Maybe email ARB and see if they can provide some engineering info for you… optimal neutral position, whether your extra compression might cause an issue, etc
Rear shock mount bending
- Thread starter kcjaz
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- mount rear rear shock shock
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- Thread starter
- #122
I’ll try to call them. Thought about calling Slee too.
UPR LC
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What TeCKis300 is saying is that you may need to lower the bumpstop to limit the compression travel of your axle since you are raising the lower shock mount. Effectively, limiting compression so you don't bottom out your shock before the bumpstop fully compresses and stops the axle from upward movement.
I had the Timbren bumpstops on my tacoma years ago and they seems to be very stiff and limited up travel compared to the stock small bump stop, so you may already be limiting uptravel compared to the stock bumpstop and you may be ok (if the LC timbrens are similar to the tacoma).
- Thread starter
- #125
Thanks. I get that and agree that I need to make sure the axle stops before the shock bottoms out. I believe I’ve done that. All I’m trying to say is that since these are existing shocks that were previously correctly set up to limit compression to prevent the shock from bottoming out, changing the normal ride height position, doesn’t change the total travel and the bump stops will still limit the compression travel to the same spot as they did before.
Any who, I did call ARB and they were not real definitive regarding measurements for the “comfort zone” but basically they said my BP51s are set up to be happy with the a 2-3” lift. Raising the lower mounting point would be equivalent to no lift or essentially stock ride height and they would not recommend BP51s for that situation. What would happen is that the truck would be in the progressively higher damped zone most of the time which would make the ride harsher. I do run with the compression set at 9 so maybe I could adjust that down to off set this a bit. For now, I’m going to focus on drilling out the bent pin and replacing it with a bolt.
- Thread starter
- #126
Update:
I’ve been spending a lot of time working out how to cut and drill out the OEM lower shock mounting pin so I can replace it with a 3/4” bolt. I most certainly over thunk it but Im OCD and well, I have time and enjoy this kind of thing.
I was pretty hung up on how to accurately drill the 3/4” hole after I cut the OEM pin off. The pin is welded front and back and goes through the back of the shock mount “tower” and id welded again.
So you have to cut the pin in 3 places and then drill out the front and back with the holes in alignment. In talking this over with a friend, he suggested using a magnetic drill press. I didn’t know they made such a thing so down the rabbit hole I went and bought this on Amazon:
VEVOR Low Profile Magnetic Drill Press, 1300W Mag Drill, Light Weight Portable Mag Drilling Machine with Cooling Device and Overload Protection, Mag Press for Equipment Installation, Industrial https://www.amazon.com/dp/B0DDXSDBCB?tag=ihco-20
The front face of the shock tower is flat and perpendicular to the mounting pin. This thing is small enough to stick to the shock tower:
Because there is a welded repad for the OEM welded pin I couldn’t quite get the annular cutter aligned with the where I wanted the holes so I bolted on a 6x7” piece of 3/8 plate to use a the mag drill’s mounting surface:
I used a magnetic with a hole to help locate a slight indent to guide the horizontal cutter’s center pin. Used a pointed die grinder in the center of the magnet.
I discovered that the Vevor drill was constant speed at 650 rpm. Too fast for a 3/4” hole. Found a feed rate/ bit speed chart for horizontal cutters, made an assumption that Mr. T used something A36 steel and came up with 408 rpm needed. So, went back to Amazon and bought a 15 amp variable speed controller to slow the drill down.
Started with a 1” bit because a 2” bit is too long relative to the base. 1” was enough to get through the front. The Vevor drill worked like a champ!
Continued in next post.
I’ve been spending a lot of time working out how to cut and drill out the OEM lower shock mounting pin so I can replace it with a 3/4” bolt. I most certainly over thunk it but Im OCD and well, I have time and enjoy this kind of thing.
I was pretty hung up on how to accurately drill the 3/4” hole after I cut the OEM pin off. The pin is welded front and back and goes through the back of the shock mount “tower” and id welded again.
