Snacktime's Bronco maintenance starring someone else's Bronco (torn CV boot fix, bushings install, and Metalcloak goodies)

[Snacktime]

So today was fix a torn CV boot, install some Rough Country Bushings and add some @Metalcloak goodies on @Rob_Bronc91 Bronco. Please understand this normal wear and tear for offroading. The only real surprise was the condition of the driver side steering bushing.

First up the blow CV boot. Definitely from an overextended axle. The hole was made from the inside from the retaining ring. Note M190 passenger and driver axles are identical except for the inner shaft section.

M190 inner shafts, Drivers side is shorter

The torn CV is the one with the bearing cage had just a small 1/2" hole. We stole the boot off my broken CV axle to save a trip to the stealership.

Treasure! This is the wear inside a CV in a Bronco with Hitachi shocks and 2" Zone lift. Look at the wear location near the outer surface. You are pretty much at max extension before you even get binding. I believe this axle was over extended and the outer snap ring came off and poked a hole in the boot. This is literally what everyone considers a safe lift.

Next is the stock steering bushings. Passenger side was fine no issues. Robert killed the tie rod on this side and we did a trail repair this last Saturday. No issues pretty straight forward deal.

Drive side was $&@# into 2 pieces! This is with 35s and stock steering.

In the housing

Housing had serious damage, filed it down and cleaned it up. Otherwise not much you can do.

Second chunk was all the way into housing and could have got caught in the gears.

Then we threw on a few goodies he won at @Wild Horses 4x4 event provided by @Metalcloak fit and finish was excellent. Milwaukee impact made this less than a 1 hour job to install.
Metalcloak adjustable track bar
Metalcloak lower control arm skids
Wild horses shock skid plates

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[87-Z28]

Great info. Thanks.

 

[Snacktime]

Great info. Thanks.

I know you're keeping an eye on CV axle stuff. Mechanic binding is not the limiting factor. I am still building my case.

 

[87-Z28]

Absolutely. Mechanical binding is obviously bad but premature wear also clearly occurs before binding. Postmortem look at failures and wear like this is great. I have an idea on how to add the changes in CV binding forces and tie rod bearing forces as angles change. Need to think it through a little more but will post. Keep these posts coming.

 

[NORCALGXP]

Excellent write up. Really surprised by the damage to the driver side bushing and on the case. He is only light wheeling? I replaced mine in April before Moab and it was fine and this was after a year and a half of wheeling and you know what kind of trails we do. Could it be related to the type of lift? The CV wear is not surprising I will be checking mine when I get back. Keep up the good work.

 

[popo_patty]

Excellent write up. Really surprised by the damage to the driver side bushing and on the case. He is only light wheeling? I replaced mine in April before Moab and it was fine and this was after a year and a half of wheeling and you know what kind of trails we do. Could it be related to the type of lift? The CV wear is not surprising I will be checking mine when I get back. Keep up the good work.

Robert has done quite a bit of “moderate” wheeling and this isn’t the first break down he has had. I believe he was one of the first to puncture his transmission pan on the trail! Definitely no stranger to trail repairs and always has a fantastic attitude about it.
Great write up again.
I’ve heard there is a difference in wear between a 2” spacer lift and 2” suspension lift. As this is a spacer lift I’m curious if that’s why there is wear already occurring. That being said the wear didn’t look that bad and more polished then anything. Of course pics can be deceiving. I definitely want a diff drop and then add my limit straps. Still on the fence with the inner stop from accutune for the shocks. I disconnected my sway bar and noted that I only gained 1/2” extra travel on 37’s with sway bar disconnected on Kings. I wasn’t binding at all either and my Icon tubular UCA was just a hair from being maxed out. Definitely can’t gain anymore down travel without going long travel.

 

[V1Rotate]

Robert has done quite a bit of “moderate” wheeling and this isn’t the first break down he has had. I believe he was one of the first to puncture his transmission pan on the trail! Definitely no stranger to trail repairs and always has a fantastic attitude about it.
Great write up again.
I’ve heard there is a difference in wear between a 2” spacer lift and 2” suspension lift. As this is a spacer lift I’m curious if that’s why there is wear already occurring. That being said the wear didn’t look that bad and more polished then anything. Of course pics can be deceiving. I definitely want a diff drop and then add my limit straps. Still on the fence with the inner stop from accutune for the shocks. I disconnected my sway bar and noted that I only gained 1/2” extra travel on 37’s with sway bar disconnected on Kings. I wasn’t binding at all either and my Icon tubular UCA was just a hair from being maxed out. Definitely can’t gain anymore down travel without going long travel.

It’s interesting to me that the Zone 2” kits use a different approach depending on stock SAS vs. Non sas. The SAS kit uses a combination of perch collar + spacer AND bump stop extensions whereas the non sas uses just a spacer to achieve the 2”. That results in 2” of overextension possibility on non SAS lifts like this one.. I could see that making a difference. I’d still consider the 2” kit for Bilstein equipped Broncos to be better than the average puck lift since half of it is achieved with a preload collar and only allows for half the over-extension vs. this kit. Obviously neither is as good as a coilover lift in that regard.

Are the axle shafts mostly physically the same between the 190 and the 210‘s? I know they aren’t identical but curious if aside from length they’re mostly the same diameter/strength

 

[Snacktime]

Are the axle shafts mostly physically the same between the 190 and the 210‘s? I know they aren’t identical but curious if aside from length they’re mostly the same diameter/strength

I have not gotten to take apart a M210 axle yet, it's on my to do list.

@popo_patty CV axle isn't worn out at all. It's the location of the wear near the outer edge of the cup. It's just a tell tell sign of that the cvs are to short or being ran at to much angle. Also I tried to leave out how famous Robert is locally lol.

 

[87-Z28]

Yes I think that lift plays a significant role. Shock extension lift. Increasing the tie rod angles at max extension starts to significantly increase bearing forces in the rack. Just due to geometry. I agree with snacktime that even a mild 2” lift at the wheel begins increasing forces. I will post a plot of this when I have some more time. Kind of surprising how bearing forces can go up.

However, I DO think the evidence now is starting to show this rack (hoss 1) is fairly well designed AS A SYSTEM. Meaning design of system components are appropriately matched and not completely out of balance. Hear me out on this before you pelt me with stones.

The tie rods are weak. Known fact. Small diameter so cannot carry much bending load. The bearings are also weak. We have seen many failures. As has been pointed out, drivers side bearing deforms and/or fails causing rack rod to bend and easily unseat pinion gear. This relieves load on housing which doesn’t typically fail. On passenger side, same load path, weak bearing deforms but pinion gear is harder to unseat so load must be carried by housing. the housing is also weak and fails.

The load paths and failure modes seem to be appropriately designed. You would not put massive tie rods into this design nor would you put massive bearings. Since passenger side housing has been shown to fail and also be weak. Probably a reasonably well match system wrt load path. I would say the design stinks if the bearings blew out easy but the housing was super stout. Doesn’t seem to be the case.

Problem is, this rack tie rod design belongs in a Ford escape. Not the right rack for the job. the expected bronco loads are much to high. I am going to give the engineers the benefit of the doubt here. Probably a poor management and business decision how this made it into production. I think eventually rack upgrades are in order for many of us.

 

[Snacktime]

Yes I think that lift plays a significant role. Shock extension lift. Increasing the tie rod angles at max extension starts to significantly increase bearing forces in the rack. Just due to geometry. I agree with snacktime that even a mild 2” lift at the wheel begins increasing forces. I will post a plot of this when I have some more time. Kind of surprising how bearing forces can go up.

There is off the shelf designs that are much better suited to our application. Really the improved operation angle and strength from the spherical cup race would warrant the added cost.

However, I DO think the evidence now is starting to show this rack (hoss 1) is fairly well designed AS A SYSTEM. Meaning design of system components are appropriately matched and not completely out of balance. Hear me out on this before you pelt me with stones.

The tie rods are weak. Known fact. Small diameter so cannot carry much bending load. The bearings are also weak. We have seen many failures. As has been pointed out, drivers side bearing deforms and/or fails causing rack rod to bend and easily unseat pinion gear. This relieves load on housing which doesn’t typically fail. On passenger side, same load path, weak bearing deforms but pinion gear is harder to unseat so load must be carried by housing. the housing is also weak and fails.

