Acceptable Rust Inside Frame?

AndyA · Apr 30, 2023

Hi! I am currently shopping for a TJ and I have an endoscope to look inside the frame. I see plenty of threads on here about rust showing external pictures and I know what is good/bad there, but what about inside the frame?

For example is the inside of the frame the same as anywhere else - surface rust is OK and treatable? More extensive rusting OK as long as there are not loose chunks? This is assuming the outside of the frame looks good. I know that some level of rust inside is inevitable.

Thanks, Andy

SSTJ · Apr 30, 2023

Welcome to the forum.

Yes, surface rust inside the frame can be treated. What you need to look out for is big chunks of rust. Or cracks of daylight coming in of course.

If you look in the 'rust treatment' link on my build thread, you'll see some pics of what I pulled out of my frame. That was after about 20 years of life mainly in NC, a little in MD, and a little in SC. But keep in mind that the pic with the quarter were the only large pieces, and most of the rest that you see in other pics were more like the width of a pencil eraser.

Some of the other info in that link might be helpful to you too.

SSTJ · Apr 30, 2023

andya said:
Hi! I am currently shopping for a TJ and I have an endoscope to look inside the frame. I see plenty of threads on here about rust showing external pictures and I know what is good/bad there, but what about inside the frame?

For example is the inside of the frame the same as anywhere else - surface rust is OK and treatable? More extensive rusting OK as long as there are not loose chunks? This is assuming the outside of the frame looks good. I know that some level of rust inside is inevitable.

Thanks, Andy

Also, you may know this already, but watch out for the area between the frame and the transmission skid.

P man · Apr 30, 2023

I'll give you a spoiled west coast point of view. If I look in the frame and see light surface rust I'm ok with that. By light I mean the yellowish stuff that wipes off with your finger.

You want to check for delaminating of the steel on the inside or lots of flakes. Look in the problem areas near the trans skid, just before the rear arches and of course at the very ends.

AndyA · Apr 30, 2023

Many thanks - that's great info from you both!

Andy

AndyA · May 2, 2023

Found one I am interested in. Waiting for the dealer to get it back from their mechanic after replacing the rear main seal. I will get a local garage to do a PPI and focus on the frame.

The seller has already told me everything electrical and mechanical works and there is "no rust". I have that in an email.

It's a two day drive from me and if I want to secure it until I can get there they want a hefty deposit, refundable if it is "not what we said it is".

Hmmm.... they have no idea I will show up with an endoscope. Seems a straightforward out - any amount of rust at all inside the frame and we can get the deposit back, it seems? (I will put it on a credit card, not debit card!!).

Obviously I expect the driveshaft to be rusty and possibly the rear drums - don't care about that - and also some level of rust inside the frame that I can live with.

Andy

SPECWAR · May 2, 2023

The newest TJ out there is already 17 years old, and frames are all made of ferrous metals. Wake up, they all have rust somewhere.
I’ve never in my life seen so many purists.

lBasket · May 2, 2023

SPECWAR said:
The newest TJ out there is already 17 years old, and frames are all made of ferrous metals. Wake up, they all have rust somewhere.
I’ve never in my life seen so many purists.

He's trying to avoid rot

Duck Doctor · May 2, 2023

SPECWAR said:
The newest TJ out there is already 17 years old, and frames are all made of ferrous metals. Wake up, they all have rust somewhere.
I’ve never in my life seen so many purists.

plenty of 100% rust free rigs in SoCal and AZ.

AndyA · May 2, 2023

SPECWAR said:
The newest TJ out there is already 17 years old, and frames are all made of ferrous metals. Wake up, they all have rust somewhere.
I’ve never in my life seen so many purists.

Read what I wrote again. Should I have put it in bold for you?

and also some level of rust inside the frame that I can live with

lBasket · May 2, 2023

andya said:
Read what I wrote again:

you're doing the right thing here lol rust is ok rot is not

AndyA · May 2, 2023

lBasket said:
He's trying to avoid rot

Exactly. Thank you.

lBasket · May 2, 2023

andya said:
Exactly. Thank you.

Why don't you have the shop doing the PPI inspect the frame, though?

AndyA · May 2, 2023

lBasket said:
Why don't you have the shop doing the PPI inspect the frame, though?

Yes, I will do, but I don't know yet if they have an endoscope - but I will ask them. Even pay extra for them doing that! Andy

Bobohunter1776 · May 2, 2023

SPECWAR said:
I’ve never in my life seen so many purists.

How's that a purist thing? Obviously who cares about surface rust, but I like my frame to stay intact.

Shank · May 2, 2023

Bobohunter1776 said:
How's that a purist thing? Obviously who cares about surface rust, but I like my frame to stay intact.

That poster seems to love rust for some reason. The cleanest frames in our area borderline have issues under the skid plate, so not sure why.....

P man · May 2, 2023

Duck Doctor said:
plenty of 100% rust free rigs in SoCal and AZ.

Almost every yj and tj I have parted out in the PNW was still most painted black on the inside. There are still tons of yjs and tjs out west with mint frames and tubs

Shank · May 2, 2023

P man said:
Almost every yj and tj I have parted out in the PNW was still most painted black on the inside. There are still tons of yjs and tjs out west with mint frames and tubs

Make me jealous....