Is it a major headache to change a 1995 Sierra fuel pump?

I found the problem with my 95 GMC, 4x4, 350. Fuel pump. $500 repair.
They say I can drop the tank or raise the bed to accomplish this. Is it more complicated than that? I count 8 bolts holding the bed, all of which may be corroded enough to break off. Otherwise, is the dropping of the tank just a matter of removing the straps, which also has bolts that may break.

What is your recommendation and advice?

sofasurfer said:

I found the problem with my 95 GMC, 4x4, 350. Fuel pump. $500 repair.
They say I can drop the tank or raise the bed to accomplish this. Is it more complicated than that? I count 8 bolts holding the bed, all of which may be corroded enough to break off. Otherwise, is the dropping of the tank just a matter of removing the straps, which also have bolts that may break.

What is your recommendation and advice?

Click to expand...

Break the bed bolts and replace them after with stainless bolts, then disconnect the wire harness to your light on the bed along the frame. The bolt to the gas tank strap may break and your going to have to weld the bolt back on to the frame to secure the strap back on.

Don't forget to replace the wire harness from the new sending unit to the frame where it connects. The wires after so many years in there internally break inside the insulator without any signs till your have fuel pump or fuel gauge not working properly. The harness is only $15.00 which is a great investment to make sure your not tearing everything apart again to replace it.

Here is a link to the wire harness to your Sierra and your fuel system, you do know you can just by the fuel pump alone and not the whole sending unit from Auto Zone for like $80.00 if not less and be safe.

http://www.compnine.com/index.php?u...delid=6896&capuid=1&majorgroup=03&grouptype=B
http://www.compnine.com/index.php?u...delid=6896&capuid=1&majorgroup=03&grouptype=B
http://www.compnine.com/index.php?u...delid=6896&capuid=1&majorgroup=03&grouptype=B
http://www.compnine.com/index.php?u...delid=6896&capuid=1&majorgroup=02&grouptype=B
http://www.compnine.com/index.php?u...delid=6896&capuid=1&majorgroup=17&grouptype=B

The guy at the repair shop where I got the diagnonsis said that I should replace the sending unit also. Don't remember the reason. But this was before I told him I would do it himself. So maybe he just assumed he could make some extra money off me.
I checked a local parts store. Pump, sender, harness and what ever else is needed, all included for $189. I requested the cheapest brand and was told about $130 (their price). It was not clear if that included everything though. But we think it did include everything because the "list" price was $259 about (WOW!!)
But if I can get away with just the pump, that is what I want. Can you guess why I would change the sender or if it needs to be inspected first?

OK, I would...

1) Remove bed (also disconnect filler neck)
2) Remove pump assembly
3) Inspect or test (if applicable)
4) Install new parts
5) Do you think I will need to replace any gas lines?
6) Reinstall bed

I was told that replacing the harness is required, and it comes with the pump.

sofasurfer said:

The guy at the repair shop where I got the diagnonsis said that I should replace the sending unit also. Don't remember the reason. But this was before I told him I would do it himself. So maybe he just assumed he could make some extra money off me.
I checked a local parts store. Pump, sender, harness and what ever else is needed, all included for $189. I requested the cheapest brand and was told about $130 (their price). It was not clear if that included everything though. But we think it did include everything because the "list" price was $259 about (WOW!!)
But if I can get away with just the pump, that is what I want. Can you guess why I would change the sender or if it needs to be inspected first?

OK, I would...

1) Remove bed (also disconnect filler neck)
2) Remove pump assembly
3) Inspect or test (if applicable)
4) Install new parts
5) Do you think I will need to replace any gas lines?
6) Reinstall bed

I was told that replacing the harness is required, and it comes with the pump.

Click to expand...

Before you go through all the issues, inspect the ground wire to your fuel pump on the frame. Common for the ground wire to corrode off older trucks like the ones you and i have and a bad ground can cause the same issues as a bad fuel pump. Sorry i am not sure where it's grounded on your Sierra, but you should see the wire harness along the frame and the ground wire will be grounded on the frame on it's own. As for the whole sending unit, it's easier to replace the whole unit then to just take the pump out to make extra money from over charging you for the unit as you realized.

