Have you welded your k member?

Kern Dog · Apr 13, 2012

A new trend that is gaining momentum is the habit of making our classics handle better than they did when they were new. Most members probably already know about the benefits of poly bushings, better shocks, wider tires and larger Sway bars. I wonder how many have ever considered how their K member affects the way that their cars handle?
On another forum, I started a thread about how welding critical areas on the k member can improve your steering precision and feel. This really isn't anything new. Firm Feel Inc has been doing this for years and still offers this service. Mopar Action magazine has had articles where they mention it as well.
As stock, the k member worked as intended. Skinny tires, conservative alignment and a 5 year lifespan.... Yeah, mission accomplished. Now we have these cars that Ma Mopar probably never thought we'd STILL be driving, 40 years later with tires twice as wide. Something has to give, right? The steering box mounts on our cars are an area that can REALLY benefit from reinforcement. If you are curious, Have someone turn the steering wheel as you look at the steering box. See how it flexes? Imagine how much worse it gets as you hit a bump in a turn! It flexes 3/8" each way while sitting still!!??
Looking at a bare K member, you can see the unsupported areas that allow that flex to occur:

Kern Dog · Apr 13, 2012

Looking again at the above photo, you can see the tube that the lower control arm shaft slides through. Often times after years of wear and stress, this area weakens and cracks out.
I welded washers over these holes but made sure that the washers were no thicker than the lip of the tube. This made sure that the LCA didn't get moved rearward at all, preserving caster.
THIS photo shows another area to consider: The strut rod mount. Many A body K members had gussets here, but my '70 K member did not. I used a 1/8" thick washer here. Also notice the welding of the seams. I doubt that seam welding helps much, since mine had the spotwelds pretty close together.

Kern Dog · Apr 13, 2012

This is the reinforced steering box mount area. Notice all voids have been filled to dramatically reduce the possibility of flex.

You can also see part of the LCA tube support washer on the left of the picture.

Kern Dog · Apr 13, 2012

One more.

Kern Dog · Apr 13, 2012

Now painted, it may be hard to see, but this is a front view.

Kern Dog · Apr 13, 2012

Pardon my welding! I did this k member using a flux core mig. I've since upgraded to Argon with .030 wire. MUCH better welds now!

Lowhound · Apr 13, 2012

I am planning on doing the same as you have. I noticed a company(Firm Feel I believe) offering this service for $400. It looks fairly simple to do & looks like it will help get the most benefit from my upgrades.So far Ive blasted it clean but I havent had the time to start on the welding. However my factory spot welds are not to consistant(some are spaced to far) so I plan on fixing that also. I had no idea there was that much flex in the K until I noticed a couple of articles in magazines.

Kern Dog · Apr 13, 2012

Tom Quad, AutoxCuda, and several others have had comments, suggestions and opinions on k member welding for reduced flex. The theory is that even with spotwelds, the 3 main parts of the K member can still twist and flex, leading to inconsistant performance. Welding the perimeter seams and steering box mount costs only a few bucks worth of electricity and welding supplies.
Another suggstion that makes sense is the seam welding of the rest of the car! Look at how the front frame rails are merely spotwelded to the floor and torsion bar crossmember! A member of another Mopar board has stated that "Unibody seam welding" is banned in some racing classes because it gives the user an unfair advantage! Sounds good to me.
A few warnings about ALL welding on these old cars: After years of use, grease and oil are embedded everywhere and small fires will erupt when welding. Its good to have a wet towel and/or a air blow gun nearby. ALSO, to avoid warping, do not attempt to make continuous welds! Stitch weld in 1 inch increments, alternating all around the perimeter until it is fully welded. My welds were not pretty enough to leave alone. I had to grind most everywhere.

Kern Dog · Dec 1, 2018

Woooo!

CoronetDarter · Dec 1, 2018

Wow Greg, you must've been bored this morning. I boxed the K on the Coronet during the resto. Along with the SBC, upgraded suspension and steering parts, the car handles as good as some new sedans.

Larrry B. · Dec 1, 2018

I've done it to my car using the kit from Firm Feel, also doing seem welding in some areas.
http://www.firmfeel.com/b_body_mopar_k_frame_reinforcement.html
Maybe not the prettiest job but it works.

