Squealing Pads, What Else To Check Before Machining?

[SS8_Gohan]

hi y'all

front pads are squealing like nothing else. I tried to follow the bed in procedure as best as possible, and even had 1 track day which i though would bed them in nicely ontop (did about 100km's between bedding in and track day).

They are QFM A1RM/K750/HP-R's whatever they're called, and two separate places told me the discs don't need machining, including one supposed reputable motorsport specialist place. So the disc's weren't machined before the pads went on.

Before i get the discs done, is there anything else i can check/do/change to deal with the squealing? From the QFM group buy and the 'brake pad' sticky, no one seems to mention really bad brake noise, but these things are HIDEOUSLY squealy, unbelievable loud. I had no idea brakes could be so loud...

so yeah, just want to see what else i can check/do first before getting the discs machined...

oh... will machining the discs necessarily fix anything?

cheers,

daniel

[Basti]

machining discs fixed my squeal. only does it on turning now. dunno if its applicable to you tho mate. RB74 front and C2 rear. stock discs

[SS8_Gohan]

i'm stock discs and RB74's are Harold's compound are they not? Harold co-developed QFM's compounds, so i would say the pads are similar

mind if i ask how much you pad for machining the discs?

[TokyoTaxi]

Machining your discs is NOT a 100% fix for squeeling.

If you do some more research on here you'll find some rather long threads discussing this topic. There's a bit more to it but you "could" get lucky.

[SS8_Gohan]

^ my bad, should have searched...

found about half a dozen threads on it recently, and this post seemed to be the most comprehensive in terms of ways to fix the problem, or areas to check

I'll be the voice of reason here. . . Simple Fix = DOSEN'T EXIST!!! You really need to give a more detailed assessment of of what is happening (worse when hot! is it, lightly braking, hard braking, trail braking? etc.) and your ability to actually fix the problem (I would assume by asking this question you are not in the trade but can you handle, and own, tools?).

Then there is what discs you have and what condition they are in (lipped? etc.). What brake pads you have.

My suggestion assuming you have reasonable street pads and your discs don't have massive lips on them - Take it to a good machanic and ask them to

1, dissassemble the brake assembly and clean EVERYTHING. As in slide pins, retainer springs, ALL the shims front and back (skylines have quite a few), the pads (as in the backing where the shims go) and so on

2, deglaze your front pads by rubbing them on coarse concrete. Still the best method used.

3, #BIG NOTE# skylines have a straight edge on the bottom of there pads. This needs to have a semi moon or cresent filed out of it to match the sweep of the inner edge lip of the worn disc (1 or 2mm)

4, have the disc removed and degazed using sand paper or a biscuit wheel on both sides

5, #BIG NOTE 2# get the inner and outter lips on both sides of the disc, steel wheeled or steel biscuited as well to remove a lot of the rust and crap that builds up. And to litterally take the edge off things!

6, All contacting sufaces ( back of brake pads, both sides of ALL shims, slide pins etc.) MUST have anti-rattle grease applied (you can get it in a can)

7, reassemble and it should be sweet.

3 and 5 are the major ones to note in my opinion and from what i've seen

Hope that helps a few people.

Told by 3 separate places that the discs were fine, and didn't need machining. One place being a motosport braking specialist.

The workshop DID remove some metal parts, as i think there were size issues?? so i might not be running these "shims" people are talking about

Another good post from Beer Baron re: grease?? Workshop never mentioned any sort of lube product being used...

well most squeal can be cured with:

installing the factory anti squeal shims

using copper grease, or the special anti squeal paste

champhering the edges of the pads if not done from factory

re-bedding them in

That seems to be the bulk of the fixes, the shims, lube, machining discs, filing down edges, roughing up the pads a bit. I might run these options passed the workshop, see what they have to say

a different product from JetPilot who knows A LOT about brakes

99% of squeal is cause by vibration between the backing plate and the calliper itself... nothing to do with the friction material or rotor face. Old trick, get some permatex and spread a small amount over your backing plate!

EDIT: just checked my box of goodies that was left after the brake pad upgrade and what do i find?? those shim things!!! all these various metal plates, no wonder i've got brake squeal. Problem is, i think they were taken out because they didn't fit??

So what now then? file the pads down so the shims fit?

EDIT: rang workshop, i did have copper grease used when installing the pads, but the QFM's didn't fit with the shims, so i don't have them. They said putting the shims back in isn't going to make a difference to the squealing?

[MBS206]

Question.

Do you still have the anti squeal shims installed between the piston and the pad?

If you don't they squeal like shit...

[SS8_Gohan]

this is what was taken out, i don't really know what is what

[godzl1975]

there the shims that go on the back of the pad...i would clean them up first then use the anti squeal stuff on the back of the pads and inbetween the 2 shims.

how come they took it off n not put them back in??

[SS8_Gohan]

apparently because the front or rear, i think front, couldn't fit with them in there???

[siddr20]

Coz the pad was too thick?

