Ive got a second hand set of original factory side steps that I'd like to install to my P38. I've got all the brackets etc the only thing I need to buy is the threaded riv nuts to go into the pre drilled holes in chassis. Due to the limited space between chassis / sill I can't get my tool in. I've seen people use 'loose bolts' any recommendations on size needed or alternative options?

Screw a suitable size nut onto a bolt, screw the bolt into the Rivnut and put it into the hole, then, holding the bolt so it doesn't turn, screw the nut clockwise so it is against the Rvinut and keep tightening it. That will pull the Rivnut into place so you will then be able to unscrew the bolt and attach your side steps. If you want to get really flash, you could even put a washer between the nut and the Rivnut.

Best to use a high tensile bolt. Especially if using the proper riv-nuts as they are stronger than the commonly available consumer types needing more heft to compress properly. Made to be fitted with a hydraulic or hydro-pnuematic gun but good luck fitting one of those in unless you have the uber expensive extension thingy for dealing with confined spaces.

Two rigid washers with a decent film of grease between them will make the job go easier.

If I ever get round to fitting my sidesteps I shall use a ball thrust race to make life even easier. Gotta find a use for a least one of the four I saved out of the brake mechanism of the Lancia Beta HPE I had to break about 40 years ago. Too obviously useful to bin. Er. Ahem.

My steps need welding and I've not figured how to either safely get the rubber treads off or source suitable replacements.

Clive