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Subframe Connectors
#1148141
01/01/12 03:58 PM
01/01/12 03:58 PM
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Joined: Mar 2005
Posts: 68
Omaha, NE
dart69bigblock
OP
member
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OP
member
Joined: Mar 2005
Posts: 68
Omaha, NE
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I don't want to "Beat a dead horse" but have a question about subframe connectors. I have searched and read all the forums I could find and just need a little more insight. I am working on a 70 RR. Right now the car is a shell only, no motor, suspension etc.. I am using 2x3 rectangular tubing and weling in through the floor. The car was on a rotisserie then placed on 8 jack stands. 2 under the front frame rails, 2 under the tranny crossmember, 2 under rear frame rails under back seat and 2 under rear frame rails just past where the rear end would be. The door frames are brace with square tubing as well as the a-pillars and back part of the door jams braced to the floor with square tubing.I have had the driver door on the car and the car seems to be squared up and level. I have read many opinions on here about having the weight on the car or have car on a frame jig, etc.. My question is will I be ok cutting the floor and rear frame rails and welding in the connectors with the car up on jack stands the way it is now? Or do i need to put the k-frame and rear end back in to install the connectors? Advice would be greatly appreciated. I attached a pic unfortunately not the greatest but rough idea where the jack stands are. Thanks again, Chris 
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Re: Subframe Connectors
[Re: Stanton]
#1148144
01/03/12 11:39 AM
01/03/12 11:39 AM
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Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
TC@HP2
master
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master
Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
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Quote:
Here's my thinking on this ...
You'd want to install the connectors in the same manner and at the same point they would have been done had they been a factory item. To me that would be PRIOR to installing the drivetrain.
So in your case I'd be doing them now with the car supported as you've indicated.
What I would though is get a digital level and make sure that every point side to side is dead nuts on as well as the coinciding points front to back.
Using a digital scale elimates the need to have a level floor since all you need is the readings to be the same irregardless of the floor slope.
The easiest way to do this short of a chassis jig is to use 4' pieces of 2 x 2 tubing on top of the jackstands from side to side. Make sure the contact points are identical on each side and then put the level on the tubing. Shim as necessary.
I've been doing connectors and cage structure this way for years with very good results. Takes a little bit of work, and you need to monitor the level as welding can curl things up, but the results are worth it.
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Re: Subframe Connectors
[Re: DaytonaTurbo]
#1148150
01/04/12 06:45 PM
01/04/12 06:45 PM
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Joined: Oct 2009
Posts: 181
Washington State
70chall440
member
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member
Joined: Oct 2009
Posts: 181
Washington State
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Quote:
These unibodies have sagged and developed some slop in their structure from 40 years on the road. IMO the best way to install them is to fully weld them in only when the car is sitting on the ground with it's full suspension, engine, etc all installed and placing their normal amount of weight on the car. If this isn't an option, I would put the car body on jackstands and try to mimic it's normal resting position as close as possible. This means jack stands under the leaf spring mounts and in the front where the k-frame would bolt up. However since you have your car squared and braced up I think you will be okay no matter how you do it.
I think this whole "sagging" deal is way over stated. I have cut apart a number of Mopars, welding in evrything from floors to frame connectors and never ever had to build any form of support structure, etc. A visit to Rocket Restorations (Oly WA) will show you several cars without quarters, floors etc that are not braced or welded to a steel plate or anything else. I asked about this specifically, and they told me that they only brace up convertibles when they cut out quarters. I agree that you should check to see if your car is striaght to start with, however you need to remember that these cars were never exactly "precision" builds. I think the TV shows have scared a lot people that you need a $100,000 layout table to make sure your car doesnt fall apart while you are installing body parts. Might be true for a Ford or Chevy, but IMO not so much with a Mopar.
I am sure I will get hammered here by these comments, however I did the research, cut up the car, reassembled it and it is still straight. I do agree that you need to be careful about how much you cut it up and where, but if you take your time, get everything tacked in and then weld it up, I beleive you should be fine. I think the one thing everyone can agree on is take your time, measure everything (repeatdly) and start with a straight car. if it isnt straight, take it to a frame shop and have it pulled straight BEFORE cutting it apart or welding in new parts.
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09 Caliber / 99 Dakota 4x4 / 52 Dodge B3B
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Re: Subframe Connectors
[Re: Stanton]
#1148152
01/05/12 02:12 AM
01/05/12 02:12 AM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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I'm not sure how much sag we are talking about either. I do know that if when the weight is on the wheels, car fully assembled and the doors closed nicely, body gaps were good, fenders, hood, etc all lined up nicely that I don't want to do anything to upset that. Like welding in fame connectors with the car supported strangely. Will it affect anything? Who knows. I do know that before installing the frame connectors, if I jacked up one corner of the car, the doors didn't want to open/close nicely. Obviously the car is twisting enough for me to know I wouldn't want to weld in the connectors when the car was supported at that weird angle. After welding in the connectors and lifting the car, no twist, doors open/close nicely on the ground and with one corner in the air.
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Re: Subframe Connectors
[Re: DaytonaTurbo]
#1148153
01/05/12 12:09 PM
01/05/12 12:09 PM
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Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
TC@HP2
master
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master
Joined: Jan 2003
Posts: 5,394
Pikes Peak Country
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Factory assembly tolerances would allow up to .125 of variation in some places, so some of these cars were put together rather shabbily right of the factory production line.
