friedgreencorrado
friedgreencorrado SuperDork
5/11/11 5:41 p.m.

1992 VW Corrado VR6. Brake shudder at high speed (above 65mph), with a slight pull to the left. Just had the shop replace the right wheel bearing & hub (yeah, I know..but without a job I'm just gonna ride the left side til it roars like a freight train). At first, I thought just pad re-seat because the caliper had been off, but I put my foot in it hard a couple of times and it didn't go away. Car has drilled rotors, there's always been some NVH, but this is a pulse almost like a warped one. Ideas?

(and I'd like to keep the rotors, it's a nice 90s period look)

Graefin10
Graefin10 Reader
5/11/11 5:55 p.m.

Are you sure the rotors aren't warped???

Was the car sitting up for a while? That can cause a diffence in the rust rate from where the pad was sitting and the open part. Has anyone done any painting, undercoating, or spray lubricating, anywhere around the brake rotors? Were the rotors removed? Could something be keeping one side from seating properly? I worked on a new XJ6 Jag that had been carelessly undercoated. The undercoating didn't burn of and caused the worst brake judder I ever encountered.

dogbreath
dogbreath New Reader
5/11/11 6:04 p.m.

Brake shudder can be in the steering, especially tie rods. Make sure the suspension is all tight, you can check the rotors before you have to commit to replacing them.

Zeitgeist
Zeitgeist New Reader
5/11/11 6:11 p.m.

Couple of thoughts. Obviously check runout on the rotors but also hub face wear rotor seats. Also look at sliding caliper bushings and see if they slide freely,no excessive play or sticking. It is harder to chase down with no money but most things are free or cheap here.

friedgreencorrado
friedgreencorrado SuperDork
5/11/11 6:57 p.m.

Y'know, I wonder if it is disc runout, and I just didn't feel it before because the bearing was bad (after all, the slack in the bearing would just let the hub wobble a little, right?) After all, if they're a "nice 90s period look", that means they've been on there since the 90s.

Graefin, car's my DD at the moment (and has been for a touch longer than a year). OTOH, I did pop the anti-roll bar end link with lithium grease (spray) a few weeks ago because it was binding.

dogbreath, I'll check the links first. Especially since I can do that without borrowing a runout test gauge. Zeit, thanx for the reminder to check the caliper, I'd completely forgotten about that (it's a single piston caliper, too! DOH!) Thanks everyone..if anybody's got anything else, I'm still listening..gonna be tmw evening before I can look at it anyway.

EDIT: Graefin, yes rotor was removed. Rotor has to come off to change the hub on these cars.

friedgreencorrado
friedgreencorrado SuperDork
5/13/11 11:31 p.m.

Update: yeah, it's the rotors. I didn't even need a runout gauge..laid a piece of flat steel on em & saw the gap. I guess I'm just gonna nurse it along until I can justify replacing them.

Streetwiseguy
Streetwiseguy Dork
5/13/11 11:35 p.m.

Pull the rotors off and sandblast or polish all the rust off the back face where it mates to the hub. It may have loose junk in there, or it may have been put on in a different position, leaving a rust hump that used to protrude through a hole on a solid part of the hub.

friedgreencorrado
friedgreencorrado SuperDork
5/14/11 4:52 p.m.

In reply to Streetwiseguy:

Good idea, thanks. It's actually got a new hub on the right side, I never even thought to look. I guess the gap I saw with the straightedge could be from the ridges.

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