@#$%!! Should be simple! Raybestos 6984R Rotors, hit dust shields! DANGIT!

JasonRP · Sep 9, 2021

I am very frustrated. My front end rebuild has been going great- until I go to put in the new Raybestos 6984R rotors, which when attempting to preload the wheel bearings, seemed to be acting strange. I just could not get the bearings tightened, and then when I did get close- the rotor was making a grinding noise.. What the heck?! Take everything back off, inspect.. The dust shield center "cone" appears to be scraping the inside of the rotor flange that is around where the inner wheel bearing and seal go. So, I hammer it down slightly- spreading the cone away from where it looks like it is dragging, and try again...

...and again. Then, I take the dust shield off, mount the rotor up, and preload the bearing- no problem, and no noise. It's perfect! But, I want to use a dust shield, trying to keep it stock and a normal driver, etc. Put a little more "english" into the cone on the dust shield, put it back on- no go, still scraping. What the heck!? I look at the old rotor, and the flange appears to have a little taper put into it, and I'm guessing this is why it clears the dust shield.

WTF!? I'd think Raybestos, being a known brand name that I thought was good, would make the freakin parts right? Or, is this a common deal? Should I file down the rotor back/flange, and try to make it clear the dust shield? I hate to monkey with the dust shield more- they do not appear to be reproduced/sold/available cheaply.

Ideas/similar experiences? I hate to can brand new rotors, but, if that's the easiest and safest, I will. Anyone got any ideas?
Jason

Gs1987GT · Sep 10, 2021

Those rotors are probably made in China like most everything else these days. It is what it is. If your certain you have identified the interference area, either grind that area with a burr, or return the rotors and buy some motorcraft ones. Just my .02

I find Ford vehicles are more sensitive to that than other brands (generic stuff does not fit quite right and have to buy the motorcraft parts)

Noobz347 · Sep 10, 2021

Gs1987GT said:
Those rotors are probably made in China like most everything else these days. It is what it is. If your certain you have identified the interference area, either grind that area with a burr, or return the rotors and buy some motorcraft ones. Just my .02

I find Ford vehicles are more sensitive to that than other brands (generic stuff does not fit quite right and have to buy the motorcraft parts)

I was going to say "delete dust shields" but I like his post better.

JasonRP · Sep 10, 2021

I'd like to keep the shields if possible. But believe me, I tested the fit last night with no dust shields, and all was gravy- I was tempted! Anyone know where I can get legit Motorcraft rotors? None of the suppliers seem to carry them. I guess I'll look at the other Raybestos rotor that is still in the box- I suppose it's possible just this one is made wrong/they missed that one machining step?

Noobz347 · Sep 10, 2021

I don't know who makes them but reviews about fitment are good:

https://lmr.com/products/79-93-Mustang-Brake-Rotors-And-Drums

Mustang5L5 · Sep 10, 2021

I don't believe Motorcraft rotors are made for thee anymore. The choices in parts are dwindling.

I don't even see 6984S rotors, i just see 6984R for an '89 GT. Are you sure on that part number?

I would check the other rotor and then if it's the same return them. There's no reason to modify a brake rotor/spindle/dust shield just to put rotors on. That's the first sign that something is wrong. Buy a different brand

JasonRP · Sep 10, 2021

@Mustang5L5 You're right, I've got the 6984R- I got that wrong in the initial post.
I'll compare the other new Raybestos rotor I have for the other side as you suggest.

Do you guys have any known-good, proven rotor brands you recommend? I'm looking for stock style (not drilled or slotted- I am running Turbine wheels, and those dudes are hard enough to keep clean!)

Mustang5L5 · Sep 10, 2021

I've used Centric brand rotors on various other cars i've done brake jobs on. No complaints and I like the painted rotor hats.

Usually i go with OEM, but those aren't always available, which they aren't for the fox body anymore

Gs1987GT · Sep 10, 2021

Mustang5L5 said:
I've used Centric brand rotors on various other cars i've done brake jobs on. No complaints and I like the painted rotor hats.

Usually i go with OEM, but those aren't always available, which they aren't for the fox body anymore

Good to know going forward. Thanks

91TwighlightGT · Sep 10, 2021

What year is your car?

EDIT: I do ask because there are differences in spindles and things depending on year/options. If you have a 2.3L conversion you will have the same parts as a 79-86, which means different rotors and dust caps.

foxbodybill89 · Sep 10, 2021

I put EBC GD7019 dimpled/slotted rotors on and like them a lot, not cheap but great fit and stopping power.

