Rear shock mount bending

[kcjaz]

Awesome! Thanks. I think we are saying the same thing. The bolt’s ability to resist bending isn’t affected by adding a welded DOM tube inside the shock bracket/tower. However, what you are pointing out is that what is affected it the strength of the bracket/tower and where a potential failure would occur. If the pin (tube) isn’t welded to the front and back of the shock bracket/tower, more stress is shifted to the bracket/tower and it becomes the weak link.

Given that I and others have managed to bend the OEM pin, we know that we can get enough force to do that. Not sure what would really happen without the welded connections in the bracket but it could be bad. Having the pin/bolt bend is better. At any rate, making the bracket weaker than OEM is probably not a great idea. Especially for very heavy rig that gets wheeled.

Looks like I need to learn to weld….

 

[bloc]

Looks like I need to learn to weld….

Other people may have figured it out too but a while back a guy on yt that goes by “welding tips and tricks” was the best at getting the videography right to show what’s actually going on when welding. The light from the arc used to make this really difficult to film well.

MIG is really easy to learn well enough to do what you need. Just make sure you don’t get talked into a 110v machine.. that won’t have enough cojones for a job like this.

Edit: and, get a decent helmet with a large viewing window. Makes a huge difference in usability.

 

[MTKID]

So what I currently have is pretty close the position of the other side that still has the OEM pin.
View attachment 4143992

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?

Looks like I took those pictures on Sept 2, 2022 and I would have ran it on a couple trips after that until I had some mechanical issues that only got resolved recently. So, realistically, I may only have 1 years worth of driving on it this way. I can try to take a look and see if I can see any issues, but I don't plan on taking it out completely to look right now. I will need to replace my rear shocks soon though since they are starting to leak a little. Replacement LX600 shocks are on the shelf to see how they may work.

 

[kcjaz]

Working on getting DOM tubing welded in. Found a local muffler fab shop. It seems like they can do it. I decided to go that route rather than buying a welder and other stuff and teaching myself how to make in a couple days will save that for a different time at the moment I just wanna get this project done.

In the meantime I’m working on the other side and thinking about my waddled out frame out hole:

The last two pics, show the lip washer setting above the frame out hole. I’m wondering if I should attempt to weld in a washer or something to repair the hole. I’m not sure it would do anything as the lip on the washer above is as tall as the shock mount is thick so even with a washer welded on the underside of the hole, the lipped washer can still slide around in the waddled out hole. I suppose I could put the lip washer upside down on the bottom then maybe a welded washer repair might achieve something.

I’m gonna proceed and just put it back together without addressing that waddle out hole. Mostly because welding anything in there will be hard and like I said above, I don’t think would achieve much. The holes in the lip washers are oversized relative to the shock shaft to allow the angle of the shaft to move as a suspension flexes in the bushings do their thing. I think it’s just something I need to maybe keep an eye on and hopefully won’t be a noise/squeak generator.

 

[bloc]

I would consider just having some tacks added into the gap to hold the lip washer in that position. You are unlikely to truly wear out the lip washer and need to replace it, the washer below the mount will prevent the tacks messing up the rubber bushing below.

Done right, you could hammer the lip washer out in the future if you needed to, and then dealing with the tack remnants if you ever had to would be less work than truly fixing it now.

 

[kcjaz]

I would consider just having some tacks added into the gap to hold the lip washer in that position. You are unlikely to truly wear out the lip washer and need to replace it, the washer below the mount will prevent the tacks messing up the rubber bushing below.

Done right, you could hammer the lip washer out in the future if you needed to, and then dealing with the tack remnants if you ever had to would be less work than truly fixing it now.

Or maybe JBWeld?

 

[kcjaz]

Or maybe JBWeld?

Not sure damaging the washers and needing to replace them is unlikely.

I think these were OEM washers. The new ones I have are thicker and I think are the OME PB51 washers. I took those out years ago when I did the original install because of the chirp.

 

[kcjaz]

All prepped and ready for welding the DOM tube pieces:

 

[kcjaz]

Welds complete.

I had them weld a thick grade 8 washer to the backside to stiffen it up. The three-quarter inch hole didn’t leave a lot of meat in the original part.

Something warped little bit in the welding process or maybe it was the washers on the backside, but initially the bolt didn’t go all the way through after welding I had to ream the hole. It was interfering at that backside washer not a huge deal and all good now.

Here’s what it looks like with the shock installed.

I don’t have any math to prove this, but I think the welds are pretty solid and with that reinforcement of the backside and a full three-quarter inch bolt through it through a 1 inch welded sleeve means the structure is stronger than OEM. I guess I’ll find out.

 

[turbo8]

Welds complete.
View attachment 4149042
I had them weld a thick grade 8 washer to the backside to stiffen it up. The three-quarter inch hole didn’t leave a lot of meat in the original part.
View attachment 4149042
View attachment 4149043
Something worked a little bit in the welding process or maybe it was the washers on the backside, but initially the bolt didn’t go all the way through after welding I had to ream the hole. It was interfering at that backside washer not a huge deal and all good now.

Here’s what it looks like with the shock installed.

View attachment 4149051

View attachment 4149052
I don’t have any math to prove this, but I think the welds are pretty solid and with that reinforcement of the backside and a full three-quarter inch bolt through it through a 1 inch welded sleeve means the structure is stronger than OEM. I guess I’ll find out.

Looks good, that should make installation/removal a lot easier.

