Vibrations in steering at speed after driveshaft boot change ...

[Shardz]

Hello guys !

Before taking my NSX to another specialist dealer, I would like to seek fellow owners here for some opinions ...
Here's the story:

• Just before a huge driving weekend in the Alps a few weeks back I realized while my car was on the lift that the inner drive shaft boot (right side of the car) was damaged and grease was going out.
• At this stage my steering feel was perfect, and I had not the slimest vibration in the colum, whatever the speed.
• I took it to a regular Honda dealership in Geneva as the job needed to be done quickly (this was 3 days before I left for the roadtrip) and I didn't have the part to do it myself on such short notice.
• When I got the car back, I noticed a small vibration, getting bigger at higher speed : and assumed they had fucked up the wheel balancing, and some of the small metal weights were probably gone.
• After getting all wheels checks, the alignments were all perfect.
• I sent back the car to Honda after the roadtrip and they did a complete geometry of the car (which was needed as I had recently installed a KW V3 suspention anyway) which seemed to improve things a bit but the steering vibration was still there albeit being bearable. At highspeed though the steering would still be noticeably shaking if I removed my hands from it.
• Now I just killed my Michelin Pilot Sport 3 tyres last weekend on the track, and replaced these by a set of AD08R semi slicks.
• After getting the tyres mounted yesterday and the wheels balanced, the vibration is now much much worse than with the Michelin PS3.
• I would like to point out, that besides the vibration I have no issue whatsoever with the driveshafts, or any part of the chassis, even under heavy track use.

I assume the new tyres being significantly more rigid than the Michelin PS3, they would "hide" the vibration even less.
My question is : what could Honda have messed by changing the Driveshaft boot, that would end up with such vibration in the whole car ?
Is there something that can be done or some part forgotten while putting the driveshaft back in place ?
I understand the only parts involved to do this job are the driveshaft itself and the right side upper knuckles ... I can't see anything wrong with the knuckles and it would not be a source of such vibration anyway.
Whatever happens with the driveshaft now must be pretty badly balanced now for it to affect the steering wheel in the front ...
I'm a bit desperate, and I'm not sure I want to take the car a 3rd time to the guys that could not fix it in the first place ...

Any help is appreciated here,

Mike

 

[darock]

Wheel related imbalance starts at around 80km/h and stops at 100.

It might be, that the mechanic messed up the position of the tripod inside the cj joint. This can cause vibration. They have to be 60° spaced inside and outside to provide even load distribution inside the driveshaft.

Mostly, vibrations related to the driveline are load sensitive. If the vibration gets worse under more load you definitely want to go back and have them look at the driveshaft.

If it wasn't there before the driveshaft repair, it must have something to do with it. Ask them how they performed the boot change. Did they loosen the ball joints? If so its likely that they damaged one. The best way to do the driveshaft service is to loosen the lower arm instead of the upper ball joint.

The other thing that you might want to check is the big center nut on the outer cv joint. If this one is not tightened correctly, there is a chance that the wheel bearing gets damaged. Don't know how the wheel bearing of the NSX actually looks like but normally it is hold together by the spline on the outer cv joint.

As I did my driveshaft last weekend I don't see any other part that has to be worked on that may cause vibrations.

Bernhard

 

[Shardz]

Thanks for the details Darock, I think I'll go back to Honda and ask to have a chat with the workshop mechanic/manager who did the job in the first place.

 

[Larry Bastanza]

Wheel related imbalance starts at around 80km/h and stops at 100.

It might be, that the mechanic messed up the position of the tripod inside the cj joint. This can cause vibration. They have to be 60° spaced inside and outside to provide even load distribution inside the driveshaft.

Mostly, vibrations related to the driveline are load sensitive. If the vibration gets worse under more load you definitely want to go back and have them look at the driveshaft.

If it wasn't there before the driveshaft repair, it must have something to do with it. Ask them how they performed the boot change. Did they loosen the ball joints? If so its likely that they damaged one. The best way to do the driveshaft service is to loosen the lower arm instead of the upper ball joint.

The other thing that you might want to check is the big center nut on the outer cv joint. If this one is not tightened correctly, there is a chance that the wheel bearing gets damaged. Don't know how the wheel bearing of the NSX actually looks like but normally it is hold together by the spline on the outer cv joint.

As I did my driveshaft last weekend I don't see any other part that has to be worked on that may cause vibrations.

Bernhard

This is exactly what I was thinking as I read this. The orientation of the two CV joints is critical. At each end, as stated they must be 60 degrees offset.

HTH,
LarryB

 

[Shardz]

Hey Larry, Darock,

Thanks for the contribution, my English is not that great when it comes to mechanical technical terms though and I'm not sure I get the point.
What do you mean when you say the CV joint should have a 60° offset. 60° from what to what ?

So far i've done a few driveshaft on my CRX/Civics, and it's more or less a "plug & play" operation:
* I don't get how you can mess up with the tripods (there's only one way to fit them in the intermediate shaft housing ..)
* I don't get either how you can give any of the CV joint assembly a specific angle/position.