So you have to cut the pin in 3 places and then drill out the front and back with the holes in alignment. In talking this over with a friend, he suggested using a magnetic drill press. I didn’t know they made such a thing so down the rabbit hole I went and bought this on Amazon:
VEVOR Low Profile Magnetic Drill Press, 1300W Mag Drill, Light Weight Portable Mag Drilling Machine with Cooling Device and Overload Protection, Mag Press for Equipment Installation, Industrial https://www.amazon.com/dp/B0DDXSDBCB?tag=ihco-20
The front face of the shock tower is flat and perpendicular to the mounting pin. This thing is small enough to stick to the shock tower:
Because there is a welded repad for the OEM welded pin I couldn’t quite get the annular cutter aligned with the where I wanted the holes so I bolted on a 6x7” piece of 3/8 plate to use a the mag drill’s mounting surface:
I used a magnetic with a hole to help locate a slight indent to guide the horizontal cutter’s center pin. Used a pointed die grinder in the center of the magnet.
I discovered that the Vevor drill was constant speed at 650 rpm. Too fast for a 3/4” hole. Found a feed rate/ bit speed chart for horizontal cutters, made an assumption that Mr. T used something A36 steel and came up with 408 rpm needed. So, went back to Amazon and bought a 15 amp variable speed controller to slow the drill down.
Started with a 1” bit because a 2” bit is too long relative to the base. 1” was enough to get through the front. The Vevor drill worked like a champ!
Continued in next post.
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- Thread starter
- #127
switched to 2” cutter to get the back side:
3/4” bolt fits”
- Thread starter
- #128
I’m wondering if I should grind down the OEM filet weld down the the repad so the washer has a full mating surface.
Good job.
It is best to retain the shock in its original OEM position. If you grind down the weld is, you will still need to add a spacer to the flat surface to ensure the shock body clears the mount/axle properly.
- Thread starter
- #130
Agree. I’ll measure the other side and either bring to or add washers to adjust placement.
Might want to consider how the original stud was welded and that relying on clamping force may not be sufficient long term. There are challenges to rewelding. Also avoid threads as they are stress risers that will fail. Perhaps modifying for double shear might be an easier solution
- Thread starter
- #132
Yep. Both have occurred to me. I think statically speaking, what I have right now is probably the same strength as OEM but in the dynamic situation of real driving and associated vibrations, it is just a clamping force preventing the bolt from wiggling. It is a three-quarter inch bolt and a three-quarter inch hole so it’s fairly snug.
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- Thread starter
- #133
So what I currently have is pretty close the position of the other side that still has the OEM pin.
It’s temping to grind it down another 1/4” and then weld a 1/4” washer to the repad. It would look nicer and would give the backside washer a full flat face to press against. I’m just not sure that doing that would achieve anything other than looking nicer. I could have the welded washer custom cut to make the fit with the 3/4” bolt tighter but again, I’m not sure that really achieves anything much better than what I currently have.
Hey @MTKID, How long have you been running your through bolt in the upper location? Have you had any issues with the bolt or the 3/4” holes in the shock mount tower getting ovaled or deformed?
In an effort to over engineer why not put a nut inside the shock mount too, the inner nut holds the shock in place and the nut outside the back of the shock mount prevents any motion from the leverage
I was hoping you would weld (as best as possinle) a 1" od .120 wall tube between the 2 mounting surfaces.
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- Thread starter
- #136
I thought about having a bushing made to put into there. Didn’t think there might be special wall pipe that would work. It would be pretty difficult to get in there to weld it. maybe get tack on the bottom but you’re not getting all the way around it unless you cut the backside off for access.
Maybe the better way would have been to drill it out at 1” and insert the 1” pipe/bushing then weld it into place.
Yeah, you might have to go all the way through. This should be more than strong enough and allow removal of the bolt. This is something I might do on mine as I hate taking the rear shocks off the oem pins.
This tube
- Thread starter
- #139
I like the DOM tube idea and agree 1” DOM tube with a 3/4” bolt in it would make the shock tower stronger than the OEM 16mm (0.63”) bolt/pin that is in the stock configuration. What I don’t see is how adding a sleeve to the inside of the shock tower affects the actual cantilevered 3/4” (19mm) shock mount. The OEM pin is welded and, as I and others have proven, will bend if hit with enough force. If the part of the pin that is inside the shock tower was bigger diameter, I don’t think it would make any difference wrt the bolt/pin the shock mounts to. The cantilevered part would still have bent.
I think you're asking why weld it to the other piece? If you don't weld it to the other piece the base metal becomes the weakest point. If you weld it to both pieces then the pin becomes weaker and will bend but can hold 100%+ more load. Toyota engineers did that for a reason.
