Wanted Potential Diff Needed
- Thread starter ktnez99
- Start date
I've been to see @gookah and Dave today.
I've copied and pasted Dave's post from Airbag Reset Light Tool thread here. I know how to do this now!!!
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@gookah writes:
no problem (ps. Jemma not Jo)
It was the connector under the drivers seat, had to unplug and redo the connection before it would reset, as it kept coming straight back on.
The passenger seat needs a new up/down motor
I took that seat out, removed the motor altogether, and fed a direct live and negative to it and it would work intermittently with a tap or by putting an allen key and turning by hand, but it just locks up in each direction. could not get it to work reliably. Sometimes it would run for 20 seconds then just lock up. It didn't sound too good either. One for a Spurs fan replacement spare part..
Then put it up on axle stands and ran the rear wheels off the ground
No play in either bearing, no rumble from them, just the normal brake pad rubbing noise.
One thing I did notice is that rotating either wheel could be done without the other one turning, yet it is an LSD.
Runs with some irregular knocking, and at the same time the diff jumps about in the bush. then on a test drive the noise is really bad and is coming from the centre of the car
I wonder if driving it after an incorrect length one was fitted, has caused an issue inside the diff itself. Or if it has been done when the driveshaft was changed maybe unsympathetically,
Also the asc when switched on and off no longer lights up, and there is no light that comes on with the ignition either....!
The mechanic said he has has changed and refurbished both driveshafts. I will let the photo's do the talking:
Passenger side
Nice new clips..... not!
Drivers side:
So.... both sides?
and refurbished?
hmmm
Oh and also G8JKA noticed.
After all wheels have been refurbished, and new 'rotational' tyres fitted,
With both front wheels, the tyres are on wrong way around .Both wheels need swapping over (ran out of time)
Rear wheels, The passenger tyre is rotating in the correct direction, but the drivers tyre is rotating backwards, That one needs changing on the rim.
Click here for my Z3 Build
Click here for Wifey's Z4 Build
Pete..... The //iMposter
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I've copied and pasted Dave's post from Airbag Reset Light Tool thread here. I know how to do this now!!!
---
@gookah writes:
no problem (ps. Jemma not Jo)
It was the connector under the drivers seat, had to unplug and redo the connection before it would reset, as it kept coming straight back on.
The passenger seat needs a new up/down motor
I took that seat out, removed the motor altogether, and fed a direct live and negative to it and it would work intermittently with a tap or by putting an allen key and turning by hand, but it just locks up in each direction. could not get it to work reliably. Sometimes it would run for 20 seconds then just lock up. It didn't sound too good either. One for a Spurs fan replacement spare part..
Then put it up on axle stands and ran the rear wheels off the ground
No play in either bearing, no rumble from them, just the normal brake pad rubbing noise.
One thing I did notice is that rotating either wheel could be done without the other one turning, yet it is an LSD.
Runs with some irregular knocking, and at the same time the diff jumps about in the bush. then on a test drive the noise is really bad and is coming from the centre of the car
I wonder if driving it after an incorrect length one was fitted, has caused an issue inside the diff itself. Or if it has been done when the driveshaft was changed maybe unsympathetically,
Also the asc when switched on and off no longer lights up, and there is no light that comes on with the ignition either....!
The mechanic said he has has changed and refurbished both driveshafts. I will let the photo's do the talking:
Passenger side
Nice new clips..... not!
Drivers side:
So.... both sides?
and refurbished?
hmmm
Oh and also G8JKA noticed.
After all wheels have been refurbished, and new 'rotational' tyres fitted,
With both front wheels, the tyres are on wrong way around .Both wheels need swapping over (ran out of time)
Rear wheels, The passenger tyre is rotating in the correct direction, but the drivers tyre is rotating backwards, That one needs changing on the rim.
Click here for my Z3 Build
Click here for Wifey's Z4 Build
Pete..... The //iMposter
---
I would be 99% certain the ASC bulb has been removed from the dash. People do that to hide errors from the system being flagged by the dash light which causes an MOT fail. Although a keen eyed MOT tester will spot the bulb removal as the light doesn't come up when the key is turned and fails it anyway. People do this because they don't want to or don't know how to fix the error.
When that is done the ABS is no longer operational. You are driving round on a car with no ABS or traction control.
You will see my own experiences here:
https://zroadster.org/threads/abs-not-working-no-error-codes-or-lights.25169/
It's a 10 minute job to replace the bulb. But you are most likely to have errors, probably wheel speed sensor failures to then deal with. Possibly an ABS module fail. Thankfully all easy enough to resolve.
As for the diff/driveshafts. Don't want to say too much more as there are lots of theories and you know you need to get it assessed by a competent garage.
However those driveshafts don't look refurbished to me. Repaired possibly. Refurbished no.
There are also heavy dents on the outer drive flanges which suggests it has been battered back into the trailing arm bearing.
Personally I would find a specialist like one of these to make the assessment with a view to the repair too. This is not a recommendation for these people just what I found googling to show the sort of specialist I would look for.
https://www.mandttransmissions.co.uk/differentials_transmissions_sheffield.html
https://www.hardyengineering.co.uk/
I'd also encourage you to read up on diffs so you can have an informed discussion with them. This shows a full rebuild for instance.
View: https://www.youtube.com/watch?v=qeMIh9mGwRY
When that is done the ABS is no longer operational. You are driving round on a car with no ABS or traction control.
You will see my own experiences here:
https://zroadster.org/threads/abs-not-working-no-error-codes-or-lights.25169/
It's a 10 minute job to replace the bulb. But you are most likely to have errors, probably wheel speed sensor failures to then deal with. Possibly an ABS module fail. Thankfully all easy enough to resolve.
As for the diff/driveshafts. Don't want to say too much more as there are lots of theories and you know you need to get it assessed by a competent garage.
However those driveshafts don't look refurbished to me. Repaired possibly. Refurbished no.
There are also heavy dents on the outer drive flanges which suggests it has been battered back into the trailing arm bearing.
Personally I would find a specialist like one of these to make the assessment with a view to the repair too. This is not a recommendation for these people just what I found googling to show the sort of specialist I would look for.
https://www.mandttransmissions.co.uk/differentials_transmissions_sheffield.html
https://www.hardyengineering.co.uk/
I'd also encourage you to read up on diffs so you can have an informed discussion with them. This shows a full rebuild for instance.
Passenger side is a new driveshaft yet (old one was given back) but the drivers said hasn't even been off, so couldn't have been refurbished or replaced. Passenger side was also leaking so hasn't even been done to a decent standard. The garage charged for replacement of passenger side and removal and refurbishment of drivers side. We suggested to take it to another garage, even BMW to get a full report of what the problem is and the work that needs to be done before assuming what it needs. The diff was definitely making the noise though, could have been damaged by the mechanic. It was jumping around when we had the rear in the air and was running though the gears.
@mrscalex interesting and researched post: thank you. The video is an eye-opener. Looks a massive job to refurb. Rather daunting, tbh. I'm of the opinion that I need to find a Z roadster mechanics course and get myself on it for future reference.
That would suggest to me a broken gear tooth. Perhaps draining the oil might show something?
Tony.
I did have some bulbs changed on the dash about 3-4 years ago. I've had my car from new so to the best of my knowledge, there should be bulb/s in situ.
Hopefully you are in the 1% of my uncertainty then and have a blown bulb
Nice to hear of another owner from new. I’m not but my brother is.
I would think so. The test would probably work off resistance which would be there without a bulb or if the bulb is there but blown.
Hope it’s that anyway. If not might be a fault in the dash panel and you don’t want that.
Hope it’s that anyway. If not might be a fault in the dash panel and you don’t want that.
Unfortunately I didn't spot the ASC light not working until after I had removed and packed away the code reader (INPA) or else i would have seen if there were any faults. It may be just a bulb but I find that is unusual.
After noticing the asc light not working, there was no way i was going to try and prove a fault by attempting to spin a wheel, with the diff sounding like that.
The drivers side looks like it has never been off, let alone refurbished, . New clips on both sides would have indicated refurbishment work, but all the clips look old.
'D.....' I think your next move should be take it to an independent BMW mechanic, well, at least another garage,
and get them to take the back cover off the diff, check for enough oil, but more so for broken bits or something else unusual.
Also take off the passenger side rear wheel and check that the driveshaft bolt looks fully tightened (can be compared with the drivers side)
Getting the cover off the diff should not cost a lot, just a bit of labour and some new oil, but will show up a problem immediately.
That would show the next thing that needs to be done.
After noticing the asc light not working, there was no way i was going to try and prove a fault by attempting to spin a wheel, with the diff sounding like that.
The driveshaft that is on the passenger side did not look new, or even refurbished, to me. It may be new to this car, but it looks like a second hand unit that has been fitted. There is evidence of it being bashed but there is black paint over the marks, so may have just been sprayed. I have seen spray can 'refurbishments' before.
The drivers side looks like it has never been off, let alone refurbished, . New clips on both sides would have indicated refurbishment work, but all the clips look old.
'D.....' I think your next move should be take it to an independent BMW mechanic, well, at least another garage,
and get them to take the back cover off the diff, check for enough oil, but more so for broken bits or something else unusual.
Also take off the passenger side rear wheel and check that the driveshaft bolt looks fully tightened (can be compared with the drivers side)
Getting the cover off the diff should not cost a lot, just a bit of labour and some new oil, but will show up a problem immediately.
That would show the next thing that needs to be done.
That is not a driveshaft, ........that is a rear shock absorber...!!!!!
I never noticed new shock absorbers either, and the photos don't show new ones from what I can see, rear shock absorbers are parts that are definitely not refurbished, they only cost about £40 each new. it would cost more in labour and parts to refurbish them than to buy new.
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Did he tell you this was a drive shaft, I think this is where some of the confusion has come from, as a shocker thats too long will make the car sit high
This isn't good. He told me he was giving me the original driveshaft - only took it out of the box today.
Yes, he said he was giving me the driveshaft back and I've only opened the box up today. He keeps all the parts he takes off in a big storage container. Yes, I had rear new shock absorbers fitted and top mounts.
I hope this is all a misunderstanding and innocent. Otherwise it’s looking increasingly like you have been turned over I’m afraid.