Rotors available (for now) for K-H disc brake cars

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I’m pretty sure Raybestos rotors are not made anymore. Which is too bad as the old ones worked as they are supposed to.
 
str12-340 said:
No rebuilding calipers doesn't solve the problem. The configuration of the "hat" of the new rotors is such that it just barely rubs the side of the seal and wears it away. Only clearancing the hat so that it doesn't rub the seal will fix this. As far as I can tell all the different rotor manufacturers have this problem even though their rotors are different from each other. I have been following this thread for a long time hoping to find a new rotor source that fits without work, but so far no luck...
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Could it be possible there is more than one seal that could be used in the rebuilding of these calipers? Maybe a seal that isn't so fat?
 
I just hit it with a grinder to take off the excess casting that rubs the caliper piston seals.
It was such a small amount, took all of a minute, no negative impacts.
 
Bob Jasinski said:
Could it be possible there is more than one seal that could be used in the rebuilding of these calipers? Maybe a seal that isn't so fat?
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Possible? Maybe. But when caliper pistons are all the way in with new pads seals get squished bulge out so as pads wear they can stretch as pistons move out.
 
matthon said:
I just hit it with a grinder to take off the excess casting that rubs the caliper piston seals.
It was such a small amount, took all of a minute, no negative impacts.
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Let me get this straight. When you say "hit it with a grinder", what does that really mean? Are you turning the rotor while you grind away with a hand held grinder? How do you maintain consistency that way? Sorry, but it sounds sloppy to me.
 
Some of you guys are putting way more hardship into this rotor issue.
Your not building the next generation of a space shuttle.
Don't worry about taking a grinding disc to a rotor.
 
hemi71x said:
Some of you guys are putting way more hardship into this rotor issue.
Your not building the next generation of a space shuttle.
Don't worry about taking a grinding disc to a rotor.
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So just knock the casting down smooth?
 
matthon said:
I just hit it with a grinder to take off the excess casting that rubs the caliper piston seals.
It was such a small amount, took all of a minute, no negative impacts.
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I think we're talking about two different rotor hats, finished (machined) or rough cast. I've been working with machined hats. I could see grinding a rough casting hat using a flap grinder, take it down 'til smooth and even around hat, makes sense. Don't see doing that with a machined hat.
 
hemi71x said:
Some of you guys are putting way more hardship into this rotor issue.
Your not building the next generation of a space shuttle.
Don't worry about taking a grinding disc to a rotor.
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I have a set of rough cast ones on my car now that rubbed just briefly in one spot as the casting was poor and had a predominant raised spot. So, I did just this (grind them) and have had zero issue.
 
ir3333 said:
Glad this popped up again.
...has anybody had caliper boot interference with new rotors that come with the hubs and hats machined?
I dug mine out and they are completely machined.
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That's too bad. I was assuming that this was some company's answer to the casting issue which goes back at least two decades now. The problem seems to be there is only one factory casting these things. Then the different brands buy them and finish (or not) them to various quality levels.
Bob Jasinski said:
I do have concerns about removing a third of the hat wall thickness, but since the hat only carries force when braking, is not a friction surface, does not support the wheel only the rotor, has safety been compromised? The failure mode I could envision would be under heavy braking, but I would think the wheel would lock up before the hat cracks. I am not a metallurgist or a machinist, although I did have take some classes in both areas in tech school. Is there a safety concern here? Comments welcome.
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I hate to comment on safety stuff and understand why you have some concerns, but your reasoning seems sound. The heat will be concentrated in the disc. I have temperature sensative paint on the rotors and they've never got excessively hot. I'd be more concened with drilled rotors cracking than what you've done. Contacting the caliper, or even dust boot is just unacceptable. Note that the orignals I have did not have machined hats but were ballanced with weights in the cooling fins. So that's what they cared about! Balance. Probably faster and cheaper than machining the hats which I expect does about the same for balance.

If you are doing track days at Willow Springs, the first thing to get too hot will be the linings. You can talk with Tim and Steve about what you can get away with first times out there. I'd think Porterfield R4S would be sufficient until you get some experience, but they know the track and these cars. So does junkyardhero - and I think he had 4 piston K-H in his early A.
 
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Mattax said:
That's too bad. I was assuming that this was some company's answer to the casting issue which goes back at least two decades now. The problem seems to be there is only one factory casting these things. Then the different brands buy them and finish (or not) them to various quality levels.

