1990 740 Turbo Wagon 156k
----------

As the subject line of this post says, my steering wheel shakes under braking.

I recently replaced the lower control arm/strut rod bearings which made a HUGE difference (thewy were completly shot), but it still shiimys, though now only at highway speeds.

I do not feel vibration at the brake pedal, so I'm figuring that my rotors are okay.

I'll be taking the family on vacation this summer, and want the car to be safe and shake-free.

Any thoughts?

jddaigle is correct. My brakes were warped and didn't give a pulse at the pedal, either. I have an 86 740 GLE with Bendix "one piece" rotors (hub and rotor assembly - OEM equipment). After replacing all front bushings and making sure the calipers were not the culprit, I made the mistake of having new aftermarket replacements for the OEM style installed. After 2 months, I had the same exact problem as before. AKA the rotors warped again. I HAD TO GO TO THE DEALER to fix the problem. If you search the brickboard archives you will find that there was an engineering design problem with the hub and rotor one peice design. So, Volvo designed a conversion kit to "convert" the one peice design to a two piece design. The car is braking just fine and it has been 2 months.

fyi, the fix wasn't produced until after the 1992 model year. Any car older than that has a good chance the conversion was never done by any of the previous owners.

I'll make this short: Bent rim, rusted hubs (where rotor meets the hub). My Vo was shaking fairly bad when braking. My mechanic pulled the rotors to send them to be turned and he found that the hubs were fairly rusty. He cleaned them up, and remounted the rotors (we moved a slightly bent rim to the back as well). It has little shake when braking now. It's not nearly as bad.......
--
Chris. Halifax N.S. '91 745Ti, 273K km.

Hey Chris,

This is interesting. When I replceced the strut bushingsa a few weeks ago, I was unable to remove the right front wheel, and at the time, I imagined that the hub might be rusty.

I'll definitely try to remove the wheel, and then wire brush the hub.

Is it okay or insane, to consider applting anti-sieze or something similar to the hub to prevent this from happenning again? Obviously I don't want any lubricant to leak onto the disc surface.

Finally, though I will certainly give the wire brushing a try, why would a rusty hub cause the front end to shake?

Thanks for the help.

I have a '92 940T. Do I understand correctly that if the rotors were warped there would be a pulsing from the brake peddle? Like m rad, I dont' have that. So I too was leaning towards bushings/steering problems. I guess the question is should I have to rotors checked?

Thanks
Sam

Bent rotors don't necessarily cause a pulsing pedal. I had an '87 745 with wickedly warped front rotors, and the steering wheel shook like it was going to come off when I braked from 70mph, but the brake pedal didn't vibrate much at all. With lesser levels of warping the vibration might not be felt through the pedal.

jeff daigle
'89 745GL 142,000mi

Any time I had steering wheel vibration while braking I checked the brake caliper pins. If these pins get stuck then some vibration may occur. Does the car pull to one side or the other under braking? Another thought would lead me to the tie rod end joints. If these balljoints wear you can get vibration without the vehicle wandering or pulling. Just some esay fix problems, check them before tearing into wheels and steering systems. Good Luck.
RM

Well I would get the wheels electronically balanced. Also you dont mention anything but I supose you have the stock wheels that came with your car. Original Volvo wheels are kind of soft so check for a bent or warped wheel. Hope this helps!

Thanks chaman.

Tires, I might have thought of (though my brain is feeling dense tonight), but the wheels themselves, I would never have considered. I'm hoping they are okay, as they are the rather expensive looking wheels that came with the Intercooled Turbo model in 1990.

Will the tire guys notice a bad wheel when they balance the tires?

Thanks,
m rad.

A bent wheel will be immediately obvious when they go to balance the tires. Ask them to look for that though, so the guy is aware that it's a possibility. If these are trhe 16-inch "Hydra" wheels, they are unlikely to have survived this long without SOME minor bend somewhere along the way. If it's not too bad and doesn't make the tire out-of-round, have them balanced and try it out. If there's one bent a little, have it mounted to the rear and start looking for a spare.
I just replaced a severely out-of-round tire on my wife's 740... a 14" tire but somehow became almost D-shaped. We suspect a radial belt shifted or came apart internally. Gave a low-speed "wobble" in the wheel, and something of a high-speed vibration. Actually got better up to about 60 mph and then worse.

HOwever, your problem is also just as likely to be bad brake rotors, and I think you may find that they are badly warped. Happens to a lot of 740s, especially when they have bad cone (control arm) bushings. Since you've fixed one thing, now fix the other.
Good luck!
--
Rob Bareiss, New London CT ::: "Roterande Fläkt Och Drivremmar!"