XJ11 brake shim & caliper curiosity redux

[KA1J]

More curiosities...

I'm trying to understand if this is the way the brakes are supposed to be or if parts are missing.

The front R. brake only had one pad shim and it's a diagonal shim .015 thick which only covers 1/2 of the piston. The left pads had no shim of any kind.

Here's the one existing pad shim and pad next to it (you can see the residue left where the caliper was resting):


Here is the shim on the pad. Notice how the piston had been pushing on the pad itself as well as the shim:


And here is the passive pad on the inside of the caliper which contacts the caliper itself:


Question 1: The shim seems to be only 1/2 of what should be there. Is part missing?

Question 2: If I were to put stainless shim material (as used on car disc brake pads) which attaches via an adhesive on one side, onto the entire caliper, would that be a good choice?

On the Left caliper, there was a very thin rectangular shim plate which was recessed inside the thick stainless plate on the top section. The shim was .005 thick. On the right caliper there was no thin shim.

Question 3: Is this shim used for leveling or for heat/noise issues? I'm not sure if I should try and form a replacement or not.

[petejw]

hi KA1J,

those shims are only used to help prevent
brake squeal,
the shims u have pictured looked to
be home made, no problems with that, ive made my own
using an old soda can.
u can run the shims or not.

heres a pic of a new set of pads that come with the
shims attached.

[Ken Talbot]

Tsunami has a mix of full back shims and the half shims. Somewhere deep in distant memory, I seem to remember something about the half shim helping to just slightly cant the pad as it is coming into contact with the rotor.

[CatatonicBug]

I have the half shims on my MNS, since it uses the same brakes as the XJ. That's the way they came to me, and they are definitely not home-made shims.

[SFerinTEXAS]

Look in the service manual. Those shims and the correct position are clearly described.

[SFerinTEXAS]

Look in the service manual. Those shims and the correct position are clearly described. Tho I doubt they are critical.

[KA1J]

Thank you all for the replies. It seems there's both full shim, "Factory installed 1/2 shims" and no shims being used. Since there's such a hodgepodge of possibilities I just installed the factory shim on the right front caliper in what according to a diagram looks right (with the two clips at the top and the one clip at the bottom). The way it was done, the one clip was at the top & the two at the bottom as in the photos above. I'm going to try the adhesive sided shim on the left side piston/pad.

There was no pad on the rear nor does the diagram show one. Think I'll try a piece of that adhesive stainless laminated shim on the rear pad & see how that goes, can't hurt and it's easy to remove.

Thanks again!

[petejw]

hey KA1J,

if ur going to use the half shims, as ken said,
itll slightly tilt the pad into the rotor, in affect
acting as a leading/trailing pad,
when u install them have the half shim facing forward
on each pad. (hope that makes sense.)