The back end body design of the GMC's are not very good at all. Water, dirt, grim, and dust gets continously trapped on the top inside wheel well edge and if not constantly scrubbed with a brush and pressure washer it will rust on you. Also GMC had the idea to put clean out/drain holes along the entire inside outer edge of the wheel wells with a black rubber plug. Ideally, you need to take the plugs out every time, spray them with a pressure washer, oil them up and put the plugs in but even this is not full proof...as you can see by the pictures, what ends up happening is moisture builds up between the plug and the quarter panels and just eats away at the metal. Once it goes, there is no stopping it unless you replace a section of the paneling, replace then entire quarter panel, or best scenario is get a brand new box from factory and get it re primed, painted and clear coated.
The 3M strips GM puts at the bottom of the quarter panels behind the back door is a 3 year at most protective measure. There are so many rocks that hit it (even with good aftermarket mud flaps), that the 3M strips rip off in 3 years and you are left with rust. A better measure would have been to spray the bottom with a thick coat of line-x. This would protect it 10 x better and the cost is quick insignificant.
If you pay attention to older GMC's, pay attention to the quarter panels. You will notice most, if not all have rust of varying levels. I have seen the odd one without it, but it's far few and between.
I would say, these are Rust buckets...if you are ok with rust, she's a good truck mechanically. Solution: Put fender flares on them and spray the bottoms with line-x...The fender flares won't fix the rust but they will made you feel like it's in better condition than it is for few extra years until, you know, they fall off as there is no metal left to hold them in place!!
A D V E R T I S E M E N T S
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The back end body design of the GMC's are not very good at all. Water, dirt, grim, and dust gets continously trapped on the top inside wheel well edge and if not constantly scrubbed with a brush and pressure washer it will rust on you. Also GMC had the idea to put clean out/drain holes along the entire inside outer edge of the wheel wells with a black rubber plug. Ideally, you need to take the plugs out every time, spray them with a pressure washer, oil them up and put the plugs in but even this is not full proof...as you can see by the pictures, what ends up happening is moisture builds up between the plug and the quarter panels and just eats away at the metal. Once it goes, there is no stopping it unless you replace a section of the paneling, replace then entire quarter panel, or best scenario is get a brand new box from factory and get it re primed, painted and clear coated.
The 3M strips GM puts at the bottom of the quarter panels behind the back door is a 3 year at most protective measure. There are so many rocks that hit it (even with good aftermarket mud flaps), that the 3M strips rip off in 3 years and you are left with rust. A better measure would have been to spray the bottom with a thick coat of line-x. This would protect it 10 x better and the cost is quick insignificant.
If you pay attention to older GMC's, pay attention to the quarter panels. You will notice most, if not all have rust of varying levels. I have seen the odd one without it, but it's far few and between.
I would say, these are Rust buckets...if you are ok with rust, she's a good truck mechanically. Solution: Put fender flares on them and spray the bottoms with line-x...The fender flares won't fix the rust but they will made you feel like it's in better condition than it is for few extra years until, you know, they fall off as there is no metal left to hold them in place!!
- Cody C., Edmonton, AB, Canada