I snapped off a diff fin last weekend trying to remove the inspection bolt (its a bit rounded) and almost broke my thumb too!

I assume these fins are purely for aero-dynamics? I always wondered why differential cases had this design. I am also surprised that I snapped it off with my knuckle although it was quite chilly/brittle.

 

It is for cooling. One being a little chipped won't hurt anything.

 

What he said. Assist with cooling and nout to do with rear downforce. You'll be fine unless you drive over a volcano.

 

I wouldn't drive it until you get the diff replaced! Them fins are crucial to the stability in the 27.68-29.87mph bracket. I've no doubt that you'll flip over in a huge firey mess if you drive it without

Now i think about it, it's more likely is that they're there to increase the surface area of the diff casing and aid oil cooling.

 

Yeah ok it was a bit thoughtless! But I have been having a nightmare trying to remove the inspection bolt and snapped it clean off. I don't like things snapping off the car. And when I drink wine, I worry more.

Now be more useful and tell me how the hell I remove a slightly rounded bolt from the diff? 24mm spanner slips. 22mm is obviously too small. The 24mm socket is a better grip but I can't get the 1/2" drive on it because of the bar blocking it. Fitting an extender to the socket hits the subsequent bar. I'd rather not drive it anywhere as it means taking it off the jacks which is a total hassle in my garage, just for someone to whip it off.

I would hammer something else onto it but there is no room to manoeuvre. I've got a replacement so don't care if I muller it in the process. What would a mechanic use, that won't further destroy the diff casing and ruin my aero-dynamics further.

 

You can get grab tools to remove them or you could weld a new nut onto it

 

I've got a reverse thread socket but again can't get the drive on the space.

With my comments about aerodynamics gives you a hint what I'm likely to be like near a welder!

Looks like I'm going to have to take it somewhere.

 

Good set of mole grips and you'll be fine

 

Chisel just on the end of a flat and gently tap it

 

It was only meant as a light hearted comment! No offence intended Do you mean your diff drain plug right at the bottom is the one causing you the problems?!

I'd try a multi hex socket on it first and if there's no joy there try and beg/borrow/steal (delete as applicable) an imperial socket that's a snug fit. Not sure what size it'd be off the top of my head?! Failing that it's time to break out the hammer