anyone snapped a driveshaft UJ before?

[andy-m]

just done my bi-weekly shopping, 100 yards from the store i hear a loud bang as i pull away from the lights, lose most of my traction,and theres a godawful racket from my n/s rear wheel.

had a quick look under the car while i wait for the RAC and the green cylinder on the diff end of the drive shaft was obliterated. half of it was lying in the road!!!

luckily i still have my old silver saloon as i'm half way through pulling a few bits off it before i scrap it so i'm gonna swap the drivesafts over this weekend (Weather permitting).

anyone else had this happen before? the whole UJ assembly looks quite sturdy to me so i'm a bit suprised at whats happened TBH

[andy-m]

well, pulled the old driveshaft/hub assembly of and swapped it with the one from my old silver scoob.
thought i would post pics up of the part that failed;-



I then held the back together as its the only part of the break that still fitted together:-

[Jolly Green Monster]

usually the cage breaks inside that or the shaft itself if power related..

perhaps a weakness in manfacture?

[Mortster]

Bloody hell, never seen that before.

[andy-m]

Originally Posted by Jolly Green Monster

usually the cage breaks inside that or the shaft itself if power related..

perhaps a weakness in manfacture?

must have been cuz i cant see no other reason it would fail.

the car was converted to manual from automatic at some point in its past, and then a low ratio RA box was fitted, so its current setup would deliver more power to the rear driveshafts than originaly. thats the only reason i can think of as to why it failed now and not sooner.

i'll bring it along to the pease pottage meet tomorrow if anyone wants a quick look

[Mike L]

Yes a few times

[DukeBoy]

For different reason I think Mike

[asperformance]

i have had a car that the knuckle seized on (was possibly ran with a split gaitor for a period of time), and whilst it never got to your point it did occassionally "lock/jam" holding the suspension funny.......guess its possible if it wasn't rectified it would have split the outside as yours has??

Originally Posted by Mike L

Yes a few times

Why doesn't that surprise anyone

[andy-m]

Originally Posted by asperformance

i have had a car that the knuckle seized on (was possibly ran with a split gaitor for a period of time), and whilst it never got to your point it did occassionally "lock/jam" holding the suspension funny.......guess its possible if it wasn't rectified it would have split the outside as yours has??

nah, it had a lot of grease in it, half of which ended up on my exhaust when the joint went. it had started making a knock occasionaly on accelleration which i thought was a wheel bearing going and was gonna investigate this weekend, but it didnt happen all the time, just occasionaly. i guess the ends must have started to open, hence the knock n then one dy just went completely

[andy-m]

confident that my new UJ was working fine, I tried a sprited pullaway from the lights today.
guess what snapped again ???

this time the outer casing hasnt gone. the shaft is still in the diff end of the joint but jumps up n down n rattles so i'm guessing the cage has gone this time. i'm gonna go pull it apart in a minuite n sort it.
i am beginning to think maybe the wiring on my DCCD box is such that all the power is going to the rear. gott aget a job n a dif controller before the country runs out of rear drive shafts that i can buy

[andy-m]

yep, i did it again. same failure, same wheel
i think the DCCD box must have been wired with all power to the back wheels. just waiting for a callback from someone to see if i can get a replacement shaft:-



Edit:-
Saj just sorted me out a shaft which should be here tomorrow. last thing I needed was having to fork out for a new shaft while i'm still unemployed !!!

[asperformance]

i have a budget controller if required..........one left out of a batch i sorted

[andy-m]

could you PM me a price, delivered to SE london please.
and how easy is it to wire in?

[Justin]

Are you sure all you diff ratios are correct?

How much power are you running? because I dont think this is power related

[andy-m]

its about 280bhp. dunno what the diff is, but ive done about 1000 miles in it since i bought the car n i figure if the diff was wrong it would have gone pop before.
its gotta be because all the power is going to the back 2 wheels only.
new driveshaft turned up this morning so i'll get the box n dif codes off the car when i fit the shaft so i cn double check, but i expect they will be fine.

saj also said i am running standard driveshafts

[asperformance]

we dont do that on the rally cars............?? as Justin says its got to be more involved??

[andy-m]

well the first tiem it went, it probably was just component failure. it had been making a noise which i thought to be a wheel bearing.
now that ive had the shaft off to fit a replacement, i can see the shaft has bent about 5-8mm. it probably got bent the first time the UJ went n thats probably what made it go a second time as a bent shaft would have meant its out of ballance and would have put sideways force on the UJ assembly when i was driving along

[andy-m]

gearbox is a ty752vb4ca which has a 3.9 final drive ratio
where is the code on the diff? i couldnt see it

[Justin]

There isn't, you have to take it off and either count teeth, or the easier way is count number of prop flange rotations to one full driveshaft rotation.

3.9 cwp turbo rear diffs are rare, did you get the rear diff with the box?

Even if the DCCD box had no controller fitted, worst case would be 65% to the rear which is fine and what its designed to do

[andy-m]

diff n box were in the car when i got it.
so as ive done about 1000 miles before failure, it must be the right ratio right?

[C. J.]

no loads of cars are taken to surrey rolling road and it shows up.
take nothing for granted

[andy-m]

right, so if i spin the diff input flange 3.9 times, both back wheels should turn once right?

[Justin]

Yep, remember there is also a 4.1 diff out there so measure it well! Its only 4 small bolts to take off the prop, or you can get all 4 wheels in the air and spin the prop and compare front and rear wheel rotations

[andy-m]

the car is on the side of the road, so i dont think i'll risk all 4 in the air !
i'll check in the next few days n see what i have.
only problem is if i get this new job, i am gonna have to do 50 miles a day before i can afford a replacement diff! if its wrong, i am just gonna have to take it easy n chance it.