Wheel alignment, suspension & braking advice?

RINGER

RINGER

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Following on from the tread about braking that has helped others & myself immensely, but probably has outlived it's usefulness for now, I'll switch.
Not being an 'expert' but having dabbled in this area of the trade I'd like to learn from those who may be considered sporty or racing types who are 'much more expert' & here are some things I know & questions asking for comments & suggestions.
1. Tyre pressures, suspension wear & condition are critical to doing a wheel alignment job correctly.
2. Vehicle height & weight i.e. balance is extremely important in getting 'perfect brakes' & what I've been working on.
3. I know doing a corrective wheel alignment won't correct or even out tyre wear - so if toe or camber wear 'for examples' were present, replacing the tyre or tyres is the only real course of corrective action before doing an accurate wheel alignment.
BTW I don't have this issue tyres have done about 1200km & no feathering or obvious wear pattern.
4. I had the vehicle checked out & adjusted being told it was good for the track. Then checking again on a Brake Roller Test that it was not as good as I expected.
PLEASE this is not a criticism of anything that was done to the vehicle as it is getting better & better with everything that is being done.
It is in my nature to strive for perfection & not near enough.
As many watching this know about these BRT tests, they really tell the truth IMO & here is what they do:

"Brake Roller Testing is a service that safely measures the vehicle's braking system while stationary, using an automated weighing system which accurately calculates the braking efficiency. This method allows us to assess the braking force for each individual wheel and any imbalances across the axles, as well as the testing of emergency brakes and parking brakes without the risk of accident due to faults."

So with that & the last BRT after our field work, the heights of this Light 15's all are similarly 275mm within 2mm. The rear axle weight balance, brake readings & deceleration concern me ~ is any weight/alignment issue likely to be causing this ~ maybe front/rear axle distances, that should have been measured & may have been? - any feedback appreciated

AXLESTATIC WEIGHT LHS TSTATIC WEIGHT RHS TBRAKE FORCE
LHS kN		BRAKE FORCE RHS kNPEAK DECELERATION LHS %GPEAK DECELERATION RHS %GPEAK DECELERATION BALANCE %
FRONT0.300.301.41.547.651.093
REAR0.250.300.90.636.720.455
VEHICLE SERVICE BRAKES PEAK DECELERATION39%G
 
FI:
Suggested by Ken the wheel aligner guy ~ silentblock was neoprene ~ drill right through to inside portion metal engaging the torsion bar [not through] & fit grease nipple.
silentblock.jpg
 
RINGER said:
FI:
Suggested by Ken the wheel aligner guy ~ silentblock was neoprene ~ drill right through to inside portion metal engaging the torsion bar [not through] & fit grease nipple.
Click to expand...
I'm a bit bamboozled by that photo, not knowing the Citroen torsion bar setup at all, but if that spline is for the end of a torsion bar, then why would you want to let it pivot at all, let alone lubricate it? I would have thought the silentbloc was merely to insulate vibration/road noise, and would only be effective if it was totally bonded inner and outer, allowing just a bit of flex in torsional movement. If the end of the torsion bar can pivot, it is no longer a torsion bar.
OK, I may have it completely wrong, do you mind explaining the operation of the components shown - maybe a diagram of the arrangement from the manual.
Cheers, Chris M.
 
Very good point Chris & gives me another project tomorrow! I didn't question the suggestion of a suspension guy & perhaps should have.

As I know silentblocks used on engine mounts, shocks, spring shackles etc. the rubber between the round metal components is the twist mechanism. It is important with these parts that the inner be in an unloaded position when tightened ie. Spring shackle bolts are only tightened in the wheel on ground position or stands under the axle.

Same with rubber bushes when they are used. Catches dyi folk out often.

Not doing so will cause early failure of the silent block or rubber bushes.

The part in the picture on both sides has a neoprene portion inserted between the two metal components & seems more like brass bushing in a spring shackle.

Thanks for the observation & I'll certainly get on to it & back with those interested.

BTW I knew nothing about Light 15's when I bought this one - I just liked them & most other low slung vehicles of the period with suicide doors - WW2 Humbers as well!
 
