Serious Steering Wheel Vibrations- whoever can solve this gets $20

["Jason Hagen" <hagen_jason1@xxxxxxx>]

OK, since we are on the topic of steering wheel vibration and pulsing, 
perhaps someone can help me troubleshoot a related issue that I have had no 
success in solving.  15 years of mechanical experience (me) as well as a 
dealer have looked at this and no solution to date.  I have held back on 
asking via the digest because it is on one of my non-Alfa vehicles, but for 
the hardcore mechanical guys out there, perhaps you will respond for me 
anyway (I would appreciate it).  I suppose you could sub in the Alfa 164Q 
for this scenario to make it more interesting!

Here's the deal.  1988 BMW 735 with ABS.
-  Brakes worked great, no vibration at any speed off or on braking.  All 
pads were getting worn and needed replacement.
-  Replaced front and rear pads and bled through all new fluid (cheap skate 
method of a brake job)
-  The car then immediately exhibited significant wheel jerking at around 40 
to 45 MPH on light to moderate braking. Only at this speed.  Can occur 
braking from high speed coming down through the 45mph mark, etc.
-  Replaced front and rear rotors and front calipers to try to resolve.  
Problem did not go away.
-  Re-bled system with manual bleeder.  Problem still there!
-  I have had the tires balanced twice and have tried two sets of rims 
vibrations with both sets.
-  Then took apart all four calipers and cleans and lubed mounting/slide 
pins, etc.  Problem still there.
-  BMW shop checked for worn bushings and components- none!
-  Alignment was done very recently, but before initial brake job.

What could be going on?  I ONLY get vibration on braking and it can get very 
serious until I get out of the 40 to 45 MPH range.  Could I have a bad 
master cylinder that is only working well on one channel or the other and 
still have solid pedal feel?  What should I double check next?  Another 
alignment?

I hate going to a dealer so I really don't want to go back!

Thanks for listening.  Seriously, if someone can solve this, I will promptly 
send a check!  No laundry lists though please ;)

- Jason Hagen

'73 Alfa Spider
'95 164Q
'88 BMW 735i
'98 Land Rover Discovery



> From: "Giller,Bruce C." <bgiller@domain.elided>
> Reply-To: "Giller,Bruce C." <bgiller@domain.elided>
> To: alfa-digest <alfa-digest@domain.elided>
> Subject: RE: Steering Wheel Vibrations
> Date: Mon, 02 Jun 2003 09:18:29 -0400
>
> 	I need to get the front wheels of the Spider balanced on the car.  No
> amount of high tech off-car balancing have solved the problem.  And I've
> found a local shop that has one guy who has mastered this almost lost
> art.  My Spider rides glass-smooth on their balanced tires.
>
> 	Bruce
>
> 	'73 GTV
> 	'86 Spider
>
> > Yup, wheel balance is most likely the culprit.
> >
> > Usually starts somewhere between 50 and 60 MPH, and will go away at 
> higher
> > speeds. Why it behaves this way I don't know, but it does.
> >
> > One word of advice ... try to find a shop that has a wheel balancer
> > (dynamic, anything else is a waste of time and money) whose main 
> business is
> > not tires. Tire shops beat on their equuipment 10 hours a day six (or 
> more)
> > days a week, and seldom (if ever) calibrate the equipment.
> >
> > I've also seen guys at tire shops not check the balance. IOW, the wheel 
> is
> > mounted on the machine, old weights removed, spun, new weights added. 
> Some
> > guys will stop here and remove the wheel from the machine. The wheel 
> should
> > be spun a second time on the machine and should come up 000 indicating 
> that
> > it is balanced and requires no additional weight.
> >
> > High speed balancing is a misnomer ... once a wheel is balanced 
> (statically
> > or dynamically) it is balanced at all speeds.
> --
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