Trailing Arm Bolt change procedure

[Martin Gutkowski <webmaster@xxxx>]

Hi All

I thought I'd better write up instructions for changing the TABs as I've 
sold several pairs of the new Inconel bolts lately. Dave and I would be 
happy to take on the task in Stevenage if you want the job done. We will 
have another 10 pairs of bolts available in a week or so.

1) You will need to manipulate the weight placed on the back wheels so 
the best method involves either a 4-post ramp or ramps you can drive the 
rear wheels on to. Halfords sell pairs of ramps for £25 ish.

2) with the rear on the ramps and the front wheels chocked, set about 
removing the dust cowlings that mount to the trailing arms and the 
underbody via three M6 studs which SHOULD be bonded into the fibreglass 
but more often than not, come loose and spin when you try to undo the 
nuts. These can be gripped with narrow-nosed pliers in the bottom of the 
compartments behind the seats. This means removal of the battery and the 
carpet in the cubby hole, and you will need an assistant.

3) Pick one side and locate the trailing arm bolt. If you're unsure 
which it is, there's a pic here

The bolt should be an M12 with 19mm hex-head, and corresponding nut. The 
factory originally installed these with a single nylock nut however 
common practice in the US has been to replace with double nuts. Note the 
positioning of all the washers and alignment shims. Make sure they get 
replaced in the same order. You may well have different numbers of 
alignment shims on both sides, this is normal. Loosen the nut a couple 
of turns. Make sure the bolt is free to turn.

4) Using a ratchet on the head of the bolt, start turning it. This 
serves two purposes. Firstly if you watch the trailing arm while turning 
it, you'll get an idea if and how much the bolt is bent by seeing how 
much the trailing arm moves. Secondly by gradually jacking the back of 
the car up, turning the bolt continuously, you should find a "sweet 
spot" where the position of the trailing arm offloads any tension on the 
bolt, allowing it to turn freely. The sweet spot should be when the rear 
wheel is ALMOST off the ramp.

5) Once you've found this sweet spot, you can remove the nut(s) and tap 
the bolt out. There're no hard and fast rules here, but you should have 
an idea of how bent the bolt is by now and IF you have to cut it out, do 
so using either an angle grinder or air-hacksaw if you have access to 
one. If using the latter, you are liable to go through several blades as 
the original bolts were hardened. If the bolt is bent, the "kink" will 
be between the arm and the chassis, though to get enough clearance to 
cut, you will not be making the first cut in the middle of the bend and 
this means you'll end up making 2 or 3 cuts to remove the bolt. Do NOT 
try and remove a bent bolt by forcing it out through the bushing, you 
may damage the steel sleeve.

6) On fitting the new bolt, coat the entire bolt, shank and threads with 
copper grease. Ensure all shims are fitted correctly. With the weight of 
the car back down on the back wheels (pre-loading the trailing arm 
bushes) torque the first nut to 60 ft-lbs. Use the second nut (the 
nylock) to lock the first one.

NOTES: The above instructions are pertinent to Manual transmission cars. 
Automatic transmissions make it a lot tighter in the area of the bolt 
head. Actually removing the bolt on an automatic transmission car 
involves removing the trailing arm from the rear hub carrier (you can 
gently let it hang and avoid having to disconnect the brake hoses) and 
removing the bush mounting the TAB to the chassis.