JasonRP · Sep 11, 2021

91TwighlightGT said:
What year is your car?

EDIT: I do ask because there are differences in spindles and things depending on year/options. If you have a 2.3L conversion you will have the same parts as a 79-86, which means different rotors and dust caps.

'89 GT Hatch. It's interesting, because if you look on Rock Auto or other sites, they appear to list the convertibles separately from the regular 5.0? I did measure the old rotor and new ones to be safe- as I know some of these cars had 10" front brakes versus the aero V8 cars which got the 11" front brakes.

So here's my update, and thanks for the info everyone! (And thanks for talking me off the ledge there, too!)
In my experience, with a 1989 GT, is that the Raybestos 6984R rotors DO NOT FIT (yet are listed at many places as direct fit)... The rear of the rotor, the area the "flange?" that accepts the inner wheel bearing seal, is almost square around it's outer diameter. There is only a very slight radius. The rotors that came off the car (which unfortunately I cannot tell what they were- heavily rusted by now) had a fairly significant radius.

I went to Napa, and got their "Duralast Premium" rotors, part number 4885984. While not being radiused as much as the one I removed off the car originally, it was radiused much more than the Raybestos one. With the dust shield in place, the Duralast rotor installed fine, preload and tighten of the bearings completed without drama, and now the rotor spins without noise and smoothly.

PS: both the Raybestos and the Napa/Duralast rotors came with bearing races stamped with the same part numbers (no brand though) as the wheel bearings I'd bought to install- so, they "probably" would have worked fine. I'm not taking any chances if I'm this far into it, and knocked them out/drove in the races that came with the wheel bearings I'd bought.

91TwighlightGT · Sep 11, 2021

JasonRP said:
'89 GT Hatch. It's interesting, because if you look on Rock Auto or other sites, they appear to list the convertibles separately from the regular 5.0? I did measure the old rotor and new ones to be safe- as I know some of these cars had 10" front brakes versus the aero V8 cars which got the 11" front brakes.

So here's my update, and thanks for the info everyone! (And thanks for talking me off the ledge there, too!)
In my experience, with a 1989 GT, is that the Raybestos 6984R rotors DO NOT FIT (yet are listed at many places as direct fit)... The rear of the rotor, the area the "flange?" that accepts the inner wheel bearing seal, is almost square around it's outer diameter. There is only a very slight radius. The rotors that came off the car (which unfortunately I cannot tell what they were- heavily rusted by now) had a fairly significant radius.

I went to Napa, and got their "Duralast Premium" rotors, part number 4885984. While not being radiused as much as the one I removed off the car originally, it was radiused much more than the Raybestos one. With the dust shield in place, the Duralast rotor installed fine, preload and tighten of the bearings completed without drama, and now the rotor spins without noise and smoothly.

PS: both the Raybestos and the Napa/Duralast rotors came with bearing races stamped with the same part numbers (no brand though) as the wheel bearings I'd bought to install- so, they "probably" would have worked fine. I'm not taking any chances if I'm this far into it, and knocked them out/drove in the races that came with the wheel bearings I'd bought.

I have had Autozone list 5.0L parts as interchangeable with 2.3L parts, which is not the case. I'm not sure why the parts stores sometimes seem to not have reliable data on cars that are this old and have not changed in 30 years.

7991LXnSHO · Sep 11, 2021

91TwighlightGT said:
I have had Autozone list 5.0L parts as interchangeable with 2.3L parts, which is not the case. I'm not sure why the parts stores sometimes seem to not have reliable data on cars that are this old and have not changed in 30 years.

Catalog consolidation often introduces stupid errors. There is no good reason, but they do it.
I was wondering if the rotor hits the dust shield, how well are the calipers going to fit.

@#$%!! Should be simple! Raybestos 6984R Rotors, hit dust shields! DANGIT!

JasonRP

Gs1987GT

Active Member

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

JasonRP

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

Mustang5L5

That is…until I whipped out my Bissell

JasonRP

Mustang5L5

That is…until I whipped out my Bissell

Gs1987GT

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91TwighlightGT

foxbodybill89

Active Member

JasonRP

91TwighlightGT

7991LXnSHO

wanna catch the space herp

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@#$%!! Should be simple! Raybestos 6984R Rotors, hit dust shields! DANGIT!

Active Member

Stangnet Facilities Maint Tech... Er... Janitor

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That is…until I whipped out my Bissell

That is…until I whipped out my Bissell

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wanna catch the space herp

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