VS Statesman - Driveline/Center Bearing Help (IRS)

[Macca177]

Hey everyone,

I'm wondering if there is any guides/diagrams on how the setup for the spacer configuration/center bearing mounting should be for a lowered IRS?

Story so far. (I have owned the car for a few years 100,000kms on it in my time and suspension was already in it) I had the center bearing replaced as it had failed - Used Repco as replacement. It failed after 1 week of driving. Repco then paid to have another installed under warranty, this too also failed in a week. Repco then paid a Diff shop to replace it again and diff shop used a Burson's center bearing. Diff shop also re-balanced and checked driveline and I had the gearbox mounts replaced as well. I have no idea how the config was of the spacer/mounts.

This worked for a little while however under heavy acceleration I still got a vibration. I did some forum searching and found a thread about the spacers under the center bearing. I moved the spacers on top (lowers center bearing and makes the angle straighter) of the mount plate and then FIXED!

4000kms later, center bearing failed again! Diff shop just replaced this last week under warranty (I also got a rebuilt LSD put in at the same time, axles repacked uni's etc).

I want to see if anyone can shed some light on what angles or any other ideas for me to check out. I dont want to be going back again in another 4000kms.....the diff shop said they think its okay......

I have checked the mount and the spacers are in between bracket and mounts. IRS marking facing front of the car too. (unsure of positions after the first few bearings replaced....)

its a 99 vsIII v8 Statesman with IRS. I believe its on super low king springs in the back. The car does tow occasionally or put the bike racks on.


I did do a search and found some similar problems and a diagram as to how to spacer appears it should be -
https://forums.justcommodores.com.au/threads/centre-bearing-spacers.52462/#post-530265

Mine is setup with the spacer on the outside bolt. So reading this thread - im not sure now if there is meant to be a spacer at all (i thought the IRS cradle wouldn't changeno matter the car height where solid axle does change?)
The phasing off my shafts are not 90deg out - they are the same at both uni joints. - however i have no vibrations as the car sits - just chewing the rubber around the center bearing.

 

[losh1971]

Firstly get a gen bearing the aftermarket ones are generally poor quality as the rubber mounts are soft and have too much flex. I can't be any help with the other issues. I just know i had issues with aftermarket bearing.

 

[Macca177]

Firstly get a gen bearing the aftermarket ones are generally poor quality as the rubber mounts are soft and have too much flex. I can't be any help with the other issues. I just know i had issues with aftermarket bearing.

Im hoping my luck isn't as bad as 3 poor quality aftermarket bearings.....

 

[Big steve]

Hey everyone,

I'm wondering if there is any guides/diagrams on how the setup for the spacer configuration/center bearing mounting should be for a lowered IRS?

Story so far. (I have owned the car for a few years 100,000kms on it in my time and suspension was already in it) I had the center bearing replaced as it had failed - Used Repco as replacement. It failed after 1 week of driving. Repco then paid to have another installed under warranty, this too also failed in a week. Repco then paid a Diff shop to replace it again and diff shop used a Burson's center bearing. Diff shop also re-balanced and checked driveline and I had the gearbox mounts replaced as well. I have no idea how the config was of the spacer/mounts.

This worked for a little while however under heavy acceleration I still got a vibration. I did some forum searching and found a thread about the spacers under the center bearing. I moved the spacers on top (lowers center bearing and makes the angle straighter) of the mount plate and then FIXED!

4000kms later, center bearing failed again! Diff shop just replaced this last week under warranty (I also got a rebuilt LSD put in at the same time, axles repacked uni's etc).

I want to see if anyone can shed some light on what angles or any other ideas for me to check out. I dont want to be going back again in another 4000kms.....the diff shop said they think its okay......

I have checked the mount and the spacers are in between bracket and mounts. IRS marking facing front of the car too. (unsure of positions after the first few bearings replaced....)

its a 99 vsIII v8 Statesman with IRS. I believe its on super low king springs in the back. The car does tow occasionally or put the bike racks on.


I did do a search and found some similar problems and a diagram as to how to spacer appears it should be -
https://forums.justcommodores.com.au/threads/centre-bearing-spacers.52462/#post-530265

Mine is setup with the spacer on the outside bolt. So reading this thread - im not sure now if there is meant to be a spacer at all (i thought the IRS cradle wouldn't changeno matter the car height where solid axle does change?)
The phasing off my shafts are not 90deg out - they are the same at both uni joints. - however i have no vibrations as the car sits - just chewing the rubber around the center bearing.

Did you happen to find the culprit for this problem as I’m in the same predicament

 

[Immortality]

Set it up exactly the same as it came from the factory.

On a IRS car the diff does not move when you lower the car so there is no need to modify the drive shaft in any way.

The centre bearing mounting bracket is offset and is stamped with IRS on one side and STD (IIRC) on the other side with arrows. You want to fit the bracket so it looks like the centre of the drive shaft has a small bend at the centre mount.

 

[Macca177]

Did you happen to find the culprit for this problem as I’m in the same predicament

Not really. Ive had the shaft built with genuine centerbearing and they also pashesed the shaft correctly for the statesman. Its lasting still with the Holden centre bearing but I still have stupid amount of vibrations - eg accelartion onto the highway - espically if I have the jetski on the back.
Diff shop it took it back to again - they claim "ACCEPTABLE" amount of vibration. IMO is rubbish.
I dont have the spare $$ to get another shop to check the diff.

I think next centre bearing failure I will see if I can get my hands on another drive shaft to try.

Have you had some luck?

 

[shane_3800]

Not really. Ive had the shaft built with genuine centerbearing and they also pashesed the shaft correctly for the statesman. Its lasting still with the Holden centre bearing but I still have stupid amount of vibrations - eg accelartion onto the highway - espically if I have the jetski on the back.
Diff shop it took it back to again - they claim "ACCEPTABLE" amount of vibration. IMO is rubbish.
I dont have the spare $$ to get another shop to check the diff.

I think next centre bearing failure I will see if I can get my hands on another drive shaft to try.

Have you had some luck?

The shaft likely got a ding in it.
I used to work with a diff guy, even the smallest ding can throw them out of balance.
You either need to put a a second hand shaft on or get the shaft balanced.
If the diff shop you went to can't figure that out than they're just oil changers that think they can work on diffs.

 

[Immortality]

A diff shop is different to a drive shaft shop. Drive shafts are a quite specialised field with specific equipment.

Just phasing the driveshaft won't necessarily fix a balance issue and Holden played with drive shaft phasing to try and fix vibration issues so you'll find driveshafts under Commodores where the uni's are not exactly 90° to each other.

Drive line vibrations can also come from other things under the car, wheels been a common one.

The thing most people tend to forget is that we are dealing with cars that are 20+ years old where everything is tired and worn out, unless you replace everything you can't be sure you have fixed the problem.

Vibrations from a drive shaft would be speed related and shouldn't change with load unless something else is changing under load forcing something out of alignment hurting the drive shaft.