Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Front suspension

Who ever suggested that you should get a few inches of movement by pushing down on the front wings has something wrong (with the wings), there is barely a few inches of bump travel anyway.
There are two BIG problems of trying to push down on the front to get the front springs to give:
1. If you are running with a compressed rebound spring your initial rate will be around 400 lb/inch or more (125 lb/inch main PLUS 275 lb/inch rebund typically). So 800 lb/inch for the front of the car. I weigh 80 kg = 176 lb. So the suspension will move in bump if I stand on the front bumper by 176/800 = 0.22 inches!!!!!!!!!!!!!!! or 6mm, oh that is noticeable then?
AND
2. When you try to push down or lift the front of the car the wheels need to move outwards at the same time, so the high tyre sidewall stiffness ADDS to the vertical rate - when stationary(ok when rolling)! So it is easier to do this test on older cars with soft 80% aspect ratio tyres, than on later cars with lower profile tyres and high tyre pressures. Put one wheel on a Trakrite (for setting toe) and try again and watch. The change in track in bump is quite significant, try measuring you toe angle with an empty car and one with two people just rolled into the garage!
Regards PJB.

Quite agree with you PJB This is what i was thinking.I have just recently rebuilt my front suspension ,new kingpins and bushes and achieved a good fit.It is only possible when removing the main spring when doing this job to compress the spring with compressors by about 2 inches max to remove the spring so there is no way the spring will compress this much under road use.As you say my suspension will only compress by about 6mm if i stand on the front bumper.also as you say the car must be moving for the geometry to allow the sliding pillars to move freely.
Regards barry 78 4/4 4 seater.

Thanks alot every body i under stand what you mean there are all clean now and regreased and i have about 6 mm movement now
Thanks
Steve

Sticking nylon bushes?: Raise the car on a jack and listen for a squeking noise when turning the steering wheel.
I have nylon (Devol - http://www.gomog.com/allmorgan/Greasing2002to2006.html) bushes on my -99 4/4 and it was very stiff when I bought it (~12000 miles). I cleaned the lower part of the kingpin and greased it by spraying White Moly Grease (a lithium grease) on it. Lifting and lowering the car a couple of times and using the one shot oiler more often than normal has more or less solved the problem.
Nylon bushings are hygroscopic and will absorb moisture and swell if exposed to it (for to long).

When I re-build my front suspension I am minded to use PEEK FC30 for the bushes which is a high performance thermoplastic used in the automotive, aerospace and oil and gas industries for bushings and other high wearing parts. Better than Nylon and I think would be better than Vesconite, it's only draw back is its an expensive Thermoplastic but it wont swell, is chemically inert to oils and greases and has a continuous use tempreature of between 240 and 260 degrees C.

Peek is maybe better than Vesonite, BUT is it better than the recommended product from Vesco Plastics, ie 'Vesconite HiLube' (this is different from the plain old Vesonite Edgar mentioned).
Vesco Plastics themselves recommend HiLube over the older material Vesconite.
However Edgar is spot on wrt the use of PEEK: when I worked in military vehicle suspension PEEK was/is used for the sliding bearings in suspension units, best we found!
There are also some nice German materials from http://www.igus.co.uk particularly http://www.igus.co.uk/iPro/iPro_02_1004_0000_GBen.htm?c=gb&l=en

Regards PJB.

PJB, I have a slightly vested interest as I have been involved with PEEK and the applications that it goes into for many years.Wear testing does not always determine which is the best material for a given application unless you can replicate the exact wear conditions. I did actually mean the Hi Lube product wich has solid lubricant additives similar to PEEK. The only other plastic material I have come across which can sometimes match PEEK in wear applications is Torlon.
I agree Igus make some very good bearing materials from plastics - especially ones from PEEK.
Glad you had a good experience PJB using PEEK during your suspension development days.