cv keeps breaking

[xcilim]

Giday my 91 mu seems to enjoy breaking cv's last night i broke my second one going up a hill that is not that steep has any one else had or heard of this problem before ?

[geeves]

You say its all standard. If so there is minimal excess strain on the cvs. What tyres are you running. Im going to shot saying this but anything over 32 inches (measured) will overstress the CV joints so breakages are inevitable. Otherwise its all driver error.
Be careful not to keep the power on if the front wheels are bouncing and spinning If a sudden change in traction occurs the cv becomes a weak spot. Also avoid turning with lots of power on.
Dont use after market cv joints Get second hand originals

[xcilim]

Thanks for that. Yes id put alot down to driver error from what you just said . And i have been talking to another friend of mine which pretty much said the same so thanks very much for your input and help and ill be being a bit more cautious in the future .

[Yarno]

What are the supporting bearings inside the hub like (not the hub bearings)?
If these are shot then the CV will bend along the outer shaft and break.

[xcilim]

ive replaced both wheel bearing at a cost of $130 per side and the inside bearing which are the knuckle bearing also were replaced at $40 per side they were totally sloged out . but went for a drive tonight in same track and nothing broken so driver error. Maybe i need to wear my jandals instead of steel toe work boots lol less weight on the throttle .but thanks for the info all is appreciated .

[xcilim]

Well tonight i was down our track and once again (number3 ) outer cv broke going over a a small mound into a entry of a track. about a meter rise nice and smooth with no air under the wheels or loaded up under turning . So now i am thinking there is a possiblity that there has been a diff change in the past as i do not have very much info on what it has had done to it in the past i am unsure if the original diff is even in it . So the question now is who know's if different diff ratio's would cause this ???? because i took the blame for the first 2 cv breakages but i cant take the blame for the 3rd lol so any info would be great . ill get a pic up of my mu very soon

[geeves]

interesting
A quick rough and ready test of the whole drive train would be to lock the hubs and put in 4wd on a straight flat piece of sealed road. With the car in neutral it should role fairly easily. If it binds up there is a problem. This could be anything from uneven tyre wear to diff ratio diffeence to a diff problem etc.
4 questions
What tyres are you running?
Is it the same cv every time?
If you look at the half shafts are they parallel?
Where do you get your cvs from?
On my wagon after a driveshaft failure I had to drive 100km with no rear drive and front wheel drive only with no issues so I dont know whats happening here

[xcilim]

Previously to taking my truck down to our track i tested the drive train just as you have said to and there was nothing binding up or was there any ugly noises anywhere .Ive just looked at the tyres so here we go
Tyres are different on both ends on the front i have :Bridgestone dueller m/t 265/75/16
the rear tryes i have on are Silverstone m/t 117 ex 275/70/16 the rear tyres were put on as spares to pass a warrant as they still had 3 mm of tread on them .
CV's first time one broke was the passenger side 2nd time was drivers side now 3rd time was passanger side again . Ive looked to make sure the half shafts are parallel and they are sitting nice and straight. Im getting my cv's from a shop in town here (westport) for a cost of $80 per outer cv ive been in and seen the guy who im buying them off and he has said pretty much the same that it could be driver error but after last night to me it proves that it's not my error something else is wrong do you think because of the tyre difference this could be causing some problems ?. well thanks again

[geeves]

First get a matching set of tyres size wise. I havent checked but those tyres do not sound equivelent in diameter.
What part of the CV is breaking?
All the failures Ive seen have been the outer case breaking but according to the book the design does not allow this to be dismantalled. I have heard so many bad stories about after market cv joints and so few good ones (none) that I would not buy non genuine cv joints. Visit a local wrecker and get joints from there and all your problems will go away. Cv joints from any Mu, bighorn/trooper 88- 91 or any rodeo 88 on will fit. They are normaly sold as a complete unit with both cvs and complete shaft

[xcilim]

Cool thanks for that when i first got the mu it had original cv's in it with auto hubs after breaking the 1st cv i changed the hubs to manual ones hopeing that was the problem but it wasnt so im undecided now on what im going to do maybe ill look for another mu and keep my one for parts the cost is building up very quickly and im not getting to enjoy what i thought i was going to . Ive had my cv's out so many times now that im pretty dam quick at changing them now but because the inner cv wont break free from the front diff i have to get the grinder out and cut the brocken cv off from the shaft .

[xcilim]

looking into changing tyres to a full new set today possibilty the two different profiles have caused this breakage another new cv going in tomorow as i cant be bothered doing it today but hopefully new tyres this afternoon .

[geeves]

"thought i was going to . Ive had my cv's out so many times now that im pretty dam quick at changing them now but because the inner cv wont break free from the front diff i have to get the grinder out and cut the brocken cv off from the shaft ."
The inner cv is the one next to the diff
The correct way to remove this is to remove suspension "like you already do" remove 4 bolts holding diff to chassis remove 4 bolts each side holding diff mounting brackets to diff These brackets are part of the axle assembly so when you remove them the cvs come out as well.
The normal way to do it is remove suspension remove band round inner cv joint reach inside and find and remove wire spring clip This allow you to pull the inside and axle out of the inner cv. I have seen a cv changed this way in 15 minutes.
Unfortuanatly the way you remove the outer cv from the shaft is the only way Much easier on the bench but if you use second hand they come complete so no need.

[xcilim]

Another thought i had to the breaking of cv's is: i have a smaller steering wheel than the factory one i think the previous owner changed it .It measures 345mm across and has a turning circle of 3 1/4 turns from hard left to hard right .I know with the smaller steering wheel that it should be less turns than the factory one and im unsure if the steering stoppers have been adjusted.It has a excellent turning circle while moving but does this sound like it has to much ? Whats your knowledge of this ? Thanks

[geeves]

Steering wheel size has nothing to do with things If anything the smaller wheel removes stress except from the drivers arms.
Turning radius is quoted as 5.3 meters. This does bring up one thing though. Mus are more prone to breaking cv joints than bighorns but all the suspension parts are the same. The bighorn turning radius is 5.4 meters.

[xcilim]

Put my new cv on this moring So i have to wait till monday for my new set of tyres so fingers crossed monday arvo ill be out to see if it was the different tyres causeing the breakages.

[xcilim]

New tyres and another brocken cv wtf ?????? i dont think isuzu is the way to go .......

[xcilim]

New tyres and another brocken cv wtf ?????? i dont think isuzu is the way to go .......

[pig75]

There must be a problem with your setup i have only ever broke CV. Have a look at my videos ether that or you drive a lot harder then me

[xcilim]

lol by the look of your vids you drive harder than me but i have been thinking that possibly my front shocks are to soft and they are compressing alot . My cv's keeps smashing through the top side of the caseing when i come down. i ve seen alot of your vid's and they are pretty awesome but at $80 a pop i cant afford to be blowing one every day this is the 4th one i have brocken out of four drives . my mates toyota surf has never brocken one and that is ifs just like mine but he has coil's over shocks is there any thing else you could think of that could cause this because it looks like you really know what you are talking when it comes to mu's your help would be very appreciated .

[Yarno]

Have you checked if the diffs are the same ratio??