Maybe since you have done one track day, try putting that cover back on. Clean it up with degreaser or something before putting it on the pad.

See if this works first.

If not, then maybe try and look into buying some goo stuff.

[Basti]

Machining your discs is NOT a 100% fix for squeeling.

If you do some more research on here you'll find some rather long threads discussing this topic. There's a bit more to it but you "could" get lucky.

i didnt say that. it reduced the severity in my case, and continues to squeal on turning. anyway there is already a hell of a lot more info in here than i could ask for. cheers to the OP for compiling

[Suj]

I had the same pads fitted and they've left off the shims too as the pads were too big (QFMs). Squeals like nothing I've ever heard before....its insanely bad even with the windows up. I'm going to try sanding the pads down a little at my mate's workshop and fitting the shims back in after a bed-in session and see how it goes

[Trav33]

I put new pads in, and could fit the shims in, but not these shim clips.

Pads squeeled like cops. I filed the edge of the brake pad down so i could fit clips in, still squeeled.

Tried some brake goo, still squeeled.

Got rotors machined, for $55 for a pair, 100% silent!

Other mechanic quoted $15 a rotor ($30 per pair), but he didnt work Saturdays, so had to pay a bit more.

[ClutchBurndout-:(]

as i suspected, my brakes squeal like the apocalypse is coming, i need them machined, because ive been told that the disk will have tiny ripples in it that will be in the brake pad also, thus creating the squeal that can rip womens clothes off

[SS8_Gohan]

update on this saga

had the shims put back in, reduced the noise by about 90%, almost completely fine now, but will still "slightly" squeal on a slow stop, eg coming up to a red light. Not all the time though, pretty much not an issue anymore.

But i checked the box of shims i gave them and the little parts haven't been put back in, just the main plates.... do you think putting the little corner pieces back in will stop that last little bit of squeal?

those 2 little pieces weren't put back in the 2nd time round...

Confirmed with distributor of QFM pads in Vic, these pads WITH shims. If the pistons are in working order, everything should fit. If they don't fit, there are other issues, R34's aren't special in that they don't fit. They do.

[Rekin]

hehe i have the same pads and had some bad squealing at first.

Did 6x 110-70km/h hard stops on the freeway and then a 30minute cooldown drive without touching the brakes.

This reduced the squealing by a lot but still squealed.

Took car to Traction Tyres and they added some anti-squeal, lightly sanded the rotors. This got rid of the sound for a couple of days, but usually comes back when doing very light braking.

Let us know if you fix the remaining squeal

P.S; from what ive been told, the rotors should be machined when putitng in the new pads, as my rotors were brand new I did not need to machine them

[faysie]

Hi everyone,

I just bought my R33 series 2 GTST last week. The brakes were squealing when I test drove it and the guy told me they had done that since he put Bendix Ultimates in. They were ok if you braked really hard, but no good for driving around town. So, today we put Bendix Ct pads in front and back and also put in the red sticky goo stuff in.

Now they are squealing even worse! Tried to bed them in as much as possible but it didn't make any difference.

What we noticed though, was that the old pads did not have a metal backing plate, so assumed these didn't have them (sorry for ignorance but I we just don't know these cars very well yet) So, therefore the new brake pads do not have a metal backing plate either. The old pads had a sort of soft plastic stick on sheet in the place of the metal backing plates, but we didn't put these back on.

I would really appreciate any help anyone can give, have read as much as I can on previous issues with squealing brakes but no one seems to have mentioned missing metal plates.

[BRUNSKIGTST]

if u can get some of those shims i suggest u get some and install them, and another thing also bendex are known to squeal also read the sticky about the pads and find out im useing lucas brake pads and have those shims installed made them fit just needed to push piston back in place befor i instaled them and then give good pump on the brake peddel have no noise what so ever plus good brake fluid helps also i use penrite HELL which boiling point is 600+

[faysie]

if u can get some of those shims i suggest u get some and install them, and another thing also bendex are known to squeal also read the sticky about the pads and find out im useing lucas brake pads and have those shims installed made them fit just needed to push piston back in place befor i instaled them and then give good pump on the brake peddel have no noise what so ever plus good brake fluid helps also i use penrite HELL which boiling point is 600+

Thanks mate, I think we will try putting the shims in, also we will try to bed them in a bit better and see if that helps, I'll let you know!

[Kinks]

I have this curse as well, and initially found an anti-squeal spray you spray on the discs. Applied to all rotor surfaces except for the inboard side of the rears, which has a heat shield all the way round. Squeal was gone for a day, then started coming back. Mainly the rears though.

Today, I pulled it all apart and did 3 things:

1) Applied anti-squeal spray to both sides of rear rotor

2) Sanded pads with 80 grit to rough them up

3) Applied anti-squeal goo to the backing plate and both sides of the shims

Silent for now, will give it a week or two and see what happens!

I started with brand new rear discs and machined fronts, and new pads all round. Squeal came after about 250km, and a track day made it no better.