Front suspension Top Link

[Sam Bee]

The good book implies 2 washers at each end of the Top Link. But mine has 3 at the rear end, as per photo- is that correct?



 

[3litrekiwi]

Just had mine apart and there was one inboard thin washer then the rubber bush, then a heavy washer so two each end of the top link.

[Sam Bee]

Thanks, that tallies with the manual, so I have an extra washer for some odd reason.

[djm16]

There is a possibility that on the other side you have a missing washer, and this is it.

[Ken Nelson]

Mine likewise has a thin inboard washer, rubber bush, and thick outer washer.

[Roy of the Rovers]

Hi Sam
Is it possible yours has had the washer added to improve the straight line stability? I seem to remember on here reading about a Rover approved modification by adding washers to help with handling? I'm afraid I don't have the details to hand though ...
Roy

[enigmas]

One washer won't improve the lack of postive caster Roy! There was some type of shim arrangement that tilted the top wishbone assembly back (to the rear of the car) an added either a 1/2° - 1° of postive caster. You really need at least 3° to improve the lack of self centering and straight line stabilty at speed...especially on the P5Bs.

[Sam Bee]

Thanks chaps. Re. caster angle, tilting the link thus would imply putting a shim under the forward mounting of the top link mounting arm. An extra washer merely puts the top link arms further apart - but to what end, a bush not long enough perhaps? 

[enigmas]

Hi Sam, by 'tilting' I meant moving the top balljoint/pivot rearwards to increase the positive caster.
As an aside 20 years ago I modified the top suspension wishbones on my coupe to do the above adding 3.5° of positive caster.

[johnwp5bcoupe]

Jan 21, 2020 23:51:44 GMT enigmas said:

Hi Sam, by 'tilting' I meant moving the top balljoint/pivot rearwards to increase the positive caster.
As an aside 20 years ago I modified the top suspension wishbones on my coupe to do the above adding 3.5° of positive caster.

When I built and raced my Kart Chassis Vince I could dial in the Castor and Camber a tad more difficult on the P5

Previous discussion roverp5.proboards.com/thread/5450/modified-steering?

[Sam Bee]

Thanks. Now we are getting somewhere. Mine has an additional thick washer at the rear end, about 3/16th, both sides, so looks like it was modified already. However, I cannot recall, or deduce from photos, that this was replicated at the top ball joint end, as mechanically it ought to be; rather than washers a plate with two holes for the bolts would be better and the 'loose' bolt replaced with a longer one to compensate. 

[Deleted]

Ive been making such a plate and washers to alter the castor angle on mine.
The castor angles for the three litre versions are all listed in my workshop manual and show that Rover moved progressively from negative to positive camber as each version came out.
Its quite simple,to increase positive castor (or at least reduce negative) the rear wishbone (and the attached top swivel) is moved rearwards by placing a thick washer between it and the rear of its mounting,washers were also added between the front of the top swivel and rear of the front wishbone moving it rearwards.I doubt Rover recast the wishbones and swivels so the difference on models was achieved in this way,explaining why different cars have 'odd' washers added or missing.
Looking at the wishbones they are drilled to allow a positive location with the step at the swivel end of the holding studs,fitting a washer over it removes this positive location. As the wishbone is still held by two bolts,and rover themselves approved and indeed recommended the washer method presumably this is of no real consequence,however I am making a plate that still incorporates the raised section.
According to a mathematically astute relative and his computer,plates and washers of 3mm thickness will increase the Castor angle by 1/2 degree, the angle of the P5b depending on which source you use is from 1/2 to 1 degree.
To increase the castor angle more would involve modifying the wishbones.The Rover is over engineered and a skilled welder might be able to modify safely but personally I prefer a nut and bolt method. 
Maybe altering the castor by one degree or less makes no real difference but it keeps me out of mischief. I'll post pictures eventually.