Goblin vs Crown Rally North - 1500 miles, 3 shredded CV axles, a whole lot of new goblin fans

Zklonne

Member
As some of you may have seen on the Goblin FB page, a few weekends ago we launched for Crown Rally North 2020 in the Goblin. This was the first of hopefully many rallies to come in the Goblin and was really a test to see how it would hold up in a field filled with mostly supercars and other heavily modifieds. All things considered, I would call this first rally a true success even though we shredded up 3 CV axles on the passenger side throughout the rally (more to come later in the thread and hopefully some help on how TF we managed that).

More on the Crown Rally - for those who do not know the rally is part of Rally4aCause Foundation which raises money for causes like Epilepsy Foundation, Shriners Childrens Hospital, Hear the Cheers, and most recently the COVID relief fund. This year, through 2 of 3 total rallies, over $110k has been raised for these great causes.

We decided to dress up the purple Goblin as a Waluigi/Wario theme this year and go full Mario Kart... and let me tell you, it was a HIT with everyone. Nobody really expected to see a car like the Goblin show up for the 3 day rally from Minneapolis to Cedar Rapids then to Chicago and back, much less with a set of pocket rockets strapped to the top....

Day 1 - we launched fine and made it about 4 hours in with steady cruising speeds ranging much of the time from 90-110 mph. Our only problem during most of this was overflowing some brake fluid which then blew behind the dash and splashed a bit onto us. I think the cap was maybe just loose as we cleaned and tightened it and didnt have the issue anymore. Shortly after our gas stop and fixing that, as we accelerated past one of the media cars was a big poof of smoke and no power. First thought was "f*$k there goes an overheated tranny". Turned out to be the CV axle that exploded and threw grease onto the turbo which cause the plume of smoke. We got towed and fixed up at a local shop (it was a pain sourcing an axle so we had them get us a spare in case the other side blew out later). Fast forward and we b-lined and made it to Cedar Rapids by nightfall to meet back up with ralliers and get some much beers in us.

Day 2 - started the day at Hawkeye Downs Speedway where we did some short lap runs just to give people a feel for an oval track. After launching to head to Chicago, we survived roughly an hour on the highway, most of which was steady over 100 mph before POP goes the axle again.. same exact story. But hey, lucky for us we had a spare and some very nice companions with tools to help us do a roadside axle change. It only took one run to the auto store to get a socket for the axle nut, and an hour later we were on the road again, milking it out to Chicago where we had another fellow rallier get us another spare axle.... and after reviewing the 2 cases and he dark purple heat discoloration on the axles, we drew a conclusion that maybe a stock Cobalt SS axle isnt really meant to see such high speeds for extended periods of time.

Day 3 - we did our annual drive through at Shriners Hospital in Chicago, no contact or stopping obviously with COVID but we could all tell the joy in the kids as they watched us drive through the hospital parking lot. Now we just had to make the 6 hour drive back home, planning a pace of 60-70 mph max. Low and behold we made it an hour out of Chicago before... the Audi R8 we were with blew a tire. After calling every remotely close dealer to try to find a tire, finally a rallier from Chicago drove out his stock S5 wheels to replace the rears on the R8 to get home and then ship back. Well.... since the R8 has zero room to haul wheels, the Goblin got outfitted with a set of massive wheels strapped to the back. To top everything off, after cruising another 2 hours at regular speeds, we noticed a slight wobble the the back passenger tire and stopped to find the CV joint again falling apart... no jack, but all the other tools and another spare to replace, so we found a log and lifted the rear of the car onto it - 37 minute later #pitcrewstatus and we were back on the road again. We drove another 2 hours to meet with the trailer to get us the rest of the way home safely (it was now midnight on a Sunday).

That leaves us where we currently sit, super busy with work so the Goblin has sat in the garage with me fearing driving it anywhere until I have a lead on what to do - which I don't. A few people have mentioned alignment so I am thinking of getting the numbers run for the current alignment to see where we sit. Anything else to start with? Based on eyesight, I dont think the alignment is going to be anything crazy out of the ordinary.
 

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Desert Sasqwatch

Goblin Guru
Wow, that was an adventure! Good to see the weather cooperated, sorry about the mechanical issues. Be interesting to hear what the final diagnosis is for the blown axles - all on the passenger outboard side? Will be a good lesson learned for all of us. :)
 

Zklonne

Member
Wow, that was an adventure! Good to see the weather cooperated, sorry about the mechanical issues. Be interesting to hear what the final diagnosis is for the blown axles - all on the passenger outboard side? Will be a good lesson learned for all of us. :)
Correct - passenger, outboard, all seemingly related to overheating being the root cause of the failure (all showed burn marks through The metal and were HOT). The question will be why so much heat is being generated in there.
 

ctuinstra

Goblin Guru
The only thing I can think of is the angle. But I can’t imagine your angle is that bad. What about pulling on them? In other words, after they are slammed in and then pulled out when installing the locking nut? Doubt it but a thought.

