I am about to change my fuel sending module in my base 91 for the first time, including fuel pump. I purchased a new unit from Corvette Mods and it should be here in a few days. In the meantime I will remove the existing module, which from what I have read is not too difficult if I can get the hoses off without cutting them.

I have read that I should have no more than 1/4 tank of gas when I start this, but no explanation as to why. I have close to a full tank and don't really want to siphon gas out unless there is good reason. It may be that the float exerts too much upward pressure when trying to secure the new one?

Anyway, I am asking why the gas in the tank should be at 1/4 level or less when installing a new sender module.

thanks in advance

 

I wish you the best of luck receiving your assembly from Corvette Mods. They are the absolute worst vendor and should only be used if you are completely out of all options.

Just search their user reviews here.

No need to siphon out the gas. Just take your time and have a rag or paper towel handy to catch any drips. You will be rotating the assembly as you extract it.

 

I've not heard about the <full tank issue. If you insert the new unit slowly should be OK, IMO.
Turned out that I had ~1/4 tank when replacing the fuel tank system in my '89 last year.

It's a good idea to spray those 9 bolts with a good PB Blaster before removing.
If you twist the rubber fuel lines with a wrench a few times they should slide off tubes fairly easily.

 

Thanks for your comments. Being a novice and unsure of the idiosyncrasies of a 91, I am edgy about items that fall under "84 to 96" compatibility category so I tried to get some degree of assurance that the sender module would fit. I at least got an answer from Corvette Mods so I went with them. That said, I ordered it on the 12th of January and it apparently has not been received at USPS on the 14th. Anyway, it is too late and my hope is that you are wrong. I will comment on this transaction later.
I will not siphon the gas and rotate as I remove it.

 

I thank you for the advice. I will clean the area, spray the bolts ahead of time and work the rubber fuel lines when removing them.

 

I just finished installing a new fuel sender ($200) from Corvette Mods without any major problems. The new sending module came with the neck gasket, fuel pump, fittings etc. but did not contain a pulsator. The strainer was longer and the connection was in the middle of the strainer. The sender assembly was made in Taiwan (which was an unpleasant surprise) and did not look as robust as the one that I removed. I needed to assemble this module and transfer the pulsator, but was relatively easy; the only problem was that the fuel pump did not fit as snugly as the original one -- i.e. there were no base tabs nor slots in which to fit the tabs -- it is held in place by the pulsator at the top and by the strainer connector at the bottom. Seems to be ok -- time will tell.

One nuisance was my fault -- it turns out that the nine filler bolts have small washers/0-rings which I did not notice until they were all on the table and, of course, two were missing. I solved this by purchasing some #47 faucet washers at Lowes and they fit fine.
The second nuisance was the electrical connector locking pin, but once I pinched the middle with small needle-nosed pliers and pushed, then it came off The last nuisance was that I lost the drain hose -- looked everywhere to no avail. Finally removed the license plate and looked through the opening behind it, then voila, there it was resting underneath the tank -- would've never found it.

Fired her up and no more long cranks.

On to the next task of removing the alternator; I am now stuck in that on my 91 base Corvette, the bottom through-bolt does not have clearance to be removed.-- completely unexpected and not sure whether to remove the round, black cannister-like device or to remove the whole base on which the alternator rests.in order to remove the long bolt. Everything else is removed but this bolt

I ask whether anyone has experience with removing this bolt on an L98 engine and can advise the best means to complete this task.

 

Quite easy, in that I simply removed the two bolts mounting the reservoir and moved it out of the way. The alternator bolt cleared nicely. Anyway, replacing the alternator was relatively easy and now all is well.