Tony Posted January 15, 2014 Report Share Posted January 15, 2014 It's triangulation and very clever way to do it...... Is there anyway to test the diff or are you just going to act on this information? Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 15, 2014 Author Report Share Posted January 15, 2014 Well at first I will try to do balance in few garages and to see if it will correct this situation than I will try to test differential but I don't have any idea how to do it without removing completely gearbox off the car. I could find any plays inside the box but for that I have to get the box on the table out of car and it is really big job to do which will last much longer than few days. I don't think it is possible to test diff on some other way than that ones but I will ask few mechanics who are masters in their job. So answer is that I am just going to act on this info and I will post findings here. I hope it is just matter of balancing but according to previous experience it is something else. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 15, 2014 Report Share Posted January 15, 2014 Remember it needs to be a studded balance plate. Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 18, 2014 Author Report Share Posted January 18, 2014 Today I was at the most advanced garage in my region and although they don't have studded plate I think they did a nice job with the balance. But unfortunately there were no difference in the vibration. It is still there and everything is completely the same. It is speed related and I think this must be 2nd order vibration which means something that run the same speed as tyre don't run true and since I have changed the brake discs, wheels hubs, driveshafts, which means everything that run the same speed as tyre (including driveshaft bearings inside inner joint on the right side) so only differential left to check.......damn car.... Quote Link to comment Share on other sites More sharing options...
Tony Posted January 19, 2014 Report Share Posted January 19, 2014 What was the verdict with the diff. Quote Link to comment Share on other sites More sharing options...
NickT Posted January 19, 2014 Report Share Posted January 19, 2014 Have you checked for run-out of the discs/ flanges and the rims themselves? It's alright balancing a wheel but mounting it on a wonky flange will still give an osvillatory vibration........ Try getting the wheels balanced on the car and see how much the extra weight is required to be added and chances are the one with the most wrought added is the one with the vibration issues. ... Just a suggestion. ... failing that, trade the car in Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 19, 2014 Author Report Share Posted January 19, 2014 Well, there must be some tinny play in the gear pinion bearing or tooth inside the diff so when the diff hit certain revolutions it could start to vibrate and I am feeling it as steering wheel shake. I can't see what else could be.... Interesting thing is that tire pressure has some relation with that vibration and that's the thing I can't figure out but following the logic of the automotive suspension where increasing or decreasing tire pressure has influence on the springing load or amortisation level of the suspension then there must be either something wrong with the suspension where some plays in components occur who can't be found or with suspension set up regarding the capability of the natural frequency amortisation. I know modern cars suspension is very sensitive on natural frequency amortisation since nowadays cars are because of that very precise in handling and gripping the road so every little play or inaccuracy in any component can cause some unexpected troubles with vibration leveling. @Nick I have already done it all that you suggest and everything was fine and as it should be. I even borrowed dial gauge and check the lateral and radial run out of the wheels while they are on the car. Run out was completely tinny (0.1 mm over all) and it is well into boundaries of the tolerance. I measured the rims also. Everything was fine. So only diff has stayed unchecked. Most likely I will sell the car as soon as I get out of my loan.... Quote Link to comment Share on other sites More sharing options...
NickT Posted January 19, 2014 Report Share Posted January 19, 2014 Out of curiosity, do you journey on the same road when the vibration occurs? I had what I thought was a minor annoying vibration that was not resolved by balancing but it was the actual stretch of motorway I drove on it at a certain speed! It was only when I moved job and didn't use that stretch anymore that the vibration"went". I confirmed this by monitoring for the vibration again proving it was the road surface. ... That section has now been resurfaced and is smooth. .... Just a suggestion Quote Link to comment Share on other sites More sharing options...
