Front Upper Control Arm checks!

Discussion in 'Technical' started by Benny_C, Mar 29, 2012.

  1. Benny_C

    Benny_C About as subtle as...

    Thought i'd just touch base and make mention that i just finished putting new suspension in the Blue Beast, and while i was under the front end checking out my steering components i noticed my aftermarket adjustable upper control arms (which i've had there for about 2 years) had a bit of play in them, which made some further sense going by recent extra feedback i've felt through my steering wheel!

    They had some lateral movement in both sides when wiggling from front to back. So I had to re-tension the grub screws again to make the steering arm firm again with no slop.

    These are the type control arms i'm referring to...
    [​IMG]

    So at the end of the day, i'd like to make a mention that if you have this style front upper control arm, i'd personally recommend inspecting them at least every 6 months to make sure of their integrity. (I'm sure CHILI would agree with me from his own personal experiences with these items)

    Cheers,
    Benny :)
     
  2. DinoZ

    DinoZ Talks sh#t for a living.

    If you have gone to harder suspension you are also more likely to bend the arms as well. The suspension exerts a twisting motion on the upper arms and this works on the adjustment thread and loosens the locking ring. Potholes transfer a shock load and the weakest part of that style of arm is the threaded bar which has been hollowed out.

    Because I was using my Zed on both track and road and varying the camber for each, I was probably adjusting them about a dozen times a year, and was able to see movement in the arms inside of a month.

    For normal road use I would definately add them into at least a 6 monthly check.
     
  3. Z32 TT

    Z32 TT Active Member

    I have had the same problems with these aswell and put them in the bin. a good alternative for those who still want the camber is to use shimming plates. A good suspension place will be able to shim your camber out to your specs (within reason).
     
  4. ZILVER-Z32

    ZILVER-Z32 New Member

    What brand are they?
    They appear to be identical to the ones sourced from EBay which AMS also recolor/resale?
     
  5. Benny_C

    Benny_C About as subtle as...

    Well mine are stamped "PZP", but yeah, they're all just the same Midori style control arms that float around like you mentioned, and people just brand them they're own.
     
  6. CHILI

    CHILI Indestructable Target

    It matters very little what branding is on them(they very nearly all originate from Asia)except Stillen, Noltec and UAS.
    I have used many of them with varying levels of success(and/or total failure).
    Most notable for failure was the Noltec(Stillen style/flat rectangular shape)and the UAS "swivel-style"(which is undergoing a re-design ATM).
    Fortunately, in my experiences, nothing actually broke apart, but several did show varying amounts of wear(except the "Stillen" type which twisted and snapped some welding)and the UAS ones that bent on the exposed threaded section.
    I am currently using a style similar(but not the same)as those Benny is using. Mine differ in that the centre/threaded section is a rectangular alloy block(rather than a threaded tube)and I have applied a Molybdenum-based grease to the threaded section. I have tightened one end clamping bolt so that the alloy block cannot rotate(but have left the other end slightly less tight, allowing very slight rotation).
    This appears to be successful(as it allows the twisting motion)and has so far shown no measurable wear on the threaded sections.
     
  7. Jinxed

    Jinxed Moderator

    shimming plates query, how much can you safely shim out the inner bracket, and how big = how much change.

    ie 1mm shim = xx camber change
    2mm =
    3mm =
    etc.... can anyone answer this for me, as its the way id prefer to go on my car....
     
  8. DinoZ

    DinoZ Talks sh#t for a living.

    From settings I calculated when adjusting mine, 2mm shim is approximately 0.25 degrees of camber adjustment.

    Not sure how much you can shim out but make sure you have at least 3 full threads still exposed after the nuts are tightened.
     
  9. Anti

    Anti 14.7 x 14.7 = 44.1

    This doesn't seem right. 8mm spacing should be reducing camber more than 1*?
     
  10. DinoZ

    DinoZ Talks sh#t for a living.

    The amount of adjustment is relevant to where it is being applied. Adjustment at the top arm requires that much. When I adjust my camber from road trim to track work I wind in my adjustable arms 5 full turns (they effectively shorten the distance by 3mm per turn) and 15mm of adjustment takes me from 0.75deg camber to about 2.6deg camber.

    I measure the change by using a level to get the offset from the top and bottom of the rim. My calcs are based on a 17inch rim and would be slightly out on say a 19inch rim (but not that much). If you are handy with a calculator and using the sign rule you can work it out for your rim size.
     
  11. bRACKET

    bRACKET Do Right Dean

    Some more relevant reading, some of the results of what CAN happen with aftermarket FUCA's.

    Linky
     
  12. mungyz

    mungyz Well-Known Member

    Angle change is not related to wheel size, it is related to the length of the j arm and upright assembly, the angle of the upper arm, the amount of change on the top arm and if we want to get really in to it the offset of the wheel.

    It all gets stupidly techo and without opening it up to peoples interpretations on things changing the length of the top arm alters the angle of the hub face in relation to the chassis. The diameter of the wheel wont alter the angle of the hub - unless you fit bigfoot tyres etc LOL!! IF you are running excessive offset then it adds another variable to things as the loading on the arm changes due to leverage etc etc etc.

    If you have added a roll centre adjustment kit then the rate of angle change in relation to change in length of the upper arm will change as the length of the j arm and knuckle assembly changes due to the longer ball joint.

    If a car is significantly lowered then the angle of the top arm reduces the effect adding length to it has on the camber IE: if a car is at standard height then it might take 2mm of extra length in the top arm to reduce camber by 1 degree. If the car is significantly lower it might take 2.5mm of top arm extension to make that same one degree adjustment. (figures pulled out of my arse and just an example and likely to be wildly wrong)

    EDIT: not trying to have a go or give anyone a lecture - just thought someone might be interested in an explanation :zlove:
     
  13. DinoZ

    DinoZ Talks sh#t for a living.

    You are correct that angle change is not related to wheel size (if overall tyre diameter stays the same), however the method I use to calculate the camber angle is by a measured distance off vertical based on the top and bottom of the rim. This is where the sine rule comes into play and also the diameter of the rim, so that is why in my previous post I mentioned that a change in rim size affects the calculation.

    Accept that the explanation could be confusing, but hopefully those reading this thread get the general idea. Thanks for your input.
     

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