# Anyone ever replace old rusty fuel lines in 1990's full size GMC trucks



## Bonzoso (Sep 15, 2011)

Hi all,

Looking for advice on replacing the rusty old fuel lines on my 1999 K1500 Suburban The lines themselves don't quite look so bad, in most of the length, but the couplings are a mess. Don't even want to try taking the fuel filter off without planning a complete line replacement. I'm leaning toward nylon lines but don't quite know how to attach them to the cut steel lines. I've seen the steel to nylon couplings for a Dorman repair kit but am thinking these require a good male fitting on the steel side which doesn't look like I'm going to find on this old beast. Any thoughts from those that have taken on this job. I was hoping to just replace the exposed line and stay away from dropping the fuel tank and also going up into the rear engine area (no rust there).


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## joecaption (Nov 30, 2011)

Before starting go buy some PB Blaster and a set of tube wrenches.
https://jet.com/product/product/c7c...siJdGM6sHNgIvKz-u6fZfn9s0DhcpIfy60aAlMi8P8HAQ


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## Bonzoso (Sep 15, 2011)

joecaption said:


> Before starting go buy some PB Blaster and a set of tube wrenches.
> https://jet.com/product/product/c7c...siJdGM6sHNgIvKz-u6fZfn9s0DhcpIfy60aAlMi8P8HAQ


Both are already part of my arsenal.


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## Fix'n it (Mar 12, 2012)

post some pics.

are they leaking now ?
you say the line is ok, just the crimps ? and/or the nut connections is rusted ?

i would need to see em. but going on what you are saying = just spray em with a good penatrant. wait a lil while. them coat em with white grease. this will not last forever, you have to check it at least once a year. 

a 99 will have a plastic fuel sender with plastic lines connected to it. but you need to check all of the otherwise metal lines.


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## GrayHair (Apr 9, 2015)

Be glad it's only fuel lines. I have a '97 that has to have a new fuel pump every 60,000 miles. Last time it also needed the "bracket" it sits in; $800. :surprise:


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## Bonzoso (Sep 15, 2011)

Fix'n it said:


> post some pics.
> 
> are they leaking now ?
> you say the line is ok, just the crimps ? and/or the nut connections is rusted ?
> ...


Yup, that's why I'm asking for help from anyone with experience with line replacement, particularly with nylon lines that won't corrode. They're not leaking now but they will soon and I don't want to let them sit and rot anymore. If I'm gonna replace fittings then I'm gonna do the lines also.


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## Bonzoso (Sep 15, 2011)

GrayHair said:


> Be glad it's only fuel lines. I have a '97 that has to have a new fuel pump every 60,000 miles. Last time it also needed the "bracket" it sits in; $800. :surprise:


Yup, Knock on wood, I've been lucky there. Wasn't so much with the brake lines. Had to do them 2 years ago.


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## Fix'n it (Mar 12, 2012)

ok. well, i have seen lines so rusted that, well, idk how they just didn't fall off the truck.
anyway. i would still like to see pics. but chances are that if you would just coat them with grease like i said, you wouldn't have to replace them. 

otherwise, "if" you could even get new lines. you would have to remove the crossmember to lower the trans. and remove the gas tank. replace lines. put back together. yes, i have done this.


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## scottfarkus (Apr 17, 2015)

Fix'n it said:


> ok. well, i have seen lines so rusted that, well, idk how they just didn't fall off the truck.
> anyway. i would still like to see pics. but chances are that if you would just coat them with grease like i said, you wouldn't have to replace them.
> 
> otherwise, "if" you could even get new lines. you would have to remove the crossmember to lower the trans. and remove the gas tank. replace lines. put back together. yes, i have done this.


Thanks for the reply. Yes I can get new oem lines from places like rock auto. They cost about $300 for the supply and return in 2 kits. I'd rather put in nylon lines and save some money and not have to worry about corrosion anymore. Apparently these nylon lines are available and people do use them so I just need to know more of the details about coupling them to cut steel lines. Hopefully someone who has done this will chime in eventually. If you've done this replacement before how did you approach it? Did you use brand new oem lines? Thanks again for the reply.


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## cjm94 (Sep 25, 2011)

Car quest has repair kits for this.


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## Fix'n it (Mar 12, 2012)

scottfarkus said:


> Thanks for the reply. Yes I can get new oem lines from places like rock auto. They cost about $300 for the supply and return in 2 kits. I'd rather put in nylon lines and save some money and not have to worry about corrosion anymore. Apparently these nylon lines are available and people do use them so I just need to know more of the details about coupling them to cut steel lines. Hopefully someone who has done this will chime in eventually. If you've done this replacement before how did you approach it? Did you use brand new oem lines? Thanks again for the reply.


you can run nylon line. the hardest paart would be putting "just the right" flair on the end of the hard line. otherwise it would be ssomewhat easy. 
and yes, i have done this also.


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## paintdrying (Jul 13, 2012)

I cut 5/16 brake line and use brass compression coupling to join them. Never had a leak. Will out last your truck.


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