Tony Posted January 19, 2014 Report Share Posted January 19, 2014 Thing about the tyre pressure is it's the first line regarding the chassis frequency, so adjusting the rigidity of the side-wall you are effectively changing the saturation level. Same could be said for the bushings, suspension, dampening relationship. Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 19, 2014 Author Report Share Posted January 19, 2014 Yes I drive on the same road way back home and there is the place vibration occur. It is because I can't drive 120 km/h or even higher on other place than highway. I think that has something with it but no matter that shows up even on the another smooth surfaces but in some different amplitude I might say. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 20, 2014 Report Share Posted January 20, 2014 Taking things right back....... When did the vibration start? was it already there when you got the car or was it after some work was done to it? Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 20, 2014 Author Report Share Posted January 20, 2014 Ok. Taking things back..... Vibs occurred on august 2012., almost three years after I had bought it (I bought the car in November 2009), while I was getting back home from the near town and while I was driving on the highway. Vibs were like car shake up and down between 120 and 140 km/h not like wheels were out of balance. On the first I thought it must be balance but it was pretty strange since in April 2011 I had bought brand new 4 Uniroyal Rain expert tires. I was at the garage to re-balance them but nothing had happen. Few days after that I had noticed some new vibs on the lower speeds, while I had accelerated from 80-100 km/h and they were like ones that comes out of run out wheels. After almost three month of seeking and trying to discover what is going on finally in the November that year, we found that hydro-bushes on the front lower arms were culprits for those strange up and down vibs (it was like your shocks don't works when you hit certain speed..very strange whole car vibration). It was new thing for me as well as for my mechanic who didn't know for those kinds of liquid filled bushings designed to pick up vibrations on precisely defined frequency and amplitude from the wheels in order to improve handling and riding of the car. You can't notice they are worn or bad in any other method but to replace them. Luckily it isn't so expensive thing to do. Those vibs on lowers speeds while accelerating had solved before with right drive shaft replacement since there were some play in the bearings on the inner joint. So, after that there hadn't been no vibrations till the summer last year when it has started to show again. In the past 4 month I changed both drive shafts (on one I even changed bearings on inner joint I managed to find brand new ones since on another side I put one shaft from scrap yard). It put some vibs under control but there were some of it left and since it is very nice car for driving where you can feel every singe part of the road and road surface so smoothly and nice, I can feel those vibs are still there. Now while I am writing about it has crossed my mind I did replace left drive shaft (used one from scrap yard) but I didn't changed bearings on its inner joint although I didn't find any plays in them...maybe I will do it since it is not so expensive.....in fact pretty cheaper then get down differential and try to find out is everything ok inside. On the other hand since the inflating tires has some influence on the vibrations I am wondering were the culprit(s) somewhere in the suspension or it might be in the drive shafts (bad bearings on inner shaft) as well but I don't see any connection between damping capabilities and drive shaft? Or maybe I am wrong and there is connection between it? I forgot to thank to you and Nick on your responses to this issue! So "Thanks you guys!". Quote Link to comment Share on other sites More sharing options...
Tony Posted January 21, 2014 Report Share Posted January 21, 2014 Curious thing is each attempt at replacing parts seems to change the vibration range...... It's really odd that it seems to return after a short time? Is there anyway of having the diff tested without replacing it. Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 22, 2014 Author Report Share Posted January 22, 2014 Yes that's the proof I have done everything need to solve it but i didn't manage to find source of vibrations. It seems that no one here can't test differential without removing it of the engine bay. And that's long and expensive work to do so I can't afford it at all. Last night I was drove home by the highway and vibrations range was moved in higher speeds I presume it is because I inflated tires on higher pressure so it affect only on the speed where vibrations are occurring. I could feel those shaking under my feet (no matter they are on the pedals) like all floor vibrate along with seats.... Few days ago my wife drove the car and I was on the passenger side where I could clearly feel vibrations through the floor and seats too. It is really clear they are sourced on the front end...... Interesting thing is that car is really stiff and really nice to drive but on that certain range of speed I am feeling like something will get of the car how it vibrate......ufff... Quote Link to comment Share on other sites More sharing options...
andyelcomb Posted January 22, 2014 Report Share Posted January 22, 2014 Fascinating. Hope you do get to the bottom if this as I'm dying to know what the problem turns out to be. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 22, 2014 Report Share Posted January 22, 2014 I confess this has been doing my head somewhat since it's clearly a frequency. I'm thinking oil viscosity -V- temperature has a hand in the speed range but there's no way of telling for sure. In addition the tyre pressure belays any question of the viscosity since the tyres are totally unaware of the running gears temp. When you replaced the drive shafts how did the inner teeth look "diff side"? Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 22, 2014 Author Report Share Posted January 22, 2014 Well I must disappoint you Tony about oil viscosity vs anything since I forgot to mention I changed the transmission fluid cause there were present some issues with gear changing during the cold mornings . During the work on changing we didn't notice any metal parts (even the tiniest ones) in the replaced fluid which should be inside if the differential tooth, pinion gears or I don't know what or something like that were worn or so. Also we didn't notice anything strange with the inner teeth on diff side either left or right. One thing left to check....I changed both drive shafts directly taken from the scrap yard but on the left one I hadn't changed tripod bearings which were done on the right drive shaft. We couldn't see any plays on that side in the inner joint but who knows how it behaves under common rail-high output torque-diesel engine load. It seems there is some bit amplified vibrations under the acceleration from 120 to 140 km/h which I could connect with worn inner joint bearings (or its tripod or more likely inner joint cup). I don't know..... Like Tony said it is vibrate and frequency related and as long as i know it is pretty precise science so I will try to dig out either source of the vibration or the vibrations path....since the suspension seems to be pretty stiff and without any plays it could be only either differential or hydro-bushing on the lower arms (you couldn't believe what influence those liquid filled bushings has on the vibrations damping...unbelievable). So, as I changed hydro-bushings what else stayed than diff and left side inner joint bearings. Definitely, bearings are more likely to be replaced since it is one hour job and not so expensive. Any other propositions? P.S. Thanks you again for inputs. If I solve this I am moving to the West since during this year and a half while I have digged out everything related to my trouble I found millions of people with same or similar troubles on every types of car so I might be a millionaire from helping people with vibrations related problems. This business could be registrated also as humanitarian or psycho therapy one since I know how this can be frustrating..... 1 Quote Link to comment Share on other sites More sharing options...
