Brake Problem

[RoboticCherry-Coke]

Hey guys,

About a week or so ago I replaced my rear brakes with RDA slotted rotors and pads. I now have a bit of an issue. When braking its really rough (steering wheel shakes madly etc.) and I took a look and noticed on the right hand side (drivers side) the outside pad isn't wearing evenly.

The pads are flush against the rotor but only the back part of the pad is wearing. I have removed and reset the pads about 4 times now and confirmed that they are sitting correctly but no matter what I do I cant seem to get the pad to make full contact with the rotor. Any suggestions? This is beginning to drive me insane.

[ephect]

sounds like the guide pins are sticking and not letting the both side. i would suggest removing the right hand side and lubricating the pins and checking all moving parts

if u have a manual, follow it to overhaul the brake caliper

[hsvpunk]

Exploded View Disk Brakes
(number 7 in the diagram)

As Ephect said,lube it up, and they should all get pressed flush.

[RoboticCherry-Coke]

Ah thanks for this guys, I will check it out tonight after work... um what type of lube should I use for this?

[ephect]

i would assume grease, i've never overhauled them, but i have greased them from time to time when changing pads

[RoboticCherry-Coke]

Ah ok then, easy as

[c.o.m.e355vsute]

go to super cheap auto you can buy small packets of calliper pin grease. $3.00ea

[RoboticCherry-Coke]

lol hmmm well I would do that but the nearest super cheap to me is about 160kms away

[c.o.m.e355vsute]

make sure the grease you choose then is high temp

[RoboticCherry-Coke]

Well I got some wheel bearing grease at home so I imagine that would be all ok to use..

[ephect]

yea that will be perfect, u might want to do both the rears if not all 4 calipers
let us know how u go.

[RoboticCherry-Coke]

I wont have much time to do it tonight so I will just see if i can get the problem caliper solved then do the other ones when I get a chance... on a different note, how do i find out the min. thickness of the front rotors? I replaced the rear ones as they were well and truly due for replacement and I figure if the rears needed it the front cant be to far off.

[ephect]

according to my manual, its cast on the disc rotors. sorry i dont know where on the disc its marked, or specific measurements

[RoboticCherry-Coke]

Ah thats cool, when I grease up the front I will have a look around and see what I can find

[holdenrocks]

its 25mm thick runout for vr front disc thats all i know i guess so ...

[Not_An_Abba_Fan]

Stock thickness is 22.8mm, minimum thickness is 20mm.

[RoboticCherry-Coke]

Cheers Abba.

Um bad news guys, It didn't work

Pulled out both guide pins, swapped pads around so I had a flat one on the outside bolted it all back together and made sure everything was nice and tight. Went for a drive and the steering wheel still shakes like a mad man and the brakes still aren't wearing evenly.

Any more suggestions?

EDIT: Just measured the front rotors, they are 21mm so looks like I am all good with them.

[ephect]

so u've checked & swapped the rear rotors and pads, it'll take a bit til u notice that the pads are wearing unevenly.

the steering wheel shakes on braking alone? im guessing that one of the rotors is heat warpped. a good test is, go for a drive then "feel" the heat of each of the front rotors and one side will be considerably hotter than the other side. Try not to touch it but rather place ur hand close to the rotor, u'll feel the heat. the side that is hotest is damaged. change rotors and u should be fine.

[RoboticCherry-Coke]

Yeah shaking is on just braking. I am bout to go out to see my girlfriend bout 25kms away. When I get there I will feel the heat on the brakes and see what I can find out.

As for the rear I just lubed the guide pins on the right rear caliper. And then put the inside pad on the outside and outside pad on the inside and went for a drive (btw I cant put the left hand rotor on the right side and vice versa as they are slotted rotors).

Um The reason I know its not wearing unevenly is that the rotors are only new and have just started getting surface rust on the sections that aren't being worn. On the right side the inside of the rotor has a large worn section, on the outside it isn't very big at all. Then on the left hand side the rotor has large worn sections on both inside and outside.

[ephect]

yeap yeap, didnt know they where slotted, all good, when u get to ur girlfriends check the wear marks on the outside to see if the pads are biting on both sides, it should by the time u get there..

another quick question, does the vibration only happen after a bit of driving, as in, after the rotors have heated up? if it gets progressively worse with heat, its a warped rotor definately. i know, i have a warpped one on my VS. just brake as little as possible to avoid the harse vibrating.

[RoboticCherry-Coke]

OK well I checked the wear marks and no luck, defiantly not wearing evenly. So any other suggestions on this one? If not I might have to swing by a mechanic tomorrow and see what they say as I am going to Adelaide on Thursday for a couple of days and want to avoid wearing the pads and rotors unevenly to much.

As for when the vibration occurs, I cant say I have been paying much attention to when it has been at its worse but I think it does get worse as they heat up. I will confirm that tomorrow.

[Not_An_Abba_Fan]

With both wheels raised, push the brake pedal down hard then release, then go and spin each wheel, they should spin freely, if the RHS is tight, you have a seizing caliper and it will need to be overhauled. That is what has warped the rotor and probably causing the pad to contact the rotor unevenly.

When you put the rotors on, did you make sure the hubs were clean? Did you do the wheel nuts up in a star pattern and to the same torque? It's not as common on the VS but the VT's warped rotors if the wheel nuts weren't done up correctly. Also, did you bed them in correctly?

[RoboticCherry-Coke]

yeah, I cleaned the hubs before I put the rotors on, did the nuts up in a star pattern and bed them by speeding up to 80 braking then slowing to about 10 a couple of times.

By the way, when I checked for warping I only checked the front rotors I didn't check the rear.

[RoboticCherry-Coke]

Just dropped my car off to Goodyear for them to take a look at it. Hopefully they can sort them out for me as they have been an absolute nightmare

[Not_An_Abba_Fan]

Hopefully they can work out what it is.