Under tray help

[Chris_edeson]

Hi all 

As usual with these things nothing is ever simple. I wanted to take my rear undertray off to paint it. Simple you’d think. 

One of the 2 large bolts that hold it it in place is completely nakerd just spinning regardless of trying to tighten or undo. How on earth can I get this out/off?? 

Of course it was the last bolt I went to undo and the only one that wouldn’t come out. These 2 seem to go in to the rear axle? My limited skill and tool pool means I’ve left it in the garage for now soaking in a bit of wd40. 

Will get back to it tomorrow night with hopefully some ideas from you legends. 

Cheers

chris 

[Lithopsian]

Rear undertray?  The diffuser?  Those bolts thread directly into the subframe (no axle on an Elise).  Should only be spinning if they are stripped, which you really don't want.  Not sure what is holding them in if they're stripped.  Might just pull out with a little effort.  You'll probably need to retap, probably to a larger M10 bolt.  Or a helicoil might be the best solution.  If you absolutely can't get the bolt out with a bit of pulling, might have to dremel the head off, get the diffuser out of the way, and see what is going on.  I wonder if someone has already been in there and bodged it, something like a (not very well) welded nut on there.

Or the "middle" undertray, the really big one?  These bolts go into the wishbone brackets, but the principle is the same.

[Chris_edeson]

Yeah rear undertray - got sent this by another member and it’s exactly what I’ve got.... 

https://www.pistonheads.com/gassing/topic.asp?h=0&f=15&t=1137225

 

[Lithopsian]

Well a rivnut would explain the spinning.  Pretty sure the S1 is tapped directly into the subframe, but maybe they changed it on the S2.  A loose rivnut can be a pain to get off, but if you can get something behind to jam it then it is possible.  Even pulling on it to get a bit of friction can work in marginal cases, or jamming a screwdriver under the washer or bolt head (possibly protect the diffuser surface).  It can get pretty corroded so anything you can do to get some decent releasing fluid into it will help.  WD40 isn't the best.  I like Plusgas.  Spraying from underneath, through the diffuser, won't be the most effective.  If you can get anything onto the top of the rivnut, it would be a big help, then leave it for a few hours at least.

Rivnuts can at least be replaced if you can get the old one off, and you'll want to replace it so you don't have the same problem next time.  It can be bodged up with a bolt and some nuts, but best to use the right tool.

[collieek]

I had the same problem, solved it by jamming a large long screwdriver against the riv nut. If you take a wheel off the side that is the problem you should be able to see the top of the riv nut that is spinning. Easier if you can get someone to keep pressure on the screwdriver while you undo the bolt.

Once the diffuser is off drill out the old one the rivnuts and tools to fit them are not expensive.

[winthattt]

5 hours ago, collieek said:

I had the same problem, solved it by jamming a large long screwdriver against the riv nut. If you take a wheel off the side that is the problem you should be able to see the top of the riv nut that is spinning. Easier if you can get someone to keep pressure on the screwdriver while you undo the bolt.

Once the diffuser is off drill out the old one the rivnuts and tools to fit them are not expensive.

This works, done it myself.  Big square shaft screwdriver jams the best.  You will need to fit a new rivnut which is easy if you have the tools.  Tbh, get a garage to do it, much easier on ramps.  Don’t let them remove the spinning bolt with a hammer and cold chisel, it could damage the subframe. The old rivnut base comes out with a drill.

[jody391]

Chris if its at all helpful if you can get to mine I can sort this for you?

[Chris_edeson]

23 hours ago, jody391 said:

Chris if its at all helpful if you can get to mine I can sort this for you?

I currently went for the easy option, not attempting to try do it myself and making it worse. so i painted it still in situ !! 

But next time i am in the area i will give you a shout mate - much appreciated 🙂 I am at donno trackday on 12/08 if you are around pop down!

[crinkle]

I have this problem .I don't fancy drilling out the rivnut so thought I might put another rivnut in adjacent to the offending item .Have looked in the manual and there looks to be nothing in the way .Will probably do the same thing on the other side as they seem to be a weak point .

Has anyone else gone down this route ?

[collieek]

If you are drilling another hole it is no more hassle to drill out the old riv nut. You have to get the undrtray off to fit a riv nut properly anyway.

[danwebster]

Very common on the toyota chassis unfortunately, the fixings are indeed rivnuts and I find myself replacing them on most toyota cars I get in! 

Sometimes if you're lucky you can get them out with some downward pressure on the bolt and an impact driver. 

[crinkle]

All sorted .Whipped the diffuser off and drilled and tapped a larger thread .