• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

850 Heavy vibration under braking, what gives?

Orange_Crusader

Moard Bember
Joined
Jun 8, 2006
Location
Ontario, Canuckistan
1996 855 GLT, 430k km's.

All work done by a shop, for reference, I lacked the time to do it myself.

Just had the rear brakes re-done, the right rear caliper was seized so a rebuilt one (which checked out fine) was bought and installed, rotors replaced (with Nordic brand ones) and OEM pads, front pads also replaced with OEM, the rotors were in good shape and didn't need replacing. Right front caliper was replaced last year with a rebuilt.

Since the work got done, the car shudders heavily on hard braking, no vibration just rolling along and no caliper dragging that I can hear, but it definitely brakes unevenly, even low speed braking where I just slightly apply brakes to creep forward, I can feel it braking much less as it rolls, as if the rotor was really warped, so the car sorta studders forward, for lack of a better term, as the brakes go between hardly any force and full force expected at that pedal position. Slowing from 60ish mph causes a lot of vibration/shaking of the entire car, kinda scary. Feels as if the shuddering is coming from the back, since the steering wheel doesn't shake at all, which I expect it would if the problem was one of the front brakes.

So what do I check/do first? Head back to the shop and have them figure it out? Call up FCP and see what the return/exchange/refund policy would be here? Enjoy my free massages?
 

I read that, but the rotors are brand new (installed yesterday morning), and acted this way the first time I pressed the brake pedal leaving the shop (they told me to just drive for a few days and it'll settle down, but it's gotten worse today).

That's awesome, but how did you fix it?

Upgraded. FCP is shipping me a set of brembo rotors (I asked about them, apparently very comparable to stock), and when the existing ones are swapped off, I ship them back to fcp for a full refund. This is the first time fcp has heard of anything like this happening with the Nordics, so don't let this turn you off from them quite yet, I read some good reviews and decided to try them, next time my rotors need replacing (fronts sometime in near future) I may try them again, we'll see.

work done by a shop and result bad? ----> back to the shop

Yep, the shop agreed to install the replacement ones free of charge.
 
Hence why I'll be in the garage supervising (and checking out the undercarriage while I'm at it) this time around to make sure it's done right this time. I figure if a 5 min drive either way and getting a beer with the shop owner's son for free.99 can save me doing the job myself for 30 min (since I'd go slow and poke at everything else while it's apart), meh, I'll do it.
 
I am glad everything worked out ok in the end. Are you still taking your car to that shop?

Yeah, the owner was super-nice about it, apologized and offered to do the replacement for free himself, I figure it'd be kinda a dick move to refuse. In either case I'll be overlooking the replacement in the shop, got a lot of pointers from raz so I'll know what to keep an eye out for. Wouldn't happen to know if the new rotors shipped yet, would you?
 
I recently bought a nice set of Zimmerman rotors for my 945T. Before mounting, I took them to my machine shop and had them trued up. They removed 1.5 thousandths off each side and all was well. Do not assume new rotors are OK right out of the box.

Another thing to watch is the tourque on the lug nuts. If improperly tightened, your rotors will warp.

If your strut rod bushings are bad, your car will shake like crazy even if the rotors are good.
 
Hmmm, not a bad idea to have them checked out, actually. I'll see where the nearest shop is and what they'd charge.

The guy installing them last time used a torque wrench on everything, lug nuts included. That said, I'm not sure what he tightened them down to. :\

Struts all around are fairly new, less than 50k on them (and the old ones last about 250k km's), and no such symptoms beforehand. I'll do a quick check of the calipers too, when the rotors are off.
 
Called 2 shops in the area, any others are about a 40 min drive off for some reason. They both want something like $40 per rotor* to check and if needed, remove any material. Eff dat, that's what I paid for the rotors themselves. Guess I'll be playing the odds, then.

*likely didn't wanna do the job so they quoted higher to scare me off, meh
 
Back
Top