I have solid lifters which need adjusting every 20k miles.
Mufflers need to come off to gain access to the lower cam covers.
My shop takes the mufflers off from under the car as they don't have the time to fiddle about taking the rear PU and ancillaries off first.
Since access to the exhaust clamps is tight with the PU on, they break the lower tab holding the heat shield.
So end up with an annoying rattle & hum.
I have just bought new shields to fit, but now realise that it will be broken the next time shop has to adjusts the lifters.

Are these heat shields really necessary, since there is already shielding /tinware above the mufflers.
Also I have heard the Fister cans don't have mounting brackets to fit heat shields

 

...sorry, what's a "PU"?
I've taken the mufflers off and on many times without taking anything off other than the exhaust tips. It's finicky, but 100% doable. Once the exhaust tips are off, you take off the clamp where it meets the cat, undo the big strap (no need to take it off), then lift and rotate the muffler towards the wheel (clockwise for right side, counter clockwise for left side), and slide it out through the big clamp. It has to rotate going out (and back in), so that by the time it's free of the strap and able to be taken down off the car, the pipes of the muffler are pointing upwards. Installation is the reverse. I have the heatshields on mine, and they come off with the muffler.

Aaannnyway.... I doubt that it will damage anything if the heat shields are off - it's certainly not going to start a fire or anything, and the bumper has its own heat shield. Maybe a factionally higher amount of heat getting up into the engine bay or heating up the rear quarter panels.

 

No reason your shop should be breaking the tab. They do deteriorate/corrode over time and break. I'd replace them and have a conversation with your shop about breaking them. No reason you can't get the muffler off with damaging heat shield. And...yes, you want to keep them.

 

I've had Fabspeed mufflers without heatshields for several years, no issues.

 

Thanks for all your replies and Dplus for confirming no issues for many years without heatshields
PU = polyurethane rear bumper/apron.
My shop have been taking it off whilst the tips are on (probably to save time).
I get it that they wear and become fragile with time, but unsurprisingly its only the tabs closest to the clamps that are broken clean - on both boxes.

I guess top tip is to get the tips off first ( no pun intended) and also take the rear portion of the arch liner out for room to wiggle the boxes out. Will persuade my shop to do so at the next 20k miles.

 

First time refitting exhaust mufflers back on the car.
Do I align that clip to latch onto the top edge of the exhaust bracket ?
Also do I need any exhaust paste for the O ring when joining the box to the cat ?

 

That tab sits on the ledge that holds the strap. When you set the tab in it, it will support itself and enable you to tighten the strap. I have never used any paste either.