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Has anyone removed and re-fitted the prop shaft on the AWD Mokka? and if so could they advise on the process / tools required before I become the Guinea pig ;-)

We recently had to re-gas the aircon and the noise it was making, we have since discovered, was masking a general, dry, grating noise coming from somewhere central in the car. It sounded just like a worn out brake pad grinding on a disc, but wasn't effected by braking or turning. The noise starts over 20 miles an hour and increases in volume / pitch with road speed.

I changed all the brake pads and discs as they needed doing anyway but guessed that the noise was either rear diff, centre "contraption" or a prop shaft bearing failing.

ad the car up on a lift this morning and it is indeed the prop shaft support bearing. Quick call to Vauxhall and, are you sitting comfortably, the bearing is only supplied as part of a new prop shaft. So, given the car is 6 months and 1000 miles out of warranty, thats £1400+VAT for the prop shaft plus fitting!!!!!!!!! - for a bearing worth £20!!!

I am in the process of screaming at Vauxhall customer services and Evans Halshaw who supplied and serviced the car, so will report on what they say. However, and fortunately, there are aftermarket bearings available for about £60 hence my question about dropping and splitting the prop shaft to replace the centre bearing.

Any takers?

On another note, I found it odd how little detail there is available on the Mokka's AWD system but after a fair bit of research I have worked out its a Haldex (Borg Warner) 4th generation with what appears some kind of modification. There is a post about the Australian Mokka having a Borg Warner developed system and they purchased Haldex a while ago then if you lookup Haldex on Wikipedia it lists some GM vehicles. Looking at the car today, it also looks like a Haldex unit but we couldn't see an oil filter fitted to it. Because of this I am not sure about the oil / filter servicing requirements, which for a normal Haldex would be oil every 20,000 miles and filter every 40,000 miles.
 

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Can't help specifically with the mokka prop shaft but in general they are pretty easy to remove, just the four bolts on the rear flange two bolts from the centre bearing bracket and slide out of the gearbox/transfer box with a bucket ready to catch oil, (or a big lump of water pump grease to stop it running out), with the shaft out undo the four bolts holding the front and rear flanges together, remove the nut from the front of the centre bearing flange, tap the flange off the spline then tap the centre bearing off, yours sounds bad enough that the centre race will stay on the shaft and need tapping off separately, as long as VX have followed tradition it should be easy enough.
 

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There is some information here with lots of links which might assist, hopefully.

https://www.mokkaownersclub.co.uk/forum/19-engine-drivetrain/1823-haldex-awd.html
Thanks for that, the centre diff sounds more like a Borg Warner NexTrac because Haldex uses hydraulics and the Mokka uses electro magnets which might explain the lack of filter. However my main query was prop shaft related rather than the centre diff, but thank you for leading me to an interesting post.
 

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Many thanks for that, I haven't looked at it yet but I thought the Mokka shaft had a CV either end and as such would have been oil free. If sufficient gushes out I guess I'll need some gearbox oil to hand then, thanks for the heads up.
 

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So, finally solved.

Symptoms as above, with the prop shaft off, spinning the centre bearing you can hear a dry grinding noise. Bought a new bearing for £60 off eBay and got a prop shaft specialist to swap the bearing (£60) which is possible "with a big hammer" (quote from the very experienced prop shaft engineer). Total cost £120 rather than the £1400+fitting+VAT quoted by Vauxhall.

I removed and re-fitted the prop shaft, which is straight forward. If anyone else reads this then...

1) Jack car up, onto axle stands, so front and rear wheels are in the air.

2) Remove heat shield (6 plastic hex nuts, 10mm socket)

3) Unbolt front and rear CV joints (6 hex bolts each, 8mm thin walled socket)

4) Loosen the 2 centre support bearing bracket bolts (15mm socket)

5) Using two short bolts (M8 I think - same as CV bolts) and an 8mm dowel, plus two of the CV joint brackets. Push the rear CV mount out of the centre/rear diff cup. You do this by placing the dowel into one of the unthreaded holes in the rear of the diffs cup (there are two). Place the pair of brackets (two for strength, so they dont bend) over the dowel and then pass the two short bolts from the rear through the brackets into the back of the diff cup. As you tighten the bolts the dowel pushes the CV flange out.

6) Once both CVs are loose (there is no oil loss as the CVs are sealed units) you can undo the 2 15mm bolts loosened above and then juggle the prop shaft out past the exhaust. The tricky bit is the centre bearing bracket, its does fit with some giggling about and a few scratches to the underfloor.

Fitting is the reverse of removal. The 8mm head bolts are a pain to remove / re-fit because you can only get at two at a time and to lock the shaft you have to stick it in 1st gear. So helps if 2 people. Also, they have copious amounts of thread lock on them which makes it hard to turn them even when they are loose. I managed to get an impact driver onto them using a long extension bar - thats the best way to remove.

Obviously clean the threads and re-apply thread lock before re-fitting. I tightened them initially to 40Nm but that felt a bit too tight compared with removal, so I ended up tightening them to 37Nm.

