Trying to solve a vibration problem that has recently developed in my daughters car.

More noticeable under moderate to hard braking, I get a shuddering in the front and in the body maybe at the rear.

I replaced the right front caliper with a rebuild as it seemed to be sticking, I have checked the other 3 calipers for brake release and none seemed to have a problem. Front and rear pads were replaced about 4 months ago.

I replaced front rotors even though they looked fine and there was no improvement with new Bosch rotors. I have not replaced rear rotors but I do have a set on hand. But not sure if that will help any?

Can the drive shaft cause this kind of shudder from a soft center bearing support?

Thanks
Dan

While we never had a shudder in any of our 4 740s except when front rotors were thin, this shudder was in the pedal.

Unless you have checked them already, check the tie rod ends, in over 300K miles in these 4 cars, the only suspension parts that were replaced were tie rod ends - perhaps 4 sets.

I once read that about 70 percent of vibrations start with the wheels - perhaps you should have their balance checked. A wheel weight may have fallen off - look for this?

Replace rubber brake line if new caliper is sticking. Also check your transmission rear tail mount.

Replace rubber brake line if new caliper is sticking. Also check your transmission rear tail mount.

Is there any brake pedal vibration when you brake hard?
And is there any shudder of the steering wheel when you do that?

No, the vibration does not seem to be in the pedal, more so in the steering wheel but that may be coming from the body.

No vibration in reverse.

I just drove it again and I do seem to be felling a slight shudder on decelerating from about 45 mph and then again by forcing a downshift when manually shifting from drive to second gear. And then again from second to first gear. I may have a problem with the rear u joint after all.

Thanks
Dan

Rear U Joint was the problem probably 90% froze up, but not anymore!
Thanks
Dan

how did you diagnose the bad u-joint?
did you lube or replace it?

You have to remove the drive shaft in order to flex the joint. The rear u joint seems to be more prone to failure than the others.
Dan

Hi Dan,

Did you need to replace the rear u-joint?

Bill

^^
In my limited experience, it has always been the final u-joint at the differential. I'm guilty of suggesting these be lubed for maintenance, and then never actually doing it myself.




--
Art Benstein near Baltimore

Two cows are standing next to each other in a field. Daisy says to Dolly, "I was artificially inseminated this morning." "I don't believe you," says Dolly. "It's true, no bull!" exclaims Daisy.

Hi,

I don't know about the center bearing, it's possible, but it definitely could be a bad u joint. I had what I believed to be a sticking caliper, but it turned out to be the semi seized center and rear u-joints weren't noticeable until I applied the brakes. It took me a while to figure it out.

Peter

I replaced the center support and bearing 4 years ago and the u joints were fine at the time.

I did have a rear frozen u joint in my car, those symptoms were a vibration while decelerating from about 45 mph but I don't think braking was involved.

I may look at the drive shaft and u joints as nothing related to brakes or front suspension seem to be causing this.

Thanks
Dan

Had a similar problem years ago in my 90 240. If you haven't already, check the ball joints. That was my issue. Look at the control arm bushings too.
--
Will I buy another Volvo??? We'll see....

Thanks for the reply, I just checked both sides and there is no play in the bushings or ball joints. Control arm bushings were replaced a while back with poly.
Dan