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Splitting Frame Rails

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Gday how is everyone? Im trying to restore an R615RS. I bought it as a rigid tipper but I want to make it back into a prime mover as it was originally, and restore it to new condition. The chassis rails need splitting as there is a bit of growth between them and it is parting them. Ive never done this before and would appreciate any info if someone has done it. Just the best way to go about it, any helpful hints or where I could run into trouble. Thanks everyone in the hope of hearing something, cheers. :mack1:

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hi skip my friends did the job on a dump truck last month they started washing the truck let it dry put some wd40 or equivalent to all the bolts let it stand few minutes aplyng some more, jack the frame secure they use wood so it doesnt slip beneath the cab and at the end of the chassis and the front also lift little by little to take the pressure out of the tandem with the bots out of place they sPlit the frame. pressure wash again let it dry they used red oxide paint primer then painted black again this took about 5 days but they cleaned the end of the frame to the back of the cab but since thats the area that usualy splits it was good enough for me because the front was in good shape ,remember that when you split the frames the inner frame is still helping the other side work safely never alone .the best work is the one we make our self but sometimes is beter to leave it to the experts if you find a buddy who has done it before ask for his help there are many people who enjoys woking on trucks for the fun of it good luck with your proyect, RODERICK

Edited by rodperformance

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Thanks old mate. My chassis is completely stripped, no cab or body, suspension, driveline etc. Im a bit worried about actually getting the 2 rails apart. Someone down here said there is a good chance that I will damage the inner rail removing it from the outer, because of the amount of rust and growth between them. Would it be helpful if I tacked the cross members to the inner rail and supported them, and then try to pry the outer rail out? Was yours the black DM with a red chassis?

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Would it be helpful if I tacked the cross members to the inner rail and supported them, and then try to pry the outer rail out?

I wouldn't recommend that. Try not to weld on a frame rail unless it's a repair for an already broken frame, a splice to lengthen a rail, or to weld a dump body hinge to the rear end of the frame.

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I wouldn't recommend that. Try not to weld on a frame rail unless it's a repair for an already broken frame, a splice to lengthen a rail, or to weld a dump body hinge to the rear end of the frame.

That sounds fair. Do you have any thoughts on splitting them? I want to keep the rails because its a very rare truck out here. cheers :mack1:

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I've never tried to separate the 2 rails of a rust spread double frame, but if I did, I would make double sure all fasteners from one end to the other are removed, then try to start from one end, maybe put a chisel between the 2 rails (in the vertical section) and hammer it in like a wedge to try to get it to start separating, then use something larger, like a wood splitting wedge once it starts coming apart.

Just go easy, so the frame doesn't get distorted.

I'm sure Matt Pfahl would have a method for doing this, perhaps he'll see this and chime in.

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I've never tried to separate the 2 rails of a rust spread double frame, but if I did, I would make double sure all fasteners from one end to the other are removed, then try to start from one end, maybe put a chisel between the 2 rails (in the vertical section) and hammer it in like a wedge to try to get it to start separating, then use something larger, like a wood splitting wedge once it starts coming apart.

Just go easy, so the frame doesn't get distorted.

I'm sure Matt Pfahl would have a method for doing this, perhaps he'll see this and chime in.

we do use a small chisel to get them going and then use a wood splitting mall after , then because of the length of some of the rails we start pounding in 4x4s watch out when they finally come out they are heavy and you will be suprized at the amount of rust. sandblast .etch prime,paintand reasemble them with large alignmet punches and c clamps. some times we do re rivet ,or cheat and use bolts with the head rounded off

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hi guys those are good ideas when one starts to hammer all the debree will fall.check the chassis bolts and replace as nesesary is mega important because there is the strengh of the chassis and the most is back of the cab. HK is right do not weld on framerails since they are forged it loses some of the hardneded properties unless crucial.dont forget to hand tight all the bolts in place before you fasten completly sometimes is a pain in the neck goodluck again RODERICK