When i replaced the sending unit twice on my Jimmy, the second time i replaced my fuel line with nylon fuel lines to the filter only since that's where i found the lines to corrode and also you may want to inspect your transmission line for corrosion. A break in the transmission line can cause you to have a $1,700 bill to replace the transmission over a $40.00 section of new lines.

Here is a link to where i got my nylon fuel lines http://ken-co.com/fmsi/fmsi.htm, They were just 30 min from where i live and the guys there are help full. http://www.ken-co.com/search/search.asp?mfg=fmsi

I raised my truck box today. I used an air gun with a slightly weak compressor to remove the bolts. I needed to break them loose with a breaker bar first. It was not a bad job at all. I was surprised how good of condition the bolts were in. The whole chassis looks pretty good. No through rot. Just surface rust that flaked off into my eyes.

Raised the box 8 inches (2-4x4s) front and rear. Gonna go a little higher, maybe double that.

So far so good.

sofasurfer said:

I raised my truck box today. I used an air gun with a slightly weak compressor to remove the bolts. I needed to break them loose with a breaker bar first. It was not a bad job at all. I was surprised how good of condition the bolts were in. The whole chassis looks pretty good. No through rot. Just surface rust that flaked off into my eyes.

Raised the box 8 inches (2-4x4s) front and rear. Gonna go a little higher, maybe double that.

So far so good.

Click to expand...

When disconnecting the fuel line fro the sending unit, take your time and be genital. You don't want to break the tube that the fuel lines connects to on the sending unit.

Keep up the great work.

Word of advice, buy a GM or AC Delco replacement parts. Most all of the aftermarket fuels pumps etc are coming from China and have a very high failure rate. A long time friend has a ASE repair shop and he warned me about the shoddy foreign parts. He told me he will absolutely never install anything but OEM fuel system parts. He has lost money on comebacks with the other parts but never one AC Delco (furd and Dudge either) part has every failed, IF PUT IN CORRECTLY!

Always disconnect the battery before doing any work that touches on anything electrical. Never pull a live electrical connection, it could cause many problems.


You can almost always finds GM parts cheaper from AC Delco.

Got er done yesterday. A fairly fun job when you consider how bad it COULD have gone. Bed bolts came loose really easy and an air gun made the removal fast. Putting the bed back was more difficult because I didn't reverse my process properly. I tried thinking instead. Screwed it all up

The pump and sender woked fine except that the guage did not read...it bottomed out. Turns out that the new float was a half inch higher than the old one, and when you combine that with the fact that my tank was near empty you can see why my guage did not work. I had to bed my float down 1/2 inch and then add a gallon of gas to the tank before the guage would register. Let that be a lesson. Leave a 1/4 tank of gas in the tank so you can see if the guage works properly before putting the bed back on.

Thanks for the help.
Heres a couple pics for anyone who might need a few visuals before attempting this.
Sorry they didn't turn out bigger.

sofasurfer said:

Got er done yesterday. A fairly fun job when you consider how bad it COULD have gone. Bed bolts came loose really easy and an air gun made the removal fast. Putting the bed back was more difficult because I didn't reverse my process properly. I tried thinking instead. Screwed it all up

The pump and sender woked fine except that the guage did not read...it bottomed out. Turns out that the new float was a half inch higher than the old one, and when you combine that with the fact that my tank was near empty you can see why my guage did not work. I had to bed my float down 1/2 inch and then add a gallon of gas to the tank before the guage would register. Let that be a lesson. Leave a 1/4 tank of gas in the tank so you can see if the guage works properly before putting the bed back on.

Thanks for the help.
Heres a couple pics for anyone who might need a few visuals before attempting this.
Sorry they didn't turn out bigger.

Click to expand...

Glad to see you kept all you fingers. Keep up the great work.

one thing im not sure if anyone mentioned (and im sorry for being a day late and a dollar short) clean out the tank! i did the pump and in tank filter on a 97 silverado i had a while back it had been in a field for 5 years (title issues when the guys dad died) anyways we did the all that work only to have it go back out a couple weeks later. had a shop redo it and same thing again, they drained the tank and rinsed it and no more problems since...

Is there an easy way to determine if the fuel pump is the problem?

I have disconnected the fuel line at the throttle body and no fuel exits line while cranking. When the fuel line is disconnected at the frame mounted filter fuel seems to gravity flow freely at that point.