Thanks John, the exploded diagram in the link gives me the answer. That photo is really one of two inner control arm bushes, one each side of the crossmember, with a short splined joiner located in the arm. So the silentbloc is meant to twist, and could be lubricated, because the torsion bar is extending through it to the arm. Interesting and clever design.
 
Something I found when checking through CAS's website. It has been translated from Dutch to English so I have tried to correct in a few places. JG.
Traction Tip 12: Watch your weight.

This Traction tip is about the weight distribution of the car per wheel. It turns out that almost all tractions do not have a good distribution of the weight over the four wheels. We come across differences of 100 to 200 kg per wheel! This is possibly caused by the fact that there is no control whatsoever over the wheel weights when the car is on the road. It looks like the car is horizontal and at the correct height but it's not.

Because the car is a monocoque design it can be balanced on e.g. the support of the left front wheel and right rear wheel. As a result, the right front and left rear have too little wheel weight. This makes for very unstable driving behaviour, incorrect braking deceleration and poor road holding resulting in unsafe driving and additional tire wear.

Make sure that the wheel weights are checked, especially after restoration / repair of the front or rear axle.
Click to expand...
 
The diagrams explain it if you can put them together. The original silentblocs were bonded rubber to both inner and outer metal sleeves and the rubber flexed so there was NO FRICTION in that bottom suspension arm movement area. Silentblocs were used in the rear also. The rubber in the silentblocs bottom suspension arm also allowed flex, for and aft, in the suspension arm for better ride as modern vehicles have. The bottom suspension arm is a heavy arm with a silentbloc bearing either side of it. And they are a bugger to get together correctly with the splines and are all a pressed fit on the splines. Hmm a PITA and needs more than three hands to get together in a press and correctly assembled in the crossmember.
But that bearing(s) that John has has had the rubber removed and a polly/neoprene bearing made up to fit. Possibly a grease nipple might help to reduce friction but will not give any improvement in compliance like the rubber would give. But people seem to like hard suspension bushes to replace compliant rubber bushes these days and shake their teeth out !!
Jaahn
PS yes that CAS's web site article is interesting but who reads that sort of interesting stuff ?? :rolleyes:

What are Silent Block Bushes?
Silent Block Bushes are very important components of an automobile, and are also known as Silent Block Bushings and Silent Block Rubber Bushes. These bushes are made from premium quality two concentric steel sleeves with rubber that ensures strong design and construction. The rubber is flowed into the gap between two sleeves in order to fill up the void and further vulcanized at constant temperature & pressure. Moreover, the pressure will be added to ensure maximum dynamic strength as well as endurance. The silent block bushes used in automobiles are capable of taking varied types of load intensity such as torsional movement, axial & radial load.
 
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Thanks Jaahn, EXACTLY!
The reason folk don't like 'proper' silentblocks is that they are usually installed incorrectly & fail as I tried to explain earlier.
I will be in EU next May & will get the right parts less freight & VAT. JG.
 
Not to be confused with Fluidbloc bushes where the rubber is not bonded to both steel surfaces, as used in some other Citroens and the upper wishbones pivots on Renault R8/10 series. I'm not sure whether anyone makes them nowadays as the Renault parts suppliers only offer Silentbloc replacements.

I do wonder whether folk who replace Silentbloc bushes with various turned plastic bushes understand how the Silentbloc system works.

That Traction front control arm mounting is pretty sophisticated and expensive!
 
Here for information is how I made a tool to adjust the front torsion bars.
Pretty EZ ~ just fit enough discs on an angle grinder to cut a wide enough slot 4 on mine ~ remember to reverse the disc holding nut if multiple discs are used so the nut goes into the outer disc & others are lined up
tool.jpgTool1.jpg
As well on the rear I fitted a spacer under the adjuster nut so that an ordinary 24mm open ender wrench could move the nut easily.
rear adjuster.jpg
 
Hi while we are talking about torsion bars I will just add this for future readers for reference. When removing torsion bars always refit them the same way as they were before. That means the torsion under load is the same as it was before. Used torsion bars will fail early after being refitted with the stress reversed.
Jaahn
 
Correct - more knowledge - also the same reason why used tyres shouldn't be run in anything but the same direction on your [or a] vehicle if rotated. So cross rotating as suggested in some manuals is not the best recommendation?
 
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