Pre-mature cv boot tears

[Rickalicka18]

So since the suspension lift has gone in since around Christmas, I have be going through cv shafts like a mother****. As of now I have the markmc 3" lift then 87 springs and hd bilstein struts. I have gone through 3 cv shafts, now on cv shaft #4 on the drivers side. The two replacements were both napa cv shafts and like the stock one they all have torn in the exact same place (the cv boot that is closest to the differential). Now I just replaced with a detriot axle cv shaft while also changing the hub on the drivers side since it was bad. I'm not sure if it's just the napa cv shafts are bad, something is tearing the boot, too much lift (the lift is 4"), or if It's because I have yet to flip my uca's. Anyone have an idea of wht might be causing my cvs boots to keep tearing??

[mason10198]

Hm. The only time I had a boot actually tear was when I tore it with my own hands trying to pull it out of the truck. Other than that, I've never had any problems out of mine. I've been using Precision shafts from Oreillys. I remember when I bought them the guy behind the counter said alot of other brands get returned due to failure, but the Precisions seem to work very well for "this vehicle". Of course, he could have just been running his mouth.

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[Rickalicka18]

Yeah that's what I'm saying. I think I should flip the uca's, Maybe that'll help. But the cv I have on now seems to be good. The passenger side cv shaft is still stock though, which is what's making me think that its the napa brand cv

[Fisker]

This is off topic and I apologize for that, but I am really curious how you got 4 inches of lift. Is it the springs plus spacers?

[Rickalicka18]

This is off topic and I apologize for that, but I am really curious how you got 4 inches of lift. Is it the springs plus spacers?

Well the springs raised it an 1" then the lift is 3". Maybe more like 3 3/4" I guess

[Fisker]

Okay so I have a rough country lift so it isn't 3 inches. I'd i put those springs that you have for example it would still only cause one inch correct? Or could I not do that because yours would be to long? I'm just trying to figure out what i could do for an extra inch safely. Lol

[Rickalicka18]

Okay so I have a rough country lift so it isn't 3 inches. I'd i put those springs that you have for example it would still only cause one inch correct? Or could I not do that because yours would be to long? I'm just trying to figure out what i could do for an extra inch safely. Lol

Well It all depends on what you have for stock springs. I had like 84s and went with 87s. There's a formula on the Factory Spring part numbers and associated lift thread in the suspension and lift discussion that'll get you exact numbers

[HARDTRAILZ]

At 4 the CVs bind from what I remember playing around with. About 3.5 is as much As I could get without binding iirc. Do your CVs bind?

[Rickalicka18]

I'm not sure to be honest, but if I am still getting a shake from that side, then it must be... But when I lifted the tire off the ground with a jack and went to spin it there was no wobble or bind from what I could see, just rubbing from the brake on the caliper. Then from what it looked like, when I was taking out the cvs with the torn boot, the cv boot would tear then eventually bind up due to a lack of grease. BUT I could also be wrong and the cv could be binding from the start then the boot eventually tears, then it just keeps binding worse and worse.

I don't think that my actually gain in height is 4" exactly because I am just going off of the fact that I bought the 3" lift and since I went from 84s to 87s that I got about 1" inch of lift from the springs (which my calculations could be wrong). I think it is more like 3.5".

Here are some pictures of what the new cv looks like in though.

[Jrgunn5150]

My Detroit Axle boot's haven't torn yet, just FYI. I have MOOG 8114's and the Mark MC 3"

[Rickalicka18]

Yeah man. I put the detriot cvs in this time and they seem fine. I also cleaned up all the grease and made sure that the spacer was torqued to 90 ft lbs and the wheels were torqued to 140 ft lbs (I think thats what wheel torque specs were, feel free to correct me if I'm wrong). This weekend or sooner, I'm hoping to go a retorque all the spacers and wheels to be sure there all torque to spec

[Jrgunn5150]

IDK torque specs, I don't torque things lol. I must be pretty good because I don't warp it and it doesn't fall off lol.

There was another brand people were recommending in addition to the Detroit's, but I think it's just the boots can't handle it. We could probably get some different boots as well, but at the time, i felt like I should change CV's anyway, they had 180k on them lol.

[HARDTRAILZ]

140 is too much. I do 100ish on both.

[Rickalicka18]

140 is too much. I do 100ish on both.

Okay haha I'll retorque them all to around 100 ft lbs. I was doubting myself anyways lol. This is why I can't wait for my damn rims to be here

[Rickalicka18]

IDK torque specs, I don't torque things lol. I must be pretty good because I don't warp it and it doesn't fall off lol.

