Topic: Squeaky Front Disc Brake

[smrshl]

I just got a 750a that sat in a shed for 3 years.  I got it running good, but the front brake squeaks constantly when I ride it.  I've went through the manual and adjusted the caliper like it says, but that doesn't help at all.  Do you guys have any suggestions?  Also, do you guys have any "quick fixes" for leaky fork seals?  How hard are the seals to replace, would it be easier just to take it somewhere and pay to have it done?

Thanks!

[crazypj]

there is no quick fix for fork seals, and I've seen a few half arsed attempts when I did MOT testing. The brake is probably sticking and the pads rubbing will glaze them . Its also happens when brakes dont get used hard occasionally. there are various remedies on the market
PJ

[Jonesy]

For the sticky brake, the caliper might be full of gunk, preventing the caliper piston from retracting. I've also had good luck using a product called "Disc Brake Quiet" by CRC. You coat the backsides of the pads with it and it absorbs the high frequency vibrations that make for the squeak.

[southbound]

I just rebuilt my front caliper on my 550 for the same reason.  It took 3 times, but the last rebuild seems to be working.  I bought a new piston seal from honda, removed the piston (seperate the two halves of the caliper, then use the brake lever to drive the piston out- but make sure you keep fluid in the reservoir), removed the seal, and scraped all the scale out of the bore and seal land.  A brass wire brush attachment on a dremel tool works great for this.  then, using brake fluid as lube, i dressed the piston and the board with 1200 grit sandpaper.  when the bore looked good, i placed the seal in its land, then the piston, and- really important here- lubed the back and sides of the brake pads with high temperature lube.  no more squeek.  If you're looking for a quick fix, you may be able to get away with just lubing the backs of your pads, but if your piston is sticking, your pads may still rub.

[number13]

Good solid advice from Southbound.
Also, a major source of front brake squeak is the caliper pivot.
It has to actually PIVOT, or that squeak will never really go away.
The fix, as always, is to remove, clean and grease.
Mine was bound up pretty tight when I first got my 500,
some penetrating oil and light heating (heat gun) helped a lot.

Once installed, you must adjust the pivot tension bolt.
Put the bike on it's center stand and have a friend sit on it
so you can spin the front wheel. Adjust the pivot bolt
until the stationary pad just touches, then back off about
1/4 to 1/2 turn

[crazypj]

Good solid advice from Southbound.
Also, a major source of front brake squeak is the caliper pivot.
It has to actually PIVOT, or that squeak will never really go away.
The fix, as always, is to remove, clean and grease.
Mine was bound up pretty tight when I first got my 500,
some penetrating oil and light heating (heat gun) helped a lot.

Once installed, you must adjust the pivot tension bolt.
Put the bike on it's center stand and have a friend sit on it
so you can spin the front wheel. Adjust the pivot bolt
until the stationary pad just touches, then back off about
1/4 to 1/2 turn

Forgot to mention that I also fitted grease nipples to the pivots, (dual disc)  Was a littlle concered at first that it may weaken the pivot but in 20 yrs it wasnt a problem! Got fed up with greasing every year ( it stops being fun when you do it for a living)
 didnt know if you want to do that much work?
PJ

[Tyrsson]

Hi all. First post here.

I ride a K8. 1st bike! I had the same problem with my front brakes sqeaking. The rotor measures within spec and after replacing the pads with new ebc, and greasing the points outlined in my clymers manual, they still sqeaked. I tryed an old trick I've used on cars and put on a little bit (as in a couple of 1/2" strips across the face of the rotor) of valve grinding compound. This somewhat resurfaces the rotor and gets rid of the squeaks.

As to the leaking fork seals, mine leaked (a little) too. I didn't have time to order new seals before a MSF class and the manual said I could use 10-30 motor oil or transmission fluid. I used valvoline's max life 10-30 oil for high-mile engines, which is supposed to contain additives that swell the rubber seals in an engine. So far they haven't leaked on me.

Hope this helps, Deek.

BTW, this board is an invaluble resource.

[csendker]

My 550's rubbed a little in addition to squeaking.  I rebuilt the caliper: cleaned & painted, bought a new phenolic piston and a new seal (the pads were new last fall).  I'm waiting on the new hoses to arrive so I can install it all.  I bought spare stuff off e-buy so I could keep riding while I'm working.  Supposedly the new piston eliminates the need for the nylon washer (it's the same height as the original piston and washer combined).  I report back when it's on to let everyone know how it turns out.

[jph550]

I've heard references made to the washer in the caliper/piston assembly, but haven't been able to find a listing for them in the parts fiche booklet I have.
I must be running the front brakes without. I have a squeak that is more anoying than anything.
Mostly during light braking.

Thanks for the insite.
I'll try the grease on the back of the pad for now and try to find a washer if needed.

Just about to get the bike back out after new high temp paint job to the headers and hope all's well after a complete tune-up (for the first time). If all's well with this spring I may put off addressing a caliper rebuild until next winter or the heat of the summer.

[csendker]

It looks an awful lot like in the picture.  And the other pic shows the phenolic vs. standard piston & nylon washer.

[jph550]

If I don't have a washer, where can I get one? Does anyone know a part number I can give a Honda shop? The phenolic looks interesting. What, besides the lack of washer are the benefits of it?

Maybe the lack of washer is accentuating my squeak.

[csendker]

The phenolic looks interesting. What, besides the lack of washer are the benefits of it?

I doubt it will experience the pitting problems like my original piston.  And it is lighter, for good or bad.  However, as it's currently sitting on my workbench and not on my bike, I can't vouch for it's performance yet.