I have downloaded the workshop manual and will be looking into it, sorry if I come across a bit thick on this one...

 

[jwmelvin]

The tripods on the two ends of a shaft should be clocked 60 deg relative to each other.

 

[Shardz]

As only one end was disassembled for the boot change, does this means I have now to take both appart and somehow try to get to a 60° alignment between them with the shaft on a flat surface ?

 

[darock]

At least the boot of the outer CV joint needs to be opened to check how the tripod is oriented.

Bernhard

 

[Kaz-kzukNA1]

Hi, Shardz.
You don’t need to open the boot in order to check the tripod offset.

First of all, the visual description of the 60deg offset.

If you look at each joint housing, you will notice that there are flat and round section on the housing body itself.
This is the same for the inboard as well as for the outboard joint.

So, just lift up the car and look for the relationship between the flat and round section of the inboard and outboard joints.

If the offset was correctly done at 60deg, then the centre of the flat section at one end will be at the centre of the rounded section at the other end.

If it doesn’t have the correct 60deg offset, then since someone opened the right side Inboard joint to replace the damaged boot, you can adjust it by opening that side again but I would be surprised if someone will even try to remove the tripod while keeping the drive shaft on the car just to replace the boot...... May be the tripod was never touched??? Or, it was already at wrong offset from the previous service (if any....).
Having said this, unless someone used the 'separated style' aftermarket boot or the 'boot end stretch tool' with aftermarket one body boot, I don't think you can fit the OEM boot without removing the spider first.....

Also, I’m not sure the vibration you are feeling through the steering is from the wrong offset at the drive shaft unless you have heavily lowered the ride height or using super aggressive negative camber.
Even with the wrong offset, the inboard and outboard joints can cope with the suspension travel and camber change for a certain level until the shaft body itself hits the internal housing structure.

I have driven many NSX with wrong offset at the drive shaft but most of the times, you won’t notice it until the joint breaks down. If you get vibration, you would feel it more through the seat/frame than the steering.
It is still possible that you have problem with the drive shaft resulting in vibration at the steering wheel but I would also check the front end.

You can simulate how the roller/tripod assy moves inside the joint if you disassemble the drive shaft.

Even with the correct offset, if you lower the ride height too far or use very aggressive negative camber, the drive shaft body and the inboard/outboard joints won’t be straight and always at some angle even on the flat road surface.
Under this condition, with the suspension travel and camber change under load/unload, you could crack the roller inside the joint if the ride height and camber got beyond the design spec.
The result of the out of spec setting….
The shaft body itself first touched the internal structure of the joint, deformed that super hard treated metal material and then eventually the roller couldn't move freely inside the deformed channel and then cracked itself.

Even with this damaged drive shaft, the owner didn't notice it and there was no strange vibration.....
Another owner actually popped the drive shaft joint during track day and that was the first time when he noticed something was not correct.....


Kaz

 

[Shardz]

Wow ... that's more than helpfull right here. I'll definitely have a look into this when I get a bit of time.

regarding the steering vibration, I was pretty sure as well the issue would be with the front end, but after wheels balancing and a full chassis alignment it seems unrelated.
It probably is the entire car vibrating and shaking the steering column as well.
The impressive bit, is that the vibration was not that bad with the Michelin PS3, but has gotten horrible since yesterday and the new ADO8R mounted on the rear ...

FYI The car isn't that much lowered as I mostly street use it (mountain roads = need proper height and softish settings for crap roads).
And it clearly all started when I got it back from Honda so ... I guess I'll have to check myself. I'm finishing cleanup in my garage, have the lift ready, I just need to create a small work area with a solid work table ...

Many many thanks, and apologies if there's already a tutorial on this somewhere and I missed it ...

 

[Larry Bastanza]

Thanks Kaz,

I was reading the post thinking about "how" am I going to explain how to see the orientation without pics. You have them!! Awesome......

Regards,
LarryB

 

[darock]

I could have figured it out myself that you see the position of the tripod on the outside of the cup

Awesome thread! Thanks!

Bernhard

 

[Shardz]

So, 6 month later ... the NSX is on my lift and I'll get the drive-shaft out today, I have another torn boot that needs changing anyway ...
I'll take pictures and report here if anything is worth mentioning !

Now I'll print the guidance from Kaz and go to my garage with that, thanks again mate :smile:

[edit] I have removed the drive shaft, the boot Honda installed 2000km ago is already dead (big hole in the center and a lot of the grease gone already.
And bang on the money for the tripods alignments ... which not right at all.
I'm dropping the whole shaft at Honda on Tuesday, and I'll expect them to re-do the job correctly this time and of course free of charge.

[eidt²] Got my driveshaft back from Honda, tripods installed properly and ... the vibrations are gone !
So that was definitely the issue, now I'm off triyng the new AD08R and the DIXCEL pads and disks