There was another brand people were recommending in addition to the Detroit's, but I think it's just the boots can't handle it. We could probably get some different boots as well, but at the time, i felt like I should change CV's anyway, they had 180k on them lol.

Yeah from what I could see its the boot that tears first then the binding follows. I just bought my torque wrench today and I'm lovin it. $79 at habor freight then got it on sale for $21.

[Jrgunn5150]

I have a torque wrench, i just don't use it on wheels lol. I hardly use it at all, rod's, mains, head bolts, that's about it. i have an inch/lb one for pinions. Of course, I don't recommend doing what I do lol.

[v7guy]

viewtopic.php?f=72&t=2701&hilit=CV+boot

As is usually the case, it has been discussed, at length. It helps that I've been here awhile and remember a lot of this stuff. For future reference, using Google, trailblazer CV boot site:forums.offroadtb.com shows the thread I linked first. If you type in your search words and then site:forums.offroadtb.com into google you'll get a really solid list of threads, works a bit better than the site search.


The CV binding, in itself, won't cause the boot to rip. Generally the boot just isn't flexible enough to operate at the angle you're trying to get it to. Most CV boots seem to be made of a cheaper plastic that self destructs relatively quickly in a lifted application. The Detroit axle pieces have (had) better materials for the boots and they hold up accordingly. Kyle is the one that pointed us in the right direction originally as I recall... I didn't go back and read my own thread.

If the CV itself is destructing, I find it unlikely your angle is a problem, I ran a 3" lift and 89s with washers on the shocks with no binding, there will be other more dramatic representations of the problem if the CV is actually binding.

As an added note, the CV angle won't change by flipping upper control arms if you have a good alignment already. CV angle is dependent on the angle of the spindle to the differential. Flipping the upper A arm does nothing to affect this. It does put the upper ballpoint at a less extreme angle. The reduced angle keeps it from maxing out and allows it to transfer the load at less of an angle since the joint isn't at a 40ish degree angle or binding at full droop. But that's about the extent of it.

[Rickalicka18]

I have a torque wrench, i just don't use it on wheels lol. I hardly use it at all, rod's, mains, head bolts, that's about it. i have an inch/lb one for pinions. Of course, I don't recommend doing what I do lol.

Haha. Only reason I'm using a torque wrench is so I can rule out possibilities for why my vehicle is shaking

[Rickalicka18]

http://forums.offroadtb.com/viewtopic.php?f=72&t=2701&hilit=CV+boot

As is usually the case, it has been discussed, at length. It helps that I've been here awhile and remember a lot of this stuff. For future reference, using Google, trailblazer CV boot site:forums.offroadtb.com shows the thread I linked first. If you type in your search words and then site:forums.offroadtb.com into google you'll get a really solid list of threads, works a bit better than the site search.


The CV binding, in itself, won't cause the boot to rip. Generally the boot just isn't flexible enough to operate at the angle you're trying to get it to. Most CV boots seem to be made of a cheaper plastic that self destructs relatively quickly in a lifted application. The Detroit axle pieces have (had) better materials for the boots and they hold up accordingly. Kyle is the one that pointed us in the right direction originally as I recall... I didn't go back and read my own thread.

If the CV itself is destructing, I find it unlikely your angle is a problem, I ran a 3" lift and 89s with washers on the shocks with no binding, there will be other more dramatic representations of the problem if the CV is actually binding.

As an added note, the CV angle won't change by flipping upper control arms if you have a good alignment already. CV angle is dependent on the angle of the spindle to the differential. Flipping the upper A arm does nothing to affect this. It does put the upper ballpoint at a less extreme angle. The reduced angle keeps it from maxing out and allows it to transfer the load at less of an angle since the joint isn't at a 40ish degree angle or binding at full droop. But that's about the extent of it.

I guess that I was right about the napa cvs being the main problem then. I didn't think it was a binding problem, mainly because the passenger cv is stock. So It must just be the rubber on the boot isn't as durable. Now I know though..

[v7guy]

I have a torque wrench, i just don't use it on wheels lol. I hardly use it at all, rod's, mains, head bolts, that's about it. i have an inch/lb one for pinions. Of course, I don't recommend doing what I do lol.

Haha. Only reason I'm using a torque wrench is so I can rule out possibilities for why my vehicle is shaking

Nah, just tighten that shit up, ain't nobody using torque wrenches. I usually use a lil spit on the threads too, it's like free loctite. There's no way loose or overly tight nuts and bolts can cause any problems.