Tony Posted January 23, 2014 Report Share Posted January 23, 2014 Sounds like a plan. Thing is though it's one thing for me/ us to make suggestions regarding the vibration but we still haven't found the cause. One thing that keeps bugging me is there's no mechanical noise when the vibration starts and this leads me the think it's bushing related but yet these have been changed? Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 23, 2014 Author Report Share Posted January 23, 2014 I thoughts about bushings too Tony. Although I had replaced them in November 2012. where vibrations were put under some control. I mean there were some of it but nothing significant and I thought it might be due unbalanced wheels. I don't know how it is possible they have become worn in such short period of time. I remember they were OEM (no matter I bought them in Febi bilstein box) and we aligned them as previous were placed on the lower arm. I am confused with absence of any kind of noise (but wind and tires on the road only) too as I heard and learned that differential kind of vibrations are followed and accompanied with some noise or harshness. Yet, it is possible that there aren't any causes of the vibrations out of specifications but something might gone wrong with the components of the suspension who takes part in the damping those normal wheel inputs from the road. So the first thing related to that possible scenario is bushings where I saw what influence they have on picking wheels input. So it is all nicely explained here: http://www.vibratesoftware.com/ and i like how people gave an simple explanation of it.... All automotive vibrations have three basic components: Source - The source of the vibration. Most of the time the source of the vibration is a rotating component that is out-of-round or out-of-balance. In these cases, the source of the vibration can be repaired. Engines however, have vibrations which are a natural part of the engine running. If the engine is the source of the vibration, it cannot be repaired because it is not broken. Instead, the transfer path for the vibration must be repaired. Transfer Path - The transfer path can be anything that is connected to, or touches both the vibration source and the responding component that the driver notices or feels. It can be the suspension system, a motor mount, transmission mount, body mount, exhaust system, propshaft, running boards, etc. Whenever normal engine vibrations are felt in the passenger compartment, the transfer path should be repaired rather than the source. Responding Component - The responding component is the part that the driver notices or feels is vibrating. It can be the floor, the seat, the steering wheel, the sun visor, the dash or instrument panel, etc Quote Link to comment Share on other sites More sharing options...
Tony Posted January 24, 2014 Report Share Posted January 24, 2014 In your country does the MOT testing stations use "shaker plates". These vibrate the wheels so the tester can check for worn components. Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 24, 2014 Author Report Share Posted January 24, 2014 Yes they do use that plates. But they use them mostly to determine whether your shocks good or not. And as I know those machines are pretty accurate. On my last testing they didn't find anything bad there. In fact, suspension on Mondeo is rock solid and there are anything with play in there. I have checked it with very experienced Ford mechanic and we didn't find anything, only thing we could imagine as vibrations cause that left unchecked or tested is differntial. But we doubt in even that since there are any noise or something like that in there which is main sign differential is gone. I will see to change those bearings on the left inner joint tripod to see what will happen. Quote Link to comment Share on other sites More sharing options...
SMARTLY Posted January 24, 2014 Report Share Posted January 24, 2014 Could it go on a rolling road to try to isolate the problem? Quote Link to comment Share on other sites More sharing options...
Tony Posted January 25, 2014 Report Share Posted January 25, 2014 I used to use an on car wheel balancer years back but i don't think there's many around nowadays. Quote Link to comment Share on other sites More sharing options...
bojcistv Posted January 25, 2014 Author Report Share Posted January 25, 2014 I don't know how it could be isolate on rolling road any way...I will see to change those tripod bearings and how it will get affect on it. After that maybe i will try to change complete lower arms just to see if they have any influence. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 25, 2014 Report Share Posted January 25, 2014 It would be nice to witness the rotating mass before blindly changing parts..... This is the type of thing i'm thinking Quote Link to comment Share on other sites More sharing options...
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