Hello: I am replacing the damaged k-frame on my 72 Demon. I replaced the original more than 10 years ago and all was well. I like the horn type mounts. So I manged to bend the k-frame on a high curb at speed, and I bent it badly. (more that that one later) Any way the replacement I have is a little tight and doesn't want to bolt up correctly. Hmmm. I am thinking of opening up the rear bolt holes about a 1/16 of an inch on one side that should work. but I am unsure about this approach. Will this mess with the alignment or the car tracking straight? I called around to see if any one could put this car on a frame machine and check it out. But no dice. I am told I need an old school bench frame machine to do this. This is due to the fact I have no front suspension right now and it is rolling on trailer dollies. Most body shops don't want to touch it. To use a normal frame machine I need a front suspension to roll it on the rack. So I have no choice but to get out the Die grinder. I haven't gone that far yet. So just wondering if any one has any thoughts. please post. Thanks caxey1 AKA Bo Duke.
73 kframe on 72 abody
- Thread starter Caxey1
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doug 371
Well-Known Member
can u just spread the frame rails with a porta power?
doug 371
Well-Known Member
even a bottle jack and some blocks
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Take a look at the mounting bolts.I dont know about your bolts, but mine IIRC had a special ramped area that helped to center the K to the frame.Grinding out the K will not allow the ramps to do their job. Moving the frame rails will. But that begs the question, Whats going on here?
The FSM shows in detail how to check the frame alignment using nothing more than a flat floor, a level, plumb-bob,and a sharpie.
The FSM shows in detail how to check the frame alignment using nothing more than a flat floor, a level, plumb-bob,and a sharpie.
d55dave
Well-Known Member
Yep. You best break out a tape measure, level and get the factory frame diagram. I love old school.
is the new K frame un-bent & in good shape?
you need to see if any local A body guys have a parts car or test k to verify-- these should bolt up to all 67-76 cars with minimal effort.
if K is good then you have to get your bent frame rails fixed to match the factory specs--
I would not use a die grinder I think you are creating another issue,
the shoulder on the k bolts are chamfered to tighten the K to the rails you don't want to mess with that mounting area.
Lawrence
you need to see if any local A body guys have a parts car or test k to verify-- these should bolt up to all 67-76 cars with minimal effort.
if K is good then you have to get your bent frame rails fixed to match the factory specs--
I would not use a die grinder I think you are creating another issue,
the shoulder on the k bolts are chamfered to tighten the K to the rails you don't want to mess with that mounting area.
Lawrence
Woods74
Broke Senior
Make sure you reinforce that bad boy before you slap it in; you'll be glad you did! :blob:
Don't file/grind the holes!!!
The K frame not fitting is a symptom, not the problem.
Sometimes the K frames can be a little interesting to install, make sure you have it well supported with a jack, then you'll want to thread one bolt into the frame and leave it very loose, not even up to where the shoulder of the bolt widens. Then you can use a pry bar or similar to work your way around the K frame until all of the other holes line up. They don't have to be perfect, you just have to be able to start all of the bolts. The shoulders on the K frame bolts will take care of the rest. I usually like to jack the K frame up until there's just slight pressure on the frame, then start working with the bolts, but sometimes you might have to drop one side down a little to start the bolts. Make sure the car is supported evenly, if the body dolly or jackstands aren't level they can make your life a lot more difficult. Some are just more difficult than others.
If none of that works, check your frame and K frame dimensions. You can download a body service manual for your car here MyMopar - Mopar Forums & Information - Service Manuals
And this is the chart with the measurements you're looking for. For some reason I can upload a much larger picture if it's tall (not wide), so turn it sideways after you download it.
The K frame not fitting is a symptom, not the problem.
Sometimes the K frames can be a little interesting to install, make sure you have it well supported with a jack, then you'll want to thread one bolt into the frame and leave it very loose, not even up to where the shoulder of the bolt widens. Then you can use a pry bar or similar to work your way around the K frame until all of the other holes line up. They don't have to be perfect, you just have to be able to start all of the bolts. The shoulders on the K frame bolts will take care of the rest. I usually like to jack the K frame up until there's just slight pressure on the frame, then start working with the bolts, but sometimes you might have to drop one side down a little to start the bolts. Make sure the car is supported evenly, if the body dolly or jackstands aren't level they can make your life a lot more difficult. Some are just more difficult than others.
If none of that works, check your frame and K frame dimensions. You can download a body service manual for your car here MyMopar - Mopar Forums & Information - Service Manuals
And this is the chart with the measurements you're looking for. For some reason I can upload a much larger picture if it's tall (not wide), so turn it sideways after you download it.
Last edited:
Jim Lusk
Well-Known Member
Where are you located? I managed to straighten one that sounds much worse than yours and I've got the jig to set it up on...
I need to squeeze the rails if that is the case. I was able to straighten the front frame rails where the K-frame bolts up using a steel I-beem (custom made)and the original bolt. so front frame rails now look good and k-frame bolts in front holes no problem. Just the back two holes are about 1/16 two tight.(both sides) Other words, the frame rails or the new k-frame rear holes are centered about 1/16. The frame rails do not look bent now. Front hole are larger than the rear. So why not open the rear holes up a little? I maybe confused. Thanks all. Still thinking on this one.
You don't want to open up the holes in the K frame because the holes aren't the problem. It sounds like your frame is damaged, and opening up the holes won't change that. You need to fix the frame, not damage the K frame to match.
This is the best post yet. Cool diagram. I have two custom steel I-beems that bolt to the bumper brackets. These are very strong! have several locations to hook on to and bolt to. So all I think I need is a really good come-along. All I need is that 1/16. other wise I'll bolt up front two put it mostly together and make it roll so it can now go on a car-o-liner frame machine. Still seems a lot of work for a 1/16. I am just surprised how thin the frame rails are on these A-Bodies. It doesn't take much to bend them. This is not my first rodeo. Thanks all
moparmat2000
Well-Known Member
The K bolts, are a tapered shank design. These are special in the fact that the tapered shanks on the bolts exactly fit the K frame bolt holes. The K frames are built on a jig at the factory to an exact dimension. This is so on the production line when the k frames are bolted up they fit exactly the same. Any adjustments end up having to be made in the suspension for alignment. For this reason, like a previous poster said , if you enlarge the bolt hole you are not correcting the problem. Only putting a bandaid on a bigger problem.
This being said, if your new k frame has a hole thats 1/16" off in relation to your framerail after you bent the old K frame by hitting something, then its your framerail thats out of alignment and not your new K frame.
Easy test is stick your old K back under and see if all its holes line up, if it does and its bent, then your framerail is likely bent as well.
This being said, if your new k frame has a hole thats 1/16" off in relation to your framerail after you bent the old K frame by hitting something, then its your framerail thats out of alignment and not your new K frame.
Easy test is stick your old K back under and see if all its holes line up, if it does and its bent, then your framerail is likely bent as well.
All is well! I managed to straighten out the frame rails on my Demon. I used two custom made steel I-Beems and a come-along with a big hammer. K-frame bolts in now and rails now look straight. This was not the first time I had to modify a-body frames. I now wonder how much horse power these cars can take in stock forum. Just saying.
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