squeaky brakes

Now that Kristen has her licence Boris is now on the road a lot more. The problem we have found that as the front disks get hotter they squeal like a pig when used. They are fine for the first half hour or so. It has new pads and disc rotors. Any suggestons
Thanks AL

id say your disks need machining or your pads are cooked because of hard braking ,my magna did the same thing and the guy reckoned they needed machining so i did that and no more squealing

maybe pull everything and give a REAL good brushing to get rid on any dust
Rub some emerypaper over the rotors and pads to rough things up.
May have glazed up

Clean the rotor with prepsol

See how that goes

Check to see if the pistons havent got stuck

Hmm, bugger. The brakes on my bus are squealing as well, and I replaced the rotors and pads and rear wheel cylinders two years ago only. Wasn't very cheap. There's also a little pulsing during braking - that is usually a sign of worn discs isn't it?

I didn't think I was harsh on them! Machining discs already, grrr...

A.

Al,

Aside from any mechanical problems, the usual culprit with disc brake squeal is dry/rusty anti rattle/retaining plates, spreader spring and retaining pins. In simple terms everything that holds the friction pads in place. Remove the pin or pins, the retaining clip, remove the pads, and the piston retaining plates. Clean everything and reinstall. A very light smear of lubricant, applied very carefully you do not want it on the pads or rotors, is sometimes required. Some of the brake shops sell a special lube for this purpose.

Its usually dust causing the problem in the country..

rust just gets cleaned off by the pads...

Years ago when VWs were My daily drivers, dust on the discs usually caused the squealling...

I tried products made for squelling brakes but they didn't work...

I eventually came to the conclusion , that if the brakes are squelling or making a noise, its because they are working....

so I didn't really have a problem....

Lee

http://community.webshots.com/user/vw68autobug

Chad, If you have Girling calipers you MUST have the original noise-damping plates/shims behind the pads. They work fine wihout them, but may scream more & more as brakes are used and warm up (as you noted). If you have the ATE callipers instead, they don't have the shims but do have a piston retaining plate that may also help eliminate the squeal.. The pads for the ATE type should have a thin layer of papery stuff stuck on the back; not sure but think the Girling pads also have. You can also get spray-on stuff (a pink "paint") for the backs of pads, which presumably helps in the same way. If shims or reatinang plates are missing & all else looks good, try replacing those before doing anything more drastic. If everything is in place & in good cond., try a different brand/type of pads. Some 'harder' pads might squeal anyway?

aggri1 wrote:Hmm, bugger. The brakes on my bus are squealing as well, and I replaced the rotors and pads and rear wheel cylinders two years ago only. Wasn't very cheap. There's also a little pulsing during braking - that is usually a sign of worn discs isn't it?

I didn't think I was harsh on them! Machining discs already, grrr...

A.

The 'pulsing' during braking is either going to be warped discs, warped, damaged or mis-aligned calipers, leaking/seizing pistons or seals, or occasionally worn wheel bearings.

I'm not familiar with bus calipers, are they full-floating? If so disassemble and clean/lubricate the guide pins, checking for uneven wear or catching marks.

My guess is that would be the most likely culprit as your discs shouldn't have warped if they're only two years old, and you don't 'race' the brakes. It will also give you a chance to check the physical condition of the calipers.

Keep in mind that Holden recommend machining every 20,000 kms on their Commodore discs, maybe newly manufactured rotors are similar. Check with the rotor supplier for the manufacturers recommendation.

[ Edited on 17-3-2007 by sinecure ]

[ Edited on 17-3-2007 by sinecure ]

what type of pads do beetle use?

brake pads😀😀😀😀😀

my daughters car is running ate type calipers. I pulled them apart on the weekend and found that the pads were glazed fairly badly even though they had only done 200 or so k's. Filled the glaze off and touched up the leading and trailing edges. The calipers were clean as I reconditioned them when I replaced the rotors etc. I also put some anti squeal paste on the back of the pads. So far so good. The pads may have glazed up due to the new rotors. I also used some prepsol as suggested by barry to make sure the rotors were super clean. Fingers crossed.

Thanks all AL

sinecure wrote:

aggri1 wrote:Hmm, bugger. The brakes on my bus are squealing as well, and I replaced the rotors and pads and rear wheel cylinders two years ago only. Wasn't very cheap. There's also a little pulsing during braking - that is usually a sign of worn discs isn't it?

I didn't think I was harsh on them! Machining discs already, grrr...

A.

The 'pulsing' during braking is either going to be warped discs, warped, damaged or mis-aligned calipers, leaking/seizing pistons or seals, or occasionally worn wheel bearings.

I replaced all the vacuum lines between the carbies and the elbows to the brake booster and stuffs on the weekend. Wow, sure is nice now, she runs smooth as! Anyway, the point is, the brakes have stopped pulsing and are now much firmer. I understand the latter (proper vacuum at the diaphragm), but not why the pulsing has stopped. Perhaps it's just not noticeable now that the booster's doing more of the work...?

Anyway, for anyone wanting a cheap and easy thing to do which can be extremely beneficial (high return on investment!), replacing the vacuum lines is a good thing to do.

Sorry that this is kinda off topic, just wanted to share!

Cheers, A.

Good stuff.

It will also be running a lot cooler as all those leaks will be making that motor run hot

Yeah I'll see about the temperature. It did get the hottest I have ever seen recently (before fix); just under 120*C on the oil temp (1). That was going up a long hill after being on the freeway. Had me worried for a bit, but I checked the valves afterwards, and there was no change. The oil itself 'looked' the same, for whatever that's worth. I will do the same drive again sometime and see how it compares.

I understand that 120*C is considered by some to be the upper limit of acceptability of oil temp. I haven't got a head temp gauge.

Cheers, A.

(1) Gauge was calibrated in boiling water and was spot on at 100*C, with a degree or two allowance for local atmospheric pressure and water purity variations.