Skoda yeti 4x4 question

[dfps]

Skoda Yeti 2012 4x4

 

Is it possible to jack up both front wheels off the floor and put the car in drive to be able to get the engine to slowly rotate the front wheels or will the electronic 4x4 cut in and drive the back wheels and push the car off its front supports.

I am trying to locate a clunking sound which is coming either from the driveshaft area or maybe the propshaft region.

Have done much work on my Yeti but not familiar enough with how this particular electronic 4x4 works if the front wheels are off the deck.

Thanks

[Urrell]

If the front wheels are rotating and the back are not it will think it's slipping and send power to rear wheels.

Edited 13 January, 2023 by Urrell

[Kenny R]

Check the prop shaft coupling, well documented as to disintegrating and causing noises/ vibrations.

Edited 13 January, 2023 by Kenny R

[Schtum]

55 minutes ago, Urrell said:

If the front wheels are rotating and the back are not it will think it's slipping and send power to rear wheels.

 

Although it may well be that with the handbrake applied the Haldex clutch will not engage and send drive to the rear.  I'm not sure if that's the case for Haldex 4 but it certainly seems to be the case for the Haldex 5 on my car, given the ease with which I can handbrake turn it on

low friction surfaces.

[J.R.]

1 hour ago, dfps said:

I am trying to locate a clunking sound which is coming either from the driveshaft area or maybe the propshaft region.

Under what circumstances please?

[dfps]

Hi Guys

Thanks for the answers. Much appreciated.

So I have just jacked up one of the back wheels and got my son to turn one back wheel  manually. This is turning the propshaft.
It appears that the propshaft at the engine end is turning eliptically ( like an egg shaped rotation) so its not turning evenly which would support Kenny R's 
assessment that it is probably the front propshaft bearing that has totally failed.
It is now pouring with rain again so I could not check  any further to see if any other components will have failed or been damaged by the bearing failing.
Any thoughts please on the likelihood of additional damage  ?

As soon as the weather improves I will get the front of the car jacked up/supported  and get underneath it.

Has anyone done this job and could dierct me to any youtube or other links or offer any advice before I start ?

Thanks ever so much.

[dfps]

ok guys...intriguing development.

It appears that all three M10 x 30mm bolts that hold the front flange of the propshaft to the gearbox have dropped out !!!!

This has allowed the propshaft to drop off the gearbox. Not sure how the hell that has happened !!

All I can think is that when the clutch slave cylinder that is inside the clutch housing was changed by a garage 3 years ago they

forgot to torque up those bolts and they have subsequently loosened themselves as the propshaft was rotating.

Hopefully  replacing the bolts will sort it ?
Would be far easier if I had a hoist but not such an easy job on the wet floor as locating the bolts in such a confined space is a bit of a challenge
laying on my back and making sure I dont cross thread them.

Has anyone else experienced the bolts falling out ?

[J.R.]

Similar but the driveshaft bolts after my neighbours clutch was replaced.

 

The problem with any fastener loss on a drive flange is the damage caused by the last 2 bolts when they liberate themselves, minimally you will have oval holes which will no longer take the drive torque without the bolts forever coming loose, worse will be one or more damaged threads.

 

But what you do have going for you is that its a part time 4WD set up and if you are really lucky then the Haldex may have had a fault & not have been engaging (as crazy as it sounds to be lucky to have another fault!) & the bolts will have made their bid for freedom while the propshaft was not transferring torque.

 

If you are really really lucky then the garage will have forgotten to refit the bolts completely and there will be no damage! Actually a bigger chance of that than the bolts not being tightened enough.

[dfps]

Hi guys...back again.
New question on same thread.

(For clarity : This is the FRONT propshaft end that locates onto the gearbox flange.
and the propshaft is still connected to the car at the central bearing and the back haldex end.)

As the front flange has rotated independently of the gearbox flange I'm wondering if the 3 bolt holes need to be in a particular orientation 
in order to locate as there seems to be something stopping the two flanges mating up to pull together.

Vision and access is quite restricted due to the location and at this stage I'd rather not have to drop the propshaft completely if I can
just get the 3 bolts back in and pull the two flanges together.

My questions :

Is there a central spigot shaft that needs to locate  ?

 

or

Is there some sort of hidden peg that needs to locate in a certain orientation relative to each other to allow the two flanges to pull together ?

PS : I have already put longer bolts  in ( temporarily with the car stationary) to see if I can pull the two flanges together but if there is a spigot or peg that is not aligned properly then 
I could be doing some damage doing that.
I guess the bolts are 30mm for a reason as there is limited space behind the gearbox flange and any longer bolts may protrude and  may foul the gearbox casing when they rotate.

(Photo to show bolt holes being discussed.)

Any help or advice would be appreciated.



