rust in double chassis rails

gday gents
i have a question about the rust that developes between the sheaves of double chassis rails in trucks like accos and km bedfords etc.
what is the best way to fix it besides dismantling chassis.
ive seen lotsa realy good trucks that were spoiled by this problem.

Hi Sparks

I'm in no way an expert but I've been told you can blast in between the rails and then paint but, of course, no guarantee you get it all. My B61 was starting to have this problem when I sold it on (made the buyer aware of it of course as it was bought over the phone) and I'd scraped some rust out but the only way to sort it was to split them. Imagine having a triple-railed Mack!

I reckon if the rails have started to spread the only fix is splitting them otherwise it'll look like shite.

Seem to remember another Mack owner who wasn't going to do any heavy work decided to turn his truck into a single rail job thereby removing the problem. Can't remember if he was in the US or Oz. I know you're planning on working your trucks so not really an option.

i bought a 700 dodge once ..the rear was double chassis rails .. it looked like the previous owner had a go at cleaning the rust between the rails then along the join there were a few large "spot welds" i guess t keep the chassis from spreading

Once they start spreading between the rails they are usually cactus, you can split the rails if you get them early, but usually by the time anyone sees it, it is too late. Very expensive and time consuming to fix.

if its only on top and bottom flanges and not too bad,i've heard that you can pulverise it by putting a jackhammer chisel point in the spread and rattling it ,then blow away dust with air.
has anyone tried this.

sparks

Rust is like the BIG C unless you get it early and fix it properly then you will be forever chasing and eventully it will win, so if you are going to keep the truck pull it apart and do it correct and see how bad it is, if its to bad then maybe the truck should not be on the road anyway without a major repair.

Trevor

the rust is on the chassis rails of a truck that i was thinking of buying for parts and could use on my property,as its dirt cheap and has good motor gearbox diff
and lots of other good parts,i think i'll pick it up to get the bits.
thanks.

total strip down sand blast and paint re assemble and touch up paint as required if the pitting is to severe you might be better off getting another set of chassis rails sand blasting and painting then swap every thing over just cleaning up what you see wont fix the corrosion going on where you cant see it make model suspension type wheel base and some one hear may be able to find you a set of clean rails don

What you mean is- I can only see it on the top and bottom flanges. If you can see it there it is knackered. You cam use the oxy and heat it up and the scale will sort of opo out, you can beat the shite out of it with a hammer, sometimes you can put a cutting wheel on a 9" grinder and run it between the flanges, but at the end of the day, you will only clean it up a bit to hide it, maybe get another couple of years of going over the pits out of it, but you won't fix it. To fix it you need to pull it apart.

if its only on top and bottom flanges and not too bad,i've heard that you can pulverise it by putting a jackhammer chisel point in the spread and rattling it ,then blow away dust with air.
has anyone tried this.

You can get the rust out of the rails or at least the flakey loose stuff by wedging lightly and using a air chisel with a blunt end about 1" diameter, thin blade and a air nozzle. It is dirty, heaps of work the more bolts that is pulled out the better, it will wreck the paint and the chassis rails will be thinner because the rust has removed something. The flanges tend to return back reasonably straight, I have only rattled a few yank trucks to make them look correct but it doesn't fix the problem as there is no paint from original so most trucks suffer in this area. You need to get something like a cavity wax between the rails to slow the rust down. It's not a perfect world but better then truck go to scrappy