Vibration

[Darren Groves]

Have been living with vibration at higher speeds for a number of years now, but after the winter jobs seems to be a little worse so is getting a little tiresome. Vibration starts to get noticeable at around 50pm and worsens the faster you get, and it’s felt through the car itself, nothing through the steering.

Have had both steel & alloy wheels on the car, recently fitted 2 new tyres, balanced all 4 wheels and rotated them but still no better. The propshaft was new about 3 years ago and of course came balanced, that didn’t help. I’m pretty convinced that the vibration is worse when the OD is engaged, but even if disengaged it’s still there. 

This winter I rebuilt the rear driveshafts and replaced the bearings and seals on the diff.

Could this be gearbox related or should I be looking elsewhere. Any suggestions, other than wheel & propshaft balancing?

Darren

[Clive]

We're the driveshafts new? Or checked for straightness?.

Plan b, disconnect prop and run car up to speed. See if it vibrates. Then disconnect driveshafts and reconnect prop. May help pin the issue down.

New prop may still be the issue. Or alignment?

[JohnD]

The flanges either end of the propshaft have two pairs of boltholes, spaced so that each can only go two ways, so there are four ways in which it can be fitted.

One is ideal, one is terrible, two are so-so. May be worth marking up the shaft and flanges, and trying the alternatives.

Have you tried running with the car up on axle stands?    Risky, don't go under it!  And ensure that there is a free run-off, not a brick wall, if the vibration could jump it off the stands.  

John

[Pete Lewis]

Does it do it if you knock it out of gear

Clutch damper springs can make hard to find vibros

On the OD the Dtype has specific timing best run marks on the 3 planets they must be aligned with marks on the carrier , on assembly

They are hard to find  there are   pics in the wsm.

this makes sure all 3 take the same drive load, if wrong can cause driveline vibration . the vibration wheelspeed 

As you have played with wheels is the vibro wheel rotation speed or prop rotation speeds  ?

Pete

 

[Pete Lewis]

Whilst john is on propshafts are the yokes phased correctly

Looking down the shaft   The tube end yokes should be in line  

Pete

[dave.vitesse]

Vibration due to out to balance generally happens at a given number of revolutions. The prop on the Herald normally starts art around 45 mph and ends at 55 mph. If the vibration increases with speed and cannot be driven through then its less likely to be an out of balance situation. Rubber mounts are used to reduce normal mechanical vibration being transmitted in to the chassis and body. Therefore ensure the exhaust is mounted using rubber straps or mountings. The engine, gearbox and diff should also use rubber mountings. In some cases where the rubber mounts become hard or worn through age this can cause vibrations problems. Look at the easy things first before going to deep.

Just my thoughts.

Dave

[Nick Jones]

It is almost certainly the propshaft, so-called balanced or not.  Every propshaft ever fitted to my Herald or Vitesse has vibrated, even brand new, bespoke, twice balanced ones and the only cure has been to balance on the car with two jubilee clips.  Not sure if this is a propshaft angles thing (both cars always had non-standard gearboxes).  Was also an issue on my PI, which was completely standard though to be fair I never did have that pro-balanced, just did it on the car.

Worth checking that the UJs have no free play and move very freely in both axes.  One stiff axis is enough to cause vibration.

Nick

[Darren Groves]

Apologies for not feeding back/acknowledging your replies, life is a little hectic at the moment....

On 04/04/2018 at 6:38 AM, clive said:

We're the driveshafts new? Or checked for straightness?.

Plan b, disconnect prop and run car up to speed. See if it vibrates. Then disconnect driveshafts and reconnect prop. May help pin the issue down.

New prop may still be the issue. Or alignment?

One driveshaft was new, the other I reused.....did I check for straightness? Eerr, no! Guess that's pretty impossible now they're on the car.

On 04/04/2018 at 9:02 AM, JohnD said:

The flanges either end of the propshaft have two pairs of boltholes, spaced so that each can only go two ways, so there are four ways in which it can be fitted.

One is ideal, one is terrible, two are so-so. May be worth marking up the shaft and flanges, and trying the alternatives.

I have improved vibration in the past by doing this, so have tried 2 of the 4 possible positions so far.  Pos 1. Vibration from 50mph onward. Pos 2 Vibration from 60mph onward and not quite so bad, so some improvement. Will try the other 2 when I get a chance and then select the best.

On 15/04/2018 at 5:48 PM, Nick Jones said:

It is almost certainly the propshaft, so-called balanced or not.  Every propshaft ever fitted to my Herald or Vitesse has vibrated, even brand new, bespoke, twice balanced ones and the only cure has been to balance on the car with two jubilee clips.  Not sure if this is a propshaft angles thing (both cars always had non-standard gearboxes).  Was also an issue on my PI, which was completely standard though to be fair I never did have that pro-balanced, just did it on the car.

Worth checking that the UJs have no free play and move very freely in both axes.  One stiff axis is enough to cause vibration.

Nick

UJ's seem fine and if John's suggestion of trying the 4 prop positions don't work I will try the jubilee clip trick.

On 04/04/2018 at 9:07 AM, Pete Lewis said:

Whilst john is on propshafts are the yokes phased correctly

Looking down the shaft   The tube end yokes should be in line  

Pete

Yep!

On 04/04/2018 at 9:05 AM, Pete Lewis said:

Does it do it if you knock it out of gear

Clutch damper springs can make hard to find vibros

On the OD the Dtype has specific timing best run marks on the 3 planets they must be aligned with marks on the carrier , on assembly

They are hard to find  there are   pics in the wsm.

this makes sure all 3 take the same drive load, if wrong can cause driveline vibration . the vibration wheelspeed 

As you have played with wheels is the vibro wheel rotation speed or prop rotation speeds  ?

Pete

 

Vibration still there if in gear or not and seems to be roads speed related, though a little difficult to tell. Living rural it's not that easy to find a stretch of road where I can get to the speeds I need to recreate it and then experiment.

Thanks again and I will keep playing given some free time!

Darren

[Pete Lewis]

whilst props have two aligning holes on the prodn line its thrown in and whacked up tight , the only thing to affect the fact its diametrically located in a register  with about  a 0.005"  toleranced spigoted fit

 the bolts just hold it together  any runnout i is damage to the mating faces giving runnout as the couplings not sitting 'flat' 

Pete

 

[Nick Jones]

One of the issues with my PI propshaft was that one of the UK flanges was duff.  Duff in that it had been manufactured with the locating spigot not concentric with the bolt holes.  You could either have the spigot sat snugly in the hole in the gearbox output flange or you could have the bolt holes lined up.  Not both.  When I found this, I was quite happy.  I can fix this, I thought.  So I fitted a new flange and new UJ at each end for good measure.  That'll sort it I thought.  Wrong!  Jubilee clip time........

Propshaft issues are normally a bit worse when the power train is unladen - coasting - and slightly less bad under power.

bent driveshaft shows up if you put the car securely on axle stands and run slowly in gear with the wheels on.  Bent shaft makes the wheel wobble around and usually the whole of the vertical link and end of the spring.  Bent wheel (also possible) just wobbles the wheel.

Nick