 

[Urrell]

If it has been spinning differently could the coupling have been damaged.
Are the bolt holes clear for the full depth or is a broken bolt obstructing them coming together?

[Ootohere]

 

 

[dfps]

Hi Toot

Thanks very much for that vid. Much appreciated.

Unfortunately it doesn't show the refitting process of the propshaft at the gearbox end where I am having all the difficulties.
I'm going to spend some time on youtube looking to see if I can find one of the refitting process to a Audi Q3/Tiguan etc
as it is more likely to show those cars.
If I find anything I will post it here.

One thing I have found out is that each bolt has a raised locator ring around it which is acst into the gearbox flange.
I think these m must be there  to reinforce the union of the two flanges when all the torque is applied through the propshaft
otherwise all the pressure with be on three M10 bolts.
I think these are causing me problems as they are probably a snug fit and may have become damaged or burred as they bolts 
became loose and the propshaft shifted around out of alignment until all 3 bolts eventually fell out.

Resided to the fact I am going to have to remove the propshaft completely to check these and check that the threads in the holes
I am trying to locate have not been damaged.

Hours of fun !...NOT 

Have attached a rough drawing which I 'THINK'  is the set up on the clutch flange 
please excuse the drawing.
 

[Brijo]

No excuse necessary - that looks like a very commendable freehand sketch 👍

[Yety]

I've never done this, but recently got the rear coupling changed. I chickened out and and got my local village garage to do it. They struggled until they moved the diff/haldex unit back a bit in the rear subframe in order to engage the centralising spigot in the hole square on. It was a close non interference fit and would only engage when square on.

Perhaps, if you have not got enough clearance to move the propshaft back, engine forward enough you won't be able to insert the spigot into the hole. Perhaps you could try releasing the centre bearing assy and perhaps "kink" the prop shaft enough to get the spigot engaged - I don't know, only a suggestion if you are getting desperate!!

Edited 15 January, 2023 by Yety
spelling

[dfps]

Hi Yety

 

Thanks very much for the input.

Believe it or not ...either through perseverance or sheer good luck and not wanting to drop the exhaust and the propshaft to start at the gearbox end I had another go and I think I've got it sorted.

The car is still up on axle stands with all 4 wheels in the air so yet to put it under any load on the road as I have used standard M10 bolts which I chopped down to diminising  lengths to use the bolts as pullers to pull the joint together.

Now thats the flanges are pulled together I need to order and fit the high tensile bolts needed one by one.

As the car is in the air its possible in first gear to rotate the driveshaft by carefully lifting the clutch till each bolt becomes more easily accessible along the arch tunnel of the chassis

making locating and tightening the bolts a lot easier when lying underneath the car.

 

The process I used : 

 

Rotated the propshaft by hand and tried a few different options to mate up.

Not sure if there is only one way all 3 holes line up correctly so tried a few different ways until one felt best when putting finger tips up between the mating flags.

Located one bolt but used a bolt cut to 45mm to close the gap between the flanges taking great care not to cross thread.

The 45mm bolt started to pull the flags together but eventually bottomed out on the casing behind.

At this point it was taking the weight allowing a bit to locate in the second hole.

I used a small 3/8 racket with 17mm socket to then locate and similarly pull in the second bolt till that also bottomed out behind.

 

 I then removed the first bolt and cut 5mm of it and put it back in and tightened it up but only till it took the weight.

I removed the second bolt and also cut 5mm off it and replaced.

I then used both bolts a few turns at a time on each to put the flange in as square as possible till they bottomed out the back of the holes of the gearbox flange.

It was possible to feel the thread at the back.

I repeated the above process cutting another 5mm off so the bolts were now approx 35mm and put the back in one at a time trying to pull the flange in square on.

 

Once both bolts are in fully its possible to feel that the gap between the flanges has now gone.

 

To get the ( impossible 3rd bolt) located my son started the car put into first and slowly lifted the clutch.

It was then possible to watch the 3rd bolt hole rotate to the easy location spot.

The 3rd bolt went in easy as the other 2 bolts had done all the work and could be accessed and tightened with a 17mm socket on  long extension with ratchet along the bodywork tunnel.

 

Using the car in gear to rotate the propshaft brought each bolt in turn to a position where it could be tightened easily.

 

I then put the car in 4x4 mode and all wheels turned as they should.

HAPPY DAYS !

 

Hopefully all I have to do now is wait from the proper spec tensile steel bolts ( 12 spline M10 x 30mm to arrive and fit them one by one using the engine to bring the bolts round to have easy access.

 

Hopefully this will sort the problem.

 

I hope maybe helps anyone else doing this job without having to remove the exhaust mid bearing and carrier and the back Haldex flange.

 

 

 

[dfps]

Ps : 

Will probably put a spot of loctite on the tensile bolts when they get fitted to hopefully prevent the bolts falling out again.

[Bexhillian]

Chapeau !

[J.R.]