Also, could the wheel bearing be going bad and causing it to heat up?

Mismatched tire sizes? Maybe the same tire but one worn more or slightly smaller causing the LSD to put extra stress on the axle?

Just tossing out thoughts. It maybe sometime you would normally think of.
 
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George

Goblin Guru
Also looking at the car with the added weight and stock sings when car is in a turn the axle joint may get excessive angle and damage it. Also it could happen on hard accelleration.
Brad
 

Zklonne

Member
Dumping a whole bunch of pictures here - I haven't had much time to actually look at the car but I'm hoping to confirm what I think may be our cause... let me know what you guys think (some kind of eluded to this above). I do believe the extreme heat marks on the housing point towards heat being the root cause which leads to poor lubrication/metal on metal contact in the ball bearing.

I confirmed in RichRich's build that he had cut the rear suspension to lower the ride height/lower the motor height 1.5", which in turn drove the camber way negative (my backyard measurement with a level and ruler put it around -3/-4 degrees). This was wearing the insides of the tires and looked a little goofy so I bought some of the adjustable camber bolts that a few others have used and have them maxed out on both slots which put me back in the -1/-2 degree range. I would imagine the stock height/stock bolt setup on the Cobalt has the axle nearly perpendicular the the wheel which creates very little longstanding movement in these CV joints (remembering they're front axles so they would only see this kind of movement inn the horizontal plane while turning).

As the pictures verify, my axles are no longer horizontal and by changing the camber to flatten out the tires they would no longer be perpendicular to the wheel, causing a tiny amount unnecessary motion 100% of the time the wheels are moving, added to the fact that the motion is now in the vertical plane which is also carrying the load of the car. Maybe not a big deal during short travels, but at extreme speeds or regular speeds over a long period of time with no time to to fully cool off, this could make sense.

I am thinking to test this I could measure the heat rise from start to finish of a 15-20 minute drive with the current camber bolt setup, let the car cool overnight and then put the stock bolts back in the suspension and repeat the test?

I'm definitely not opposed to spending $1k on Driveshaft Shop axles, but if I replace them and still destroy one or both in the future I might cry LOL

Anybody know of a way to test an LSD? Jack the back up, put it in gear and try to spin the wheels? We did think of that failure as a possibility causing excess load on the passenger side axle if the driver side is failing work. I can tell you the first 2 high speed failures lost ALL power and revs shot to redline when it popped. Wouldn't as LSD still allow the unbroken axle some function, or no? MY LSD experience is none as you can probably tell.

Thanks,
Zach
 

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baustin

Well-Known Member
Quick comment on the LSD question: my donor cobalt had a broken axle, driver side was fully disconnected from an accident before I bought it. With only the passenger side connected to a wheel/ground, there was zero driving possible, it would only free spin the driver side axle (portion still on the transmission but hanging free) and couldn't budge the passenger wheel when on the ground. Once jacked up it spun both axles. The LSD isn't a locker, it couldn't do 0/100 friction split and still move.

edit: yes, my transmission has a stock LSD, not just an open diff
 
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baustin

Well-Known Member
I wonder if the axle issue is related to getting axles that are slightly too short or just not manufactured to correct specs.

I looked back at pictures I took during my build but couldn't find anything specific but I feel like I got a couple new axles that were also discolored like what you're seeing, mostly heat from the manufacturing process instead of during failure. I didn't use them and they already had color on them, they were fresh from the packaging.

Same brand, same order time from same store but entirely different axles were shipped to me. I think one may have been slightly different length or it just didn't fully compress/extend. One was terrible to move (both extend and/or bend), as if the clearances weren't right and the grease wasn't filled properly. If I had run that instead of returning it under warranty then I would expect it to fail similar to what you have seen.

Even in the stock image there is discoloration showing up at the edge of the boot:
16662
 

Desert Sasqwatch

Goblin Guru
Dumping a whole bunch of pictures here - I haven't had much time to actually look at the car but I'm hoping to confirm what I think may be our cause... let me know what you guys think (some kind of eluded to this above). I do believe the extreme heat marks on the housing point towards heat being the root cause which leads to poor lubrication/metal on metal contact in the ball bearing.

I confirmed in RichRich's build that he had cut the rear suspension to lower the ride height/lower the motor height 1.5", which in turn drove the camber way negative (my backyard measurement with a level and ruler put it around -3/-4 degrees). This was wearing the insides of the tires and looked a little goofy so I bought some of the adjustable camber bolts that a few others have used and have them maxed out on both slots which put me back in the -1/-2 degree range. I would imagine the stock height/stock bolt setup on the Cobalt has the axle nearly perpendicular the the wheel which creates very little longstanding movement in these CV joints (remembering they're front axles so they would only see this kind of movement inn the horizontal plane while turning).

