Quote:
Originally Posted by edwinn
Thanks for replying to the paint restore post. Funny I didn't realize the hood was aluminum. Thinking of it more.. the hood could have been removed by sinking three hook-eyes into the garage ceiling and coming down with some rope/pullies to form a cradle, etc.
Good to get some feedback on the rotors. After the four wheels were pulled (see other topic) I noticed a LOT of rust on the rotors that were going on the front.. IIRC and I scotch-guarded and applied some flat black spray paint to keep the rust down. THEN.. when test driving on I-90 it started shaking a little at 65 MPH and definitely shaking at 70+ MPH. I attributed this to one of my wheels needing a bit MORE weight correction to balance.. which should be on the right rear.
So there are TWO issues.. 1st is the imbalance at 70 MPH after road force balancing, painting two rotor faces and rotating all four wheels. 2nd is fact that I spray-painted the faces of the NEW rear rotors that haven't been installed yet. The coat is very light!! however I remember having an issue with vibration before, and moved the front wheels to the rear. That fixed it.
Need to be able to cruise at 80 MPH like last year driving across the USA. The speed limit in Nevada is 75 so cruise control was set at 79 or 80 MPH for hours. There was no shaking or vibration for 3000 miles. 
Please advise..
-Ed |
...remember that advice is usually worth what you pay for it...
that said:
- check wheels with dial gauge for roundness and flatness (runout and warp)
- maybe you have a tire belt slipped, a good tire guy can tell you. How this happens: supposedly tires are cured enough to roll when sold but cure some more in service, and if something is amiss a belt can move before they are 100% cured. I used to think the "slipped belt" was BS... then a tire guy showed me you can tell by measuring for out-of-round/skew on a properly installed and inflated tire. I still don't really believe it but Who Knew?
- you need to think twice about painting the insides of the rotor hats. The outsides don't matter all that much, paint away, but on the inside - let's just say that a properly set up brake system has such tight tolerances that if the rotor hat is cocked to the degree of a sheet or 2 of paper at the hub you'll feel it in driving. But instead of guessing, just measure - use a dial gauge. Take off the wheel, bolt the rotor hat down to torque spec (100#) and then set up the caliper and measure the runout. See, if the paint is absolutely even it does not matter. If the paint film is not uniformly evenly thick, it matters. And you'll be able to meaure it with the dial gauge. Your goal is no runout.
- if you only have a wee bit of runout you can usually deal with it by repositioning the wheel on the hub. That is, you take the wheel off, turn it 72 degrees (one position of the 5 possible) with respect to the hub held stationary, then reassemble. Remeasure runout... when you find the minimum runout position mark the wheel and hub (the stud) with a sharpie marker or some such. A number or some such on the stud end and corresponding by the hole on the wheel nearest that stud, at minimum runout, should work. If you move that wheel/tire to a different position just re-index and re-mark.