4kq, thrum at speed

[Robert Mangas]

  Hi Jan, thanks for the detailed response.

Replaced the following:  Dampers (Boge TG), springs (from 90Q), strut 
bearings, control arm bushings, rear diffmount bushings, brake lines, brake 
rotors, brake pads.  The why is because the car is old and was wallowy, had 
original brake lines and bushings, and no ride height left.  Also front ball 
joints and tie-rod ends.

Sound/vibe is speed related; can kind of feel it at lowlow speed but it 
starts to become obvious at 40mph.  Under load or coasting makes no 
difference.

Fresh tires are snows; Hakk 2's.

Did the thrum exist before.... that's a tough one.  I think so, but it's SO 
different now (go figure!) that it's hard to sort before after.

Stock rims.   I'll swap them around tomorrow; they're always at 85lb-ft.  
Once the car is up I'll also check the tranny and diff fluid (hate to miss 
something so obvious) and wiggle the propshaft.

   Thanks again for the input!

Robert

>From: Jpinkowish at aol.com
>To: porter_t_dog at hotmail.com
>Subject: Re: 4kq, thrum at speed
>Date: Wed, 16 Feb 2005 13:03:52 EST
>
>In a message dated 2/16/05 9:52:15 AM EST, porter_t_dog at hotmail.com writes:
>
> > I just redid the suspension on my 4kq, and now
> >  have a sort of shudder or thrum at speed.  Tires are fresh, so I don't
>think
> >  it's that.  Bearings are 75% brand new and 25% <20k, so I don't think 
>it's
> >  that.  It's either a CV joint issue  or the propshaft center support
> >  bearing.
>
>Hi Robert,
>A few more details on what you replaced, and why, would help.
>--Did you have noises or the thrum defore you rebuilt the suspension?
>--Also, does the thrum change with car speed or engine speed?
>--the "fresh tires" are summer or snow?
>
>I offer these suggestions for starters:
>--Just to eliminate the tires, switch the front ---> back.  Also, sometimes
>the tires do rotate on the wheels.  All it takes is one super hard
>brake-to-stop.
>--Just to eliminate the wheels, torque the bolts to 85 ft-lbs.  BTW, stock 
>or
>aftermarket wheels?  If aftermarket, like Borbet, etc., check that the 
>little
>hub inserts seat properly.
>--All the original wheel weights still attached?
>--You can get under the car and shake the driveshaft at the center bearing.
>The rubber should flex, but nothing else.  Another technique is to start
>rolling the car in 3rd gear and punch the gas.  What happens?
>
>Make sure you post to the list to get others involved.
>
>Jan
>'85 4ksq
>Bristol, CT