1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Grinding from the rear?

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Old 05-18-12, 09:29 AM
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Grinding from the rear?

I have my re-speed coil overs in the rear installed. I have the threaded collier all the way down for the highest ride height. There is about a 2” gap between the fender and the wheel. I don’t have the fronts done yet because I can’t break the some bolts free (taking it over to a buddies garage that’s going to do the fronts). The front is about .50-1” higher than the rear…

My question is this. I’m hearing a grinding noise in the rear. Sounds like a break rotor being re-surfaced. The sound starts around 25mph and does not go way. Until under the 25mph mark. Do you think this could have anything to do with the rear being lower than the front? I’m taking it over to a shop and having them look at my drum brakes… maybe it’s just a coincidence.
Old 05-18-12, 10:16 AM
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Grease your u joints on the driveshaft.
Old 05-18-12, 12:08 PM
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Could be any number of things. My first guess was brakes. U-Joints would be a vibration, increasing with road speed.
Old 05-18-12, 12:54 PM
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I had the same problem exactly, I greased the u joints, grinding went away.

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Old 05-18-12, 01:09 PM
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I'll give greasing the u joint a try... can’t hurt anything and is a quick fix. I did drop it off at a shop during my lunch hour for them to look at the breaks (Drums are just something I don’t want to mess with). No vibration at all... she is a smooth ride. I was also told to see if the ebrake cable is hitting the driveshaft.
Old 05-18-12, 02:18 PM
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Originally Posted by challer2000
I'll give greasing the u joint a try... can’t hurt anything and is a quick fix. I did drop it off at a shop during my lunch hour for them to look at the breaks (Drums are just something I don’t want to mess with). No vibration at all... she is a smooth ride. I was also told to see if the ebrake cable is hitting the driveshaft.
I have that same issue in my 85 track car and I have disc brakes in the back. I haven't greased the DS in a while either.
Old 05-18-12, 03:49 PM
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I’m getting the car back in about 30mins. I’m going to try greasing the DS and hopefully that’s it, because the mechanic couldn’t find anything wrong with it… and there guessing it may be a throw out bearing. But that don’t seem right to me. Does anyone think the difference in ride height (1" max) from the front to back could be it? Maybe stress on the DS???
Old 05-18-12, 04:47 PM
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Just got done greasing the u joints and the noise it's still there. Any other ideas?
Old 05-18-12, 05:26 PM
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Ok get this.... I jacked up the rear as per Sam's suggestion and get it up to speed.... No noise. I decided to put those stock rubber upper mounts in with the coil overs. The ride is now only.25" off, no noise during test drive. Could that.75" difference in the front put that much stress in the rear? Well noise is gone thanks guys for all the help.
Old 05-23-12, 07:00 AM
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Pinion angle at the differential? I know this is very important when installing a Trilink/Panhard setup. Or, how about driveshaft rubbing on the tunnel?

Also, when you installed the perches, you had the spring on the bottom and the adjustable perch on the top, right?



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