Caliper to Caliper Bracket Clearance

Wbulk · #1 (**permalink**) 12-06-2012, 08:06 AM

I am fixing some poorly designed caliper brackets for some GM metric calipers where the pads were hanging over the edge of the rotors. In the process that changes the clearance between the bracket and the caliper. See picture.
The picture is just for representation. The actual brackets are on the rear axle and are welded on. My intention is to add weld to that area and grind it to get the clearance correct.
On a long shot would anyone know what that clearance is supposed to be.

Wbulk · #2 (**permalink**) 12-09-2012, 01:35 PM

I found it in an S-10 service manual. It is supposed to be .005-.012. A lot of after market brackets are way off.

Wbulk · #3 (**permalink**) 12-09-2012, 02:46 PM

After looking at these closely the braking weight of the vehicle is supposed to be taken by the bracket rather than the caliper slide bolt. When the clearance exceeds the .012 the rubber bushings are compressed to the max and all the weight is then transfered directly to the bolt. In actuality the bolt is supposed to only keep the calipers centered and supply a guide for the calipers as the pads wear.

Before I fixed my rear welded on brackets the clearance was 3/16" and larger. Clearly mine were made way wrong.

Wbulk · #4 (**permalink**) 12-10-2012, 08:33 AM

This picture shows the excessive clearance between the caliper bracket and the caliper. Because the caliper bracket far exceeds the required clearance of .005-.012 to the caliper, the braking force is transferred to the guide bolds instead of to the bracket.

Wbulk · #5 (**permalink**) 12-15-2012, 03:48 PM

I finished fixing all four brackets on my B&B and I thought I might as well post how I did it in case someone else wants to fix theirs. I have seen pictures of others rear brackets that have the same to much clearance issue.
The key to doing this was to make a steel pattern. I measured with a 6" digital caliper the total thicknes on the caliper where the brackets sets. I then took some 1/8" steel strap and C clamped it against the caliper bracket mounting bolt holes and maked the holes with a transfer punch. I then found the center between the marked punch marks and layed out the caliper mounting points and squared them with the mounting holes. I then cut the area where the caliper would slid in a little smaller and then slowly ground it down until it would just fit over the caliper. I also drilled the holes that were marked for the guide bolt pins. The end result is you need the pattern to be able to just fit over the caliper with the pins going through the pattern and the caliper guide holes. Accuracy counts !
I built up the bracket ears with weld and ground down the sides flush. I then put two thicknesses of masking tape on each of the ears of the pattern and bolted it to the brackets. I then cut the weld with a thin cutting blade on a 4 1/4" grinder using the pattern as a guide. When I had just cut the masking tape I knew I was close. I then removed the pattern and tried to fit the caliper in the bracket. At this point I would just take a few light passes with the flat of the cutting blade disc and try the caliper by bolting it up and checking the clearnce with a feeler gauge until I got it within the .005-.012 clearance specified. I must say this was time consuming and took patience. I also found that the front S-10 calipers were not exactly the same thickness as the rear Cadillac calipers.

I hope this helps anyone else that wants to do this.