Fuel Cell Bladder Replacement

[NormB]

Hi folks, I have a 2003 Van Diemen RFS03 sports racer that I need to replace the fuel cell bladder. The bladder resides in the cockpit all along the entire rear bulk head. It is covered by a sheet of fabricated aluminum that also serves as the seat back rest. I have removed the “inspection” plate and have tried to remove the bladder through that opening and I simply can’t compress the bladder enough to pull it through the hole because of a series of baffles built into the bladder. I believe the proper removal and instillation process is to remove the aluminum cover that covers the entire bladder. This would involve drilling out the rivets and releasing the sheet from its epoxy bond, replacing the bladder and re-epoxying and riveting the sheet back in place. Because the sheet is so thin (.050) I don’t believe it is a critical part of the tubs integrity, thus removing and replacing it would have no consequences. But to be on the safe side I thought I’d throw this out to you folks to see if anybody had some wisdom on tricky bladder replacements. I have searched the forums and have not been able to find anything on bladders. Thanks in advance for your time.

[Fred Michael]

Is the panel a sheet or is it honeycomb?
Been a while since I have seen an RSF03 but after pulling the foam out of the bladder you should be able to get it thru the access hole. It is not easy.

[Bob L.]

Had similar on my Tiga S2. Small access panel, larger cell. Was able to remove cell through the panel on rear bulkhead of tub (cover was riveted to tub, drilled rivets), plugged openings on cell, and pulled a vac to collapse cell... then worked it out the access hole in tub. (from photos looks like I left whatever foam was in cell while removing...)

May or may not work on yours. Really depends on space and those baffles/internals... I was replacing my aged out cell, so extra damage wasn't an issue (put in a custom cell from Harmon, with access plate located under the hole in the tub). The older cell will fold in, may crease, which can be failure points in future, depending on how brittle stuff is.....putting new one in was a reverse with vacumn assist. (new cell was more flexible than old one, no issue with creasing.) I covered rivets with tape and thin sheet rubber, applied talc to facilitate cell installation/sliding over rubber sheet...

If you use vac. make sure not to use any source that sparks or arcs like a std. shop vac. >>> in presence of gasoline/fumes. I used a vac. pump for ac to remove mine...totally enclosed electrics... I did use a shop vac to reinstall...moved more volume.

Of course if you're replacing the cell, can always cut old one to bits to remove...figure out rest to install a new one...I loose those baffles, as foam does that job just fine... Try to keep pieces for a pattern. Cut up cell should be cheaper to ship to fabricator, too..

Bob L.

[Farrout48]

Just a vote for removing the aluminum plate. It will make the removal and, more importantly, the installation easier. It will also make it easier to do a full inspection of the fuel cell area. You never know what you might find since that area has probably not seen daylight for many years. As most have indicated, it all depends on your access to the area.

In my WF1, the cover plate is attached to a couple of aluminum angle braces on the side of the cockpit. The plate itself is screwed into the side angles. It is not a structural frame member but does serve as a backrest.

[NormB]

Fred: It's 0.050 aluminum, not honeycomb. That's why I'm comfortable to remove and replace. Thanks so far... All good thoughts.

Norm

[Fred Michael]

Fred: It's 0.050 aluminum, not honeycomb. That's why I'm comfortable to remove and replace. Thanks so far... All good thoughts.

Norm

In that case, don't even hesitate. Pull the panel.

[DanW]

Ken at Fuel Safe gave me some great advice about fuel cell installation.

• Cover any and all exposed rivets and fasteners inside the enclosure with protective tape so they will not wear holes in the bladder.
• Put a rubber mat, like the perforated tool box mat under the bladder to keep grit from abrading the bottom of the bladder.
• Vent the tank with a loop of hose above the cell to prevent unnecessary spills of fuel, then route the vent to the rear of the car away from the headers.

[Steve Demeter]

To add to that in case I missed it, Put several layers of duct tape on the bladder where the new rivets that hold the plate in place will contact it. Can't be too careful.

[Fred Michael]

To add to that in case I missed it, Put several layers of duct tape on the bladder where the new rivets that hold the plate in place will contact it. Can't be too careful.

No tape on the bladder. Put the tape on the enclosure only. The expansion and contraction of the bladder will make whatever you put on it fail.
Yes it's a pain but it can be done.
If it was mine, I would change the attachments for the panel to buttonhead screws so that it is far easier to access and inspect the cell

[DaveW]

No tape on the bladder. Put the tape on the enclosure only. The expansion and contraction of the bladder will make whatever you put on it fail...

Also any fumes that make it through the cell wall by osmosis would try to dissolve the adhesive on most tapes.

[DanW]

Also any fumes that make it through the cell wall by osmosis would try to dissolve the adhesive on most tapes.

Or the occasional overfill spill...

[NormB]

I appreciate the time you have all taken. I feel good about pulling the panel. Happy New Years to you all!

[Steve Demeter]

Well shucks I thought I was giving good advice.

Maybe I misunderstood the OP's plan to remove and rivet back in place the panel behind the seat. I was thinking how could you get tape on those rivets?

[Fred Michael]

Well shucks I thought I was giving good advice.

Maybe I misunderstood the OP's plan to remove and rivet back in place the panel behind the seat. I was thinking how could you get tape on those rivets?

You can pad where the rivets go by reaching thru the access hole,(not fun, but doable) or you can put foam pad on the back side of where the rivets will be installed before the panel is in place.