaking from the same spot, very very slowly. I could tear it apart and try to fix it but I think I would be back here again in 6 months. I am looking for a new to me/used tank. 928Intl "might" have one but they still need to get it out of the car and test it. It will be at least a week at the soonest. Sharktoberfest is coming and I would like to get her back on the road in the next 2 weeks if possible.
where are you located I have a tank that came out of a 83 that needs a new strainer kit but will work.
im pretty sure it has no leaks.
im in new york
10-04-2019, 02:48 AM
George Layton March 2014