This Mod Left Me Speechless

[landrovered]

The angle places all of the force on one side of the bolt, the bolt is designed to have equal force applied to it. Result...sheered bolt head. Now Whizzboy McEngineer doesn't know the plate is wiggling and quickly wearing out the other two bolts. Proud of his baddass engineering prowess he gasses the truck a little harder than normal around the turn and whole thing lets loose. The wreck makes the evening news.

 

[MarkP]

Two issues actually.

The bolts are intended to be under tensile loads and are now both tensile and shear loads. Good article by a rocket scientist a little farther north of me:

Making the Grade
A Technical Discussion
Grade 5 vs. Grade 8 Fasteners
By David M. Potter​

In addition to loading the bolts incorrectly, the flange of the bushing is now not flush with the support bracket. Flange load is now not distributed across the flange face but focused at the bolt holes. I suspect the flange will fail before the bolts do.

Sometimes creative engineering can get out of hand.

 

[landrovered]

Mark,

I think we basically agree on this one. I am putting a star on my calendar right this minute!

 

[robertf]

Now tell me this... Besides it looking cheap-ass and somewhat ugly, -

How do you guys think it makes the bracket or the bushing or the trailing arm weaker?
Do you think all this area between the bushing flange and the bracket is necessary for something? Do you think the bolt would shear, or the bolt/washers would damage the bracket?

quit making sense, its too much fun to jump on the bandwagon. That guy used grade 5 metric washers, what a dumbass

 

[MarkP]

Mark,

I think we basically agree on this one. I am putting a star on my calendar right this minute!

Won't be long before we agree on a lot more ....... :rofl:

 

[MarkP]

.....Do you think all this area between the bushing flange and the bracket is necessary for something? ....

Distributing loads is so over-rated.

 

[landrovered]

Won't be long before we agree on a lot more ....... :rofl:

I knew you would come over from the dark side at some point.

 

[MarkP]

I knew you would come over from the dark side at some point.

I've been having this long running discussion with some local liberals and leftist. I tell them classic liberals and conservatives have a lot more in common than they think. The leftist just look at me with this deer in the headlight look. It really is fun.

 

[MarkP]

The washer material is pretty soft and malleable. On the other hand the rusty bolt is not.

I think he needs to tighten that rusty bolt really good. It looks a little loose.

 

[osiristheclown]

Who owns that, Red Green? The other bolt doesn't look like it's had a wrench on it since the factory.

 

[p m]

Distributing loads is so over-rated.

Oh how smart.
Now calculate how much load there is.

The only real concern I would have with this is indeed shear load on the bolt, but it is easily checked. The minor thing is stacking washers is uncool in my book.

 

[MarkP]

Oh how smart.
Now calculate how much load there is. .....

There are several load profiles to deal with but I suspect the one missed by most is that the force along the trailing arm is incident in two directions, both pulling on the bushing AND pushing .... on the flange. With the flange no longer flush to the bracket ALL force is now focused on the edge of the flange bolt holes. Static force won't break the flange but peak dynamic shock loads probably will.

It all depends on the load profile. A mall crawler would probably see the bolt holes enlarged as the flange floats. Someone who actually uses the vehicle off road will most likely see a flange failure.

 

[LRflip]

should we start a group buy on the insurance?

I'm in.

 

[ArmyRover]

and this year's Darwin Awards Candidates are.........

 

[ptschram]

There are several load profiles to deal with but I suspect the one missed by most is that the force along the trailing arm is incident in two directions, both pulling on the bushing AND pushing .... on the flange. With the flange no longer flush to the bracket ALL force is now focused on the edge of the flange bolt holes. Static force won't break the flange but peak dynamic shock loads probably will.

It all depends on the load profile. A mall crawler would probably see the bolt holes enlarged as the flange floats. Someone who actually uses the vehicle off road will most likely see a flange failure.

While I'm certainly not disagreeing, I'm also worried about the possibility of side loads on that bolt now that we have a lever arm that wouldn't be there when the bolted fastener is tight against the frame ear-or at the very least heavily distributed when tight to the frame ear.

Given how inexpensive cranked arms are, there is no excuse for this cobbling.

 

[williambrea]

Don't y'all be jealous of my awesome rear links

But on a more serious note im going to take this flaming with stride and remove the ghetto washers. I did not think that this was a big issue due to the fact that i have been running these rear links for about 2-3 months on and offroad without problems. But after looking at some of the more intelligent/mature posts the idea was not smart, just something that i thought of on the spot and decided to try.

Regardless, dont hate on my angle iron/grade8 washers to fix castor angle.

Good Day Sirs

 

[Mike_Rupp]

It is pinion angle, not caster angle. That is unless, of course, you've created some booty-fab rear steering.

 

[jrose609]

Don't y'all be jealous of my awesome rear links

But on a more serious note im going to take this flaming with stride and remove the ghetto washers. I did not think that this was a big issue due to the fact that i have been running these rear links for about 2-3 months on and offroad without problems. But after looking at some of the more intelligent/mature posts the idea was not smart, just something that i thought of on the spot and decided to try.

Regardless, dont hate on my angle iron/grade8 washers to fix castor angle.

Good Day Sirs

:applause:

 

[jhmover]

Don't y'all be jealous of my awesome rear links

But on a more serious note im going to take this flaming with stride and remove the ghetto washers. I did not think that this was a big issue due to the fact that i have been running these rear links for about 2-3 months on and offroad without problems. But after looking at some of the more intelligent/mature posts the idea was not smart, just something that i thought of on the spot and decided to try.

Regardless, dont hate on my angle iron/grade8 washers to fix castor angle.

Good Day Sirs

Glad you got a hint. Ranting and raving and laughing aside, no one here wants you to kill yourself, kill someone in your Rover, or kill some innocent person in another car. Best to check before you start modding things if you're not sure what you're doing BEFORE you do it.

 

[p m]

Mark,

For your entertainment - when I got rid of stock trailing arms, I've looked at the contact pattern. The bushing flange was barely touching the frame outrigger - with the total area of contact less than three times the area of these washers.
So... pulling on these bolts (while reversing) is completely unaffected by this ghetto mod. Pushing on the flange is affected, but barely - and to me the shear load on the top bolt would be the most, albeit still minor, concern.
Speaking of the frame bracket - this mod creates somewhat higher local stress on the mating surface of the bracket, but removes persistent stress from the weld between the bracket and framerail. Pick your poison.

The roll-eye attitude of DW does not always mean something's right or wrong, as it very often is with any collective opinion.

That said... I would never do it like that, but I see a 1/3-ass and 2/3-ass approach to it - use a spacer instead of stack of washers on the top bolt, or make a tapered 2-degree shim. Better save some dough for heim-jointed arms.