How much slop is built in to them, that depends. From bumper to bumper you could see movement of up to a few inches. I'm thinking of the old bumper jack usage that would twist the heck out of a uni-body. Flex at any particular suspension pick up point would be next to nothing. It all depends on where you check it.
I've always held and shared the opinion that there are two ways to do connectors; if you car is complete, assembled, and in driver condition, put it on stands to simulate wheel loads. If you car is all apart and under construction, support it in multiple places and make it as level and square as possible.
The reasons for this are because if your car is together, you do not want to radically alter any door or panel alignments that could ruin paint jobs or crack glass or cause any other cosmetic issues. If you car is apart, it only takes a bit more effort to put it into a situation that will create a more consistent foundation for the suspension to hang from.
Aligning the unibody and making it square and level for connectors is kind of like using a torque plate on an engine build. You don't have to, the results acheived are only nominally different, but when you add up a number of small, subtle differences, it can make a big difference in the final result. Additionally, not all drivers are going to be able to notice the difference between the two methods, I beleive there are some out there who can, but almost everyone will notice the change from having no conenctors to having connectors. Even thin wall, 2x2 bolt in connectors will do wonders for rigidity increases. Decide what type of driver you are, what level of performance you want, and how much effort you can afford, and you will know which way to proceed.
I'm not suprised at the info in the Hotckis instructions. They are a corporation that needs to be cognizant of product liability and cater to the lowest common denominator of customers. Remember the average processing capability of a majority of people out there is at an 8th grade level. If anywhere in their install sheets they implied stripping a car for install was prefered, they would be opening a can of worms for liability.
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Re: Subframe Connectors
[Re: TC@HP2]
#1148154
01/05/12 03:58 PM
01/05/12 03:58 PM
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Joined: Jan 2003
Posts: 1,607
Western Washington
Sixgun
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,607
Western Washington
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I find this discussion stimulating and informative. Hats off to you guys for exchanging views without "alpha dogging" the whole mess, seems to happen a LOT. If I sifted the data presented properly, one needs to get the car more or less stiffened up in the "as-is" condition, that is to NOT pre load it in an unnatural way (however you achieve this). I could see where pre-loading might create more problems than it solves. Both my E bods were done by the same guy, he digital leveled it on a known "flat" slab, and shimmed the stands as necessary. The result is and always was good, both in the street car, and the 14 point tied in "race" chassis.No changes in panel alignment,door open/close or weirdness.Race car had no motor when done, street car was complete, I think he used the frame at the usual jack-up points (under door hinge area and in front of tire) Right or wrong, it WORKS! Thanks, C 
I'm 55 now, no time to waste. Not a week goes by that I don't hear about someone passing on.Let's get out there,smoke some tires,have a beer with a good friend,do what you have always wanted to do.I am pretty sure no one will ever say on their deathbed "gee I'm glad my life was calm and boring"
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Re: Subframe Connectors
[Re: Sixgun]
#1148155
01/05/12 10:59 PM
01/05/12 10:59 PM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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One thing I will add, is I've never heard of anyone welding in frame connectors, then having body alignment problems because of them. I don't think it's as critical as some of us may like to believe. There's enough adjustment capability built into the way the doors, fenders, hood, trunk, etc all bolt up that I don't think you even could both the frame connector install job bad enough to mess up your car.
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Re: Subframe Connectors
[Re: DaytonaTurbo]
#1148157
01/06/12 10:29 AM
01/06/12 10:29 AM
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Quote:
One thing I will add, is I've never heard of anyone welding in frame connectors, then having body alignment problems because of them. I don't think it's as critical as some of us may like to believe. There's enough adjustment capability built into the way the doors, fenders, hood, trunk, etc all bolt up that I don't think you even could both the frame connector install job bad enough to mess up your car.
I did mine on a rotissierie. First pressure washed the bottom of the car clean.
Then blasted it bare.
Then welded them in with the car sideways.Blasted a second time lightly and painted it. The car turned out great with no issues.
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Re: Subframe Connectors
[Re: Challenger 1]
#1148159
01/06/12 07:16 PM
01/06/12 07:16 PM
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Joined: Jan 2008
Posts: 2,592
None
71rm23
master
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master
Joined: Jan 2008
Posts: 2,592
None
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Quote:
Quote:
One thing I will add, is I've never heard of anyone welding in frame connectors, then having body alignment problems because of them. I don't think it's as critical as some of us may like to believe. There's enough adjustment capability built into the way the doors, fenders, hood, trunk, etc all bolt up that I don't think you even could both the frame connector install job bad enough to mess up your car.
Looks great, Gary!
I did mine on a rotissierie. First pressure washed the bottom of the car clean.
Then blasted it bare.
Then welded them in with the car sideways.Blasted a second time lightly and painted it. The car turned out great with no issues.
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Re: Subframe Connectors
[Re: 71rm23]
#1148160
01/06/12 07:16 PM
01/06/12 07:16 PM
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Joined: Jul 2003
Posts: 1,212
Canton, Ohio
Crazy68Dart
pro stock
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pro stock
Joined: Jul 2003
Posts: 1,212
Canton, Ohio
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It has been some years but I think I used .100 tube also, welded in. I slotted the pans and welded around for more strength.
383, Hemi 4-Speed, AlterKtion, D60
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