940 brake judder

[Alan]

I wonder if anyone can help. My 1991 940 2.3 estate suffers from brake
judder when braking from speed. I have replaced the front discs and pads a
few months ago, but notice the problem is still there when braking from over
60MPH - before I replaced the discs the judder was noticeable at all speeds.
Any ideas? I assume the new discs are OK otherwise I would get judder at all
speeds as I did before.

Thanks in advance,

Alan.

[Closet Lib]

I did rotors, calipers and re-balanced the wheels. One of those fixed it!

"Alan" <al...@nospam.trisys.co.uk> wrote in message
news:e1oL8.54063$wd3.8...@news6-win.server.ntlworld.com...

[Byong Park]

I still had the problem after front pads rotors. After i did the pads on the
rear the juder disappeared...

Byong Park
"Closet Lib" <cl...@lib.comorg> wrote in message
news:ZPrL8.9064$E22.42...@newssvr16.news.prodigy.com...

[Alan]

Did you replace the calipers or recondition?

I will get the wheels re-balanced soon, they do need it.

Alan.

"Closet Lib" <cl...@lib.comorg> wrote in message
news:ZPrL8.9064$E22.42...@newssvr16.news.prodigy.com...

[Mike F]

Alan wrote:
>
> Did you replace the calipers or recondition?
>
> I will get the wheels re-balanced soon, they do need it.
>
> Alan.
>

Generally, shudder when braking that is felt mostly through the steering
wheel is caused by the front brakes, evenly throughout the car, the
rears.

--
Mike F.
Thornhill (near Toronto), Ont.

Change cant to ca and remove parentheses to email me directly.

[Alan]

The judder is felt through the steering wheel, not the car. As I've swapped
out the discs (rotors) and pads, I can't see what else would be causing it.
The slightly inbalanced wheels cause a slight steering wheel shake when
cruising, but it's really noticable when braking - not seen this before
caused by inbalanced wheels.

Alan.

"Mike F" <"mikef2316()"@attcanada.cant> wrote in message
news:3CFF51F0...@attcanada.cant...

[Larry Bumgardner]

Would suggest two things:

1. If judder was fixed when front discs were replaced, then the discs
have probably warped since you replaced them. If possible, it is good
to have them resurfaced when this happens rather than replace. The
heat does strange things to metal. After they have warped and have
been resurfaced, they are less likely to warp again. Severity of warp
and nature of warp would give different results at different speeds.
Take off tire and hold a screwdriver or other tool very close to the
rotor. Give it a spin and observe if the gap between the screwdriver
tip and the rotor surface stays constant as the rotor is spun.

2. Be very sure that the surface to which the rotor is bolted is CLEAR
of trash, etc. Taking perfectly honed rotors and bolting them to an
uneven surface is asking for trouble. Don't overtighten bolts that
hold the rotor in place. Use a torque wrench to be sure you are ok.

3. Verify that the front bearings do not have too much play in them.
There is an adjustment on the bearing spindle. Don't get it too
tight. Low probability that this has anything to do with it.

4. Check that tie rod ends have no play.

Good luck.

L Bumgardner
Durham, NC

"Alan" <al...@nospam.trisys.co.uk> wrote in message news:<e1oL8.54063$wd3.8...@news6-win.server.ntlworld.com>...

[Peter Milnes]

You should NEVER resurface (skim) rotors as the metal removed will make them
more prone to warping.

Cheers, Peter.

"Larry Bumgardner" <lar...@qvssoftware.com> wrote in message
news:10676a6.02060...@posting.google.com...
: Would suggest two things:

[Mike F]

Alan wrote:
>
> The judder is felt through the steering wheel, not the car. As I've swapped
> out the discs (rotors) and pads, I can't see what else would be causing it.
> The slightly inbalanced wheels cause a slight steering wheel shake when
> cruising, but it's really noticable when braking - not seen this before
> caused by inbalanced wheels.
>
> Alan.
>

Well then, the problem is coming from the front, again. Start by making
sure the hubs are clean and straight. Then make sure the inside of the
rotors, where they touch the hub is also clean. Then, if you can, put a
dial gauge on the braking surface and measure runout. Mount the rotor
in the position on the hub where runout is a minimum. Make sure that
the caliper piston and sliders are move freely. Then have a look at the
control arm bushings. Bad bushings can amplify an acceptable amount of
brake shake that good bushings will absorb. And your new rotors could
be warped, make sure you always torque the lug nuts with a torque
wrench.

[Vrparts]

Check strut rod bushings
Had
79 245 D,
81 240 D,
86 248 320,000mi and running when traded
Have
94 940 255,000 mi
94 940 126,000 mi