Double Frame Rust

[bobo]

Im stripping the rw713 down for paint. I was just going to have the frame blasted, sealed and painted, but there is a fair amount of rust scale between the two(double) frames. I was thinking of cutting the outer rail off some where by the cab cleaning out rust and painting inside before rewelding and installing the outer rail. any thoughts? bobo

[Rob]

Im stripping the rw713 down for paint. I was just going to have the frame blasted, sealed and painted, but there is a fair amount of rust scale between the two(double) frames. I was thinking of cutting the outer rail off some where by the cab cleaning out rust and painting inside before rewelding and installing the outer rail. any thoughts? bobo

I've done that when there is spreading of the rails. If it is just rusty and not spread, have your blaster "delve" in the area(s) to root out the rust. Then pressure wash the blasted are leaving the truck frame in the sun to dry. By the time you acid etch the bare steel to promote undercoat adhesion, the flash rust will be nothing to worry about.

Rob

[bobo]

I've done that when there is spreading of the rails. If it is just rusty and not spread, have your blaster "delve" in the area(s) to root out the rust. Then pressure wash the blasted are leaving the truck frame in the sun to dry. By the time you acid etch the bare steel to promote undercoat adhesion, the flash rust will be nothing to worry about.

Rob

hey rob its pretty bad in some spots maybe 7/16 between the flanges, monday im pulling the 5th plate/slider off. see how bad it is under there. The truck was a float tractor, wasnt used much, only 280k on truck. It was washed more then it moved! bobo

[Rob]

hey rob its pretty bad in some spots maybe 7/16 between the flanges, monday im pulling the 5th plate/slider off. see how bad it is under there. The truck was a float tractor, wasnt used much, only 280k on truck. It was washed more then it moved! bobo

I have done exactly what you are proposing to do. It would be in your interest to purchase a small right angle grinder jig to limit depth of cut. I then use the perimeter of a 3/64ths, 3/32nds, or 1/8th inch thick grinding cutoff disc to basically slice the outer frame wrap from the inner. It takes a bit of time, but there is no damage to the underlying material. I use my grinder to cut 1/4's from wrecked cars and it works slick. Your line of cut will be so straight that if it is not damaged, or thinned from the rust, it can be beveled on the edge and reinstalled after the rust is removed. Be sure to use enough heat to penetrate the baseplate completely but not enough to melt into the underlying frame, (inner rail) as it isn't needed.

Rob

[vanscottbuilders]

Hey guys - I don't want to burst anybody's bubble here but -

My own experience is:

If you really have 7/16" spreading between frame rails - it will never pass a DOT inspection.

And welding it together isn't an option. That really draws attention to your problem.

Rust jacking is really common here in the Northeast, and has already caused me to part out a beautiful low mileage 1966 R-600 after having a creeper cop look it over before I started a restoration project. For minor spreading (1/8 - 1/4"), cleaning and painting as Rob suggests is a viable solution. Any more than that and you really are looking for trouble with the law.

Some spreading is a natural ocurrence with the flexing of the frame under load. But excessive spreading like you are talking about will definitely draw attention in an inspection.

I don't know how practical it is, or how far you might be willing to go, but you might consider splitting the rails, thoroughly sandblasting out all of the rust, epoxy priming and reassembling the frame. That's a very labor intensive fix, but at least it gets the job done right, and you have no further worries.

Just my two cents,

Paul Van Scott

[phildirt]

I agree with Paul- On my RW 613 the inner and outer frame rails were separated almost 3/4" just in back of the sleeper. As the two parts were forced apart you could watch the rails regain their original shape. I would never have thought they would come back in line.

I sand- blasted to white metal on the mating surfaces and coated with Zero Rust coating.

See the attached picture- the inner rails are on the ground under the frame.

Phildirt

[Rob]

I agree with Paul- On my RW 613 the inner and outer frame rails were separated almost 3/4" just in back of the sleeper. As the two parts were forced apart you could watch the rails regain their original shape. I would never have thought they would come back in line.

I sand- blasted to white metal on the mating surfaces and coated with Zero Rust coating.

See the attached picture- the inner rails are on the ground under the frame.

Phildirt

I've done this plenty also. However, if you don't plan on breaking the truck apart complete to separate the rails, (it is a LOT of work) the earlier mentioned way is very effective as the cab, crossmembers, or driveline is not removed.

At today's cost of labor and materials, the most cost effective solution is usually best. On my own trucks they come apart or are lengthened as I've never had occasion to shorten.

Rob

[bobo]

Rob Im doing just like you said, shallow cuts. frame is striped and will cut her up on sunday....

[bobo]

ROB I did just like you said! It work out beautiful, I was getting a little discouraged when having trouble pressing outer rails off. 4 porta power jacks and some good friends that can take my abuse, BUT well worth the time and effort to do it. I painted the inside of the outer, and outside of inner with POR-15, We didnt even have to straighten any of the flanges out, they poped back into place on thier own. hope to have it welded by next monday, then sand blast and epoxy priming the frame boB0

[Rob]

ROB I did just like you said! It work out beautiful, I was getting a little discouraged when having trouble pressing outer rails off. 4 porta power jacks and some good friends that can take my abuse, BUT well worth the time and effort to do it. I painted the inside of the outer, and outside of inner with POR-15, We didnt even have to straighten any of the flanges out, they poped back into place on thier own. hope to have it welded by next monday, then sand blast and epoxy priming the frame boB0

Great news and congratulations! It still is a lot of work I know but will be worth the effort when complete.

