The rear shocks on an OT car I have are too long by about 1-1/2". No replacements are made by Koni. What would the pitfalls be of shortening the dead end of shock by cutting and rewelding the shaft? Would the shaft be too hardened to weld?
I don’t see a problem shortening the shaft. If you have to weld on the shaft, I would be sure to pack it with cold, wet rags or welding heat sink material to be sure the heat doesn’t get to the body and seals. If it’s a stud type end, could you just thread it farther down the shaft and cut off the excess?
It is the double fork upper, so the carrier eye will need to be welded. Main thing I am concerned about are cracks.
what vehicle working on? stock rear suspension? guess have measured fully with shocks off. done an online search using measurements?
They will fail. The shafts are hardened, and there will be no way to not ruin that by welding, or to recreate it when you are done. Just make different mounts.
The brackets on the axle are just mild steel. Weld on extra metal on the bottoms. That is cheap and easy, and will allow you to use an off-the-shelf shock absorber when replacement time comes.
Good idea to put a cable tie around the shaft where it will be shortened to and go for a drive that will give the shocks a workout. If the cable tie doesn't get moved you know the eye won't "bottom out" on the shock body when the shaft is shortened. EDIT: .....and then I read @gimpyshotrods posts and now know why not to even try...
I had Chevelle top shock mount welded to frame but needed a short shock. Fiero front shock used same type mount but was metric. I elongated top holes and drilled out and removed the 10 mm bottom sleeve ( a real pain). Had 2-5/8" travel. I forget closed and open but I found it on Monroe site.
I suspect Summit sold me the wrong units, and Koni does not make 1964-72 GM A stuff (!). Not sure what the app was they sold me decades ago. Maybe a hybrid solution is best - do as you note to the housing and use the existing Koni's then when they finally go bad replace with the correct units in the original mount holes.
It is a simple job Find a guy with the right lathe [where the shock body can hang out the back] and get them to cut and tap the top again. we've done this on Mac-Strut inserts before [on a lowered car to keep the springs located] Konis are simple over engineered shocks, the shafts are usually solid
Are they too long because the coil springs are binding, or because the shocks are bottoming out on full compression? Maybe something as simple as cutting a coil or two off the spring will allow you to use them up.
Uh: https://www.classicmuscleparts.com/...Bbl3cWuJgnS9_RmK8OqhO6XMKTqOBT8NJP80rKXIYGtfm https://www.ss396.com/chevelle/8040...cF7KwLpHd6Jt-z8prZHW9IQMK2DP7X-JNyD87MieobI2y
This is not that style of shock - looks like this: The top is the dead end here. And as Gimpy notes the shaft being hardened precludes any welding or threading operations on it. Gimpy's second link does indeed show an app for the coupe/sedan, but Koni itself does not. The Elky in the first like is based on the wagon and uses a different unit - most likely what I have now. Noting Gene's comment - the shocks are too long, not too short, and the issue is the springs possibly falling out at full suspension extension. The shocks are supposed to provide that limitation. Another solution may be to use travel limiting straps like a MGB.
Most shock manufacturers have a detailed list of all of their shocks with the top and bottom mount styles, and compressed and extended lengths, stroke length, etc. with corresponding part numbers. It takes a little bit of time, but if you lock in on a part number that has the combination you want, say for Gabriel or Monroe, then cross reference that part number to find the application, then find a Koni or better brand that offers a shock for that application. I've put custom length shocks on so many of my vehicles, and this is how I find the exact shock I'm after every time.
if the shocks compressed are 1.5 too long... you're SOL.... measure how long the shocks have to be with car sitting to have the shock in the middle of the stroke.. get the right shocks or re fab the mounts on the car to accept the shocks you have
No, it is too long extended. Not a bad idea - though these Koni's are almost 3 bills each from the link above. I will mod the mounts.
So what you are saying is the problem is not that the shocks are too long, its that the springs are too short. When the shocks are too long, the internal movement stops before the suspension runs out of movement. If your concern is primarily with the springs falling out of position when the shocks reach their full extended range, limiting the amount of suspension drop is the good plan, unless the vehicle is an intended off road vehicle where the full suspension travel is desired. If that is the case, are longer coil springs available?
thats why they make limit straps..put those on and be done with it ...any off road shop will have them... you never want the shock to limit the travel
the real thing to be worried about is if you use the shock to limit the travel is it ripping the forks loose from the 2 bolts... that mount is designed to absorb bumps.. sounds like the stock springs were changed??? heated ., cut, or shorter springs???
No, if the shocks are too long the suspension drops more than designed. Only time this has been an issue is when the car is on a 2 post lift. I do not - I sold the company 2 years ago.
Further examination shows the same shock as specified by Gimpy. Evidently Koni dun goofed somewhere unless there is something I am missing. I cannot see GM making a different setup for the 8.5 equipped 1971-72 Skylark and Cutlass versus the rest of the A body. Or the aftermarket 1971 442 FE2 spec spring was made wrong? I am not sure if the wagons/Elky's got a different shock either. I drawn up a simple tab to be welded to the mount - it should suffice.
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