skyline brakes and warped rotor

[jdmser]

About two years ago I got a good deal on a set of Skyline front calipers and rotors. I know they aren't from the GTR because the rotors are 4 lug. I had the rotors turned before I put them on and used the 300zx-240 conversion lines. After about six month of driving I noticed a shutter when braking at anything over 40mph. I've had to do a crank collar and then my turbo blew the exhaust wheel off so I've been putting off looking at this. With my turbo upgrade almost finished I'd like to have good, working brakes before I hit the street. What I'm wondering is would a bad tension rod(all the goo leaked out) have anything to do with a wraped rotor? When I mounted the calipers I had to use washers to push the capliper out so it was centered on the rotor, could not having perfectly matching washer thickness cause this? What 300zx rotor should I replace these with? Thanks in advance for any help.

[elwesso]

Welcome to NICO!!!

Do yo uknow what model skyline they came off of? That would help recommending the right 300Zx rotor to use... I bet that putting washers is not helping any bit... I would take those off and see if that helps.. What you would ideally do is get special washers that are made for this and get out your dial gauge and measure the runout as mounted on the car and get it as close to in spec as possible.

[jdmser]

They are 26mm aluminum calipers and 4 lug rotors from a gts-t. I saw that Heavy Throttle has z32 rotors drilled to 4 lug for a decent price. As far as the washer, where would I find "special" washers for spacing the calipers out. The calipers would not fit on the rotor without them. It pulls the rotor in at the caliper. I was hoping that the z32 rotors would be a better fit than the r32 rotors.

[elwesso]

thats weird, they should be the same.. Take in mind that they wont center until you bolt everything up. It may seem they off but theyre really not... Basically my point is when you install the calipers with the pistons pushed all the way in and then you bolt everything up and then press hte brakes it will work fine.... You dont need to use washers to align the rotor.... I cant imagine them being so far off as you couldnt even bolt things up.... I know when i installed Z brakes on my Q (which in effect is the same as doing it on a 240 except Q is 5 lug) I didnt do anything what you describe neither does anyone else...

That is probably why your rotors are warping! I wouldnt pay a ton extra for pre-drilled 4 lug rotors, however the $130 HT wants isnt TERRIBLE, but you could probably do better if you had the rotors drilled yourself.... You could probably do better than $65/ea if you wanted to but the convenience isnt such a bad thing.

[nismofly]

280x26 is your rotor size btw

but like wes said, you need to get them drilled

i know people that do it themselves, but its up to you if you do that or not

also fyi, just because they came with 4 lug rotors didnt mean they werent gtr, gts came with 5 lug too...yours were 4 lug because somebody before you with a 240 had them that way

[jdmser]

Yeah, with out the washers to push the caliper farther toward the wheel, the outside edge of the rotor extends past groove in the caliper. The rotors are within machine spec thickness but, I'd have to take out so much to get them true that they wouldn't be before I was done. They are about 0.010 in warped. I almost think they were put on the lathe cocked but, I think it has more to due with the washer and the rotor hat thickness. How thick are the hats on the z32 rotors? The pictures of the z32 rotors I've looked at the rotor hats look thicker that the gts-t rotor hats. That would put the rotor farther inboard and allow the caliper to bolt up without the washers.

[jdmser]

I got the set from ebay.com.au and after doing a little more research it was the n/a skylines that came in four lug and not the gts-t. I don't have redrills, they are 26mm oem four lug 4x114. Prolly off something like this http://www.trademe.co.nz/Trade...2.htm
Modified by jdmser at 3:30 AM 12/23/2006

[elwesso]

I wonder what motor it had in it? Like an RB20DE?

Anyway, back to your issue, id just get the Z32 rotors and call it a day.... But dont think you need to pay extra just to have 4 lug rotors, any machine shop can redrill them for little money.