Well done, I hope you ordered the bolts from VAG rather than using generic ones, aside from the tensile strength they will be bolts and not setscrews and should also be close tolerance fitted bolts to transmit the torque.

 

Having said that you may find the VAG ones are actually setscews (threaded the whole shank length) as they have included the counterbore locating elements into the design.

 

I had a nagging feeling that the garage may have used the wrong fasteners which resulted in their escape, that usually happens where fitted bolts should be used but again it seems that VAG have foreseen this in the design.

 

Chapeau to you for working out what was going on by feel alone, to answer your earlier question, yes there must be a spigot (as there is at the rear) to prevent the prop dropping and the vehicle pole vaulting if the joint fails or the bolts fall out, yours must have got very burred with the differential movement between the two parts, you did well to get it back together.

 

I actually witnessed a Toyoto minibus (carrying twice as many passengers as it was designed for) pole vault on a road in South Africa, I had been warned not to travel in these taxis but as a backpacker thats what I loved doing, most of them were death traps, I noticed that pretty much every small village had a repair shop/garage that would tackle everything and most had specialist propshaft repair and manufacture shops, at the time I was building motorcycle engined 7's and there was only one single propshaft manufacturer left in the UK (Bailey Morris) quite a comparison.

[dfps]

Hi JR

Thanks very much for your reply.

I bought these off ebay as they seemed to be a very high quality ( US company that manufactures high quality car parts to the competition racing
industry )
If you think these are not suitable please do let me know and I will order direct from VW.

 

Also your thoughts on using loctite on the threads ?

Thanks very much.

[Urrell]

Will the flanges on the bolt leave movement clearance to the carrier here?

[TruckbusUK]

Re the bolts, TBH, I'd just order them from your local Skoda dealer ... at least they will be the correct bolts.

[J.R.]

If not for you mentioning the counterbores and matching spigots I would say 100% never use a setscrew on a torque drive joint and don't even use a bolt of the correct tensile strength and plain shank length unless it was a close tolerance "fitted" bolt intended for the application.

 

From what I can see of the image of the fasteners you have bought they are setscrews, that the seller calls them bolts is concerning to say the least.

 

Now I know there are some exceptions like the Sierra diff drive flange but I believe there they got away with it by using a much larger diameter and larger machined clamping faces and pre-loctited bolts, if the correct tightening torque is not respected the holes will oval.

 

The principal is that you should never transmit a drive torque by the major diameter of a thread, it will quickly compress and the joint start slipping, it has to be a plain shank and also a close tolerance one going through a reamed not drilled close tolerance clearance hole, otherwise once again there will be significant radial slippage and the drive is only likely to be transmitted by one fastener only leading to ovality.

 

The holes in your Guibo joint may already be damaged, putting an undersized setscrew in there may result in slippage and loss of the new bolts, its possible that it how your old ones became detached.

 

I would buy the correct bolts from VAG, if they turn out to be setscrews then I have given you bad advice and I'm sorry, but better to be safe than sorry.

 

I have removed mine to remove the gearbox for the clutch change and I would have remarked if they were setscrews but my memory is poor so I can't be sure.

Edited 17 January, 2023 by J.R.

[dfps]

Hi Urrell

The original bolts were also flanged so the new bolts should be the same.
Can't believe some of the prices being quoted for the original VW bolts online.
Fraction of the price in the US and Eastern Europe counties  etc  BUT ...there are  significant postage delays.

There is no reason why VAG group should be charging these prices in the UK.  Typical VAG rip off UK again.
 

[dfps]

Hi J.R.

Going to wait until the bolts I have already ordered arrive and see what they look and fit like.
If I am not happy with them then I will have no choice but to order the original bolts and pay the extortionate VAG group UK prices.

What are your thoughts on a medium liquid thread lock when replacing the bolts ?
I don't want to use a permanent thread locking liquid as the bolts  may need to be removed at some point in the future  for any clutch or gearbox repairs ..
but medium thread lock should allow the bolts to be removed in the future but help stop any unwanted unscrewing of the bolts..... as has happened previously.

 

[J.R.]

I would not use any initially, torque them up and if they start to come loose then my pessimism will have been validated, in which case get the proper bolts but also remove the coupling and check it and both the spider flanges for damage.

 

If the bolts don't work loose then a medium strength Loctite won't do any harm and means you won't really need to check again but if the correct bolts are used in an undamaged coupling and drive flanges tightened to the correct torque threadlock would not be needed, but for all I know VAG may in fact use it.

 

My concern is taking the drive torque on the threaded portion of the fastener, you are buying setscrews and not bolts, ARP bolts are intended for big end and main bearing caps that have the load in pure tension not in shear and the caps are located by dowels or hollow dowels, do you have an image of the genuine VAG fastener? Is it a bolt or a setscrew? If the former do not use the ARP ones.