Also using the LCA kit from PST.
https://p-s-t.com/i-23159728-performance-mopar-lower-control-arm-deluxe-rebuild-kit-b-e-body.html#!year=1969||make=PLYMOUTH||model=ROADRUNNER

This as well: https://xvengineering.com/collections/frontpage/products/lower-radiator-support

That with all of the other suspension upgrades made the ride a lot better, car doesn't feel "fast" until about 90 mph.

Kern Dog · Dec 1, 2018

Nice sheen on the parts, Larry. Good job.

Larrry B. · Dec 2, 2018

Kern Dog said:
Nice sheen on the parts, Larry. Good job.

I work in the industrial area on the south side of the Anheuser-Busch brewery in Van Nuys (just north of Woodley Park - Spring Fling) and there's a lot of various shops, one being Ajax right up the street.
http://www.ajaxsandblastingandpowdercoating.com/

If you spend the time and effort redoing parts always a good idea to get them powder coated to protect your investment.

ckessel · Dec 2, 2018

I spent a lot of time on my k doing improvements. I added on 120+ rosette/spot welds to it on top of the 30 or so factory welds. For you construction types, I likened it to the nail pattern for a shear wall. On some areas the were multiple layers, like the idler arm bracket, I drilled a small pilot hole first then went with a 5/8" cutter on the first layer, a 3/8 on the next. When I welded, I started with the small hole first then circled out to the larger one to tie them in. On pretty much all the holes I punched, I used a Blair Rotabroach hole cutter tool. On the mounts for the strut bars, I cut out sections on the road side so I could add some material in to box that area in to the sides/top/base of the strut rod pocket area. From the factory there is only one reinforcing piece on the back side. Now its all tied in. For the control arm tubes, I cut access holes on the roadside again to get at the inner areas of the tubes. Added some material to reinforce the tube and weld them on both ends to the k. On the outside of the k, I added some large washers, got them from Fastenal, welded the arm side of the tube to the washer, welded the washer to the k, cut some holes on the washer with the rota unit, rosette welded the washer to the k. On the other end I used the thick washer that came with the new lower arm shafts, got them from Firm Feel, welded those washers to the k, found some more washers from Fastenal, put those around the FF washers, welded them in too. I still need to finish up the topside of the k around the motor mounts/steering box/idler arm areas. Just rapping it or moving it around on the floor it has a totally different sound to it from an un modded unit. I had the thing tanked twice before I started on it but I'm amazed at how much stuff was still in there. Good thing I have a Victor hot wrench handy! You can see some of the k work on my thread for that and what I've also done for the core support and surrounding areas.

astjp2 · Dec 16, 2018

I seam welded mine after I got it back from Al Debevec for the Hemi conversion. Took it in for hot tank so no grease and oil to burn out and it came out great. Tim

Mocajava · Dec 16, 2018

I also cleaned and reinforced all seams and areas needing more weld for integrity on my 69 Coronet k frame....just because when I looked it over I wasn't pleased with the lack of strength/detail. This was done over two ears ago when I was taking the car down to ground zero. I didn't realize the amount of flex as Kern Dog indicated but glad I went to the extent I did! THX Dog!

Don Frelier · Dec 16, 2018

HawkRod · Dec 16, 2018

I welded my K-member on my 70 Road Runner, and also added some steel inside the steering box mount to stiffen that up. I boxed my lower control arms, and I also put a sector support kit on it with a Firm Feel stage 2 box. All that, along with all new suspension parts (actually mostly rubber with selected areas like sway bar and lower control arm poly), have made my car handle REALLY well for an old b-body. I love driving it!

Hawk

Kern Dog · Dec 16, 2018

Aftermarket front end kits with coil overs... :jackoff:

You don't need to REinvent the wheel, just reinforce the spokes.

Have you welded your k member?

Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

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Life is full of turns. Build your car to handle.

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Life is full of turns. Build your car to handle.

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Life is full of turns. Build your car to handle.

Life is full of turns. Build your car to handle.

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Life is full of turns. Build your car to handle.

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