As the pictures verify, my axles are no longer horizontal and by changing the camber to flatten out the tires they would no longer be perpendicular to the wheel, causing a tiny amount unnecessary motion 100% of the time the wheels are moving, added to the fact that the motion is now in the vertical plane which is also carrying the load of the car. Maybe not a big deal during short travels, but at extreme speeds or regular speeds over a long period of time with no time to to fully cool off, this could make sense.

I am thinking to test this I could measure the heat rise from start to finish of a 15-20 minute drive with the current camber bolt setup, let the car cool overnight and then put the stock bolts back in the suspension and repeat the test?

I'm definitely not opposed to spending $1k on Driveshaft Shop axles, but if I replace them and still destroy one or both in the future I might cry LOL

Anybody know of a way to test an LSD? Jack the back up, put it in gear and try to spin the wheels? We did think of that failure as a possibility causing excess load on the passenger side axle if the driver side is failing work. I can tell you the first 2 high speed failures lost ALL power and revs shot to redline when it popped. Wouldn't as LSD still allow the unbroken axle some function, or no? MY LSD experience is none as you can probably tell.

Thanks,
Zach
Zack, wow those bearing carriers and cages are definitely way overheated. There was definitely a lot of motion in the bearings, much of which appears to have happened on a dry bearing surface at some point (blue steel indicating a temp of at least 550 degrees was reached). Makes me wonder about the bearing lubrication from a rebuilt or even a new axle and if they are using the correct high temp grease? And it happened on three different axles.
Granted, it appears the angle in the CV at the knuckle looks very awkward - for lack of a better description - and correcting it properly, not using camber bolts, is likely needed to make a permanent fix. Not exactly certain what you may need to do, but raising the engine/transmission up to attain the correct perpendicular angle appears to be the proper fix.
 

ctuinstra

Goblin Guru
This makes no sense. There are CV axles that run at a much worse angle than that all the time for the life of a vehicle. Wheel bearings see non-stop movement in grease for years and don't heat up like that. The only way they do heat up is if they are too tight for instance. I'm not arguing with anyone, I just saying I cannot understand why they can take a slight angle under load and high speeds.
 

Lonny

Administrator
Staff member
Both CV axles are seeing the same loads and angles while driving yet one has had no problems and the other keeps self-destructing.

I would focus on installation differences.

Check the distance from the knuckle to the transmission on one side and compare it to the other side.
It is possible the subframe was damaged in a collision or maybe the control arm is bent in.
If it is cramming the axle into itself it could create metal fragments that would start circulating inside the CV joint and eventually self destruct.

Check to see if you have any movement in the rear suspension that would allow the knuckle to move towards the center of the car during a turn. This could also cause the CV joint to fail.
 

Lonny

Administrator
Staff member
Another test would be to take the axle nut off of the axle and push the end of the axle toward the transmission as far as it will go and take a measurement from the end of the axle to the face of the bearing hub.
Repeat this for the other side and compare measurements.
 

Rauq

Member
How much worse was the angle with two passengers and two mini bikes on the roof?

Also, my understanding of the Torsen LSD, when one side it completely unloaded it can act like an open diff. So losing all propulsion when you pop a CV is not really an indicator of an issue with the diff, as @baustin was saying.
 

Fozda

Well-Known Member
Were those tires brand new when you started this journey? If you went from brand new tires to what you have in these pictures in 1500 miles, your alignment is really bad!
 

Zklonne

Member
Looks like I have a bit of a to-do list.. went back through some old photos to verify and check some stuff. If anyone here is out cruising this weekend, do me a favor and feel your CV joint after driving and just let me know how hot it gets for comparison. Both sides of ours did get extremely hot, but driver side never failed. At one point on the return trip both sides were hot enough to boil off water sprayed onto them. Just don’t burn yourselves;)

1) the 3000 miles I’ve put on the car has worn the tires pretty well from being nearly new, so definitely a laser alignment in order to check how it’s sitting right now. Not sure this has anything to do with the axles either way though.

2) the donor had front end damage, so as Lonny states movement in the suspension or if the passenger side is over (Or under) compressed could be an explanation. Maybe I’m seeing things, but In the donor pic the front end appears to have quite a bit of camber (Maybe damage induced or just the body panel damage making it look that way..), right?! Whether that matters or not, I always felt like the car had way too much negative camber when I got it, but maybe that’s normal after cutting the spring down?
 

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ctuinstra

Goblin Guru
As far as the tires go, it looks like most of that is over-inflated since the centers are worn the most (from what I can tell in the photos). If they are a very soft compound (treadwear rating of 100), we didn't get much more than that out of our first set and the were worn slick over the entire tire. Granted on our first build, the alignment could have been off some.
 
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