ducky698 Posted April 20, 2009 Share Posted April 20, 2009 Hello, any one split a R model chassis? the one with inner and outer rails. I have this thing stripped and cant get the inner rail out of the outer rail, it does have rust between the two but am surprised to see it still together after 3 hours of argueing with it. pic attached is prior to cross beams out, i now have the two rails laying flat next to each other, would like to see 4 tho.are they hard to get apart? any specific techniques?any help would be great, thankyouGrant Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/ Share on other sites More sharing options...
Lmackattack Posted April 20, 2009 Share Posted April 20, 2009 they can be a pita to split if the rust is bad. When the rails rust the inner rail tends to spread and pinch the outer rail. lots of prying to get it out sometimes, use a wedge and hammer it down the rail adding blocks behind it. hopefully once it starts coming out it will get easy.Trent Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34111 Share on other sites More sharing options...
ducky698 Posted April 20, 2009 Author Share Posted April 20, 2009 they can be a pita to split if the rust is bad. When the rails rust the inner rail tends to spread and pinch the outer rail. lots of prying to get it out sometimes, use a wedge and hammer it down the rail adding blocks behind it. hopefully once it starts coming out it will get easy.TrentIts gone about 60inches down and stopped, am now worried about kinking the channel, will find a wedge, need a long bar tho.thankyou for suggestion.Grant Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34138 Share on other sites More sharing options...
ThaddeusW Posted April 21, 2009 Share Posted April 21, 2009 Could heating the outside rail with a torch and then cooling the inner rail with a squirt from a water hose help any? Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34149 Share on other sites More sharing options...
Lmackattack Posted April 21, 2009 Share Posted April 21, 2009 last time I split some double rails we placed one end of the channels up aganst a tree and then used a bob cat to force long round blocks of wood inbetween. it took a few tries but at the halfway point they seaparated. I woudent use heat as they are likely just pinched from rust and the heat wont do much unless the rust works its way out.. I know you should not weld on frame rails but not sure if heating them is just as bad. i suspect it is not a good idea????Trent Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34152 Share on other sites More sharing options...
ThaddeusW Posted April 21, 2009 Share Posted April 21, 2009 last time I split some double rails we placed one end of the channels up aganst a tree and then used a bob cat to force long round blocks of wood inbetween. it took a few tries but at the halfway point they seaparated. I woudent use heat as they are likely just pinched from rust and the heat wont do much unless the rust works its way out.. I know you should not weld on frame rails but not sure if heating them is just as bad. i suspect it is not a good idea????TrentYou don't need that much heat to get them to expand. You only need a few hundred degrees, and even though tempratures of about 270 degrees can temper steel it usually takes a while to happen. So heating the rail and then trying to seperate it quickly might work. But good point on the rust acting as glue. I guess brute force is the best method at the moment. Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34160 Share on other sites More sharing options...
Rob Posted April 21, 2009 Share Posted April 21, 2009 Although it will tire you out in a hurry, apply a smart "slap" with a 12 pound hammer to the outer rail where the wedge is jammed inside and stuck. This may take a few times. If you have access to a small jackhammer the job is not too bad even when rails are damn near fused. Use a blunt ended bit. The impacts and resonance will separate the two frame sections. As the sections release, force the wedge in further until they come apart.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34166 Share on other sites More sharing options...
Mark from OZ Posted April 21, 2009 Share Posted April 21, 2009 Ducky. Get a air chisel with a blunt / flat tip and run it along the corners. You will be amazed at the stuff that comes out. I found that the corners are the ones that hold it together. once you get the rust out of the corners it will come apart. I don't like using heat. Mark Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34178 Share on other sites More sharing options...
mackdaddy1911a1 Posted April 21, 2009 Share Posted April 21, 2009 If the rail is "HEAT TREATED" you could weakin it . ON my truck there are big signs on the rails ..."DO NOT HEAT,WELD,CUT, OR NOTCH FRAME FLANGE". I would rather have a few hours of hard work than destroy a good rail. Ducky becareful and if you get aggravated with it take a break and come back to it. Robs idea sounds good as well as the others . Quote THE GREATEST NAME IN TRUCKS MACK TRUCKS Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34182 Share on other sites More sharing options...
