Jump to content
HybridZ

S12W on 73' Z MM adapter plate issues


Recommended Posts

@Six_Shooter : Nice idea! I like the bracket you made, but I think you are correct in the cost factor. I love the different ideas here that people go with.

 

@Miles : I re-read my reply and it might have come off odd, but I truly do appreciate your help and information provided. You've been a great resource throughout this site and very knowledgeable in all matters Z. :-)

Link to comment
Share on other sites

  • 2 weeks later...

So, got the plate on after some fussing and bolted everything up. I have read that there are some installations that require a little bit or grinding here or a small spacer there and wanted to check with you guys.

 

After putting the hub/rotor assembled back on the car and bolting the calipers up I have clearance issues with the rotors and the calipers. Once the calipers were bolted onto the hub the slit that the rotor fits in to touches the rotor face on one side and only the top. I did a little grinding on the caliper slit (on the top inner side of the slit) and the rotor moves freely now. My question is, will this be a problem in the future?

 

My thinking is that as long as the rotors clear the calipers and don't touch once everything is bolted down (as is the case now that I have made the corrections with a grinder on the calipers) that it should be fine. But, I want to make sure that this is the case. Since the rotors sit EVER SO SLIGHTLY (maybe 1mm) closer to one side of the caliper there will be a small difference in the distance the pistons are extended on one side of the caliper.

 

My thoughts are that this should be ok since the distance is soo small, but I wanted to check with the board to get their thoughts. Sorry for the long winded explanation. 

Link to comment
Share on other sites

These aren't my calipers, but they will do :-)

 

Basically, where the rotors slot into the caliper body, one side of the slot touches the rotor. I just ground down a small amount of material off the caliper slot face. the rotor spins freely now but it sits closer to the face that I ground down then the other side of the slot.

post-2769-0-90687700-1430239785_thumb.jpg

Link to comment
Share on other sites

Is there some reason that you can not take a picture of the caliper mounted on the car that shows specifically the rotor contacting the caliper?  Otherwise this is just a guessing game.

 

The attached picture shows a S12W Toyota caliper and 300ZX rotor installed on a Z.  Does your caliper and rotor look like the picture?

post-178-0-62143900-1430245426_thumb.jpg

Edited by Miles
Link to comment
Share on other sites

Here you can see the clearance of the rotor to the caliper sides. This was after making the necessary grinding. Everything fits without problem now, and the grinding really was minimal. Nothing is ever 100% perfect on these old cars. 

 

post-2769-0-76650500-1430324242_thumb.jpgpost-2769-0-85051500-1430324248_thumb.jpgpost-2769-0-53212200-1430324252_thumb.jpgpost-2769-0-55692900-1430324256_thumb.jpg

 

So, what do you think? Any issues? 

 

@Six_Shooter : That was my thought too. The piston on the side that may have to travel a tiny bit more will just have to extend out further on the first brake push. But after that, it shouldn't have any problem and should be equal pressure on both sizes.

Link to comment
Share on other sites

@Miles : Any thoughts?

 

I am  real anal about understanding why things work or don't work. If it were my car I would want to know why the parts were not fitting rather than grinding parts to make them work. You may be able to get by with grinding the caliper, but check for the rotor rubbing on the caliper under load and when cornering. Also, do you want to grind future replacement calipers?

 

 

Other variables:

  • Are the bearing races in the hubs installed correctly - are they seated?
  • Are the hubs seated properly on the spindles?
  • And, most likely the problem, is the spacer machined to the correct thickness to center the rotor in the caliper?

Look at the dimensional stack up of all of the parts. How far does the caliper have to move to center the rotor?  Something is off.

Edited by Miles
Link to comment
Share on other sites

@Miles : So, the bearings and races were replaced about a year ago, and when I took everything apart to put on the new spacers I took out all the grease and inspected everything. No marrs or marks on the races and the bearings looked in great shape. I tightened down the hub to the spindle per the FSM (tighten to soo much, then back off a 1/6 turn (i think that was it). But I also tested the amount of force needed to pull spin the hub/rotor combo with a fish scale (not the BEST method, but better then guessing) and it checked out. 

 

I'm worried about the grinding under cornering too, after thinking about it, I don't see a way for the rotor or caliper to bend one way or the other after everything is bolted up tight (as long as the bearings are good). Do you think that this could become a problem?

 

I'm going to go home again and re-install everything and see what happens at that point. I was just wondering everyone's thoughts on the grinding. I wouldn't think it would cause a problem once everything is setup correctly, but I may be wrong in that assumption. 

Link to comment
Share on other sites

The 240Z MM spacer I bought from Ross is 17.09mm thick (0.673in)

 

 

Is your new spacer 17.09 mm thick?  Seems like your grinding job should be fine.  It's not a critical surface.   You might get back to Joe though so that he can get the dimensions right for the next guy.

Link to comment
Share on other sites

@NewZed : I'm going to do a few more things first to make sure everything is correct before giving the finals to Joe. But, it seems everything is going to be ok. I'm just grinding down a bit more for safety sake and then re-fitting after making sure that nothing has any kind of uneven surface. The lip on the spacer really does seat the rotor perfectly and seems like it should be a better option then no lip at all. If you look on the first page you can see that the spacer is actually 17.26 mm wide which may account for the reason of the grinding. I'm going to let him know so that he can make the change on his side as well. (hopefully he'll even throw me a new set)

Link to comment
Share on other sites

  • 2 weeks later...

Well guys. Just wanted to update everyone. Once the grinding was done and everything tightened down I got to take her out for a test drive. Everything looks to move freely and I have no wobble in the brakes at all. (I didn't push the car as I still need to do a few more things before i feel safe taking it up to 60 mph). 

 

I let Joe know that he should probably thin the spacers to 17.09 as that is what others have stated and what would have saved me from grinding down the calipers where i did. (Hopefully he does this to save this from happening in the future)

 

The brake pedal pressure is VERY firm and to be honest I can see why some people would go with the bigger booster with the 1" MC. Once I bead in the brakes and get the car aligned I'll take it out for some spirited driving and see exactly how good everything works. 

 

Just wanted to say thank you for all your help here with this issue. :-)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...