[hcritz]

Hey csenker;
Lots of automotive folks have used the Phenolic pistons...one good aspect is that they don't transfer the heat from the pad to the caliper and fluid...Helps in heavy braking to keep from boiling the fluid and maybe less of a squealing problem too.
BUT...the do have a tendency to swell...this seems to happen after quite a few years of service.
Ford and Chrysler have both used them and both eventually have problems with sticky calipers.
Not sure if a change to dot5 synthetic brake fluid would help???
Really haven't researched the problem to know what causes it...could even be moisture causing the piston to swell...
Anyway...it seems to be a long term issue...Our fleet of Jeep Cherokees all had to have them replaced at about 3-4 years.

[csendker]

I was planning on DOT 5 anyway.  Good info to keep in mind if I start experiencing problems over time.  Thanks.

[dusterdude]

uh oh they said dot 5

[hcritz]

Hey Guys....
Got me wondering what caused the swelling of the phenolic pistons...
found this on the web...makes some sense...Of course...ANYTHING you read on the web must be true...right?

Q. Why do some brake calipers have phenolic pistons while others have steel pistons?

A. It depends on what the original equipment manufacturer or rebuilder chooses to use. Phenolic pistons are 80 percent glass fiber bonded together with phenolic resin, the same type of binder that’s used in brake pads and clutch linings. Phenolic pistons are light weight, won’t rust or corrode like steel, doesn’t transmit heat to the brake fluid, and they have a greater amount of “roll back” when the brakes are released which helps reduces brake drag. Steel pistons, on the other hand, are stronger and can take more abuse. They also help pull heat away from the pads.

Phenolic pistons and steel pistons have both been used since the 1970s in brake calipers. So have aluminum pistons.

Ford and Chrysler vehicles have used phenolic pistons almost exclusively. General Motors, on the other hand, has used mostly steel pistons in the calipers of its vehicles over the years. The same is true for many import vehicle manufacturers.

Q. I’ve heard that phenolic pistons sometimes swell up and stick. Is this true?

A. Phenolic pistons do swell slightly because the material is hygroscopic (absorbs moisture). But most of the swelling occurs immediately after manufacturing and is limited to about a .001 to .002 inch dimensional change. By compensating for this with increased manufacturing tolerances, sticking should not be a problem in normal use. Some Chryslers back in the 1970s had phenolic pistons that would swell up and stick because of moisture contamination, but that’s ancient history.

Q. Can phenolic pistons be reused in a rebuilt caliper?

A. Yes, provided they are undamaged. Phenolic pistons are brittle and can be damaged by careless handling during disassembly. But if handled with care, they can often be reused.

Phenolic pistons can sometimes develop a slight bellmouth shape when the pads wear down and the piston protrudes from its bore. In such instances, the piston would not be reused.

With steel pistons, it’s a different story. By the time a caliper needs to be rebuilt, the steel pistons are often corroded and can not be reused. Most steel pistons are nickel and chrome plated to resist corrosion, so pistons should never be sanded to clean them up. Doing so removes the protective coating and encourages corrosion.

[Bob Wessner]

Nice Q & A on the subject, thanks for posting it.

[csendker]

I'll let y'all know how mine works out, when and if I ever get the hoses in...

[TXmudman]

Here's how I fixed my very badly squeaking brakes:

Coat the back and metal sides of the pads with a very thin coating of high melting point caliper grease. 

Use about 150 grade sandpaper to sand both surfaces of the rotor.

If you've already been using the pads, sand their surfaces, too.

Go to Autozone and buy a can of CRC's disc spray that is sprayed directly onto the disc.  This will leave a greasy-feeling graphite powder all over the disc.

Ride the bike carefully and use your front brake a lot.  At first, it will seem that you have no front brakes.  After about the 10th time you try them, they will start to grab.  Be careful now, because pretty soon the brakes are going to grab as hard as they always did, so you don't want to squeeze them too hard.

This stuff really works.  It's what Mercedes uses on their new brake pad installations.  It's supposed to burnish the pad surface so that it breaks in slowly and doesn't get real hard, which may make is squeak, or so I am told.

[GroovieGhoulie]

Any technique for loosening the pivoting arm?  My brakes sometimes squeak and I think the arm isn't pivoting freely since I've done everything else to cure the squeaky brakes and it's reduced the problem by 90%, but there is still some squeak left.  I pulled the caliper just now and tried to see how easy it was to rotate the arm.  Not hard, but it wants to stay whereever it is and not spring back.

There doesn't appear to be a removable bolt or any other way to pull the arm.  How do I get grease in there?

[supersport_CB400F]

Any technique for loosening the pivoting arm?  My brakes sometimes squeak and I think the arm isn't pivoting freely since I've done everything else to cure the squeaky brakes and it's reduced the problem by 90%, but there is still some squeak left.  I pulled the caliper just now and tried to see how easy it was to rotate the arm.  Not hard, but it wants to stay whereever it is and not spring back.

There doesn't appear to be a removable bolt or any other way to pull the arm.  How do I get grease in there?

Whack the pivot out grease and put it back in the hole  Ghoulie you can and do have to hit 30 year old bikes with hammers 

[TXmudman]

Any technique for loosening the pivoting arm?  My brakes sometimes squeak and I think the arm isn't pivoting freely since I've done everything else to cure the squeaky brakes and it's reduced the problem by 90%, but there is still some squeak left.  I pulled the caliper just now and tried to see how easy it was to rotate the arm.  Not hard, but it wants to stay whereever it is and not spring back.

There doesn't appear to be a removable bolt or any other way to pull the arm.  How do I get grease in there?

I thought that I had a pivot arm problem for a long time.  Part of my problem was the pad occasionally hanging up some in the caliper and not being able to fully retract.  This made a nice squeak.  I still needed to treat the pads and rotor, though.