MarkB Posted July 10, 2015 Share Posted July 10, 2015 Hi all I have bought some Avo shocks for the rear of my Vitesse and replaced the polyurethane bushes with 1/2" spherical bearings. The original top bolt is I think 5/8". i have purchased some 1/2 shouldered bolts that I will need to cut down. My concern is there is a little play between the inside of the bearing and bolt, not a lot ,but enough to feel. Do you think this will be a problem and likely to create more wear. the alternative is to get the originals turned down on a lathe to be a tight fit. The bottom mount /long bolt for the shock is a better fit in the spherical joint. What are your thoughts. I wish I had a lathe and knew how to use it.thanksMark Quote Link to comment Share on other sites More sharing options...
sparky_spit Posted July 11, 2015 Share Posted July 11, 2015 Yes, I think it will be a problem, unfortunately. I had a very similar problem with AVOs on the back of my Spitfire, although as mine is non-rotoflex I was using the supplied polybushes and stainless tubes. Firstly, the width of the bottom of the damper is very narrow and offers a narrow surface for the tube/bush to bear upon. It therefore wears very quickly and needs changing ay least yearly on a well used car. This is well known and probably why you are upgrading yours? However, I have found that the tube itself has too much clearance on the upper bolt and also the lower stub, even when new. This frets over time and quickly starts knocking when going over bumps. I've now gone back to conventional rubber bushes on the rear because of this.I think you will get the same issue too, if there is any clearance and vertical play between your sphericals and their bolts. It will fret over time, wear, and then drive you mad by rattling over bumps. I'd say get the originals machined to be a tight fit in the spherical, as you suggest.BTW - if you have AVOs on the front and suffer the polybush wearing due to the narrow surface of the bottom of the damper, a slightly more compliant method of changing this is to use cut-down rear spring-eye bushes in their place. When I say more compliant, I mean that they have slightly more give than using sphericals, and would give a slightly easier ride. Marcus put me onto this idea and it works very well. You do need a lathe (or someone with access to one) as about 1.5mm needs to be taken off the width of the bush to allow it to fit between the wishbone ends. Quote Link to comment Share on other sites More sharing options...
esxefi Posted July 12, 2015 Share Posted July 12, 2015 mark,side spacers should be used with sphericals to prevent movement and vibration of the ball,they are available from various tuning co's(got mine from rally design),you do not really want a tight fitting bolt as it could/will corrode onto it making dismantling difficult.as sparky says,...i'll bet you will be changing back to bushes of some sort in a year especially if you use the car frequently,the ride can become tiring as a lot more bump loading will transmit into the chassis. Quote Link to comment Share on other sites More sharing options...
MarkB Posted July 12, 2015 Author Share Posted July 12, 2015 Hi Thanks for the replies. I have the Spacers to take up any side ways movement yet to be tried and fitted. These are new shocks and unfitted so no wear to the poly bushes. The reason I fitted spherical bearings was the angle of the shock top to bottom from the chassis extension to the bottom of the rear hub where the lever arm would have originally attached. There was definite lean from left to right because of the position the pick-up points. The bearing will compensate for this, thats the theory. As soon as you start modifying anything it usually creates other problems down the line and this is what I am finding. I may end up making my own chassis extensions but then I would have to modify the spring tunnel to give me a bit more room which at the moment I m trying to avoid. I will get the bolts turned down at some point.ThanksMark Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted July 12, 2015 Share Posted July 12, 2015 These dampers appear to have spring seats. Are you fitting springs to them as well as or instead of leaf spring? If so the bolt will be under constant tension making fretting and clonking alot less likely, especially if properly clamped with spacers.Nick Quote Link to comment Share on other sites More sharing options...
MarkB Posted July 12, 2015 Author Share Posted July 12, 2015 Hi NickYes I am fitting springs to the shocks as well as using a flatter leaf spring. The bolts may be OK once bolted with the spacers. I'll use them for now to set everything up.Mark Quote Link to comment Share on other sites More sharing options...
MarkB Posted August 1, 2015 Author Share Posted August 1, 2015 Hi allIs there any reason the chassis extensions that are sold kick up at he ends? Presumably its to allow enough travel for the standard shocks. I am thinking of making some straight ones level with the top of the chassis mounting point, as I am using particulary short shocks in conjunction with short springs and a single leaf. Another concern is will the chassis be overstressed where the extension bolts on if using coil overs? any thoughts?ThanksMark Quote Link to comment Share on other sites More sharing options...
thescrapman Posted August 1, 2015 Share Posted August 1, 2015 If you are intending to use coil overs on the rear, you need to note what happens to the rear vertical link when it is loaded on the offset lower shock mount.Normally the loading goes up through the link and into the spring which is mounted centrally. Quote Link to comment Share on other sites More sharing options...
GT6 M Posted August 1, 2015 Share Posted August 1, 2015 frae my experiance wid that type of joint, its OK for track use, limited road use.Butt no constant road use, they become slack in there housing an rattle away when worn.well mine did on the anti roll bar mounts / links front and rear, horrendous clattering noise.As Mike says, {which I kem up wid yonks ago}, fit the rear spring eye bush init if it wears.same bush as inner wishbone lower roto one., not the OE avo one, as thee,s just wear oot v v fast.As for yer bolt being slack, as Ian said, go metric, make it tighter.Butt, as its tight, it,ll also be liable to rust in spot even moer than if slack and well lubed up.M Quote Link to comment Share on other sites More sharing options...
MarkB Posted August 30, 2015 Author Share Posted August 30, 2015 Hi allI have just fitted a new flatter leaf spring along with the coil over set up. I made up some different chassis extension brackets so that the shock and spring are vertical and not leaning left to right due to the offset of the mounting points. I have added another mounting point between the tunnel and the top of the chassis extension to hopefully reduce any stresses on the chassis turret. The coil overs are 150 lb each not sure what the rate of the leaf spring is. Its made of three leaves, each 8mm thick and is 1.5" high measured from the centre. On full droop the driveshafts just start to touch the chassis as the shocks are fully extended so they are not being pulled apart by the force of the spring. I really don't know if this is going to be a better than the original set up but ,something I always wanted to try since seeing it on a race Vitesse years ago. I know there are going to be different forces exerted on the vertical link due to the load being off centre but hope the leaf spring and wishbone will help manage this. Whats your thoughts?Thanks Mark Quote Link to comment Share on other sites More sharing options...
esxefi Posted August 30, 2015 Share Posted August 30, 2015 one advantage with coilovers is that it is easy to change the spring rate to fine tune the handling. Quote Link to comment Share on other sites More sharing options...
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