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hi guys those are good ideas when one starts to hammer all the debree will fall.check the chassis bolts and replace as nesesary is mega important because there is the strengh of the chassis and the most is back of the cab. HK is right do not weld on framerails since they are forged it loses some of the hardneded properties unless crucial.dont forget to hand tight all the bolts in place before you fasten completly sometimes is a pain in the neck goodluck again RODERICK

Thanks mate, and everyone else who has chipped in too. Can you buy the stepped shank chassis bolts anywhere or will they be a special order? Im going to use all new bolts because there are different bolts everywhere along the chassis. Someone along the line somewhere has attempted to do the truck up but its just a disgrace, its quite possibly the roughest job ive ever seen on a truck. They mustve been in a hurry. Cheers all :mack1:

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Thanks mate, and everyone else who has chipped in too. Can you buy the stepped shank chassis bolts anywhere or will they be a special order? Im going to use all new bolts because there are different bolts everywhere along the chassis. Someone along the line somewhere has attempted to do the truck up but its just a disgrace, its quite possibly the roughest job ive ever seen on a truck. They mustve been in a hurry. Cheers all :mack1:

When I separated my frame rails I started with an air chisel and a flat hammer bit to loosen the rust. Then a large firewood type wedge in the end all the while with more hammering from the air chisel. Then when the gap was too big for the wedge I slipped in a portapower jaw type spreader I could keep sliding this farther in with it's hyd hose. Once the frames were apart a needle scaler takes the heavy rust of fast, that will make the sandblasting go much faster.

The frame bolts Macks calls "body bound" thier shoulders have a interferance fit that requires a special reamer, and it is a odd size that is not availible through industrial supplies. These bolts can somtimes be purchased from other sources Huck fasteners makes them as "Huck Fit" bolts. With any of these type of bolts the shoulder length is critical and generally 2 flat load washers are used. There is an entire section in Mack manuals on frame repair and proper bolt selection.

Chuck

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When I separated my frame rails I started with an air chisel and a flat hammer bit to loosen the rust. Then a large firewood type wedge in the end all the while with more hammering from the air chisel. Then when the gap was too big for the wedge I slipped in a portapower jaw type spreader I could keep sliding this farther in with it's hyd hose. Once the frames were apart a needle scaler takes the heavy rust of fast, that will make the sandblasting go much faster.

The frame bolts Macks calls "body bound" thier shoulders have a interferance fit that requires a special reamer, and it is a odd size that is not availible through industrial supplies. These bolts can somtimes be purchased from other sources Huck fasteners makes them as "Huck Fit" bolts. With any of these type of bolts the shoulder length is critical and generally 2 flat load washers are used. There is an entire section in Mack manuals on frame repair and proper bolt selection.

Chuck

That is the method that I use also. Don't go "balls wild" with the wedgie, or you'll have deformed rails but use slow deliberate jacking, and beating to loosen the rust. The combination of hydraulic force, and impact will loosen the rails with time. I usually weld up a striking pad that hangs over the top flange so I don't beat directly on the frame itself. Pay particular attention to the inside of the flange area when the rails are apart to ensure the steel is not wafer thin from rust.

Good luck as you have a job ahead of you.

Rob

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When I separated my frame rails I started with an air chisel and a flat hammer bit to loosen the rust. Then a large firewood type wedge in the end all the while with more hammering from the air chisel. Then when the gap was too big for the wedge I slipped in a portapower jaw type spreader I could keep sliding this farther in with it's hyd hose. Once the frames were apart a needle scaler takes the heavy rust of fast, that will make the sandblasting go much faster.

The frame bolts Macks calls "body bound" thier shoulders have a interferance fit that requires a special reamer, and it is a odd size that is not availible through industrial supplies. These bolts can somtimes be purchased from other sources Huck fasteners makes them as "Huck Fit" bolts. With any of these type of bolts the shoulder length is critical and generally 2 flat load washers are used. There is an entire section in Mack manuals on frame repair and proper bolt selection.

