thegfb Posted October 30, 2013 Report Share Posted October 30, 2013 Hi new member here I originally posted this as a question on the Talkford site but Rich doesn't drop in too much now and I figured I'd get a quicker and better answer here. Original thread: http://www.talkford.com/topic/221203-front-toe-has-changed-after-replacing-top-mount/ My car is a Ford Mondeo ST24. It is running on the original 16" alloy wheels with 205/50/R16 Uniroyal Rainsport 2 tyres all round. The suspension has been changed so it's running on Eibach Pro springs all round. All shocks were changed for Bilstein/Slachs parts and are good. It has standard wishbones with good bushes and ball joints. The front droplinks are thicker ST200 style parts, and the ARBs are polybushed front and rear. Back in late 2011 I had a full geometry done at my local Ford dealer on a John Bean machine, which cost about £60. This was after changing both the front wishbones and wheel bearings. Here is the print out: The only adjustable suspension angles on this car are front and rear toe, the camber and castor are both non-adjustable without modified parts. The has been handling is excellent, especially for such heavy saloon car and I am very happy with it. However a few weeks back I noticed that the handling was becoming a bit odd when the NSF was going over bumps, I got some odd bumpsteer and it just generally didn't feel right. There was some knocking too, but I had an advisory at my last MOT for the droplink balljoints. I changed this and it cured some of the noise, it didn't change the bad handling (and I didn't expect it too). I got my pry bar in and around the NSF strut/wishbone and could find no play, however I whipped the strut top nut off and the problem was immediately visible - the second nut (which sits right on top of the top mount, and for some reason isn't a nyloc) had loosened allowing the thread part of the strut piston to move excessively. This in turn had worn the centre hole of the top mount to about twice it's normal size! This was of course allowing massive movement and would have been playing havoc with the geometry. So I ordered a new top mount and replaced it. As I guessed, the toe has been changed presumably due to different manufacturing tolerances in the top mount dimensions as well as wear. The steering wheel now needs to be held slightly to the left to go straight, but you can actually 'feel' that the handling isn't right still. So my questions are: 1) Now that the steering wheel needs to be held left, does this mean that my suspension changes have made the NSF toe in? 2) The car has not done many miles since the last geometry and I am happy the other three wheel toe settings are good. Would it be permissable for me to make small gradual adjustments to the NSF track rod until I get a centred steering wheel again? I figure once the steering is straight then the front total toe must be back to zero again (as in the geo print out)? Thanks for any help, I could do without spending another £60+ on a full alignment again if I could fix it myself quickly and cheaply Quote Link to comment Share on other sites More sharing options...
Rich Posted October 30, 2013 Report Share Posted October 30, 2013 Hi mate, welcome to WIM I have not been on TF for ages, although I think I briefly looked online a while ago, my first time in months though! I do miss my old MK2 sometimes. Those top mount nuts are a PITA, mine were always coming undone and I think I put locktite on eventually. It doesn't take much to throw the toe angle out on these cars. If your last geo was 2 years ago then personally I would get it done properly but it can't hurt to make gradual adjustments to the TRE and see what happens with the steering wheel but you would also need to brace it so it doesn't move while you adjust it. Obviously keep an eye on tyre wear as well. Quote Link to comment Share on other sites More sharing options...
thegfb Posted October 30, 2013 Author Report Share Posted October 30, 2013 Thanks for the reply mate Ideally I'd like another full geo too but the car has been SORNed most of the time since the last one and hasn't done much mileage at all. So do you think I need to give it a little toe out then and see what happens? I'll mark the nut and rod so if worst case scenario it gets even worse then I can revert it. Quote Link to comment Share on other sites More sharing options...
Rich Posted October 30, 2013 Report Share Posted October 30, 2013 Yes mark the nut and threads with chalk so you can put it back if needed. As the front only has adjustable toe I don't think you will cause any problems like you would having adjustable camber and castor as well. I'm sure Tony will be along soon to tell you if I'm wrong though! Quote Link to comment Share on other sites More sharing options...
Tony Posted October 30, 2013 Report Share Posted October 30, 2013 Welcome to wim.... Changing the top mount alone wouldn't directly change the toe position because it's pick-up point is in the wrong direction. What it will change is the castor position which was deeper than the OSF as shown on the printout, this is also consistent with a worn top mount. Relocating the strut would have moved the castor position toward negative ( forward ) this in turn would push toward the rear mounted position ( rack ) that being mounted behind the wheel. In this event it would toe the NSF wheel in ( positive ) meaning you would need to correct for this by holding the steering left hand down. You could mark the NSF steering arm and screw it in incrementally until the steering position is level but it's not wise if i'm honest, fine track side but given the cost of tyres do you really want to chance it? Quote Link to comment Share on other sites More sharing options...
