riverracer au

Back in July '22 I rebuilt my trailing arms with a lot help from GTR1999 and others on here.
At the time whilst it was all apart I installed new locally made brake rotors, as the park brake linings were very badly worn and undercut on the ones I struggled to take off.
My new local rotors were machined with the extra holes for the park brake adjustment, so on they went.
Everything went back together and I continued driving around.
Just got back from a 3000km cross country drive over easter weekend, where I destroyed an inner passengers side uni joint. (should have replaced them when I did the arms )
When replacing the uni I noticed that my brake pads were over to one side of the caliper, same on the other caliper on the other side of the vette.
The pads have worn the front side of the disk, cannot see the back yet, hence all the brown pad dust all over the place....



I haven't taken the calipers or rotors off yet, as I'm wanting to have parts on hand to change over at the same time.

Over the weekend searching on the forum, I found that there is a difference in the inner hat height and the thickness of the face that bolts to the spindle between the front and rears.
Rear - 2.82 deep with 0.28 face thickness
Front - 2.72 deep with 0.38 face thickness
So it has got me thinking, maybe they sold me the wrong rotors, ie: fronts drilled with the park brake holes, these would push the rotor out further, does this seam feasible?
One side bracket could have gotten bent during the rebuild, but I doubt that both sides could be damaged and exactly the same amount....
The rotors are out of warranty (was 18mths) and the supplier has not responded to my emails asking about this.

So to make a long backstory worth reading, here's the question,
I'm going to buy new rotors from RockAuto and have them delivered downunder, even with shipping, they'll be about 100$ cheaper than I paid for local ones.
https://www.rockauto.com/en/catalog/...hub,rotor,1896
Not racing or track use, just occasional spirited driving thru the hills .
Which ones would you purchase or have had experience with?

69L88

There is a difference between front and rear rotors. You need to put fronts on the front and rears on the rear.

kansas123

I was going to say the ACDELCO 18A101 Gold Professional Black Hat.

GTR1999

I think most rotors are from the ROC these days which can range from good to poorly made. Here, I use NAPA premium rotors. They are Chinese and don't have the rivet pattern on them- which I don't want anyway. I transfer the river pattern to them. The last I checked the price went up to $101 each now. Buying online can be cheaper but you add in the shipping cost and time. For you, it may be a wash but for someone here if they get a discount and can avoid shipping cost they may pay about $80 maybe less.
Confirm you have the correct rotors. Not all have the parking brake holes- Wilwood hats don't for one. The caliper appears to be centered over the rotor, if a puller was used that bolts to the caliper bracket it can bend them and cause problems.

riverracer au

They were sold as "rears" from the seller.
https://www.vmaxbrakes.com.au/rtype-...models-6~15064
only reason I went slotted was that was all they had in stock at the time.

Peterbuilt

riverracer au

Yes, I have found those dimensions, that's why I think they sold me the wrong rotors.

Going to have to pull them off/apart to get a measurement.


EDIT: Just did a drawing at work with the above dimensions and it would appear that "IF" they have machined "front rotors" with the "rear" parking adjustment holes in them, then I would be seeing the results that I am seeing.

riverracer au

Update time. Finally got back on to this this weekend.
Removed the rotors, they are in fact the correct rear rotors, the depth (2.820" as above Vettemod drawing) from the rear face to the mounting face is about the same, give or take a few thou for wear.
Being a toolmaker, i brought some parallels home to check the alignment to see if anything is bent out of shape.
The photo shows how they are bolted onto the brake caliper mounting point and to the spindle face.
The "red A" dimensions are all parallel and the same front to back and top to bottom.
If i put a straight edge along the "blue B" line, the faces of the parallels, it is flat, not twisted.
Same on the other side, nothing out of the ordinary.
So this tell me the mounting points have not been bent during the rebuild process.

The only thing I don't have a correct dimension for is the "yellow" line, back edge of the caliper mount and the front face of the spindle.



Thinking out loud, maybe the tapered bearing seats were not pressed all the way in/on, ie: not seated properly, during the rebuild.
Highly unlikely as i was very methodical and was asking Gary (GTR1999) many questions during the spindle setup process.
And the chance of doing the exactly the same on both sides, well....

Measuring shows that the spindle needs to move inwards (or the caliper outwards) about 1.5mm (0.060") to centralize the rotor, (refer original post photo).
I do not have any photos of reference from before i rebuilt the trailing arms July '22 ish.

So if anyone has a trailing arm handy and can give me the "yellow" dimension so that i can check back against mine, i would be grateful.
That would rule out if the bearing seats are not all the way pressed on.

Bloke from work just said machine down the brake pad to get the clearance and check them often....

4-vettes

I'm really certain my rear calipers are straight and parallel with the rotors. You may remember me having an issue with a replacement caliper I purchased from a certain corvette vendor in Melbourne who swore up and down the poorly rebuilt caliper he sold me was new. I went mental trying to get that to work. In the end I rebuilt my original.
bottom line. I don't have the measurement your looking for. But I can assure you with the greatest confidence that my calipers are NOT centered over the rotor. In fact they look much like yours. They are true and parallel. But certainly not centered. As long as the pads fit down over the rotor without drag. Your good to go. I really believe your overthinking this one.

riverracer au

Probably, it's the problem being a toolmaker, I 'm used to working with fine tolerances, and it just doesn't look right.

I'll have to hit up a couple of club members and ask them nicely, or bribe them with booze, to remove a wheel so i can have a look at another brake setup.

4-vettes

I know I took a bunch of photos when I had that issue with the supposedly new caliper I got from Corvette Corner in Melbourne. BLOODY CROOK.
But I looked and it seems I didn't save them.
I can assure you that both of my rear calipers are parallel on both planes. But are definitely, noticeably off center. Perfect center wouldn't be possible as when ever you change, reset rear bearings it would change. Bearing endplay is critical. Whether the pistons are coming out of the caliper slightly more on one side than the other has no effect. As long as the caliper isn't on a angle front to rear, or up and down.

beachmusic

I think you are overthinking this a bit. If all surfaces are parallel ,there is equal pressure on both sides. The piston travel will be the same. They just start from slightly different points.

riverracer au

Yes the pads are parallel and even, but the outside pad is so tight to fit into the caliper that it has worn the outside of the rotor down excessively, about 0.5mm(0.020"),

So it must be rubbing/dragging the whole time, not being aloud to back off.

There is no wear on the rear face of the rotor.

4-vettes

Yes, not being perfectly centered is one thing. But dragging all the time is another.
you would think the pad would wear away before the rotor however.