I hate to comment on safety stuff and understand why you have some concerns, but your reasoning seems sound. The heat will be concentrated in the disc. I have temperature sensative paint on the rotors and they've never got excessively hot. I'd be more concened with drilled rotors cracking than what you've done. Contacting the caliper, or even dust boot is just unacceptable. Note that the orignals I have did not have machined hats but were ballanced with weights in the cooling fins. So that's what they cared about! Balance. Probably faster and cheaper than machining the hats which I expect does about the same for balance.

If you are doing track days at Willow Springs, the first thing to get too hot will be the linings. You can talk with Tim and Steve about what you can get away with first times out there. I'd think Porterfield R4S would be sufficient until you get some experience, but they know the track and these cars. So does junkyardhero - and I think he had 4 piston K-H in his early A.
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Mattax, Thanks for the thoughtful response. You make a good case about the possibility of drilled rotors being more vulnerable to failure than a solid rotor that's had the hat slimmed down. I have no plans on racing this car, but do plan on spirited driving on twisty roads up Mt Diablo and in the wine country. If you have any pictures of your original rotors I'd love to see them. You mentioned the original hat was rough cast (not machined), but how was the original hat shaped; cone, cylindrical, or stepped?
 
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@340sfasrback , no if the rotors rub it's the rotors , not calipers . you will have to turn them down as show prior in this thread .
 
Before/After.
It's not even the visible ridge that is the issue, it's right above that.

If left alone, as the rotor hat is tapered, it only rubs the caliper seals when the pads are worn down.

20201114_145718.jpg


20201114_163218.jpg
 
matthon said:
Before/After.
It's not even the visible ridge that is the issue, it's right above that.

If left alone, as the rotor hat is tapered, it only rubs the caliper seals when the pads are worn down.
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Matthon, Thank you, a picture is worth a thousand words. It seems to me we should be seeking out rough cast hat rotors, 'cause they're easier to modify. The sad part is, I haven't come across any new for sale.
 
Bob Jasinski said:
If you have any pictures of your original rotors I'd love to see them. You mentioned the original hat was rough cast (not machined), but how was the original hat shaped; cone, cylindrical, or stepped?
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Slight taper to the hat. I should be able to dig out a used rotor this weekend.
Here's a few digital photos off my computer
1711559914397.png


1711559976762.png


1711560029482.png


Search saves me from digging through my files for the rotors that I had to return to NAPA in 1992.
Bendix PRT 1054.
The hat casting was egg or cam shaped. Only hit the piston boots once each rotation.
www.forabodiesonly.com

Rotor thickness minimum 4-piston KH?

Anyone know the minimum thickness? These are for a 68 dart gt. Thanks
www.forabodiesonly.com www.forabodiesonly.com
 
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Another pic.
I recall cleaning up the entire hat because it either rubbed a seal slightly in a spot or two, and/or that's how my brain works and I went overboard, thought any rustacles that develop in the future could/would rub my new seals, or at some point in the pad wear it may, might, could, would rub and I cannot have that.

Yes, some marks on the face of the rotor, I wasn't using a 30 grit disc or grinding the heck out of them, and they aren't in the path of the pads, I checked.

I also looked at new rotors I have, and the hat looks better and more 'smooth.'
Pics pending on that.

20210406_185934.jpg
 
I got rough finish hat rotors (and new calipers) from Rock Auto less than a year ago
 
Mattax said:
Slight taper to the hat. I should be able to dig out a used rotor this weekend.
Here's a few digital photos off my computer
Search saves me from digging through my files for the rotors that I had to return to NAPA in 1992.
Bendix PRT 1054.
The hat casting was egg or cam shaped. Only hit the piston boots once each rotation.
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Mattax, Thanks for the pictures, and the link to your 2020 post listing rotor vendors, very comprehensive. I wonder if any of the listed rotors are still available. These recent posts have been very enlightening. I went though some old parts I've got and came up with a pair of correct, but old rusted rotors, worn beyond use, and it turns out they were rough cast hats too. I'm pretty sure I got them at a swap meet about 20 years ago with the calipers, backing plates and spindles. I'm getting the impression that the machined hat rotors are a fairly recent offering.
 
Bob Jasinski said:
Those are the rotors I bought and turned on the lathe (post #65) They are machined hats.
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At this point, I can't tell if my old rotors are the machined type or the same as the new C-Tek rotors.
I'll have to compare them to my old old rotors.
If I am running the machined rotors now, and those are the rotors I took a grinder to, it was fairly easy and there is no negative impacts, vibrations, rotors exploding, etc.
 
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