Welded 'brackets' on rear frame rail assembly - function?

[MKS]

Hi there.
I am in the process of replacing the rusted out rear boot floor using an excellent replacement panel from Eurosport UK. When I removed the rusted out panel I noticed that the rear frame rail assembly body panel has six spot welded 'brackets' (for want of another term). These brackets look like they may support something like wiring or exhaust heat shielding. I have outlined in green the 'brackets' in the attached image.

Does anyone know what their function is?

Thank you for assistance with this query.

Regards

 

[Dan Sarandrea (Phila)]

In stock form those are fold-over tabs to secure (as you surmised) heat shielding. The example below is from a US spec FI car, on which the exhaust passes thru the right-hand opening in the lower chassis panel. On RHD cars like yours, I'm guessing that the folded over edges along the opposite side opening in that same panel indicate that your exhaust likely passes thru the opening on the left side of the car.

IIRC there are also a couple more on each underside inboard side of the runk pockets that hold the side shield/insulator in place.

 

[MKS]

In stock form those are fold-over tabs to secure (as you surmised) heat shielding. The example below is from a US spec FI car, on which the exhaust passes thru the right-hand opening in the lower chassis panel. On RHD cars like yours, I'm guessing that the folded over edges along the opposite side opening in that same panel indicate that your exhaust likely passes thru the opening on the left side of the car.

IIRC there are also a couple more on each underside inboard side of the runk pockets that hold the side shield/insulator in place.
View attachment 73505

Hi Dan
Thank you so much for your response and the photo. Obviously, on my car any heat shielding that may have been originally fitted by the factory has been removed at some stage in its history. Replacement heat shields no longer appear to be available? I will need to look into after market options when I get to that point. As a consequence, these tabs seem to be now redundant so I may remove them to make it easier to refinish the panel.

 

[Dan Sarandrea (Phila)]

If at all possible I would keep these metal tabs and just work around them. If later on you decide to install some manner of heat shielding, the tabs are perfectly located and fit for purpose, so IMHO there is no compelling reason to get rid of them.

The original heat shielding was sheet aluminum bent into simple shapes, so fabricating suitable replacements would certainly be doable for a home mechanic. In the USA it is common for residential homes to use thin aluminum stock to install siding, trim window openings and roof fixtures using a portable brake.

If you have something similar in Australia, I would imagine you could get someone in that trade who happened to be working in your neighborhood to bend up some pieces on their lunch break to match cardboard mockups you supply, for a persuasive amount of ready cash


If you refer back to my pic, you'll note that backing the metal shielding is compressed fiberglass insulation sheets glued to the metal. This method of insulation is a double-edged sword----yes it is a safe, cheap and effective insulator, however its placement between the sheet metal and the body tends to trap moisture in unfortunate places leading in many cases to premature metal rot, especially in cars driven in colder and/or wetter climates, or cars that don't get enough use to get hot enough to drive off moisture. Many forum members have adjusted by removing the fiberglass material while retaining the sheet metal, which is not a bad compromise.

 

[Ics19]

I must admit, I've never seen the shielding on UK (RHD) carb'ed cars, as without the CAT, the whole exhaust sits lower - maybe it was a cost saving to leave out the shielding as the heating risk was reduced? The left hand opening is where the exhaust hanger bracket passes through from gearbox to exhaust top.

 

[MKS]

Thanks for your responses - much appreciated. Certainly fabricating aluminium heat shielding with or without an insulation material is an option I will consider and will retain the tabs in any case. Other heat shielding products such as those made by Thermotec may also be an option.
My car is pre-CAT so may have not had a heat shield fitted originally.

 

[PaulD]

If at all possible I would keep these metal tabs and just work around them. If later on you decide to install some manner of heat shielding, the tabs are perfectly located and fit for purpose, so IMHO there is no compelling reason to get rid of them.

The original heat shielding was sheet aluminum bent into simple shapes, so fabricating suitable replacements would certainly be doable for a home mechanic. In the USA it is common for residential homes to use thin aluminum stock to install siding, trim window openings and roof fixtures using a portable brake.

If you have something similar in Australia, I would imagine you could get someone in that trade who happened to be working in your neighborhood to bend up some pieces on their lunch break to match cardboard mockups you supply, for a persuasive amount of ready cash


If you refer back to my pic, you'll note that backing the metal shielding is compressed fiberglass insulation sheets glued to the metal. This method of insulation is a double-edged sword----yes it is a safe, cheap and effective insulator, however its placement between the sheet metal and the body tends to trap moisture in unfortunate places leading in many cases to premature metal rot, especially in cars driven in colder and/or wetter climates, or cars that don't get enough use to get hot enough to drive off moisture. Many forum members have adjusted by removing the fiberglass material while retaining the sheet metal, which is not a bad compromise.

I used rock wool insulation which does not hold water.