BigI Posted December 19, 2019 Report Share Posted December 19, 2019 About 18 months ago i hit a roundabout kerb when the car understeered at about 40 and i went up it. thankfully it was a bevelled edge kerb otherwise i might not have driven it home! Damage looked to be limited to wheel arch plastic liner ripped out, but on inspection I found the strut had kinked at the bottom near the stub axle clamp on the outside. to be on the safe side, I replaced all front struts, springs, and the nearside stub axle and lower arm - all gen ford. While i was at it i did the same at the read, including the rear bushes - again all gen ford. Had everything aligned and all good - or so I thought! About 6 months ago i managed to hit a storm drain on the motorway hard shoulder and blew out a new front tyre. when i went to have the tyres checked i found the inside edge of the nearside tyre was almost down to the belts (both fronts were less than 6 months old). I went back and had the car place realign the car again and then got a second opinion from another garage. i've checked my front tyres again and the nearside front is down to the belt again after about 6 months. I've checked for any damage to the suspension, but everything looks fine and was all replaced. The alignment printer was broken on their digital supertracker (the proper 4 wheel geometry one, not the crappy 2 wheel one!) - but i got a photo of the before and after. what concerned me is the setback on the front, and also the camber of the nearside front wheel - i seem to recall it being the offside wheel that had more camber due to the weight of the engine previously? Anyway - Can anyone make sense of this for me please? It also mentions "delta" but the guy really didn't know what it meant (not a good sign!). before i spend another £250 on tyres i'd really appreciate some advice! Wondering if the impact has knocked the front subframe out of alignment, causing the offset and dodgy camber? Quote Link to comment Share on other sites More sharing options...
Tony Posted December 19, 2019 Report Share Posted December 19, 2019 Hi ya Reads like you've been through the wars...... Delta refers to a curve and only applicable to some German cars "VAG". Your report displayed is incomplete because the castor, KPI, SAI is not measured. without this i cannot comment or diagnose a problem. However, the before toe measurement of -3.00 is dramatic and normally suggests the castor angle ( not measured ) has moved? Quote Link to comment Share on other sites More sharing options...
BigI Posted December 27, 2019 Author Report Share Posted December 27, 2019 Hi Tony Thanks for the explanations - and confirmation that they really didn't know what they were doing at the garage! The toe measurement was probably out due to hitting the storm drain at around 60 diagonally - it was allegedly correct prior to that. I've been to a proper alignment centre today, and the guy spent about 2 hours with me checking everything - even had the car on the shaker plates to check suspension movement - in his words "everything is perfect" I've attached the readouts from the Hunter machine, all within tolerances. the n.s front tyre had this same "shoulder" of wear on the inside edge the same as the last tyre that was on there. I've now fitted a brand new set of tyres on the front and went back and it was re-checked again - the n/s front was now toeing in very slightly, so he adjusted it for me. even checked the tyre pressures. His opinion was that there was unlikely to be chassis damage anywhere because the readings were not indicative of that; he checked the setback and there was 1mm difference between the sides. His parting comment was that he'd only ever seen wear like that on one other car, an Audi. and that was due to a damaged lower arm - and there was no such damage on mine. seriously confused! Quote Link to comment Share on other sites More sharing options...
Tony Posted December 28, 2019 Report Share Posted December 28, 2019 The tyre in the picture... Do it make any noises on full lock, or feel like it's "skipping" on full lock? Quote Link to comment Share on other sites More sharing options...
BigI Posted December 28, 2019 Author Report Share Posted December 28, 2019 Yes, it was one of the things a I was mentioning to the guy yesterday (note this is the first tyre that was only 6 months old (Landsail 588). the second was a 6 month old Michelin Pilot Sport 4 that had been on the rear; although the wear was higher all over, the exact same should was apparent on that). I park in a multi story car park with concrete ramps; whenever it is slightly wet, driving round the ramps results in a horrendous dragging noise from the front tyres. When i mentioned it to the guy yesterday , he said that he noticed it as well when he was turning on full lock when he test drove it before putting on the ramp. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 29, 2019 Report Share Posted December 29, 2019 Now we are getting somewhere..... There-s a bend in either the steering arm or the cast the track rod end.bolts too Both of the above control the amount of lock the inner wheel has compared to the outer wheel. This allows a different radius each wheel has on a lock. Quote Link to comment Share on other sites More sharing options...
