Was that the nsra Nationals in Burlington Vermont a few weekends ago, driving on the most potholed roads in the country. The bungs that hold my right front F1 style shock mount on, cracked and the mount came loose. Beyond welding the bungs back or new bungs, which will eventually illicit a similar fatigue crack problem, does anybody have any suggestions for something with better durability and longevity?
Instead of putting in a bung, get a piece of thick walled tubing the correct size to thread and put it right through the chassis then weld it on both frame rails and don't grind down the welds. Ideally Tig the tube in. That is my suggestion and what I have done on my cars. pat
Another vote for heavy tubes through the frame if it is already boxed and run a bolt through both sides to distribute the load.
If you still have access to the inside of the frame,you can flatten the outside of the frame where the bungs pulled through. Then you can drill holes in the appropriate position in a 1/4" thick single piece of flat stock slightly over size so bolts can pass easily through the 1/4" plate. Then weld regular nuts to the back side of the 1/4" flat stock where the holes have been drilled. Then weld the 1/4" plate into the frame. Something like this. The tube piece was for a seat belt bolt in a door jam. The flat stock slides into the tubing (you would want the flat stock to fit inside of your frame rail). The flat stock was clamped inside of the tubing and marked with the drill bit (you would want to mark the holes using the shock bracket, as it fits inside of the frame). The bolts and the nuts you will be using will fit through the flat stock like the picture above and below. The nut I used is not required, regular grade 2 or grade 5 nuts will work in your application. I would suggest you use cheap bolts that are no longer then needed, to hold the nuts in place. I would add washers under the head of the bolt so that when the bolt is tight(just tight enough so it doesn't move), little to no threads are above the nut. The bolts will be discarded after the welding is complete, you will want to use new grade 8 bolts to secure the shock mount back on the frame when you are finished. The flat stock should be bolted to the shock mount, and the nut should be welded to the flat stock. You only need to put a good tack weld on 3 of the nut's 6 slat sides (every other flat). Remove the bolts before the nuts completely cool. Sorry for the next crappy picture, but its the only one I have on my computer. Your flat stock should be wider then this one is, and it will have two nuts welded on to it. this piece should be welded into the inside of your frame, with the flat side against the inside of the frame rail.
First, I'm really sorry your ride got torn up. I hope you are able to make repairs and get back on the road. I agree that stronger mounting points are a good way to go. However, I question a couple things, First the condition of the shocks after that. They are not usually designed to be the sole bump stop. Some are, but I'd suggest looking into adding another way to limit compression of the suspension. Maybe reinforce the notch and have a rubber puck in there? I know this is additional work, but take it as a 'while you are in there' suggestion.
Broken shock mounts are often the result of a shock reaching it's full compression before the suspension does. In addition to beefing up the mount, make sure the shock is not bottoming out before a bump stop limits the suspension travel
I was thinking prison scene..... I'm with Gene, bigger plate, welded nuts then weld plate to frame expanding the area that the shock mounts exert pressure. If it had gas charged shocks I'd get rid of them and go straight to an oil filled shock. It's amazing how many shock mounts I've fixed on old vehicles due to heavy gas charged shocks. Lots and lots of Chevy trucks with the single top bolt going thru the side of the frame due to guys running out and buying the heavy duty gas charged shocks when they first hit the market.... .
X3 Tube that reaches from outside rail to inside boxing plate, welded on both ends, and through bolts, not threaded. Nothing wrong with the shock brackets themselves, as long as the shocks aren’t bottoming out.
X4........ weld in crush tubes and bolt through the whole frame rail. And check your shocks. If they have done that sort of damage they are bottoming out!!!
Happened to my buddy, twice I think, so when I did mine I used solid roundbar, about an inch diameter, drilled and tapped. Made them long with the intention of passing them through the boxed chassis to weld on both sides, as best I could. The upper one was difficult to do that so, as it was just below the upper surface of the chassis, like yours, I drilled a couple of quite substantial holes to facilitate a couple of large plug welds. I also set the tubes to be set outboard of the side of the frame some so I could get a good sized tig weld on it. Before installing I'd radiused the outer corner of the tube for a neat finish. All seems to work well. Bolts did lose torque as I'd not removed paint where the mount sits. No problem after that. About 5k miles now. Chris
No where near enough weld holding that in, hole on the rail needs to be veed (for want of a better term) so penetration is seen on the inside of the rail. Also looks like it was ground flush on the outside , not much holding the bung in. Weld it so the bung is protruding slightly and leave it that way.
Are you fixing the cause or effect. That amount of stress on the fixings looks like your shocks were bottoming out.
As Gary, Anthony, Alchemy and Twenty suggest, fabricate a sleeve from thick wall tube to span both sides of your frame, weld both sides and use longer bolts. That is the way it should have been done from the start.
Yeah whenever I saw this thread title I just knew it was going to be a wild one to weed through. But I guess we all have grown up a bit and now use our manners more I really like the idea of a solid rod stock drilled and tapped welded through the frame. Just be sure to use grade 8 or better bolts and stay away from stainless. The tubes would be my second option just because the stress is distributed more evenly. But either way I have to commend you for the thread title
Yeah, the problem is - THAT wasn't done from the get-go. The rails are boxed and this mount is directly on the outboard side of the front cross-member.
@SDS yep, looks like a fun one to put right. Just remember, the amount of force to break that was the full force of the front suspension pushing up thru a fully compressed shock. SOMETHING was going to give. If the shock was shorter compressed or not there, the spring and/or the tie rod would have hit the frame.
I'll check when I get home from work, but I can't imagine that the shocks are bottoming out. Looks like there's plenty of travel left there (see photo). The spring would bottom on the the clearance notch in the frame rail before the shock travel maxed-out collapsed. Could my frame be pinched to the point where the shocks are at too extreme angle?
What kind of shocks are you using, were they "sized" for your car? Most front end kit's come with generic "hot rod" shocks. For a correct ride several things need to be considered. When I built my '46 Woodie I talked to the Bilstein shock engineers and they asked me several questions such as the weight of the car, weight of the engine, type of front end and how it was spring, wheelbase and tire size. They even asked me what type of ride I was looking for. Once I gave them all the info including travel lengths, up and down motion, they gave me suggestion as to what shock they recommended. After almost 60K on the odometer the car handles and drives like a new car. All shocks aren't created equal!
Shock angle looks fine. Look to be Pete and Jakes too, so shouldn't be overkill on dampening? You should be able to drill through the boxing from the outside except for where you're likely to come into contact with the crossmember. Chris
My rod uses Pete & Jake's headlight/shock mount welded to frame rail. More than 60k miles. Bilstein shocks, more than 40k
I don't have access to the back-side to put the bung/s all the way through, so I made bungs with a flange. TIG welding them externally and will drill a hole from the top and plug weld from above to the bung for extra support. My solution in the making...
Drill the through hole in the boxing plate to the size of the bolt. Then the bolt will keep the bung tight to the inside, even if it’s not welded there. The good weld you do this time will have better penetration than the bad weld on your first bungs, right?
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