Performing Quality Assurance Checks on the Rear Subframe and Comparing Phosphate Primer Coating to Powder Coating

[Allan8932]

How can I tell if my rear subframe has to be replaced? It has peeling surface rust, but how do I know whether I need to replace it?

While it's off, I'm going to clean it up with a wire wheel and install new nuts and bushes, but I also want to make sure it's still safe to use.

Is it still OK if I smash it with a hammer and poke at it and no holes appear?

What is the best option if I do need one? Is it powder coated or phosphate primed?

 

[cumblechook22]

It will take forever to wire brush it, and it will be difficult to reach all of the crevices, so if you can afford it, you should look for someone local who can sandblast it for you. This will restore the metal to its original state.

 

Is the subframe assumed to be from the initial year of production?

[Allan8932]

1984, perhaps the original, but the previous owner said he repaired the vehicle and it seemed clean at the time, but now his bodges are beginning to show (most notably in the trunk floor region where he bonded metal plates over holes and smoothed it over)...

Thank you for inquiring about the cost of shot blasting.

[Allan8932]

How much does shotblasting usually cost?

[ianwh4]

About three years ago, I had the front and rear subframes of our '86 shot blast and powder coated for a total of £75.

I thought about getting a new back end, but I was set on using original equipment parts. When I took the back off, I found a sticker revealing that it was an aftermarket subby from 1997.

[cumblechook22]

I received a quotation for £120 to do the front and back?  Personally, I believe it is worthwhile.

 

Powder coating is normally done by the same folks, so I'm not going to bother, but it never hurts to inquire how much it costs and see if it works for you.

 

£75 for blasting AND coating is an absolute value. That's something I'd absolutely agree to.

[Allan8932]

Greetings and thanks for the quotes.

Don't want to spend too much money blasting it in case it comes back with holes and has to be replaced nevertheless.

[cumblechook22]

The subframes are composed of rather substantial materials, so it takes a long for rust to penetrate them. Additionally, the fact that it is an 80s model rather than an older 60s or 70s model may be advantageous.

It obviously depends on how it lived its existence, but you may certainly follow your advice and bash everything with a hammer to see if you can uncover any alarming areas.

The fronts, which are clearly covered in oil throughout the most of their lives, do seem to suffer more than the backs.

[Allan8932]

Tonight I took a closer look at the frame.

Is it just me, or is this subframe crooked, or is this how they should be? (Piece of timber to display)

 

 

There seems to be a thin sheet of metal linked to the thicker material behind the HiLo suspension on the underside of the subframe; does this thin portion show any symptoms of weakness, or is it not cause for concern?

 

[MrGreedy]

Bent and rusty where it's been used a lot.It might be possible to fix, but there could be more rust.Replacing seems to be the choice.Steve..

[cumblechook22]

Bent and rusty where it's been used a lot.It might be possible to fix, but there could be more rust.Replacing seems to be the choiceBent and rusty where it's been used a lot.It might be possible to fix, but there could be more rust.Replacing seems to be the choice

[developer]

I would toss it in the trash and replace it with a new or gently used one.

[Howard_silver]

1 minute ago, developer said:

I would toss it in the trash and replace it with a new or gently used one.

This ^

 

If money isn't too tight, a new one would be best.