Crashbox replacement: removing the old one, adhesive and which to buy

The crashbox is the composite structure on the front of the chassis that is meant to take the hit in a front impact. It is bonded to the chassis with a structural adhesive and held by rivets at the side gussets. The factory steps are in Crashbox replacement and partial body assembly. This guide is what owners added, from threads between 2003 and 2017.

Which crashbox to buy

• NA and Turbo. In 2009 one owner said the parts list gives one part number for both, so they are the same.
• New. Owners said Lotus is the only maker. In 2017 one owner who ordered one through a Lotus dealer said they are made in batches and not held in stock, so there can be a wait.
• Second hand. Used ones are much cheaper than new and come up from breakers, but check them. One owner was sent photos of a used box he was offered, and the answer from another was that it was scrap and not to buy it. Another owner found a crack in the flat section on the bottom of his own and planned to replace it. Look for cracks and crushed or splintered fibres.
• Fibreglass copies. Two owners in 2017 said to avoid the copies sold online. One described the original as high-tensile nylon down the crash tubes with some chopped strand mat between and a knitted mesh over the top, made by resin transfer moulding with an acrylic resin, and the copies as plain polyester laminate. He said the difference shows on crashed cars, where the original leaves lots of nylon strands and a copy leaves little. Another said they offer no crash protection. In 2009 one owner said a seller of one on eBay was trustworthy, and another said he wouldn't fit anything safety-related that hadn't been tested. We have seen no crash test of either, so treat the copies as unproven.

Elise and Exige crashboxes

• In 2009 one owner relayed what a Lotus contact told him: all Elise from 2001 share the same structure, with the part number changing over the years (A120B0094J in 2005, then A120B0190J in 2006). Another post wrote the 2006 number with a B prefix, so check the number with a Lotus parts supplier.
• The same account said that in January 2012 Lotus replaced it with a later version that is much stronger and uses a different tow post. It fits, but nobody at Lotus could say what it would do to the VX220 airbag set-up, and damage to the crush tube is the failure to avoid. Another owner asked whether the airbag controller part number changes with the later box, and nobody knew.
• That gives, in one owner's summary, S1 and VX220 interchangeable, S2 up to 2011 interchangeable with the tow post change, and 2012-on stronger with a different tow post and a possible airbag issue. A later post corrected the first line to say the S1 isn't interchangeable. A Lotus specialist reportedly told one owner he thought the Exige and S2 Elise boxes interchange with the VX220.
• In 2017 an owner who fitted a new Lotus box to an NA said it is the same one used by the Elise and Exige, and he needed to change the towing bracket to the S2 Elise version, which he bought in stainless from an online auction. One owner in 2009 thought the Elise box was different and couldn't remember why, and the cut-outs for the fog lights were mentioned.

These claims come from a handful of posts and some are second-hand. Verify the part against your own car before you rely on it.

Getting the old one off

1. Damaged box. Drill out the rivets holding the side gussets and cut the old box off the front, as the repair manual says (a 2003 reader). In 2017 an owner cut it off close to the chassis and removed the remainder with a heat gun and scraper. Owners said it is easy to cut and grind a damaged one off, but the fibres make it a dirty, dusty job, so wear a good mask.
2. Clean up the chassis. Trim the old adhesive back to a good surface. Isopropyl alcohol cleans but won't remove the adhesive, which one owner said is a mechanical job, and you only need a good surface to bond to, not bare alloy.

Taking a used box off its chassis stub

If you want to keep a second-hand crashbox, it still has the front of its chassis attached, bonded with very strong adhesive (one owner pointed out that the tow post depends on that bond). Owners had mixed success:

• Hacksaw blade clamped in mole grips to cut the glue. Hard work, and take care not to cut into the box itself. One owner said it was not a job he would repeat.
• Cutting the alloy away section by section with a Dremel or similar, leaving the box alone. One owner said it took a couple of hours and called it the safest way. Another thought so too.
• Heating the alloy box section, since the adhesive softens at reasonably low temperatures. One owner said breakers put a large gas blow lamp in each end of the section for a short time and then stand on it, and it falls off. Another said it takes about 20 minutes. One owner who tried heated flat stainless skewers pushed down the ends found they worked. Cheese wire didn't, as the adhesive had come over the top of the lip so the wire couldn't go down vertically and tried to cut the alloy.
• Hot wire to melt the glue took one owner hours.
• A specialist was said to remove them in one piece with a heated cutting tool. A wire saw was suggested but we have no report of it. Washing-up liquid on a blade was mentioned as a help when cutting out screens, but nobody reported it here.
• One owner removed one from a chassis but destroyed the box doing it.

Adhesive and primer

• The factory text, quoted by one owner in 2003, runs: trim down the old adhesive, clean the crashbox, clean the adhesive points on the car, prime the crashbox, prime the car's adhesive points, apply adhesive to the crashbox, place it, align it, and fix in place with strap pliers and a tensioning strap. The drawings only show the obvious.
• Product names. In 2017 one owner said the Lotus notes call for a cleaner and primer for new surfaces, and he used Betaseal 1580 (which he said replaced 1701) with 5404 primer, key the crashbox with wet and dry first, and apply the adhesive in a zig-zag pattern so it has room to spread when clamped. He said the cleaner is classed as hazardous and difficult to mail order, so he used isopropyl alcohol and the primer. It is one owner's account, not a spec sheet.
• Tiger Seal. Owners disagreed. One said someone used it and the crashbox came adrift and ended up on the floor. Another pointed out that it is a PU adhesive and that a failure of that sort suggests no proper primer was used, as you need the right primer for the right glue. A third said Tiger Seal is good for bonding mirrors and not much more. For something structural, use the specified product.
• Other adhesives suggested were a windscreen bonding agent (with its cleaner and primer), a 1K PU and Sikaflex 555, and one owner said the Elise uses Sikaflex. Nobody here reported using them on a VX220, and one owner said the Lotus adhesive is a standard-spec PU. Treat these as ideas to check, not recommendations.
• A resale point from one owner: a buyer may want to know what the box is bonded with, so keep a record.

Fitting and clamping

• It can only sit in one position, as it clasps around the chassis and sits on a lip. The hardest bit is getting the gap the same each side (a 2009 owner, repeated in 2017).
• Clamp it with ratchet straps and G-clamps, using strips of wood to spread the load, and leave it overnight. A 2009 owner warned that clamps that are too tight crush the adhesive locally, and straps even the pressure out and help the bond at the bottom.
• Work in a warm garage if you can, as the adhesive sets more slowly in the cold.
• Refit the side gusset rivets and the tow bracket as in the factory guide.
• Opinions on difficulty varied. Owners who had done several said it is one of the easier jobs when rebuilding the front end, and another said they would not like to see it done by someone with no guidance. The tricky parts are getting the adhesive and primer, stripping the front end for access, and the old box.

A YouTube channel of VX220 DIY videos was sent to us as a resource: vx220diy8. We haven't checked whether it covers the crashbox.