 

[kcjaz]

Better pic

 

[kcjaz]

I noticed that the front flat “boss” area around the new 3/4” holes wasn’t exactly flat nor exactly perpendicular to the axis of the hole. This was skewing the washers a bit. Since I have the mag drill, I took a 3/4” aluminum spacer with a 1/4” hole and JB Welded a 1/4” shank die grinder wheel to it, flattened two sides to make a “Weldon” shank so I could chuck it into the drill. This allowed me to grind the face perpendicular to the hole axis.

I also cleaned up/ prepped and painted the the shock tower.

I lubed the bolt and rubber bushings with silicon grease and torqued to the specified 72 ftlb. 72 ftlb seems like an excessive torque spec for the BP51 rubber bushings. I have always used 72 ftlb and never really thought about it. It really squishes the bushings.

Without the BB guards, the front bottom edge of the bushings that squishes out below the shock eye won’t last long on the rocks. I figure, this won’t matter as the rubber in the shock eye and between the washers is protected. Next project though is to build a better guard that works with my new bolt mounts.

 

[kcjaz]

On a side note, the enlarged/damaged holes in the upper shock mount “buckets” I do not think have anything to do with the bending of the lower pins. The washers were installed incorrectly with the lip washer on the top and a mix of ARD and Toyota OEM washers. With the lipped washer on the bottom, you can feel it “click” into the hole in the bucket when you put the truck back on the ground to tighten the mounting bolts. If it’s on the top you are relying on top nut pressure to keep the lip in the hole. Maybe you could get that to work but you would have to be pretty diligent reaching up in there as you or a buddy torqued the nut. I think mine got messed up when we swapped over all my stuff from my old 200 to the current one. That was 5 guys doing a lot of things on two trucks in 5 days.

 

[turbo8]

I noticed that the front flat “boss” area around the new 3/4” holes wasn’t exactly flat nor exactly perpendicular to the axis of the hole. This was skewing the washers a bit. Since I have the mag drill, I took a 3/4” aluminum spacer with a 1/4” hole and JB Welded a 1/4” shank die grinder wheel to it, flattened two sides to make a “Weldon” shank so I could chuck it into the drill. This allowed me to grind the face perpendicular to the hole axis.

View attachment 4151999

I also cleaned up/ prepped and painted the the shock tower.

View attachment 4152001
I lubed the bolt and rubber bushings with silicon grease and torqued to the specified 72 ftlb. 72 ftlb seems like an excessive torque spec for the BP51 rubber bushings. I have always used 72 ftlb and never really thought about it. It really squishes the bushings.
View attachment 4152002

Without the BB guards, the front bottom edge of the bushings that squishes out below the shock eye won’t last long on the rocks. I figure, this won’t matter as the rubber in the shock eye and between the washers is protected. Next project though is to build a better guard that works with my new bolt mounts.

That bushing squeeze looks excessive. Can you get measurements of the arb bushings? I'm wondering if you can find something that would fit the shock eye and have a metal sleeve to prevent that bushing deflection.

 

[bloc]

72ft-lbf is assuming a completely different clamping scheme. That is a fine pitch bolt clamping a steel sleeve, not the bushing itself.

 

[kcjaz]

That bushing squeeze looks excessive. Can you get measurements of the arb bushings? I'm wondering if you can find something that would fit the shock eye and have a metal sleeve to prevent that bushing deflection.

I looked for metal sleeved bushings before and couldn’t find any. The OD (or ID of the eye) is 35mm.

i dont like the ARB bushing design that has the protruding rubber “flanges”. Any washer will squeeze the rubber flange. I am using an oversized washer on the front. Maybe using something closer to the OEM diameter would be better. The OEM washer is 37mm diameter and would put the pressure in the center of the bushing. The washer I’m using is 45mm and is as wide as the bushing flange.

 

[kcjaz]

72ft-lbf is assuming a completely different clamping scheme. That is a fine pitch bolt clamping a steel sleeve, not the bushing itself.

Agreed but ARB install instuction use the OEM bolt and 72 ftlb. I’m gonna try a different washer and I think I’m gonna back off on the torque to something like 50 pounds.

 

[turbo8]

I looked for metal sleeved bushings before and couldn’t find any. The OD (or ID of the eye) is 35mm.

View attachment 4152046

i dont like the ARB bushing design that has the protruding rubber “flanges”. Any washer will squeeze the rubber flange. I am using an oversized washer on the front. Maybe using something closer to the OEM diameter would be better. The OEM washer is 37mm diameter and would put the pressure in the center of the bushing. The washer I’m using is 45mm and is as wide as the bushing flange.

I was wondering if we can find a new bushing kit from another manufacturer that would fit, like Energy Suspension.

 

[bloc]

Agreed but ARB install instuction use the OEM bolt and 72 ftlb. I’m gonna try a different washer and I think I’m gonna back off on the torque to something like 50 pounds.

Again, different clamping scheme. It’s a bolt running into the hollow shock mount post, meaning it’ll stop when the washer bottoms out on the post, well before it actually puts that 72ft-lbf of clamping force onto the bushings.

Unless you have a metal sleeve inside those bushings to stop the nut it’ll take a whole lot less torque. Probably too little to stay tight actually.. I’d just put what seems like enough squish on the bushings then double nut it or something.

 

[kcjaz]

Again, different clamping scheme. It’s a bolt running into the hollow shock mount post, meaning it’ll stop when the washer bottoms out on the post, well before it actually puts that 72ft-lbf of clamping force onto the bushings.

Unless you have a metal sleeve inside those bushings to stop the nut it’ll take a whole lot less torque. Probably too little to stay tight actually.. I’d just put what seems like enough squish on the bushings then double nut it or something.

Yes, I realize now that all the clamp force is going into only rubber. This is why ARB provides a little washer for the OEM bolt that is the same 19mm as the OEM mounting pin. The force goes into the pin, not directly into the rubber bushing.