The load paths and failure modes seem to be appropriately designed. You would not put massive tie rods into this design nor would you put massive bearings. Since passenger side housing has been shown to fail and also be weak. Probably a reasonably well match system wrt load path. I would say the design stinks if the bearings blew out easy but the housing was super stout. Doesn’t seem to be the case.

Problem is, this rack tie rod design belongs in a Ford escape. Not the right rack for the job. the expected bronco loads are much to high. I am going to give the engineers the benefit of the doubt here. Probably a poor management and business decision how this made it into production. I think eventually rack upgrades are in order for many of us.

I agree

 

[MyDogGoldie]

Thanks for the pictures and write up.

- about the spacer lift - I don't see how a Spacer lift could be any more damaging than a full coilover of the same overall max extended length of the (Stock Shock + Spacer) VS. (Coilover Length) All of the full coilover kits (Eibach, ICON, King, Fox, etc) are longer than the stock suspension.

Do you have the overall length of the 2" spacer + stock shock - for this case vehicle?

 

[Snacktime]

Thanks for the pictures and write up.

- about the spacer lift - I don't see how a Spacer lift could be any more damaging than a full coilover of the same overall max extended length of the (Stock Shock + Spacer) VS. (Coilover Length) All of the full coilover kits (Eibach, ICON, King, Fox, etc)

Do you have the overall length of the 2" spacer + stock shock - for this case vehicle?

You are absolutely correct that total length is the same and max extension is the same. Hitachi front shocks are 1/2" shorter than SAS so around 22.8" then add on 1.4" spacer for a total length of 24.2". Length is right there with most aftermarket coilovers.

This was just something that fell into my lap, when I got asked if I could help change a CV. I doubt if any of the companies selling coilovers bothered to take apart a CV and see what the wear patter is.

 

[MyDogGoldie]

You are absolutely correct that total length is the same and max extension is the same. Hitachi front shocks are 1/2" shorter than SAS so around 22.8" then add on 1.4" spacer for a total length of 24.2". Length is right there with most aftermarket coilovers.

This was just something that fell into my lap, when I got asked if I could help change a CV. I doubt if any of the companies selling coilovers bothered to take apart a CV and see what the wear patter is.

Thanks again for your breakdown and the photos, these real world examples are so valuable.

Do you plan on going the Diff Drop Route with this vehicle to remedy the axle angle? Or is that just pushing the problems down the line to another component?

 

[Snacktime]

It’s interesting to me that the Zone 2” kits use a different approach depending on stock SAS vs. Non sas. The SAS kit uses a combination of perch collar + spacer AND bump stop extensions whereas the non sas uses just a spacer to achieve the 2”. That results in 2” of overextension possibility on non SAS lifts like this one.. I could see that making a difference. I’d still consider the 2” kit for Bilstein equipped Broncos to be better than the average puck lift since half of it is achieved with a preload collar and only allows for half the over-extension vs. this kit. Obviously neither is as good as a coilover lift in that regard.

Are the axle shafts mostly physically the same between the 190 and the 210‘s? I know they aren’t identical but curious if aside from length they’re mostly the same diameter/strength

I tore off those exact SAS length puck spacers, yes they are 100% safe to run. They do reduce the strength of the stock CV Shafts to a noticeable amount. I find myself recommending Bilstein 5100 & 6100 due to the length and quality of product as the best lift option. I am very pro spacers as I still run .625" of spacer lift.

 

[Snacktime]

Thanks again for your breakdown and the photos, these real world examples are so valuable.

Do you plan on going the Diff Drop Route with this vehicle to remedy the axle angle? Or is that just pushing the problems down the line to another component?

That is up to the owner, I will let him decide. I am currently still testing my 1" differential drop, the drop did offset the differential a little so I am not 100" satisfied with how mine came out. I am also wanting to do a front locker by end of summer so I may wait and tear the whole front end apart then and re-weld and notch everything for a 1.5" differential drop. Its a work in progress not something I recommend currently.

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