1966 Herald drive shafts

[Charles Lowe]

Bought a Herald in good condition 3 weeks ago - BUT - I think it's got the wrong drive shafts, too short giving excessive +ve camber and 'clatter'. Are there different lengths or could something else be wrong?

[RobPearce]

There are only two lengths of drive shaft and the Herald used the short ones.

The rear camber should be very slightly positive when correctly set. It will go VERY positive if the car has been jacked up and needs to be rolled a moderate distance to clear that.

If it's riding high then common causes are an incorrect spring (many of the currently available new springs are way too hard) or the suspension having been assembled and torqued up while jacked. The manual is very clear on this - most of the rear suspension bolts should be left loose until the car has been put back on level ground, with two people (or equivalent weight) in it, and rolled forward and back to get the resting camber. Only then do you torque up all the bolts, while still in that resting position. It's also not uncommon to find that the lower trunnion bush tube is too short, and the bush thus locks up with no suspension movement available.

How familiar are you with Heralds, or cars of that age generally? They make a lot more clatters and bangs over poor road surfaces than modern cars, even when they're perfect.

[Charles Lowe]

Thanks for that very helpful reply. Old cars - I started driving in '65 in a 100E Ford Pop before graduating to Minis etc. Since then, apart from totally rebuilding a 1984 110V8 Land Rover about 20 years ago (I'm familiar with prop shaft chatter etc), nothing. My current SLK55 is quiet!

I'll do as you suggest. Was about to take the drive shafts off and lengthen them by 10mm or so.

Regards

 

[Clive]

16 minutes ago, Charles Lowe said:

Thanks for that very helpful reply. Old cars - I started driving in '65 in a 100E Ford Pop before graduating to Minis etc. Since then, apart from totally rebuilding a 1984 110V8 Land Rover about 20 years ago (I'm familiar with prop shaft chatter etc), nothing. My current SLK55 is quiet!

I'll do as you suggest. Was about to take the drive shafts off and lengthen them by 10mm or so.

Regards

 

Something else to consider is teh lower trunnions can seize on the upright, causing odd problems. 

If the spring is sitting the car too high you can add a lowering block between the diff and spring.

[Charles Lowe]

Much appreciated

Thanks

[Charles Lowe]

Back again.....

I'm fascinated by the rear suspension geometry (long retired mechanical engineer) but can't find any drawings so will do my own. Does anyone know the following dimensions:

1. Spring main leaf length from centre on diff to centre of eye.

2. Drive shaft length from centre of inboard yoke to outer side of hub

3. Vertical link. Centre of top hole (spring eye position) to centre of trunnion pivot axis (bottom hole.

4. Between the horizontal drive shaft axis through the diff up to the centre of the spring main leaf.

With these I will have the respective radii of rotation of the spring eye and the drive shaft so can plot the wheel camber at various drive shaft angles and of course the effect of fitting a spacer between spring and diff.

Have a good day.

Charles

[JohnD]

Charles,

https://www.tssc.org.uk/tssc/uploaded_files/Turning Circle 14a - February 1989 - Competition Tuning.pdf

"Turning Circle" predates the TSSC club magazine, "Courier" and was published in the 80s.   This copy from 1989  includes an article by one CH Eickoff, a Swedish engineer who AFAIK published nothing else about Triumphs.   But in this article he analyses Triumph rear suspension, both swing axle and rotaflex in great detail.    It's available online as above from page 9, but you may need to be a member to access it.

Also from the TSSC Courier is this table of rear spring data: