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Rear Disk brake conversion problem


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Hi guys;

 

 

I got the modern motorsports rear disk coversion kit for my 240z minus the disk brakes(i had some already. I went to mount the kit and everything was good until i tried fitting the calipers. As you can see by the pictures the caliper mounting points are to thick for the space between the disk and MM mount. The measurements are as follows;

Caliper mounting thickness 1 1/4"

Space available between disk and MM mount 1 1/16"

Disk size 11 3/8 diameter, 1 7/16 hat thickness, 3/8 thick rotor.

What am i doing wrong? do i have the correct parts? Thanks for the help in advanced.post-540-019855600 1285534269_thumb.jpgpost-540-067157500 1285534284_thumb.jpg

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Any clue guys? i'm really frustrated because everything seams to be in order but it just won't fit in place. All my parts are the ones supposed to be used on this coversion jet for some reason it wont fit; does someone have measurement or a picture to show the way its supposed to be? My rotors are brembo, for a '84 300zx NA. Calipers from a junk yard '89 240sx. Kit from modern motorsports.

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The Modern Motorsport kit uses the 300zx rotors.

 

Check to make sure the caliper is opened all the way. By comparing the rubber boot in the two pictures, it appears that the caliper is extended in the lower picture. You see two folds in the first picture and only a partial fold in the second.

 

Also, important, check that the piston is fully seated once you get the pads in. It is not pressed in but rather screwed into position. It takes quite a number of turns to get it to fit.

Edited by ktm
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AS 19752802+2 said, the real problem is the space between the MM mount and the rotor. The caliper won't fit into place since the mounting "ears" on the caliper are thicker than the space between the braket and rotor. The Mounts are on the correct side and torqued down to spec. The top picture is for reference to show the calipers i got. The bottom picture shows how the caliper does not fit between this space. It will only fit if it was machined down. That's why i'm puzzled? Any ideas? does anyone have dimentions or pictures to compare? Thanks again.

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AS 19752802+2 said, the real problem is the space between the MM mount and the rotor. The caliper won't fit into place since the mounting "ears" on the caliper are thicker than the space between the braket and rotor. The Mounts are on the correct side and torqued down to spec. The top picture is for reference to show the calipers i got. The bottom picture shows how the caliper does not fit between this space. It will only fit if it was machined down. That's why i'm puzzled? Any ideas? does anyone have dimentions or pictures to compare? Thanks again.

 

I will get some pictures with the zx caliper on it tomorrow. I have not yet got 240sx caliper for me. I will show you why you need 240sx calipers as well. (Tried 300zx rotors, they are to tall for my brackets with the 240sx calipers.)

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I think i found the problem or at least why it does not go on. I tried to mount the Left side and it went on without a problem, so obviously there is something wrong on the Right side. As you can see on the pictures below, things just don't line up. Why? i really don't know. All surfaces are clean, inspected the bracket and compared to the Left side and they are both the same. Rotors are not warped. So again, i'm just getting more frustrated the more i find. By the way all bearings where replaced and studs as well. Any clues?

post-540-022815500 1285579119_thumb.jpgpost-540-048751100 1285579139_thumb.jpg

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They are MM brakets. I thought the MM were fully machined pieces but i guess not. I got them directly from them, the one on the left does not look like that when it's mounted and the caliper fits. A quick inspection/comparison between left and right mounts left me with more questions since both brakets are the same (one right one left) with no visual differance. I'll inspect them more closely tomorrow. It's hard to think the stub axle or strut mounting point is off. So something is not right.

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Found the problem...thankfully the stub axle, rotor and bracket were all in good shape. The problem was a 1/16 in. interferance between the MM mount and the strut "mounting point, which in turn didn't let the bracket seat properly. I just grounded the portion down, now it fits like a glove. I have pictures of this to show but i'm at work right now. I really appreciate all the help from everyone here. Thank you!

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Found the problem...thankfully the stub axle, rotor and bracket were all in good shape. The problem was a 1/16 in. interferance between the MM mount and the strut "mounting point, which in turn didn't let the bracket seat properly. I just grounded the portion down, now it fits like a glove. I have pictures of this to show but i'm at work right now. I really appreciate all the help from everyone here. Thank you!

 

great to hear you found the problem!! :rolleyes: Did you ground down that offending "mounting point" on the MM bracket or the strut housing? A picture would help others in this case. And I would email ross and tell him what you found so he can either modify the brackets and or include instructions so this doesn't happen to other customers in the future!

Edited by fastzcars
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Here are the pics of the areas i had to ground off to make it seat properly. I don't know if the mount casting was out of spec or the defect came from the strut. I ended up grinding down both of them just in case. I hope this helps someone that might encounter the same problem. Thanks for the help from all of you!post-540-098107200 1285671255_thumb.jpgpost-540-006952700 1285671244_thumb.jpg

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