Looking for confirmation that I bought the proper shocks based off my measurements. First off, this is on the rear of my 34 ford pu with a Posies spring that I moved 4 leafs from the top to the bottom of the spring pack to lower it some. I measured the extended length between shock mounts at 13” and compressed length at 9”. I bought some Gabriel cl***ic shocks with following specs: extended length=13.42”, compressed length=8.56”, stroke length 4.86”. See pic after getting them installed I see that there is a 1 1/2”of exposed shaft or compression left it the shock. it seems to be enough compression stroke left that the shocks don’t bottom out when I stand in the bed and jump up and down (I weigh 160 lbs soaking wet, lol)
You can drive it and see, but that is cutting it mighty close. Or, you can re-engineer the upper bracket a bit and give yourself a bunch more travel. Do it while you don't have a bed floor to deal with. -Abone.
Generally, you want the ride height close to the middle of the shock travel. Your math of extended and compressed suspension does not seem to add up to what you have with the shocks installed, only having 1 1/2" of compression left?? Was the compressed measurement you took of the suspension with the car just sitting on the tires (ride height) or with the suspension at your desired fully compressed number (such as the rear end on the bump stops or a number that you don't want the suspension to compress beyond that)??? With the shock travel you have, you should have ended up with more than roughly 4 1/2 travel in the shocks each way. Somehow, I think you didn't measure the compressed height correct? Also, the fully extended height, should be less than before the spring shackles can flip over the other way. I don't think there is enough compression in the shock as it is, especially when you also have to take into account for articulation of the rear axle. Its not good to bottom out or fully extend a shock in normal use, eventually it can damage the shock, let alone what the ride quality will be if the shock is bottoming out. Bill
The amount of stud sticking out has NOTHING TO DO WITH the compressed or extended length of the shock, It only has to do with the thicknes of the material that it goes though and how tight you tightened the nuts. The bushings aren't all squashed out so it looks like you did a fairly decent job of tightening them but forgot to put the palnuts that came with the shock install kit on unless the nuts are lock nuts. My vote goes in with what FlamedAbone and Justp***inthrough said though. while I could I would cut those brackets off do some reworking, set them up so that I had the correct travel and weld them back on and hook the shocks back up and call it good. Just make sure that you have clearance for the floor above the end of the stud butI don't think that will come close to being an issue. Well done on tightening the nuts on the shocks though. I've seen too many that were rattled down with an impact to the point that the bushings were squashed so bad that they were pretty much solid and ready to split.
From Bilstein: For stem to stem shocks the dimensions are measured from the base of the stem, where the mounting hardware rests to the base of the other stem, where the hardware rests. So you did loose some travel in the thickness of the upper and lower bushings. That accounts for some of the lost travel. Taking into account the compressed thickness of the two bushings, you didn't account for in your initial measurements, at roughly 3/4" each plus the 1 1/2" you have now, you would have had roughly 3" at ride height. Bill
With the shock at an angle you will not need as much travel as the up and down measurement. You could pull the suspension down to the bump stop with a ratchet strap and see if the shock bottoms out.
I would make sure the axle hits the rubber bumper on the frame rail before the shock bottoms out. If not, either move the mount up or get a different shock.
On a slightly different subject, pin top shocks are designed to fit vertical, or near vertical so travel does not cause angular movement.
If that's all the travel there is don't complain about harsh ride. I usually factor 2/3 compression travel 1/3 the other way. Like others have said, move the upper mount. From what you say, you should have 2 1/2 - 3" travel available.
The bed floor, a tank of gas and a dried out Christmas tree and those shocks are bottoming out. Shorter shocks or alter the mounts.
You are correct, I recommend he uses shocks with loop ends instead of those. Here is a Monroe Mounting and Length catalog for anyone knowing the length of shocks they need: RC_2008_MON_ML_FullCatalog_v1.pdf (oreillyauto.com)
Thanks for all the input. But first a caveat , I’ve never measured for custom shock length and no real world experience with different shocks so my first stab at it. I am kicking myself because I did trash the old shocks. I should have kept them to measure. Duh I used a floor jack under one end of the rear axle housing to try to get compressed length but didn’t compress suspension too much. I also used a piece of all thread to try to pull the suspension down to get it compressed but that didn’t work too well either. I will try some rachet straps today and remeasure. Oh and I don’t have have any bump stops. I didn’t buy new ones yet. Will add that to my shopping list. I have browsed several shock manufacturers catalogs, Monroe and Gabriel, to try to find shorter shocks and the shortest ones are 7” compressed but around 10” extended. So I may have to look into modifying shock mounts like some have suggested. The only problem with that is my ch***is has been powder coated already and I don’t really want to alter the coating. However the bottom shock mount (4” piece of angle iron) is bolted to the frame using the 2 radius rod to axle tube bolts. So I could re-engineer that bottom mount and make it a few inches lower provided I give myself decent ground clearance.
Like has been said, go to a double eye shock or you may be bending or breaking the top pin mount as the shock rotates during compression.
However the bottom shock mount (4” piece of angle iron) is bolted to the frame using the 2 radius rod to axle tube bolts. So I could re-engineer that bottom mount and make it a few inches lower provided I give myself decent ground clearance. I don't understand this. Please explain how lower mount is bolted to frame and the shock works at all. Need a picture of whole shock setup.
I'd be inclined (!) to swap the shocks for a better length and call it done, but keep an eye on it. Because it's a truck a future rework isn't so big of a deal. It does look to me that the inclination of the bracketry, both top and bottom, is already misaligned to the shocks and arguably should be misaligned the opposite way to allow the shock to align some under compression, rather than to have an increasing misalignment. Might the misalignment be as a result of the lowering of the spring? Might the shocks be in alignment and at a happy length without the lowering? Chris
You bought a shock that is1" longer in travel. The distance between the frame and the axle is determined by the spring, the shock has no effect. Where does that extra 1" of travel go? Into the shock housing. Either extend the distance between the mounts by raising the upper mount or get the proper length shock. You do not want to be hitting the snubber, that is only there for bottoming out an overload, not acting as travel limit of the shock. Besides, I would think the shock would bottom out before you hit the snubber and that is a very bad and dangerous thing. Warren
How far you can compress your suspension by jumping up and down on it is not even close to how far it will compress when driving down the road and hitting a good pothole. That's when you'll discover true compression, and bottoming out! I think the amount of exposed shaft on those shocks wont p*** the pothole test.| I'd flip the top mounts over so they gain more exposed shaft, and give more travel before they bottom out. I also install bump stops between the axle or differential and the frame to stop the body compressing more than the shocks can travel. This protects the shocks from damage.
Yes, actually regardless which way you go, those mounts should be gusseted. As it sits right now, they will bend and snap off. Warren
I think you are going to have to redo the upper shock mount even if it has been powder coated. It doesn't appear to have any gussets and the metal thickness looks too thin. It will probably bend if you leave it as is and then you will have to redo it.
Yes I do agree that the upper mounts do seem a bit thin. It is 1/8” thick angle iron. In fact bottom mount is made from same angle iron. put on 2 rachet straps and cranked them down, compressed length still measures 9” between mount points and 3” gap between top of axle and bottom of frame, no bump stop. plan A: will call Gabriel tech support to see if I have overlooked a shorter shock from their catalog. If they don’t have anything plan B: fabricate a lower shock mount and drill hole in crossmember to use a bolt on upper shock mount stud. Got the idea from this kit: https://www.jalopyjournal.com/forum/threads/ford-1933-34-rear-shock-mount-kit.1155053/. This kit uses shocks with hoops on both ends.
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