The prop shaft needs to be split to fit the bearing. In an ideal world you would dismantle the universal joint and then use a press to push the splined shaft out of the UJ. But the UJ doesn't have circlips etc, the metal is peened during manufacture, plus dismantling the UJ means balancing issues when re-building. I'm not sure how the prop shop did it, but I imagine, lots of heat, then using a thick bar that just fits between the end of the splined shaft and the UJ - wack it with a hammer. He said it then all flew apart and was a simple bearing switch.

Anyway, all done and the noise has gone, so I'm back in the wifes good books :)
 

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Also... There is now a place on eBay selling aftermarket Mokka prop shafts, complete with CV's and centre bearing for less than £400, a quarter of Vauxhall's price. Obviously not sure about quality, but then our Vauxhall one "failed" in just over 3 years anyway!
 

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Also... There is now a place on eBay selling aftermarket Mokka prop shafts, complete with CV's and centre bearing for less than £400, a quarter of Vauxhall's price. Obviously not sure about quality, but then our Vauxhall one "failed" in just over 3 years anyway!

Have I another thing to worry about? :wink:
 

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So, finally solved.

Symptoms as above, with the prop shaft off, spinning the centre bearing you can hear a dry grinding noise. Bought a new bearing for £60 off eBay and got a prop shaft specialist to swap the bearing (£60) which is possible "with a big hammer" (quote from the very experienced prop shaft engineer). Total cost £120 rather than the £1400+fitting+VAT quoted by Vauxhall.

I removed and re-fitted the prop shaft, which is straight forward. If anyone else reads this then...

1) Jack car up, onto axle stands, so front and rear wheels are in the air.

2) Remove heat shield (6 plastic hex nuts, 10mm socket)

3) Unbolt front and rear CV joints (6 hex bolts each, 8mm thin walled socket)

4) Loosen the 2 centre support bearing bracket bolts (15mm socket)

5) Using two short bolts (M8 I think - same as CV bolts) and an 8mm dowel, plus two of the CV joint brackets. Push the rear CV mount out of the centre/rear diff cup. You do this by placing the dowel into one of the unthreaded holes in the rear of the diffs cup (there are two). Place the pair of brackets (two for strength, so they dont bend) over the dowel and then pass the two short bolts from the rear through the brackets into the back of the diff cup. As you tighten the bolts the dowel pushes the CV flange out.

6) Once both CVs are loose (there is no oil loss as the CVs are sealed units) you can undo the 2 15mm bolts loosened above and then juggle the prop shaft out past the exhaust. The tricky bit is the centre bearing bracket, its does fit with some giggling about and a few scratches to the underfloor.

Fitting is the reverse of removal. The 8mm head bolts are a pain to remove / re-fit because you can only get at two at a time and to lock the shaft you have to stick it in 1st gear. So helps if 2 people. Also, they have copious amounts of thread lock on them which makes it hard to turn them even when they are loose. I managed to get an impact driver onto them using a long extension bar - thats the best way to remove.

Obviously clean the threads and re-apply thread lock before re-fitting. I tightened them initially to 40Nm but that felt a bit too tight compared with removal, so I ended up tightening them to 37Nm.

The prop shaft needs to be split to fit the bearing. In an ideal world you would dismantle the universal joint and then use a press to push the splined shaft out of the UJ. But the UJ doesn't have circlips etc, the metal is peened during manufacture, plus dismantling the UJ means balancing issues when re-building. I'm not sure how the prop shop did it, but I imagine, lots of heat, then using a thick bar that just fits between the end of the splined shaft and the UJ - wack it with a hammer. He said it then all flew apart and was a simple bearing switch.

Anyway, all done and the noise has gone, so I'm back in the wifes good books :)
Ricardo, I would like to say a huge Thank-You for the information in your post. Recently I had a similar noise and your information guided me to the propshaft centre bearing. I confirmed the noise location by sitting in the car whilst someone else was driving. As a result I ordered a propshaft from ASC off Ebay for £355. Some feedback from my experience:-
  • An 8mm socket from a 3/8 drive set worked fine for the propshaft bolts. I needed an extension to access the front end bolts. I used a drill driver with an adaptor to wind the front bolts in due to limited angular movement available with a wrench.
  • I struggled to remove the propshaft past the exhaust so ended up cutting the rubber between the centre bracket and the centre bearing to allow more movement of the bracket. The new propshaft bracket had a smaller profile so I was able to get the new shaft past the exhaust. Ideally I would have unhooked the exhaust but was not able to do that easily.
  • The push tool arrangement you suggested worked a treat for the rear end. I struggled to get the front end apart and had to resort to levering the shaft to release the cv joint. I don't know if this would damage the cv joint, but as I wasn't refitting the old one it didn't matter. I noticed afterwards that there were some slots in the front flange that might enable some levering on the cv joint to get it out.
I now have a peaceful driving experience. Once again, many thanks. Richard
 
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