Does anyone know which way the Front Brake caliper seal orientates,,, they are a a tapered square seal,, ( large seal deepest in caliper,, Not the most exterior small dust seal ,,,

[Bill Cats]

After cleaning everything up i see that when you install the large lower square ( actually trapezoid shaped ) seal back in the caliper with the smaller tapered side facing the brake pad a small ridge sticks out of the caliper,,

BUT

when you install with the smaller and tapered side of the seal facing the internals of the caliper the entire seal seems to fit flush with no ridge / edge sticking up  ,,, hhhhhmmm,,

I have not one but 2 manuals and neither mention the correct orientation,,,,

Thanks 

[dirtrider]

18 minutes ago, Bill Cats said:

After cleaning everything up i see that when you install the large lower square ( actually trapezoid shaped ) seal back in the caliper with the smaller tapered side facing the brake pad a small ridge sticks out of the caliper,,

BUT

when you install with the smaller and tapered side of the seal facing the internals of the caliper the entire seal seems to fit flush with no ridge / edge sticking up  ,,, hhhhhmmm,,

I have not one but 2 manuals and neither mention the correct orientation,,,,

Thanks 

Afternoon Bill 

 

What are you working on?????

 

I don't understand the ridge sticking out of the caliper, that seal should be down inside the bore with piston correctly installed.

 

The manual probably doesn't mention it as most BMW caliper piston inner sealing rings are square with no taper. 

 

What seal kit are you installing? Possibly they have instructions on their web site (or a call to the company).

 

On angle cut seals they not only seal pressure but the direction of the taper controls how much piston retraction at pressure release. 

[Lowndes]

Bill,

 

Are you working on that nice '94 RSL??   

 

I'm no authority on anything but I have some pics of when I disassembled my front Brembo calipers ('99 R1100S) a few years back.  They may be similar, Dirtrider would know. 

 

I purposefully did NOT remove the square O-rings so that I wouldn't get them turned around.  You can plainly see a difference between the inner and outer O-ring:  The Outer ring has a groove in the face of it, the inner looks to be tapered (tapering "into" the cylinder hole), or the tightest - smallest ID edge deepest in the cyl.

 

 

Hope this helps.  More pics here: https://photos.app.goo.gl/kN8PyDxEirl9iVS02

[Bill Cats]

Hey folks,,,

 

So im working on the front brakes of a 1994  R1100RSL,

 

I smacked myself in the head and VERY carefully disassembled the OTHER side ....lol ( i know ) 

 

on the other side you will see IF you look Super carefully that the seals are not square, 

In fact their are shaped as a trapezoid ,,,,

So the smaller side faces INTO the caliper and then the seals sit flush,,, 

IF you assemble with the smaller edge facing OUTWARD a ridge pops out of the grove,,,, and that's not a good thing,,, 

Thanks again..

 

[dirtrider]

3 hours ago, Bill Cats said:

Hey folks,,,

 

So im working on the front brakes of a 1994  R1100RSL,

 

I smacked myself in the head and VERY carefully disassembled the OTHER side ....lol ( i know ) 

 

on the other side you will see IF you look Super carefully that the seals are not square, 

In fact their are shaped as a trapezoid ,,,,

So the smaller side faces INTO the caliper and then the seals sit flush,,, 

IF you assemble with the smaller edge facing OUTWARD a ridge pops out of the grove,,,, and that's not a good thing,,, 

Thanks again..

 

Afternoon Bill

 

Interesting, are these the original seals that were removed or replacements? 

 

[bmwnomad]

Something like this? 
 

[Jim Moore]

This guy had made a few videos of brake rebuilds. It's been awhile, but I remember him mentioning something about seal orientation.