BigI Posted December 29, 2019 Author Report Share Posted December 29, 2019 Thanks Tony. I replaced the ns knuckle after the first incident, so unless I was unlucky and got a damaged one I suspect it not to be that - unless I’ve damaged it again on the storm drain (although the first tyre was worn like this before the second incident it seems). When you say steering arm, do you mean the track rod? Quote Link to comment Share on other sites More sharing options...
Tony Posted December 29, 2019 Report Share Posted December 29, 2019 If the track rod has a natural bend then no...... Too allow the inner wheel to have more lock than the outer wheel the steering arm must move toward the wheels centre. Obviously the position is reversed on the outer wheel. The TOOT "toe-out-on-turns" or the Ackerman angle is normally on modern car generated by a curve on the track rod end. Failing that it's generated by a finger like bend on the TRE pick up point. The Hunter machine can measure the TOOT but very few places use it because it hard to understand but it is a diagnostic angle. I'm about to post a new HOTW "horror of the week" have a look at that.. Quote Link to comment Share on other sites More sharing options...
BigI Posted January 2, 2020 Author Report Share Posted January 2, 2020 I've attached some photos - went over everything yesterday and everything is straight, no signs of any bends etc. After the first incident, the track rod ends where also replaced with gen ford items, and look undamaged. I measure with a caliper gauge the distance between the ball join centre and the face of the brake disc and they are within 0.2mm of each other. I can't find any damage to the strut, the lower arm, the casting of the hub of the inner track rod (only thing i haven't done it remove the gaiter and check the end of the steering rack, although i made some measurements and both sides appear to be straight. the only thing that is bad is the tyre fittings - thought i had massive flat spots on the wheels - but there is no damage inner or outer wheel, the tyres are not central to the wheel (nice work Costco) While the car was suspended on stands I checked rack movement and no signs of and stiffness on either lock. The track rod ends is further out of the n/s (problem side) - currently 8 threads exposed vs 4 on the os, although it should be more as the wheel is off-centre atm (even though it measured true on the hunter) Literally running out of ideas - only thing i haven't now replaced is the top mounts! Quote Link to comment Share on other sites More sharing options...
Tony Posted January 2, 2020 Report Share Posted January 2, 2020 The wear on the tyre has a sharp edge meaning the wear position is lateral. Camber and castor wear is smooth and confined. 8 and 4 threads is a bit odd because it means the left/ right lock angles are different. The Hunter machine can measure this. Personally i would want 6 threads each side and then see where the steering wheel moves to when the wheels are steered straight ahead. It's possible the steering wheel has been removed at some point hence to 8 and 4 threads because the off-set was done to centre the steering rack. Quote Link to comment Share on other sites More sharing options...
BigI Posted January 3, 2020 Author Report Share Posted January 3, 2020 Thanks Tony, appreciate your advice! The rack was replaced about 3-4 years ago now (twice after they screwed the first job), I know they initially forgot to centre the rack before fitting, so doesn't surprise me if it wasn't completely right now - however the car was fine until the incidents! So, if i understand what you re saying, then there is unlikely to be any chassis alignment issues because they would manifest themselves as caster/camber wear and therefore a different kind of wear? In this case, that would also rule out damage to the lower control arm, top mount or strut or subframe? I would have expected to notice if the rack itself was bent in some way (nothing noticeable when turning the wheel on ramps lock-lock) The only possibility i guess i have left now is the inner track rod is bent underneath the bellow, or the track rod end or hub carrier have become damaged again after incident #2. any other thoughts? I'm happy to replace the subframe if that might be the cause - would rather not but i will if it stops eating tyres lol Quote Link to comment Share on other sites More sharing options...
Tony Posted January 3, 2020 Report Share Posted January 3, 2020 The Hunter machine has many ways to measure the chassis and if we used them all a geometry would take hours. So what we do is funnel what's measured according to the complaint. On your car i would next measure the symmetry and set-back. Quote Link to comment Share on other sites More sharing options...
BigI Posted January 3, 2020 Author Report Share Posted January 3, 2020 The setback was measured on my last visit and confirmed to be less than 1mm (F&R) - sadly i didn't take a photo of the results! To be honest I was half expecting to find this was an issue - as my initial thought was that perhaps the front subframe had shifted from the impact causing it to skew - but all the information pointed to that not being the case; and if i understand correctly tht might also cause the wear i am seeing here due to the angles changing lock to lock? One thing i did find a little strange was when i fitted new tyres to the front to replace the old worn ones, the toe on the front n/s needed adjusting out slightly to bring it within tolerance - the reason that was explained to me was that this was due to the changed tyre shape of the new tyre without the shoulder wear; however even though the tracking was correct, the steering wheel is now between 12 and 1 to go in a straight line - and when i leave go of the wheel, the wheel does turn slightly to the right. When the missus got in the passenger seat at the weekend, the wheel was further turned to the right to keep in a straight line. Something definitely feels a little skittish, feels a little vague to drive at the moment - something which this has never felt in the past! i have got a new set of front struts, so wondering if perhaps there is a slight bend in the piston on the NS causing a non linear movement? I would have been looking at damaged bushes that could cause the wheel to toe out under load but nothing showed on shaker plates either. All extremely confusing! Quote Link to comment Share on other sites More sharing options...
