Crankshaft thrust bearing preloading 86 1/2 model.
04-07-2002, 12:24 PM
#1
Three Wheelin'
Thread Starter
Crankshaft thrust bearing preloading 86 1/2 model.
Hello all,
When I had the foward exhaust off for a O2 sensor replacement, I went ahead and did the procedure for checking crankshaft end play and pinch collar slippage. I'm unclear if an 86.5 is subect to the thrust bearing failure syndrome, but I wanted to see what was going on in there especially since the car was suffering from bone-jarring hard shifts when I bought it which would have put aditional pressure shock to the flex plate area.
Here is what I found. At first glance, I saw a sticker on the TT shaft splines which had been peeled back somewhat from the original install to the flex plate hub. A good reference point since it was obvious that there was a major gap between the folded sticker and the flex plate hub, demonstrating that the pinch collar had allowed the hub to migrate.
I measured the flywheel position as related to the housing. I released the pinch collar bolt, and the hub popped back to the sticker, the flex plate was now relaxed and unloaded. I measured the flywheel position and it was the same (good news!). I then measured crank end float. .007 (not bad for 117k miles).
The flex plate had apparently been doing it's job of absorbing the preload from the TT, with no adverse effect to the thrust bearing. The flex plate was in good condition. I did the locktite fix, torqued to 66 ft/lbs and buttoned it up.
Even if 86.5 cars are not prone to this failure, I think that relieving the preload on the flex plate was a good idea. It will be easy to check for hub migration through the inspection hole because of the sticker on the splines.
Making my way through the list of things to check and repair, I'm getting there.
Greg
When I had the foward exhaust off for a O2 sensor replacement, I went ahead and did the procedure for checking crankshaft end play and pinch collar slippage. I'm unclear if an 86.5 is subect to the thrust bearing failure syndrome, but I wanted to see what was going on in there especially since the car was suffering from bone-jarring hard shifts when I bought it which would have put aditional pressure shock to the flex plate area.
Here is what I found. At first glance, I saw a sticker on the TT shaft splines which had been peeled back somewhat from the original install to the flex plate hub. A good reference point since it was obvious that there was a major gap between the folded sticker and the flex plate hub, demonstrating that the pinch collar had allowed the hub to migrate.
I measured the flywheel position as related to the housing. I released the pinch collar bolt, and the hub popped back to the sticker, the flex plate was now relaxed and unloaded. I measured the flywheel position and it was the same (good news!). I then measured crank end float. .007 (not bad for 117k miles).
The flex plate had apparently been doing it's job of absorbing the preload from the TT, with no adverse effect to the thrust bearing. The flex plate was in good condition. I did the locktite fix, torqued to 66 ft/lbs and buttoned it up.
Even if 86.5 cars are not prone to this failure, I think that relieving the preload on the flex plate was a good idea. It will be easy to check for hub migration through the inspection hole because of the sticker on the splines.
Making my way through the list of things to check and repair, I'm getting there.
Greg
