AndrewGP Posted January 23, 2014 Share Posted January 23, 2014 As some of you will be aware I'm part way through my lengthy and quite detailed winter refresh. With quite a bit of help from Geoff Brown yesterday ( ) we're pretty much done getting the freshly powdercoated and polybushed front suspension back on the car. My question is why do we torque the suspension bolts up to effectively pre-load the suspension to horizontal? Why does it not get torqued up so that the whole lot is floppy and just allow the spring and damper to do it's job? Potentially numpty question I know but chatting to a mate at work who has a Westie, he reckons this is how his car is set up Link to comment Share on other sites More sharing options...
simonpa Posted January 23, 2014 Share Posted January 23, 2014 Nope - you pre-load the suspension and then torque the bolts/nuts. I.e: o put the dampers and wishbones on o do up the bolts but do not nip them o put the car on the ground and then nip/torque. That way, when the car is on the ground, the bushes aren't stressed either way. Does that make sense? Link to comment Share on other sites More sharing options...
Simon.Rogers1 Posted January 23, 2014 Share Posted January 23, 2014 However you have swapped to poly bushes. The correct method for metalastic bushes is to drop the car to ride height and then torque things up. With poly bush they are effectively frictionless so IMHO you can torque them up in any position. Metalastic bushes actually apply 24kg of force when lifting the wheel to 4" of travel. Powerflex apply less than 1kg Link to comment Share on other sites More sharing options...
AndrewGP Posted January 24, 2014 Author Share Posted January 24, 2014 Simonpa, yes it does I guess thinking about it the metalastic bushes can't do their job unless they are preloaded. Simon, yes that makes sense too, although with the white nylon thrust washers in place at either end of the polybush, none of the fittings are what I would call 'frictionless', they are actually quite tight in the chassis hangars. Does this sound correct to you? Link to comment Share on other sites More sharing options...
Simon.Rogers1 Posted January 24, 2014 Share Posted January 24, 2014 Ah well the Powerflex ones are frictionless which are the ones I tested. I would drop it to ride height as per metalastic. The reason for doing it that way is that if a Metalastic were tightened at full droop and then lowered the bush is twisted under load at all times and then "over twisted" under compression. Done the correct way it twists one way then the other under bump and rebound. Link to comment Share on other sites More sharing options...
AndrewGP Posted January 24, 2014 Author Share Posted January 24, 2014 Thanks Simon, it's powerflex that I've fitted. Will torque them up with the car on it's wheels as you suggest Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted January 24, 2014 Area Representative Share Posted January 24, 2014 I've seen a set of powerflex bushes and washers were the supplied washers were too thick. If the wishbones have been plastic coated (which is generally a slight thicker coating than powder coating), then it's possible that it's the coating causing the issue. I'd carefully check the gaps between the fixed brackets on the chassis, the lengths of the spacers, the width of the bush sleeve of the wishbones, and the thickness of the supplied washers. With polly bushes, If the parts don't move freely when torqued up, then there is something wrong! Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted January 24, 2014 Area Representative Share Posted January 24, 2014 I've just found the sketch I did to illustrate how the parts fit together. See here Link to comment Share on other sites More sharing options...
AndrewGP Posted January 24, 2014 Author Share Posted January 24, 2014 The wishbones weren't plastic coated just blasted and powdercoated. I've just been out to the garage and to give you an idea of high tight they are, after torqueing the bolts up, I can just about move the wishbones with one finger. Once deflected in this way, they stay were they are, ie they don't droop. Does that sound too tight? If so, I guess I could remove them all and remove some powdercoat? Edited to add, I'm being stupid, we removed all the powdercoat from the faces of the wishbones as they didn't fit the first time we tried. Edited by - grenpayne on 24 Jan 2014 10:33:43 Link to comment Share on other sites More sharing options...
Simon.Rogers1 Posted January 24, 2014 Share Posted January 24, 2014 Yes to tight. They should droop a little. Link to comment Share on other sites More sharing options...
AndrewGP Posted January 24, 2014 Author Share Posted January 24, 2014 ☹️ Not sure what I can do to loosen them Simon, as I said above, I've taken the powdercoat off the face of the wishbones so is it worth speaking to Powerflex to get thinner white washers? Link to comment Share on other sites More sharing options...
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