Wheel shaking under braking, warped discs or no?

"Twingo Tamer - About to descend into project car hell." (oppisitelock) 04/10/2014 at 14:59 • Filed to: oppo help

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On my parents car there is a heavy steering vibration under braking, pretty sure its a warped disc but before we put £80 into replacing the discs was just wondering if anything else can cause it. Especially strange since the pads are fresh and the discs are still newish with no grooves or lips on the disc.

A sweet chevelle for your time.

Party-vi > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:00

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Worn front suspension bushing can cause that as well. I have the same issue in my car as the front control arm bushings are getting older. What's your front suspension setup look like?

505Turbeaux > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:00

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probably that, but could be worn tie rod ends or control arm bushings. Lift the wheel up and shake it in all directions and you will know

YSI-what can brown do for you > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:01

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Might be the master cylinder moving around. I get the same thing in my car and the brakes and pads are fairly new.

roflcopter > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:03

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It typically takes A LOT to warp a rotor, not something that happens on stuff that's just getting driven very often. I would say that some other issues that could cause it would be motor mounts or transmission issues. The brake are easy enough to check though, and probably the cheapest to repair.

48 Spoons > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:03

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If you can feel the pedal pulse when braking, then it could be a warped rotor, otherwise I would think its something else.

Twingo Tamer - About to descend into project car hell. > Party-vi 04/10/2014 at 15:04

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Tie rod ends are relatively new (I fitted them about a year ago) and i tested them for play earlier so they seem okay. I haven't had a good look at the rest of the suspension yet, one thing i know is that when me and my grandad replaced a front spring a while ago we had to cut the anti roll bar arm and i left my grandad to fit the replacement so never had a good look to see if it was fitted properly, maybe I'll check that for play.

anotherdayanotherburner1 > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:05

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Jack up the front and grab a wheel. Shake it side to side and see if the hub has play, or is loose. If it clunks, there is a problem with tie rods, control arms or wheel bearings. If it is tight and only turns the wheel correctly from the steering rack, the brake system is suspect once again.

Party-vi > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:07

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I'm not sure if a sway bar end link would cause vibration under braking. You should get the wheels off the ground and see if there's any play in the front suspension components. While you're at it you can look at the brakes too.

Twingo Tamer - About to descend into project car hell. > 48 Spoons 04/10/2014 at 15:07

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I can't drive the car myself since I can't afford to get on the insurance and my mam doesn't know what to feel for even if I tell her, guna have to find a private road or someone else to test it I think.

Twingo Tamer - About to descend into project car hell. > YSI-what can brown do for you 04/10/2014 at 15:08

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Interesting, not something I've heard happen before. I'll give the master cylinder a good check over, Thanks!

Twingo Tamer - About to descend into project car hell. > 505Turbeaux 04/10/2014 at 15:09

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Yeah that's my first step when I get to work tomorrow, I know the tie rods are fresh though.

YSI-what can brown do for you > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:09

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Usually it needs a brace to stop it from moving, which is fairly cheap.

Twingo Tamer - About to descend into project car hell. > roflcopter 04/10/2014 at 15:10

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This is what Im thinking, often its excess heat that warps them and the car is driven fairly carefully. The motor mounts aren't something I considered, I'll give them a look thanks!

jariten1781 > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:10

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A bad wheel bearing can also cause this symptom. Though it usually comes with noise and is noticeable at speed as well.

Twingo Tamer - About to descend into project car hell. > Party-vi 04/10/2014 at 15:12

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The sway bar seems to connect to the coilover on this car so it may be possible for it to influence the suspension, but you're right it's unlikely. Yeah I'll get it in the air tomorrow thanks!

Twingo Tamer - About to descend into project car hell. > jariten1781 04/10/2014 at 15:14

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Yeah I noticed no noise or other symptoms while riding in the car so I struck bearing off the list, will check it for play anyway though

Twingo Tamer - About to descend into project car hell. > anotherdayanotherburner1 04/10/2014 at 15:15

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Yeah this was guna be my first test once i get to work on the car tomorrow, hopefully it turns out to be something cheap haha

deekster_caddy > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:16

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If it's got cheap pads they could leave deposits on the rotor causing a 'warped' feel to braking. Try a few hard stops in a row, 40-10, 40-10, repeat 4 or 5 times. You are basically trying to heat up the material and scrub it clean. That may fix the issue (or make it worse).

Alternatively, you could take heavy sandpaper and rough up the front and back of the rotors. I'd try a few hard stops first.

If the pads were changed without changing rotors, it's likely that they are thin, which can warp easier.

Z_Stig > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:17

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Brake pad deposits on the rotor could be the culprit as well. Brake rotors don't always 'warp' per se; and you'd have to get them pretty hot to warp them in the first place.

Twingo Tamer - About to descend into project car hell. > deekster_caddy 04/10/2014 at 15:20

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The pads are just from a local parts store and were fairly cheap so sounds like that's a possibility. The rotors are a little older than the pads but theres no lip or deep grooves on either side so they definitely aren't too thin.

deekster_caddy > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 15:21

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Just because you don't see a lip or grooves doesn't mean they aren't thin. It depends on the car but I have seen some that will wear down the rotors without leaving an outside lip.

Twingo Tamer - About to descend into project car hell. > Z_Stig 04/10/2014 at 15:22

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Yeah someone else suggested this, definitely seems possible.

Twingo Tamer - About to descend into project car hell. > deekster_caddy 04/10/2014 at 15:29

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Can't say I've ever seen a disc wear that evenly but I guess it's likely if they have warped, I'll see if I can find any evidence of wear across the whole disc.

You can tell a Finn but you can't tell him much > Twingo Tamer - About to descend into project car hell. 04/10/2014 at 17:06

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Possibly the new pads and discs didn't bed in properly. When I put new pads & rotors on my car last they recommended a bed in procedure. Here is the Hawk procedure for bedding in new pads:

Brake Pad Burnishing/Bedding-In Instructions

1. After installing new brake pads, make 6-to-10 stops from approximately

30-35 MPH applying moderate pressure.

2. Make an additional 2-to-3 hard stops from approximately 40-45 MPH.

3. DO NOT DRAG BRAKES!

4. Allow at least 15 minutes for the brake system to cool down.

5. After step 4 is completed, your new Hawk Performance brake pads are

ready for use.

Twingo Tamer - About to descend into project car hell. > You can tell a Finn but you can't tell him much 04/10/2014 at 17:08

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Good advice but it isn't my car and I really doubt my parents will listen haha. My mam especially loves to trail brake into corners for no real reason.

jdrgoat - Ponticrack? > Twingo Tamer - About to descend into project car hell. 04/11/2014 at 03:55

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http://www.stoptech.com/technical-supp…

I have been meaning to show this link to a friend of mine after we had a short back and forth about "warped rotors" a few days ago... I might as well share with you, also.

Twingo Tamer - About to descend into project car hell. > jdrgoat - Ponticrack? 04/11/2014 at 10:31

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That was an interesting read, thanks. Being an engineering student I love this sort of info.