I just replaced my front rotors on my 93 and rebuilt my original calipers. I sourced new oem pads from wits end. Now when it's all reassembled, my calipers are so off center that the inner pads on either side will not go in. The outer pads have about .050" clearance. I did not replace the bearings in the hub as they are new, i just packed fresh grease in them. I'm using new brembo rotors that have all the correct oem dimensions (I checked). Can anyone tell me if they've seen this before and what's the fix? Thanks!
Off center calipers?
- Thread starter KG7STN
- Start date
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Sorry, I didn’t realize how awesome you were. Carry on
Do you still have the original rotors?
If so you could mount one and see how it lines up. If it's correct your new rotors are the problem.
If so you could mount one and see how it lines up. If it's correct your new rotors are the problem.
I agree with Cruiserdan in testing the old rotor.
The other thing I see in the top pic above is that machined section on the inside of the rotor outer edge - the way it looks makes me think the actual rotor face where the pads run is off entirely. What brand rotors are they as I have never seen that type of machining before on a rotor,
I also just checked my original rotors that I replaced with Bosch ones last year & they do not have that machining
The other thing I see in the top pic above is that machined section on the inside of the rotor outer edge - the way it looks makes me think the actual rotor face where the pads run is off entirely. What brand rotors are they as I have never seen that type of machining before on a rotor,
I also just checked my original rotors that I replaced with Bosch ones last year & they do not have that machining
- Thread starter
- #48
Yeah these are Brembo rotors which have good ratings. The material you see which has been removed is for ultra- precise balancing of the rotor itself. Both have slightly different cuts like that. The faces where the pads run is what I'm measuring in the photos. The deflection or "wobble" is very tiny. 0.002" on the right and 0.0015" on the left. I'll measure runout today before slapping the old powerstop rotors back on. Thanks!
- Thread starter
- #49
Here's my rig as it sits today. I've had to make three new hard brake lines as the old fittings were flared out to the point of splitting on the edge. Sometimes you can get away with the dremel trick, other times not.
Looks like the back lip of that spindle has had a bearing spinning against it for a bit. The pic is kinda blurry on that part, so I'm not 100% sure, but that could be the source of your difficulty because that would push the spindle and hub inboard by that amount.
- Thread starter
- #52
Seems like I'm posting to myself here but anyway I'll keep going.
With the old powerstop rotors it's a little worse. The rotor sits a little closer to the engine side caliper housing.
With the old powerstop rotors it's a little worse. The rotor sits a little closer to the engine side caliper housing.
Here's a better picture.
What I'm looking at is the face of the spindle, where the curved area meets the back.
The inner race of the inner bearing is supposed to be pressed against that surface and it looks like at some point in its life it has been grinding on that surface, wearing it away. I say this because there is a ledge partway up from the curved part. That should be a perfectly radiused corner and no lip. I'm not talking about the sealing surface where the hub seal is riding on the OD of the spindle. I'm talking about the part of the spindle towards the drive flange. This is hard to describe.
This will make the hub ride inboard farther than it should by about .050"
It's also obvious that the outer bearing has spun on the spindle a lot, as it is very shiny there.
This is one spindle only. More importantly, is the fitment offset the same on both sides of the vehicle?
Why?
If the engineers thought those weren't important they would have not fitted them in the first place. Car companies go way out of their way to save 5 cents a car wherever they can.
Not directly related to the currect issue but there appears to be a ?? deep groove where the hub seal rides, or is that just a stain??
Also not related but while it's apart the end of the spindle tube where the outer bearing rides appears to have some wear. You could check the end of the tube ie: by putting a new outer bearing on the tube to see if it rocks, if it isn't tight it may not keep it's preload on the bearings once it's all back together. Also check the under side of the tube between 3 and 9 O'clock where the outer bearing rides for a wear step. FWIW.
Also not related but while it's apart the end of the spindle tube where the outer bearing rides appears to have some wear. You could check the end of the tube ie: by putting a new outer bearing on the tube to see if it rocks, if it isn't tight it may not keep it's preload on the bearings once it's all back together. Also check the under side of the tube between 3 and 9 O'clock where the outer bearing rides for a wear step. FWIW.
I recently had a similar issue with my 80 when going to the 100 series brake pads. The rotors appear to be original as does everything else, however I am not the original owner, so I cannot 100 percent guarantee this. The rotor thickness was still at the top end of the tolerance range which didn't help things in my case. The OEM 100 brake pads are a really tight fit to start with, even without the anti-squeal shim packs. I had several different brands of new 100 series brake pads laying around, so I measured the thickness of them and found that the Bosch were just a little thinner out of the box. These gave a little more room on both sides, but there was a bit of a off center issue similar to the OP that caused an overly tight fit on the inside pad. I ended up making some thin washers to go between the caliper and the knuckle that had the proper thickness to better center it with the rotor. The caliper on one side of the vehicle was slightly more offset than the other, requiring washers of thickness .030" on one side and .016" on the other to center. With all the components that stack up and their tolerances in this assembly, it is not at all surprising to me that things could be a little off, even with all OEM parts properly installed. I think a big part of the issue is that we are using 100 Series pads that are thicker than were originally intended for the application and this makes having the rotor perfectly centered more important. Many members installing 100 Series pads probably haven't experienced this issue as their rotors have been turned and are thinner providing more clearance on both sides. I think there couple of options that could be considered to help the OP assuming that there are no improperly assembled or out of tolerance parts. 1) Use 80 Series pads as their thickness may accommodate the slightly offset rotor better, or a brand of 100 series pads that are a bit thinner. 2) Have one side of the rotor turned to provide more clearance on the side that is tight. 3) Find or make some washers to go between the caliper and knuckle that put the caliper more centered with respect to the rotor. This only works if it is off center in the direction that washers can correct which I think is the case of the OP. If considering #3, using washers large enough to provide adequate distribution of loads when the caliper bolts are torqued should be accounted for.
Proceed at your own risk as brakes are probably the most important safety feature on your vehicle, besides that nut holding the steering wheel, and best of luck.
Remember knowledge without experience is just information.
Proceed at your own risk as brakes are probably the most important safety feature on your vehicle, besides that nut holding the steering wheel, and best of luck.
Remember knowledge without experience is just information.
- Thread starter
- #60
You're exactly right and thanks for putting it so succinctly! What I ended up doing is sanding down two of the 100 series pads and using those as my inners. I put them on my bench disc sander and tried my best to apply equal pressure. Then I figure-eighted them by hand on some 60 grit paper on a granite surface plate just to make sure they were as close to level and flat as I could get them. They started out 17.5mm thick and i took them down to 16mm to get them to fit. Lubed up the backs and slapped them in. Brakes never felt so good! I attribute that to the warped powerstop rotors and the two stuck pistons I found during the rebuild process. I also found no Damn reason to NOT split the calipers for rebuild. Only a real dolt could get it wrong. Splitting them makes it infinitely easier to clean the cylinders. The other problem I came up against was the old fittings were flared out so badly they wouldn't fit into the new braided lines I got. On some I was able to run a dremel with a little drum around the flared end to reduce its diameter, that worked. On others, the flared ends started splitting so I had to reach into my FJ40 donor pile for good fittings.