Chuck

Thanks Chuck, I found the body bound bolt section in an old manual here. So far on mine Ive found the rear suspension and the front hangers have used these bolts. Because the chassis has been lenghtened and the the truck has been genarally bodged up Im not sure how many parts need these bolts. The manual doesnt say, do you know if anywhere other than the suspension needs them? :mack1:

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When I separated my frame rails I started with an air chisel and a flat hammer bit to loosen the rust. Then a large firewood type wedge in the end all the while with more hammering from the air chisel. Then when the gap was too big for the wedge I slipped in a portapower jaw type spreader I could keep sliding this farther in with it's hyd hose. Once the frames were apart a needle scaler takes the heavy rust of fast, that will make the sandblasting go much faster.

The frame bolts Macks calls "body bound" thier shoulders have a interferance fit that requires a special reamer, and it is a odd size that is not availible through industrial supplies. These bolts can somtimes be purchased from other sources Huck fasteners makes them as "Huck Fit" bolts. With any of these type of bolts the shoulder length is critical and generally 2 flat load washers are used. There is an entire section in Mack manuals on frame repair and proper bolt selection.

Chuck

Also the manual lists the reamers and their part numbers, J-26461 or similar. Is that a Kent Moore number? Cheers

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Those bolts are used on suspension and crossmembers. I believe the tool numbers are Kent Moore as that is who makes the reamers. If you are thinking of buying them check the price first they were rather expensive when I bought them.

Chuck

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Yes the bolts are expensive I think and the part no. is 3ax1827 its10.94 plus tax and the harden washer is 35ax144 its 5.37 plus tax prices are australian .not cheap :wacko:

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Yes the bolts are expensive I think and the part no. is 3ax1827 its10.94 plus tax and the harden washer is 35ax144 its 5.37 plus tax prices are australian .not cheap :wacko:

Thanks old mate Ill run the number by the local dealer. Did you have to use the reamer? I should be able to get away with using new bolts on existing holes toward the front but since Im shortening it to original length the back will want some attention. cheers :mack1:

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All new bolts is not a bad idea. Flange head bolts and nuts are available commercially, as well as hardened washers. You will find hardened washers listed as structural washers. Measure OD and ID as well as thickness to get what you want. The Mack shoulder bolts are still available from Mack. If you need anything other than stock diameter or length, be prepared for dumb looks and shrugging of the shoulders. Any thing you could buy from Kent More would be pricey. The problem with purpose built tools like these are that they are often a non standard size. Wayne Tool Co. is an excellent source for reamers. Measure every thing two or three times and don't settle for anything you are not happy with. Be creative with your thinking, a fine thread metric bolt will work just as well as an SAE. If you find you have to enlarge existing frame holes a proper reamer is the easy, safe way to do it. It is absolutely faster and more accurate. I just finished installing a used rear suspension under my RS700, and finding suitable hardware was an absolute pain in the rear. Don't become overwhelmed with your project, keep plugging at it. If I can help find something send me an email. James

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All new bolts is not a bad idea. Flange head bolts and nuts are available commercially, as well as hardened washers. You will find hardened washers listed as structural washers. Measure OD and ID as well as thickness to get what you want. The Mack shoulder bolts are still available from Mack. If you need anything other than stock diameter or length, be prepared for dumb looks and shrugging of the shoulders. Any thing you could buy from Kent More would be pricey. The problem with purpose built tools like these are that they are often a non standard size. Wayne Tool Co. is an excellent source for reamers. Measure every thing two or three times and don't settle for anything you are not happy with. Be creative with your thinking, a fine thread metric bolt will work just as well as an SAE. If you find you have to enlarge existing frame holes a proper reamer is the easy, safe way to do it. It is absolutely faster and more accurate. I just finished installing a used rear suspension under my RS700, and finding suitable hardware was an absolute pain in the rear. Don't become overwhelmed with your project, keep plugging at it. If I can help find something send me an email. James

Thanks very much James. I will have to start hunting around. Im a way off putting it back together but thats very handy to know.

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