Fuel pump replacement! Need help!
 

Alright, so I was about to swap the S5 NA fuel pump with the new walbro 255 pump but.... I found that all the screws are rusted beyond use... I haven't tried any of them in fear of breaking or stripping one, what do you guys suggest I do?

Here's a picture

I'm not a professional, but here is what I would do: Try vice scripts. If that fails, dremel off the heads of the bolts. Then use an EZ-out drill set to try to remove the now broken bolt. Get quality replacements from HMINI Racing. If they are not listed on the website, call them. They have them.

First I'd try an impact driver to remove the screws whole, then a dremel to cut the heads off, then a drill to remove the head and/or threaded rusty ass screws. Once threads are cleared out, replace the fasteners with stainless SHCS.

FYI, generally, replacing a stock FP with a high pressure aftermarket pump leads to a rich mixture unless you compensate with an adjustable FP regulator. Looks like new hose would be a wise idea also. Good luck.

SOAK the living shit out of those screws with PB Blaster and repeat..for 2-3 days..
Do Not try to get them out the way they are right now,you are asking for a big headache.

Soak the screws with Deep Creep overnight and use an impact.
Still no joy...use a Dremel to cut slots across the heads and try the impact with a flat tip.
Last resort is to cut the heads off and remove the remaining stubs with vice grips.

Thanks for the info guys, so far I've been soaking them in PB Blaster, later tomorrow I'm going to try to get them out with an impact, hopefully I won't have any problems with them

Don't waste your time. Get a drill and drill the heads off. Only drill enough, so the remainder of the screw can't stop the fuel assembly from being removed. Remove the fuel pump assembly. Once you do this, you will have a lot of thread from the screws sticking up. Grab with vicegrips, turn out. Buy new screws. If they are rusted that bad, you aren't using them again anyway.

Well I ended up getting all but three with the impact. The three stripped out, with some craftsmanship got two more out (zip wheel on drill, slotted the heads and got them with a drill) and the last one I just did everything possible until it finally broke loose! Didn't have to drill out a single one so I was happy!

A small but satisfying victory to be sure.

Small victory??? There's nothing small about replacing one's fuel pump in a FC. Styx is absolutely correct, soak them in PB Blaster for 2-3 days. This is one of the few areas where drilling/grinding should be done with extreme care and only as a last resort.

The tool I've found to work best is a 1/4" drive spinner handle and ratchet with the appropriate socket/bit for the fastener in question. This is how I got all 8 of the ORIGINAL M4x0.7 phillips screws out after 20+ years in the car. Put the ratchet on top of the spinner handle, then apply downforce with your left hand while turning with your right.

Before securing the pump back in place, it is a good idea to run a fresh bolt down each of the holes to chase the threads and ensure it can be bolted back in place. Place a sandwich bag underneath each hole as you do so to catch the rust/crap/gunk that comes out.

I can only judge by the two S5s I've personally owned, both of which came apart with no drama whatsoever, just a hand screwdriver.
Not every car is corroded all to hell.

No matter how bad it was to remove the original screws, save yourself future grief and replace them with hex headed (NOT ALLENS!) stainless bolts (even Ace Hardware carries 'em). Douse them in antiseize before install.
Your next fuel pump visit will be much less trying.

My old s4 tanks were a total snot bag.
I hacked one so bad that I just self tapped screws to get it driveable.
Mostly due to the Corrosion UP Here...(Canuckistan)
My last tank I Did put hex heads in and Yes that is the "cat's ass"..especially since eventually being an FC owner you wanna "just get a little more power out of it"..and do small things,..like TII swap,Upgrade fuel pump..Injectors,Haltech..turbo...
you know small things like that.
So even the little things like Replacing phillips screws pays off.!

Funny thing is i have taken the cover off more after my swap then before, stainless screws are good insurance.

Very interesting that the mini metric stainless screws are readily available (at Ace no less?). Note that you need to get the length right since the holed don't go all the way thru the tank (are bottomed).