Post by centennialman on Jul 7, 2009 12:20:47 GMT -6
I picked up a pair of reman STS calipers from Centric some time ago on eBay for a pretty good price. It was suggested that they should fit on my 2001. They do, but:
1) Don't do it unless you have nothing better to do. The result is worthwhile, but it was a PITA.
2) About the PITA: There were a few components to this item:
a) The caliper bracket uses a smaller bolt for the STS. I didn't bother to figure out what it was, because it didn't seem wise to use one, given the larger diameter hole in the knuckle, and I didn't want to try to construct a sleeve. Instead, I drilled and tapped the bracket for a M14 2.0 screw, which is what the stock calipers used. Drilling cast iron is easy if you first dull the drill bit slightly, otherwise the bit will grab with potentially nasty consequences. Don't use any lubricant either. Drilling this stuff dry is preferred.
Drilling and taping pics:
b) The STS calipers mount in the trailing position. Ours mount leading. (see pick below). You have two choices. Mount left caliper on the left side, and drill and tap a hole for a new bleed valve on what is now the top of the caliper. If you want further info on this, write me, because you really have to want to do this and you really need to know what you are doing. No offense meant. You need to provide for a bleed screw on the top, because the one on the caliper is at the bottom, and that doesn't work out very well (trust me!). The second choice is to mount the calipers on the reverse sides. Then the bleed screws end up on top, the flex hose on the bottom. I didn't pursue this after I determined that the existing flex hose was probably going to be too short and figuring out how to hang it properly was too difficult. FYI, Centric's pic of a caliper follows next;
c) As you can see from the comparison pic below, the hose banjo bolts to the side of the OEM calipers, but to the top (bottom) of the STS calipers.
Because of the different mounting hose mounting position, if you use the existing hose hangers, then the hose doesn't really hang all that well. It puts too much of a bend at the top. So, you will need to modify the hanger by first manufacturing a 'stand-off' out of 3/4" round stock. A 1" length is good. Drill a hole through the centre of the standoff to accommodate an 8mm bolt. A 21/64 drill should work. I used an M8 1.25 by 40mm bolt to fasten the hanger back on. Then, you need about 1" of 1/4" bar stock to provide a key between the ear at the mounting point (to prevent the hanger from rotating). See pic below - I should have taken it before I crimped it back onto the hose. And, clearly, you need to remove the hanger from the hose. Use a vice and bend the curl until the hose can be removed. I suggest that you assemble the hanger, spool, and find the proper position so that the hose hangs nicely. Tighten the bolt. Insert the 'key'. Tack weld the spool and key. Remove the hanger and complete the weld. Don't try to weld it up on the car! There is an extra 'hook' on the hanger that looks like it might hold something else, but not on my model. It looked like might pinch the hose at max upward travel, so I cut it off, and smoothed the cut. Here is a few picks of what the hangers look like when they have been modified.
Notice that I did safety wire the hanger bolt. I also safety wired the caliper bracket bolts. You can drill holes in Grade 8 bolts if you use a cobalt drill bit.
Here are some more picks, if they can be of use:
You can just see where the new bleed screw is located in this pick. The castings are symmetrical, meaning that there is a 'natural' location for the screw both top and bottom.
Does it stop better than before? You bet! Am I going to do the rears next? You bet, except that I'm not going for the GXP upgrade. I do have a set of drilled rotors, and reman calipers, though. I'll write that one up after it happens.
BTW, I also took the opportunity to remove as much rust as possible, and clean and paint everything.
1) Don't do it unless you have nothing better to do. The result is worthwhile, but it was a PITA.
2) About the PITA: There were a few components to this item:
a) The caliper bracket uses a smaller bolt for the STS. I didn't bother to figure out what it was, because it didn't seem wise to use one, given the larger diameter hole in the knuckle, and I didn't want to try to construct a sleeve. Instead, I drilled and tapped the bracket for a M14 2.0 screw, which is what the stock calipers used. Drilling cast iron is easy if you first dull the drill bit slightly, otherwise the bit will grab with potentially nasty consequences. Don't use any lubricant either. Drilling this stuff dry is preferred.
Drilling and taping pics:
b) The STS calipers mount in the trailing position. Ours mount leading. (see pick below). You have two choices. Mount left caliper on the left side, and drill and tap a hole for a new bleed valve on what is now the top of the caliper. If you want further info on this, write me, because you really have to want to do this and you really need to know what you are doing. No offense meant. You need to provide for a bleed screw on the top, because the one on the caliper is at the bottom, and that doesn't work out very well (trust me!). The second choice is to mount the calipers on the reverse sides. Then the bleed screws end up on top, the flex hose on the bottom. I didn't pursue this after I determined that the existing flex hose was probably going to be too short and figuring out how to hang it properly was too difficult. FYI, Centric's pic of a caliper follows next;
c) As you can see from the comparison pic below, the hose banjo bolts to the side of the OEM calipers, but to the top (bottom) of the STS calipers.
Because of the different mounting hose mounting position, if you use the existing hose hangers, then the hose doesn't really hang all that well. It puts too much of a bend at the top. So, you will need to modify the hanger by first manufacturing a 'stand-off' out of 3/4" round stock. A 1" length is good. Drill a hole through the centre of the standoff to accommodate an 8mm bolt. A 21/64 drill should work. I used an M8 1.25 by 40mm bolt to fasten the hanger back on. Then, you need about 1" of 1/4" bar stock to provide a key between the ear at the mounting point (to prevent the hanger from rotating). See pic below - I should have taken it before I crimped it back onto the hose. And, clearly, you need to remove the hanger from the hose. Use a vice and bend the curl until the hose can be removed. I suggest that you assemble the hanger, spool, and find the proper position so that the hose hangs nicely. Tighten the bolt. Insert the 'key'. Tack weld the spool and key. Remove the hanger and complete the weld. Don't try to weld it up on the car! There is an extra 'hook' on the hanger that looks like it might hold something else, but not on my model. It looked like might pinch the hose at max upward travel, so I cut it off, and smoothed the cut. Here is a few picks of what the hangers look like when they have been modified.
Notice that I did safety wire the hanger bolt. I also safety wired the caliper bracket bolts. You can drill holes in Grade 8 bolts if you use a cobalt drill bit.
Here are some more picks, if they can be of use:
You can just see where the new bleed screw is located in this pick. The castings are symmetrical, meaning that there is a 'natural' location for the screw both top and bottom.
Does it stop better than before? You bet! Am I going to do the rears next? You bet, except that I'm not going for the GXP upgrade. I do have a set of drilled rotors, and reman calipers, though. I'll write that one up after it happens.
BTW, I also took the opportunity to remove as much rust as possible, and clean and paint everything.