All my brakes are sqeeking!!!

[mingmong]

Well.....
I've had my restored C3.0 on the road for a couple of months now and now it's thrown up a brand new problem. I'd like to get some advice on this one before I start heading down the route of pulling everything apart again. (Been there..done that!) OK..here's the story.
Brakes have been fine since it went on the road (Jan2006). Then after a nice long run into London I put the brakes on and they squeek like crazy and the car stops fine. Then, as I pull away the squeeking gets LESS but it's still there (more of a squeek,squeek,squeek, etc) ie the pads are still touching the rotors and not disengaging fully. So I continue through traffic with this going on. Big squeek when coming to a stop, followed by squeek,squeek,squeek while moving. Then finally get home (London traffic eh!!) and check the rotors. Both fronts are too hot to touch and the backs are pretty warm too. So...something (common to all the calipers) is not working properly! I'm thinking Master Cyclinder. Could this be right?
I should just add.
Braking itself works ie there's good firm pressure, pump the pedal with the engine running and it stays firm and most importantly of all the car actually stops!
All four calipers have recently been rebuilt and tested. No sticking pistons, new seals, dust boots, correctly aligned 20 degrees etc.
All rubber brakelines replaced with stainless steel braided.
New pads alround.
New springs alround.
New 'Racing Blue' brake fluid.
No leaks.
I'm going to test the pedal adjustment later today just to make sure it's 'releasing' the MC lever back far enough.
Also going to check for play in the front wheel bearings.
If they're all Ok then I guess it's MC replacement time. Funny thing is that the cars HAD a replacement MC in the past, about 10 yrs ago. Could it be anything else? Any pointers always appriciated.
Cheers
Mark

[Oh Haha]

Nah, I don't think it is your m/c. What pads are installed? Hard pads will squeak more on the street. I would check your parking brake adjustment. It sounds if it may sticking after sitting for a long time. It could be one side or both. Take the rear rotors off and chekc the fit.

[asphaltgambler]

If the pads are anything other factory replacement P-car stuff the question becomes not if they will squeek but when. I see this stuff everyday because I'm a auto technician.

It does not matter which level of performance or aftermarket manufacturers pad they all will be of a harder/denser material than stock. The trade off usually is less brake dust and better resistance to fading.

In your post you did not mention if the rotors are new. If they are not the lateral runout may be excessive. Were the rotors rusty from sitting? Also is the hub (where the rotors mount) true and free of dirt? Did you torque the wheel bolts? Did you replace the pad mounting hardware with new pieces? This all will have a direct effect on whether or not the pads resonate.

There are several products on the market that apply directly to the friction surface of the pads that help eliminate noise. The one we use is from BG products. It has no effect on the performance of the pads. You do have to apply when the pads are new; out of the box before actual use and heat cycling.

[petrolblue83911]

if they are rubbing, -as it appears they are from the symptoms, pull the wheels and check the pad -rotor gap, also check the lines for kinks, check the connections for leaks

[Wil Ferch]

For reference....the 4-puck caliper types will always tend to squeel more than the 2-puck calipers.

Try a combination of this:
- file a small , 45 degree edge all 4 sides of the brake pad material.
- put a high temp grease on the outside-edge of the backing plate...especially those surfaces that make contact berween the pads' edges and the receiving-bore of the caliper.
- on the pads' backside, use a 3M acrylic aluminum anti-rattle self stick material made for this purpose.

I think you need to do all three for any chance of success.

---Wil Ferch

[asphaltgambler]

Excellent suggestion Will. The 45 cut on the leading edge (direction of rotation) will help decrease the pads vibrating

[mingmong]

Thanks for your replies! Good news is that it wasn't the MC! I'm afraid I was wrong about symptoms of the actual problem. The squeeking was coming from only the front brakes. Took the front wheels off and found that the pins holding the front brake pads inplace had slipped out of their respective holes and thus the pads where loose and rubbing on the rotors. The backs where fine because they have retaining clips holding the pins inplace. My fronts don't which worries me abit because there's nothing to stop the pins working themselves out again. I've circled the area on the photo where perhaps there should be a pin. Thing is there aren't any holes to put pins in and the spring kit they came with also didn't have any pins with it! Is this normal? Or have I got the wrong spring kit installed (as I'll beginning to suspect!)
Cheers Mark

[Oh Haha]

Mine don't have any clips in the front, either. Were the pins new when you did the brake rebuild? If not, it wouldn't hurt to get new ones. In looking at the picture, I noticed that the pins need to be tapped in a bit more, until the plastic holding thingy is buried in the caliper housing. Is this picture how they were as you found it after removing the wheel?

[mingmong]

Hi Wayne,
The photos of the pins after I pushed them back in. (They where out to the point where you couldn't see their ends poking out on the righthand side.) I just pushed them back as far as I could. Guess you're right tho'. I'll punch them in a bit more tomorrow just to be on the safe side. The other side was much worse and the pins had actually come out fully on one side. This jammed one pads metal backing against the rotor. Hence the mad squeeking! Pins where new with the spring kit. Rotor's where also new..did't take much driving for all these bits to look old! Also...why DON'T the fronts come with pins? Seems a bit odd?
-M

[Wil Ferch]

As shown...to the left of the red circles... the "pins" have to be hammered back-in flush .... not just hand pressed to the point where they are now....VERY dangerous !

Wil