Rob

[vxx]

Hey I know this is an old post but thought id ask as I'm going through this exact problem right now. Ive split the rails, the outer rails went back into place. However, when measuring the inner rails when removed I noticed that there will still be a gap when they are put back into place. Any thoughts or ideas as to what to do in this situation. Is there anyway to save these rails and have them align with no spreading with the outer rails?. Or do I need new inner rails? Thanks for the input(11 years later) haha

[Joey Mack]

please show pics...  rust protrusion is a bitch... is that what this is about?    jojo

[vxx]

Here are the pictures of the rust jacking before I removed the rails, note the spreading. After they were removed the rust was cleaned off, when the inner rails were off and were measured I realized that there would still be a decent sized gap between the inner/outer rails. Now Im wondering if there is a way to make them align again, or are new rails really needed? 
 

[Joey Mack]

I have only ever done fresh rail replacements... but I dont see why you couldnt reuse the rails if they are cleaned up and strong.. (based on your opinion)  so I would use 'body bound bolts'  unless you have a Huck bolt machine and the Huck bolts.. I expect more comments on this from the many smart guy's here..  I have no problem using bolts to put it back together...  thats how trucks were built since day one..  jojo

[Vladislav]

It's possible someone already rebuilt your chassis in the past and used rails which didn't mutch the size well enough. If the issue was done by rust the shelves of the rails must be slightly bent relating to the horizont. If so I would try to forse them down into the normal position hitting by sledgehammer along the edge or using hydraulic what's more preferrably.

[Vladislav]

9 hours ago, Joey Mack said:

 thats how trucks were built since day one..  jojo

Many were also hot riveted in the early days

Edited December 16, 2021 by Vladislav

[Onyx610]

That’s one of the best looking double wall frames I have ever seen. 

[Joey Mack]

i forgot about hot rivets..

[Vladislav]

To me it's difficult to forget them

[mrsmackpaul]

13 hours ago, vxx said:

Here are the pictures of the rust jacking before I removed the rails, note the spreading. After they were removed the rust was cleaned off, when the inner rails were off and were measured I realized that there would still be a decent sized gap between the inner/outer rails. Now Im wondering if there is a way to make them align again, or are new rails really needed? 
 

Maybe its just the angle of the photo

From what I can see that doesn't look to bad, even in dry old Australia were no salt is used on roads we get a lot worse rust between the rails 

So back to the question at hand, the gap should make difference in my mind and must of been there from new for the cross members to fit 

Mack Australia or any other Australian truck builder didnt use "body bound bolts" back in the 60s, 70s and 80s, just normal high tensile bolts 

Huck bolts came along much later that I know of 

If it was mine and from the photos I can see, I would clean them up as best as I can, rust proof paint, cover the mating surfaces with heaps of grease and just bolt them back up 

Do the bolts up tight with a rattle gun and drive away 

Some times it pays to not over think things 

 

Paul

 

[Onyx610]

Once you hear what sounds like a 9mm going off in the shop and later you find the head of a bolt far from the truck that looks like it came off the frame. Then it’s time to maybe start thinking about it….Also when they get bad you will start to get horizontal cracks develop on the bottom of the frame where it starts to bend in and the two frame rails will push away from eachother. 

[vxx]

Thanks for the input, the photo doesn’t look as bad as it is (at least for me). The spread was 1/2” to 3/4” in some places. Until i had my International frame crack in 4 places along the bottom flange I wouldn't of never even thought twice about rust between 2 frames. The spread on the International was just about the same as this. I have a steel wholesaler making me 2 new rails, my main concern was the fact that I heard around here they were failing double frames because of the spread. Reading the posts about this issue made it seem as if once the rust was removed that the rails would just align back into place without any gap. Heres some pictures of the International frame cracks due to the double frame rust.

 

 

 

Edited December 16, 2021 by vxx

[Onyx610]

Yup those are the cracks. Never seen them that bad. Problem with these frames is once the rust starts there isn’t much you can really do about it. It just spreads like cancer. That’s just my opinion. New rails would be the only way to go depending on money and how long you plan on keeping the truck. 

[Onyx610]

Idk where you are located but if you want to feel a lot better about yourself come see some double wall frames from the northeast, or I could send you some pictures….😄 But by looking at those last frame pictures I believe your already living it.

Edited December 16, 2021 by Onyx610

[Vladislav]

Also a question is which model your truck is. If it's CH or CX (if a Mack) they have straight rails front to rear and you are able to order a full length newly made channels. Much more job removing the engine and the cab but you would get a truck with chassis of the same or even higher performance than it was originally leaving the factory. Older Macks with "fashioned" front end of the rails don't allow such approach so welding turns out as about the only option.

The rails themself aren't extremely expensive. But the amount of job may differ.