Rich Posted October 30, 2013 Report Share Posted October 30, 2013 Good point Tony, yes the castor would change fitting a new top mount. Should the top mounts be replaced in pairs as well? Quote Link to comment Share on other sites More sharing options...
Tony Posted October 30, 2013 Report Share Posted October 30, 2013 In an ideal world i have to say yes but pounds matter these days so it's not an ideal world. You know how i pants on about the 3D geometric plane X,Y,Z. and pick-up points. And you know what plane the top mount changes from the adjustable mounts you had on the Mondeo. Pivot the castor can dramatically push/ pull at the steering arm, hence the change in toe. The camber would stay about the same since this mount doesn't pivot, so once again logic works within two planes, castor and toe. This complaint hasn't suggested a pull so we can assume the castor position is still fine but! when the toe was adjusted before it was done with a worn mount and positive castor, well the castor position has been corrected now so the past toe correction is redundant. Quote Link to comment Share on other sites More sharing options...
Rich Posted October 30, 2013 Report Share Posted October 30, 2013 Makes sense to me mate To add, those camber/castor adjusters I had were a nightmare, forever changing the angles as the top mounts moved everytime you went over a bump or dip in the road!! Quote Link to comment Share on other sites More sharing options...
Tony Posted October 30, 2013 Report Share Posted October 30, 2013 Pant's is the word i would use but given the options, there was no options? Quote Link to comment Share on other sites More sharing options...
Rich Posted October 30, 2013 Report Share Posted October 30, 2013 There is an option - don't fit them!! I would rather live with the slight tyre wear I had than the terrible handling those adjusters caused Quote Link to comment Share on other sites More sharing options...
Tony Posted October 30, 2013 Report Share Posted October 30, 2013 Twas a learning curve at the time but i would never recommend them again. Quote Link to comment Share on other sites More sharing options...
thegfb Posted October 30, 2013 Author Report Share Posted October 30, 2013 Thanks for the input Tony Now to put a spanner in the works The worn top mount I removed was brand new when the last geo was done (printout above). It has worn very quickly, but it was only about £8 so I guess it was a cheap crap one. With the utmost respect, if all a technician can do is adjust the toe the same as I (albeit not blind) how would getting it on a machine again help? Is it possible that the other three wheels may now need re-adjustment to compensate for this new top mount? For the sake of another £12, maybe it would be cheaper just to buy another and replace the other side too, or would that not help? Quote Link to comment Share on other sites More sharing options...
Tony Posted October 30, 2013 Report Share Posted October 30, 2013 The other side isn't an issue unless worn? If all reads correct all you need is all four wheels imaged and then the toe corrected on the front. There's no reason the camber or castor would be wrong but given the time since the last geo was done it's possible the rear toe has moved? Correcting that isn't as critical as the front providing the rear thrust angle isn't displaced by more than 10'. Quote Link to comment Share on other sites More sharing options...
thegfb Posted October 30, 2013 Author Report Share Posted October 30, 2013 The other side isn't worn but it's probably a different brand of pattern part? I suppose what I was getting at is that as the geometry report was fine when the worn part was new, then the new unworn part must be slightly different in physical size? Provided that all those previous good geometry measurements still hold (which I think they must do considering the car previously drove vry well and tyre wear was balanced) then am I right in thinking that the only thing that would need changing is the toe on the NSF? The last geo was over two years ago but like I said, the car has been SORNed most of that time and hasn't done much driving. I think I'll just try teasing the track rod into the track rod end a little at a time (effectively shortening it and thus toeing the wheel out). I'll see how the steering goes, and keep my eye on tyre wear. If all is good I'll consider it a quick, cheap fix. Quote Link to comment Share on other sites More sharing options...
Tony Posted October 31, 2013 Report Share Posted October 31, 2013 Yes just the NSF toe..... Screw the rod into the end and that will move the steering position to the right. Quote Link to comment Share on other sites More sharing options...
thegfb Posted October 31, 2013 Author Report Share Posted October 31, 2013 Thanks I will let you know how I get on and if it is a good long term fix or not. Quote Link to comment Share on other sites More sharing options...
Tony Posted October 31, 2013 Report Share Posted October 31, 2013 Take it half a turn at a time. Quote Link to comment Share on other sites More sharing options...
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