C900 front calliper clonk

Al wrote:

The clonk is the pads shifting inside the caliper body.  It is not a
functional or safety problem.  It is not worth worrying about.  Next set
of pads you get will probably have less slop in that dimension.  If it
really bothers you, you could fabricate some shims that you could fit
over the ends of the pad carriers.

--
-Fred W

Al wrote:

That's ok, it brings good luck.



The caliper is a sliding yoke design. The clunk is the outer bit (the
yoke) pivoting and coming to rest.

£100 won't fix it, and it isn't worth fixing anyway.



There really is no fix. You can build up the yoke with a welder, and
grind back to get a tight fit. But the clunk will be back within a
couple of thousand miles.

Learn to love it.


--
Grunff

Grunff wrote:

add a fix to your list ... a piece of copper bend correctly and fitted
between caliper and yoke.  It does for a random narrowing of the gap and
somewhat reduced the noise.  Once the OP knows what it is he will not
worry that much about it :-)

Charles

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The special Gleitmo grease that's recommended for use with the brake
calipers on C900's is probably meant to prevent much of the clonking - but I
have never found it for sale here in Australia. If there is meant to be a
special grease just for use on sliding yokes, I'd be interested to know what
brand(s) are available here and what the products themselves are called.

Craig.
--
Craig's Saab C900 Page at      | Craig's Classic Saab Workshop - Sydney .au
http://lios.apana.org.au/~c900 | http://www.classicsaab.net and other URL's
Email: c900@lios.apana.org.au  | For Saab 99/C900/9000 Enthusiasts World-Wide!
Alternate: saabonaut@gmail.com | Web-forums, galleries, library, links, etc.

If you take off one of the front wheels and look at the caliper, you'll see
that there is a u-clamp holding a strangely-shaped spring against the
backing plate of each of the brake pads and there is also a wire 'butterfly'
spring as well. I've got a pic at this URL:

http://www.classicsaab.net/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=598

which, if you look past all the cobwebs (!), shows the u-clamp, and the main
spring. The 'butterfly' spring isn't really clear but it's there too.

Those components are designed to prevent or at least reduce that 'clonk'
that you get. The kits to replace those components are low in price from
places like Parts for Saabs, etc. and it's a very cheap way to help overcome
the clonking. I've heard those parts called 'anti-rattle' components as
well.

I've been told, but have not really proven, that if you replace the brake
pads with new ones the clonking isn't as bad, but that's probably more
related to overall wear of the brake caliper components and how well
lubricated the sliding yoke of the caliper is.

Regards,

Craig.
--
Craig's Saab C900 Page at      | Craig's Classic Saab Workshop - Sydney .au
http://lios.apana.org.au/~c900 | http://www.classicsaab.net and other URL's
Email: c900@lios.apana.org.au  | For Saab 99/C900/9000 Enthusiasts World-Wide!
Alternate: saabonaut@gmail.com | Web-forums, galleries, library, links, etc.

Thanks for the re-assurance guys.  I'm going to do my brake pads in
June/July anyway as they wear out real fast.  The front handbrake mech means
they're real thin to start with unfortunately.

Cheers

Al

Craig's Saab C900 Site wrote:

http://www.classicsaab.net/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=598

The spring you ought to refer to ... is what in your photo is on the
extreme right of the caliper and is shaped like a U.  That fits (if I
remember correctly)  between yoke and caliper and stops the lateral
movement.  The clonk is mainly produced by vertical movement and the
only correct way of reducing it is to rebuilt the missing metal.


I've heard those parts called 'anti-rattle' components as

A bit of both ... new pads might help, fitting new pads means
lubricating everything etc.



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Not only the 900, my 96 has it too.
Not much to worry about.

--
MH
'72 97 '77 96 '78 95 '79 96
'91 900i