Help with seized shock bolts, can't fit lowering springs!

[andyborris]

Got a set of lowering springs for my MX5, can't fit them because I can't get the lower coil over shock mounting bolts out (front or rear!).


Tried a proper (expensive!) penetrating fluid, beaker bar, breaker bar with scaffold tube, 450 nm electric rattle gun and an air rattle, nothing!

All that's left is heat, which I haven't got! So, anyone near me in North Kent who can help me with a bit of heat?

Just so I can crack them, I know I'll probably have to replace the shock bushes, so I need to source those before I can do anything...but, it's all I can think of now.

[pcj]

Hi Andy,
Be way careful with the heat on/near the bushes. If they're original rubber types the products of combustion should they catch fire are not the kind of thing you want to be breathing. Most magazines/sites that get round to burning out bushes recommend it is done in the great outdoors. The bushes also burn well and will happily ignite anything nearby so have the extinguisher/bucket of sand etc on standby.

If spanners, even with breaker bars, are failing, then getting the beggars out is going to depend on how much access you've got.

One possibility is to hire/borrow one of the new "induction" heating guns, which have a coil (bit like a coiled kettle element) that goes over the bolt head and heats it via high frequency induction. Can't say how much danger they would pose to the rubbers though, as the bolt would turn cherry red.

Another is to give up on extracting via spanners. Grind the heads off and then prise the shocker bush over the stub (and that's assuming the centre tube isn't also corrosion welded to the bolt). Then using some good quality high speed drill bits (new and sharp) centre punch the stub and drill it out, moving up in stages from a small drill to one just smaller than the thread in the body. Cold chisel (v carefully) the remains out bit by bit then run a tap through the hole to clean up the thread. V tedious, very hard work, depends mucho on access and how patient/skilled you are with centre-popping and drilling.

If you've got access from the inside of the car then centre-popping and drilling would be a great deal easier as you'll only need to drill in far enough to get as deep as the outside of the threaded hole where it meets the bush.

Not going to be quick whichever way you go if the heating methods fail.

[andyborris]

Induction heat guns, out my price league, I'm afraid. Plus, no electric in my garage! They do look like a good bit of kit though, one for the jackpot list!

The rear bolts are into a captive nut, which will likely tear of the arm and then it's really difficult to fit a nut into the space, so something I want to avoid.

Neither bolts are turning in the housing, which suggests, even if I get the nut of, I still won't get the bolt out of the shock eye.....guess it's new(ish) bottom arms and shocks.

[pcj]

Drat, not good news there Andy.
Well since the final possibility could be new shockers any way why not give this ago:
1) Cut/grind off the nut head so you have the bolt stub remaining and flush with the inner tube of the shocker bush

2) See if the shocker eye/bush will now prise off over the remaining stub (probably not, if it doesn't prise off then skip 3 and go to 4 below).

3) If 2 above works then grind off the remaining bolt stud till its flush with the arm/captive nut then drill out the remains as I suggested earlier

4) With the bolt head gone you can drill and cut away the rubber in the shocker eye which will allow you to get the shocker off, leaving the centre tube still stuck to the bolt stub. This drilling/cutting of the rubber will take ages believe me (I've just done the rear radius arms on my Jaguar) but it does work. Rubber cuts best if you keep the blade well wetted. If you don't want that hassle then try 5 below

5) You're here if you don't want to cut away the rubber: once the bolt head is gone you can drill it out as I suggested previously.

Or, if you know the shockers are going to be replaced anyway then grind through the eye to free it from the bolt then grind off the bolt flush with the lower arm and drill out the remaining bit.

Note: with no electricity in your garage you're going to need an ample supply of charged batteries for a portable drill. Me I cheat on that one. I had a 12V portable whose nicad rechargables finally gave up the ghost. I simply clipped a lead to each of the internal contacts where the nicads made contact in the drill handle (making sure to identify + and - and to insulate between the clips with some plastic and glue) then fitted the other ends with big croc clips which go on a standard 12V car battery. Do make sure of course that it is a !2V drill. 18Volters will barely run and 6 or 9V will eventually go bang.
First pic shows old and new arms: you can see how the old needed the rubber cutting away to release it
2nd pic shows both old arms and better view of the results of cutting away.