Rich Posted January 3, 2020 Report Share Posted January 3, 2020 Don't assume something isn't bent as you can't see it by eye. I remember years a go jammy (a member on here) had an issue with his geo on a MK1 Mondeo. Turned out to be a suspension knuckle slightly buckled IIRC but to the eye looked fine. Quote Link to comment Share on other sites More sharing options...
BigI Posted January 3, 2020 Author Report Share Posted January 3, 2020 Very true Rich, i know what you mean - never trust your eyesight I had a precision caliper to measure the hub mounting point position in relation to the disc and it was the same both sides. also measured the length of the track rod ends to ensure they were right - so have relied on measurements wherever possible. The other issue is that the track rod ends (both sides) where replaced after the incident with gen ford parts, i replaced the hub with a used part, replaced the lower arm and macpherson strut with new gen ford parts and replaced the springs with a pair of KYBs. the only part i didn't replace was the steering rack and inner tie rods, or the top mounts (bearings were also replaced). So this is where i am struggling to see the issue - only thing left is to pop open the rack gaiter and double check the straightness of the inner rod! Quote Link to comment Share on other sites More sharing options...
Tony Posted January 3, 2020 Report Share Posted January 3, 2020 I don't like the 8 and 4 threads. The lock angles must be different.... Remember Ackerman and lock angles are not the same thing. Quote Link to comment Share on other sites More sharing options...
BigI Posted January 3, 2020 Author Report Share Posted January 3, 2020 so a small update - I managed to dart out of work early and the three guys at the centre stayed late to go over my car again! They put the car back on the hunter and the alignment was bang on - however when i sat in the drivers seat, the n/s front toe went out! they have now set the toe correct when i'm sitting in it. I was a bit shocked that it went from being bang on to toeing out and being in the red when i sat in the opposite side? I mentioned about speaking to the guys on this forum (your reputations precede you - he knew all about you!) and he said he was happy to try the suggestions. I've attached the setback info, unfortunately he couldn't do the total toe reading because it required the extended sensors, which he didn't have. They had the car on shaker plates again and jacked up to check for any rack play and anything unusual; they could only see a slight difference in gapping between spring coils (mm) suggesting that maybe the springs are uneven - but the gapping was less on the o/s! It was suggested the thread difference might be down to the fact it was a replacement rack (not gen ford) and the tolerances might be different on it - also that it might not be fitted centred - of course the thread counts might now have changed with the toe adjustment! 1 Quote Link to comment Share on other sites More sharing options...
Tony Posted January 4, 2020 Report Share Posted January 4, 2020 The wheel positions are fine. As for the toe change it's because the sprung chassis move diagonally rather than what most people think just compress on the drivers side. Now the toe has been set with you in the car, how's it driving now? Quote Link to comment Share on other sites More sharing options...
BigI Posted January 4, 2020 Author Report Share Posted January 4, 2020 The car is definitely driving more neutral since it was adjusted - I must admit I never realised that chassis movement worked in this way! Will have to monitor the tyre wear carefully to see if the lateral wear begins again - The guy has said if i still want to replace steering rack/tie rods/track rod ends/struts etc to go ahead and drop back in and he will re-adjust FOC as he just wants to see the problem solved! Quote Link to comment Share on other sites More sharing options...
Rich Posted January 4, 2020 Report Share Posted January 4, 2020 Sounds like a decent garage if they were prepared to take onboard Tony's advice. So many would just tell you you're wrong and have no idea what you're talking about. Quote Link to comment Share on other sites More sharing options...
BigI Posted January 6, 2020 Author Report Share Posted January 6, 2020 I always end up going back to them - old school guys - all they do is MOT, alignment and a small amount of tyres; so when they say something needs replacing you know it's not because they are upselling you! You know they can't be bad when the boss of the nearest BMW garage asks him to look at his OH's car for him! Quote Link to comment Share on other sites More sharing options...
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