FJ60 Long Travel Shocks
Ok, light tech, but hey, we need more tech in here lately :)
I have been running OME shocks of different flavors for a while but have never really been satisfied. I have no idea what lift my truck has but the axle is 6" down from the bump stop and has about 4" travel down from that point. The OME shocks are the limiting factor on the droop for sure as they are almost fully extended at rest. They have always been too soft also... I have always liked "spirited" driving in the desert while fully loaded (7k lbs total) and jumping in and out of washes there has never been enough damping.
I put lots of crap in the back so I didn't want to just lower bum stops and throw on longer shocks....
That got me looking.
Drew and I looked on the Bilstien website and noticed they made short body shocks that had decent travel, so after a while of measuring and back and forth on the web we decided the 12" short body external res shocks in Biltien's stiffest valving would do nicely... I won't even have to lower my stock bump stops and they'll reach straight to the bottom when the axle is at full droop when in the air.
So, here are a few pics and what I am working on to make them fit.
Here is the old rear shock vs the new bilstein 10" body 12" stroke shock. I am using part number ak7112sb06.
I didn't get a picture of the underneath of the truck but the original mounts are posts on the shock mount tube that goes across the back in between the frame rails. I am going to cut those off and use some plates to mount the new shocks. First step was to mock it up and make some bracket templates from cardboard.
Then trace them out on some 3/16" steel plate with the soap stone so I can cut them with the torch....
The cut away with the torch. My hand is wobbly so lines are kinda crooked but it works.
Hit it with a hammer and the new plates drop out...
Next I cleaned it all up with the good ole flapper wheel and popped a few holes in for the bolts.
The shocks came with some 1/4" cad plated spacers for the bolts but they weren't long enough for what I am doing..... So Allison and I ran to work and we machined some new ones...
Here it is mocked up... Looks like the bolts I'll have to get will need to grab 3" of stuff plus some extra for the washers and nuts. I'll get some nice grade 8 stuff tomorrow. At least the 1/2" bolt takes 3/4" wrenches which works with my 19mm wrenches :)
So here's my question.... The lower mount on my 4+ flip kit mounts are what look like 19mm (3/4") pins with the shocks bolted straight on in single shear. Would it be ok to bolt my new shocks on with 1/2" bolts in single shear like this:
Here is the original setup with the new mount bolt next to it for comparison:
So what'd da y'all think.. 1/2" grade 8 bolt in single shear enough?
Depends on how you do it.
Most stock set ups are sorta single shear. There is usually a sleeve that the shock slides over, and then a bolt threads into the tube. This is different than what I consider to be a normal "single shear" which is one side of the brackets you made, an a bolt holding it in. The difference is that there is a welded, usually fairly thick sleeve that is taking the shear in the stock scenario, whereas there is a loose interface between the bolt and the bracket in the second. The second scenario allows for a pivot to form immediately, which fatigues the bolt and is ultimately weak. The first does not allow for this pivot unless the weld fails: since there is not movement inherent in the welded "spindle" for lack of a better word, the stock scenario is stronger.
I'm not sure I explained that well, but there you have it.
The way you are picturing it is more like a stock set up, and probably okay, but I find that the stock toyota stuff is WAY harder than the grade 8 you buy at the store.
If I was building it, I'd put it in double shear, just because I've had enough stuff break embarassingly due to not building in overkill. We are hard on stuff :D
The pin in the 4+ plate is mild steel I'm pretty sure...
Maybe a threaded piece welded to the 4+ plate with a bolt going back through the shock eye?
I'll mock something up.
I have my front shock towers setup 9/16 single shear they are 1018cr and have taken a lot of abuse with no issue. I'll post a pic late. Very fine thread by the way.
I should mention that rev 1 shock towers were ht 4130. Te design wasn't that great, but the stress cracked and eventually broke, grade 8 my do the same, not sure.
Alrighty... Mamasita said get yer butt in the garage and keep working on the 60 so I forced myself to get back at it tonight.
Turns out the new brackets work well for the top of the shocks once I cut the upper shock mounts off...
So looking at the bottom we see where we gotta make some more mounts...
I kept thinking about it over and over again today and I agree... A nice double shear mount for the bottom is the way to go. I am gonna come straight off of the spring plates with flat pieces and get the bottom shock eye that way..
It'll be vulnerable to rocks but I am thinking beef it all up and it'll work? The original setup had the shocks down low like that and worked ok... I was able to keep them relatively ok so maybe this will work? Ideally I know the shocks would be mounted to the axle tubes but hey we gotta fit these long un's in there somehow..
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