ducky698 Posted April 21, 2009 Author Share Posted April 21, 2009 If the rail is "HEAT TREATED" you could weakin it . ON my truck there are big signs on the rails ..."DO NOT HEAT,WELD,CUT, OR NOTCH FRAME FLANGE". I would rather have a few hours of hard work than destroy a good rail. Ducky becareful and if you get aggravated with it take a break and come back to it. Robs idea sounds good as well as the others .Hi, they were made in 1969, so not heat treated, I will avoid heat, today they got a gallon of phosphoric acid to break down the rust, still no luck but tomorrow am putting it against a 20 foot container and putting a forklift thru it! dam thing! the rust is not bad compared to most I have seen, but I do have to split the rails, not stopping now!Grant Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34188 Share on other sites More sharing options...
ducky698 Posted April 22, 2009 Author Share Posted April 22, 2009 If the rail is "HEAT TREATED" you could weakin it . ON my truck there are big signs on the rails ..."DO NOT HEAT,WELD,CUT, OR NOTCH FRAME FLANGE". I would rather have a few hours of hard work than destroy a good rail. Ducky becareful and if you get aggravated with it take a break and come back to it. Robs idea sounds good as well as the others .Got them apart! tried by driving them into a 20ft container weighing 10 ton and failed, then welded 2 nuts half way down chassis and used a bolt to push inner rail out of outer rail. now for the clean up. what paint shuld be used to stop them rusting?Grant Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34249 Share on other sites More sharing options...
Mark from OZ Posted April 22, 2009 Share Posted April 22, 2009 Got them apart! tried by driving them into a 20ft container weighing 10 ton and failed, then welded 2 nuts half way down chassis and used a bolt to push inner rail out of outer rail. now for the clean up. what paint shuld be used to stop them rusting?GrantDucky Sandblast them. Unless you get rid of ALL the rust you can paint them with all of the expensive paintsand it will come back. Blast them. Just prime and use an enamel chasis paint, GMH chasis black is the cheapestIt will see you out. They were un painted inside at the factory anyway. Mark Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34252 Share on other sites More sharing options...
ducky698 Posted April 22, 2009 Author Share Posted April 22, 2009 Ducky Sandblast them. Unless you get rid of ALL the rust you can paint them with all of the expensive paintsand it will come back. Blast them. Just prime and use an enamel chasis paint, GMH chasis black is the cheapestIt will see you out. They were un painted inside at the factory anyway. MarkWill do, am hitting them today with a needle gun, them get them blasted! I nearly bought brand new rails yesterday if these didnt come apart, new ones were 13,000 aud for un drilled 343 inch long rails that were just under 11 inches high, these rails are only 9 inches.the price stopped me!Grant Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34256 Share on other sites More sharing options...
mackdaddy1911a1 Posted April 22, 2009 Share Posted April 22, 2009 That is a good deal...glad to hear it. Quote THE GREATEST NAME IN TRUCKS MACK TRUCKS Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34258 Share on other sites More sharing options...
Freightrain Posted April 23, 2009 Share Posted April 23, 2009 I took the outer frame off my B because of spreading. They were only about 12ft long, but still a beach to get unhooked. Took a few hits with sledge and a longgg bar to get them to fall off.Glad to hear you got them apart. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34297 Share on other sites More sharing options...
ducky698 Posted April 24, 2009 Author Share Posted April 24, 2009 I took the outer frame off my B because of spreading. They were only about 12ft long, but still a beach to get unhooked. Took a few hits with sledge and a longgg bar to get them to fall off.Glad to hear you got them apart.The first one took all day, the second one 2 hours once we had foundd a system that worked. now i have to straighten the one we bent! Grant Quote Link to comment https://www.bigmacktrucks.com/topic/9106-splitting-r-model-chassis/#findComment-34302 Share on other sites More sharing options...
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